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Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old
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Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old A. Gentile a,∗ , M. Juárez a , S. Hernandez b , A. Moya c , J. Bakir a , M. Lucion a a b c
Epidemiology, R. Gutiérrez Children’s Hospital, Buenos Aires, Argentina Infectology, “Prof. A. Posadas” National Hospital, Buenos Aires, Argentina Infectology, Misericordia Nuevo Siglo Hospital, Córdoba, Argentina
a r t i c l e
i n f o
Article history: Received 13 January 2015 Received in revised form 5 June 2015 Accepted 12 June 2015 Available online xxx Keywords: Influenza vaccines Immunization/utilization Immunization programs/organization and administration Infants
a b s t r a c t Introduction: In Argentina respiratory disease is the third leading cause of death in children under 5 years. In 2011 influenza vaccination was included in the National Calendar for children between 6 and 24 months (two doses schedule). Influenza vaccine coverage for second dose was 46.1% in 2013. The aim was to determine the proportion of delayed schedules and missed opportunities, to assess the characteristics of missed opportunities for vaccination and to explore the perception of influenza disease and vaccination from the parents of children between 6 and 24 months in different regions of Argentina in 2013. Methods: Analytical observational multicenter cross-sectional study. Structured surveys were carried out to the children’s parents who were between 6 and 24 months of age during the influenza virus vaccination season (April–October 2013). Chi-Square test was used to assess association and differences between proportions and categorical variables. A logistic regression model was built to identify delay predictor variables in the vaccination schedules. Missed opportunities for vaccination were characterized through the estimation of proportions. Results: 1350 surveys were conducted in the three centers. We detected 65% (884/1340) of delayed influenza vaccination schedules, 97% of them associated with missed opportunities of vaccination. The independent protective factors associated with a decreases risk of delayed schedules were: (a) perception of the importance of influenza vaccination (OR = 0.42(0.18–0.94); p = 0.035), (b) having less than one year of age (OR = 0.75(0.59–0.96); p = 0.022), (c) to have received information in pediatric visits or in any media (OR = 0.71(0.56–0.90); p = 0.004). There was 38% of MOIV in 1st dose and 63.4% in 2nd dose. The main cause of MOIV in 1st dose was not detecting the need for vaccination (39%) and in 2nd dose the unknowledge of the vaccination schedule (35.3%). No cultural reasons were detected. Conclusions: High frequency of delayed vaccination schedules and missed opportunities were detected. Parents had little concern about the safety of influenza vaccine. © 2015 Elsevier Ltd. All rights reserved.
1. Introduction The acute lower respiratory tract infections (ALRTI) represent an important cause of morbimortality, specially in children under 5 years of age, elder people over 65 years old and those with certain conditions that increase the risk to develop complications and severe forms of presentation [1]. In Argentina, respiratory diseases caused 787 deaths in children under 5 years old in 2012, representing the third most common cause of mortality in this group. 77% of these deaths occurred before infants turned one year old [2].
∗ Corresponding author. Tel.: +54 1149649019; fax: +54 91130887431. E-mail address: angelagentile@fibertel.com.ar (A. Gentile).
The high infection rates and the costs related with the morbimortality, particularly in high risk population, make seasonal influenza a disease of great importance in Public Health. The influenza virus is so far, the only respiratory virus preventable by means of a vaccine that has proved to be safe and effective in children older than 6 months old. Young children without medical history have a hospitalization rate associated with influenza virus comparable to the ones of high risk patients and described vaccine efficacy of the influenza vaccine to prevent hospitalizations is approximately 70% [3–7]. In 2011, Argentina introduced mandatory influenza virus vaccination to all children between 6 and 24 months to the National Immunization Program, by means of a two-dose schedule administered with a month interval. According to the aims of the World
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Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065
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Health Organization, in the so-called “Decade of Vaccines”, by the year 2020, at least 90% of national coverage and 80% in each district should be achieved for all the vaccines included in immunization programs. In 2013, the achieved coverage for the second dose was of 46.1% [3]. In this context, it is important to note that there are still barriers to achieve good vaccination coverage, including accessibility, growing complexity of vaccination schedules, fear of side effects, professionals’ lack of knowledge about vaccines and other missed opportunities for vaccination (MOV) [8–10]. The aims of this study were to determine the proportion of delayed schedules and missed opportunities, as well as to assess the characteristics of the missed opportunities for vaccination, the perception of seriousness of influenza disease and the information obtained by the parents about influenza disease, of children between 6 and 24 months old examined in the reference hospitals in different regions of Argentina in 2013. 2. Material and methods Analytical observational cross-sectional study. Structured surveys were administered to parents of children who were between 6 and 24 months of age during the influenza virus vaccination season (from April to October 2013) and who consulted on an outpatient basis in any of the three selected centers. The surveys were conducted at the end of the Influenza Virus Vaccination Campaign. To select the survey respondent, a non-probabilistic convenience sampling was carried out. The questionnaires were performed from Monday to Friday, in different parts of day to avoid possible bias related with the attitudes of the health care workers and the different characteristics of the population aim of this search. The inclusion criteria were: children between 6 and 24 months old, who went to the offices of the 3 health centers (“Ricardo Gutiérrez Children’s Hospital”, “Misericordia-Nuevo Siglo Hospital”, “Prof. Dr. A. Posadas National Hospital”) and who have vaccination cards or medical history in the health center to ascertain the vaccination status at the time of the survey. Exclusion criteria were: to be a sibling of a participant in this study or the parents’ refusal to answer the survey and to have a true contraindication to vaccinate. For the sample size estimation, reliability of 95% was considered, foreseeing an error of 5%, an expected proportion of 20% and accuracy of 2%, resulting in a necessary minimum n of 1332 surveys. Sociodemographic variables were investigated: age, gender, location, social status according to the Graffar’s modified method (Appendix 1). Supplementary material related to this article can be found, in the online version, at http://dx.doi.org/10.1016/j.vaccine.2015.06. 065 Variables related with the vaccination: • Delayed schedules: children who did not receive the influenza vaccine within 30 days of either turning 6 months of age during the flu vaccination interval in Argentina or within 30 days after the start of the recommended flu vaccination interval in Argentina for those already 6–24 months of age at the start of that interval or failure to receive the second dose between 30 and 60 days following the first dose. • Missed opportunity for vaccination (MOV): regarded as every visit of the individual to the health care center, who needed to be vaccinated and that, though true contraindications did not exist, they did not receive the necessary vaccines [11]. • Perception of the disease: the perception of seriousness was considered according to the parents’ assessment to the disease from which they were protecting their children.
• Vaccination importance: questions about the importance parents gave to the influenza vaccine were made, measured using Likert scales with the following categories: very important (5)/important (4)/somewhat important (3)/not important (2)/unnecessary (1). For the data analysis, a general description was first carried out, estimating the mean and standard deviation for the continuous variables and proportions for categorical data, with 95% confidence interval. To assess association and differences between the variables, the Chi-Square test was used for proportions and categorical variables. An alpha type I error of 5% was accepted. Due to the study design, the odds ratio with an interval of trust of 95% was used as an association measure. A logistic regression model was built to identify delay predictor variables in the vaccination schedules. To construct the model, the univariate analysis of each of the variables was first carried out by means of simple logistic regression. The age variable was introduced in models as categorical (6–11 months, 12–23 months). To construct the model, the multiple logistic regression was used. Variables were added in a staggered manner including those with p < 0.2 and/or biologically plausible. Missed opportunities for vaccination were characterized through the estimation of proportions.
3. Results 1350 surveys were carried out in the 3 health centers mentioned above with the following distribution: Prof. A. Posadas Hospital: 474 (35.37%); R. Gutiérrez Children’s Hospital: 454 (33.88%); Misericordia Nuevo Siglo Hospital: 412 (30.75%). Parents of children between 8 and 29 months were surveyed at the end of the influenza vaccine campaign (October 2013), with a median of 14 months of age. 55% of the children came from Buenos Aires province, 36% belonged to socioeconomic level IV (relative poverty according to modified Graffar method), 60% had made a consult for acute pathology and 54% had the shots given in public hospitals. The main population features are shown in Table 1. In the consult previous to the survey, 63.1% (494) of the patients had been asked about their vaccination status and the doses that they received were determined by reviewing the vaccination record card or health record. As for the vaccination status: 29.9% (404) had received only one influenza vaccine dose and 43.4% (582) had completed the two-dose vaccination schedule, that is, they were appropriately vaccinated for the age. 26.9% (364) of the survey respondent did not receive any dose.
3.1. Delayed vaccination schedules In the 65.8% (884) of the survey respondents, delayed vaccination schedules were detected and 54% showed delay in both doses of influenza vaccine (Chart 1).ln 97.9% of the delayed schedules, the delay occurred as a consequence of a missed opportunity for vaccination; in only two cases there was a true contraindication for influenza vaccination present. Different factors that could act as protectors and could avoid the occurrence of delay in both vaccination doses were assessed (Table 2). Multivariate analysis reflected, as independent predictors, considering influenza vaccination useful (OR = 0.42; CI95% = 0.18–0.94; p = 0.035), age less than one year (OR = 0.75; CI95% = 0.59–0.96; p = 0.022) and to having seen or heard messages about vaccines during the pediatric visit or in any means of communication (OR = 0.71; CI95% = 0.56–0.90; p = 0.004).
Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065
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Table 1 Socio-demographic features of the polled population. Features of the surveyed population
n (%)
CI95%
Age
<12 months ≥12 months
465 (34.7) 875 (65.3)
32.16–37.33 62.67–67.84
Gender
Female
671 (50.1)
47.40–52.82
Origin
City of Buenos Aires Buenos Aires Córdoba
187 (13.9) 741 (55.3) 412 (30.8)
12.17–15.95 52.59–57.98 28.30–33.31
Graffar
II (median-high) III (median) IV (relative poverty) V (critical poverty)
47 (3.4) 349 (26.1) 845 (63.1) 99 (7.4)
2.62–4.68 23.73–28.50 60.40–65.64 6.07–8.95
Chief complaint
Acute pathology Health control Patient companion Vaccine control
807 (60.3) 240 (17.9) 233 (17.4) 59 (4.4)
57.58–62.89 15.93–20.11 15.43–19.56 3.40–5.68
Vaccination sitea
Public hospital Private hospital Health center Private vaccination place
732 (54.6) 9 (0.7) 684 (51.1) 5 (0.4)
51.9–57.3 0.33–1.32 48.3–53.7 0.14–0.92
a
8.9% (120/1340) of the patients vaccinated in more than one site.
3.3. Perception of influenza disease and influenza vaccine As for the awareness and parents’ perception about the disease caused by the influenza virus, 84.7% mentioned knowing about the disease and 62.8% thought it was serious. Regarding the influenza vaccine: 33.7% (451) mentioned it was very important, 58.5% that it was important, 3.6% that it was unnecessary and 4.2% did not have a formed opinion in this matter. 95.3% of the parents considered that influenza vaccination was useful: 69.8% due to the risk of catching the illness, 20.5% for the increase of cases, 2.4% because it was a provision from the Ministry of Health, 0.8% for other reasons and 6.3% did not know the cause. 17.6% of the surveyed had searched information about influenza vaccination, 51.6% had seen some kind of message about preventable diseases by means of vaccines: 32.7% on television, 33.8% in the pediatric visit, 9.1% in advertisements, 4.5% on the radio, 4.1% on the Internet and 0.1% on other means of communication.
Chart 1. Delayed schedule distribution according to the number of doses where the delay took place.
3.2. Missed opportunities for vaccination (MOV)
3.4. Perception of influenza disease, influenza vaccine and missed opportunities
38% (510) of MOV were associated with the first influenza dose and 63.4% (848) of MOV were associated with the second influenza dose. The main cause of MOV was lack of awareness of the schedule (29.1%), followed by not detecting the necessity to vaccinate (28.7%). The MOV causes are detailed in Chart 2. It was significant the difference among the main causes of MOV according to the time of occurrence. Not detecting the necessity to vaccinate meant 39% in the first dose and 22.8% in the second one (p = 0.000), whereas the unawareness of vaccination schedules represented 19.3% for the first dose and 35.3% for the second one (p = 0.000).
Considering influenza vaccination useful (OR = 0.39; CI95% = 0.18–0.80; p = 0.010) and thinking that vaccination is important or very important (OR = 0.52; CI95% = 0.20–0.96; p = 0.041) resulted in MOV protection independent predictors in the first dose. While searching information about influenza vaccine (OR = 0.72; CI95% = 0.53–0.97; p = 0.034) and considering influenza vaccination useful (OR = 0.44; CI95% = 0.20–0.96; p = 0.041), were MOV protection factors in the second dose. On the other hand, knowing about the influenza disease (OR = 0.93; CI95% = 0.62–1.93; p = 0.733) and/or considering it serious (OR = 1.14; CI95% = 0.86–1.52; p = 0.337) were not associated
Table 2 Factors possibly involved in the occurrence of delayed schedules. Variable
OR
To have searched information about influenza vaccine To consider vaccination useful To be under one year of age To know about influenza disease To consider influenza a serious disease To see/hear messages about the influenza
0.8034 0.4179 0.7581 0.8238 1.7276 0.714
95% CI 0.5935–1.0876 0.216–0.8086 0.5972–0.9623 0.6174–1.0993 1.1777–2.5342 0.5658–0.901
p 0.157 0.01 0.023 0.188 0.005 0.005
Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065
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4 45.00% 40.00%
38.90% 35.27%
35.00% 30.00% 25.00% 20.00%
22.80% 19.29% 15.91% 13.58%
15.00% 8.46% 10.00% 6.65% 5.00% 0.98% 1.07%
2.95% 2.49%
1.77% 1.66 %
0.00% Not detecng Unawareness the necessity of schedule to vaccinate
Not having the card
Postpone the appointment
6.10% 4.87%
Temporary lack of vaccines
7.01% 4.53%
2.76% 1.19%
Difficulty with Cultural reasons Mild disease the vaccinaon center schedule
Other false Convalescence contraindicaons
MOV 1° dose MOV 2° dose Chart 2. Causes of missed opportunities for vaccination according to the time of occurrence.
with a MOV. Similarly, the fact that the vaccination record card was not checked during the previous consult, did not behave as a protection factor (OR = 1.42; CI95% = 1.11–1.81; p = 0.004). 4. Discussion There are two measures in Public Health that have had an extraordinary impact on health worldwide: water purification and vaccination. Immunization is one of the most efficient interventions of Public Health [12]. While vaccines represent an expense, fundamentally they are an investment. The final goal of vaccination is to eliminate diseases and its mid-term objective is to achieve primary prevention of these at an individual as well as community level. Both objectives can be achieved by means of a wide universal immunization program achieving high coverage in target populations and with an exhaustive epidemiological surveillance that acts as a monitor of these strategies. In Argentina influenza vaccination is available free for children between 6 and 24 years old. However, there exist barriers to achieve good coverage, which is particularly evident in the case of the influenza vaccine [13]. These situations demand a wide focus, which studies not only what is inherent to the program itself, but also the health staff, parents and caregivers’ attitudes. This extended view allows recognizing differences between vaccinated and unvaccinated children and those who are incompletely vaccinated [14]. The first group demands local actions, since they can be located and they represent a risk for both the vaccinated children and the ones incompletely vaccinated. The second ones demand actions essentially programmatic. Half of the polled cases showed delayed vaccination schedules for both influenza vaccine doses, nearly all due to MOVs. The necessity to promote the schedule and the importance of vaccination show themselves as a protection factor and set the need that, both the pediatricians and health authorities are responsible for promoting these prevention messages. We use a pretty strict definition for delay immunization schedules so in the absence of outreach and active notification, it is likely to result in a very high measured rate of delayed vaccination. In addition, it likely contributes to the observation that children less than 12 months of age, whose visits are more frequent, were a protective factor against delayed vaccination [15,16]. In our research, one of the most prominent barriers was the missed opportunities for vaccination. In a multi-centered study, it
was found that within the MOV causes, false contradictions (three times more frequent during the consult due to the disease than in a healthy child consult) were highlighted, the missed opportunity for vaccination for not giving all the corresponding vaccines simultaneously at the same visit and the physician’s inappropriate consulting about the child’s immune status [17], showing that postponing schedules and the MOV are important factors that reduce vaccination coverage [18]. Reducing MOV is fundamental in this setting to improving influenza vaccination coverage. Identifying sources of MOV and developing potential solutions with subsequent reassessment and, if indicated, making further refinements is necessary to achieving this goal [19,20]. In addition, the lack of perception of the vaccination necessity and the unawareness of the schedules were highlighted, particularly, in a vaccine such as influenza, of a recent introduction to the national schedule. As for the omission of the influenza vaccine prescription, it is well-known that vaccination schedules are not static but they are being modified according to the new vaccines availability and the evolution of the epidemiological situation of the different preventable diseases through vaccination, knowledge updating turns out to be a fundamental variable [21]. The described barriers causing low coverage during the introduction of new vaccines are: limited staff, unsatisfactory training, lack of topic presence in the community, lack of disease seriousness perception, vaccination schedule complexity, obstacles to accessibility, fear to vaccination adverse side effects and missed opportunities for vaccination (MOV), among others [8,9]. On an interesting study by Bosch-Capblanch et al. [22], it is shown the inequity among the different countries regarding the vaccination coverage and the need for programmatic efforts to identify unvaccinated children, generally undetected by the implemented routine systems. In this study, great relevance is given to the parents or habitual caregivers’ attitudes and their vaccination status in relation with the children’s vaccination. The survey results suggest that delayed or incomplete immunizations are not due to parental concern with vaccine or lack of awareness of severity of disease but instead with their lack of familiarity with the recommended schedule. Parents are not expected to know the recommended vaccination schedule. Instead, it appears that system issues as a lack of outreach, incomplete health records, not flagging vaccines due at visits, availability of vaccine
Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065
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(identified in 8%) and provider variables (awareness of recommended childhood vaccine schedules, failure to review vaccine records, and ordering and administration of recommended vaccine (s) at all visits) are the main sources of low uptake of influenza, and likely other, vaccine in this setting [23–25]. As regards the influenza vaccine, as we could prove in this study, the disease seriousness perception is high in the population, but it did not concur with the achieved coverage. Similarly, there still exists the paradox of having been a highly requested social vaccine after the influenza pandemic which took place in 2009, and of currently being one of the vaccines with the least coverage in the regular vaccination schedule, especially in the age group from 6 to 18 months old [3], and specially regarding the second dose. In this sense, operations research designs would be useful to adjust the strategies connected to the subject [26]. In the polled population, parents’ hesitation about the vaccines safety was not detected. This profile is different from the one described in Europe or North America. However, it is remarkable the communication about the benefits and risks of vaccination. Many parents have doubts about these topics, mainly about the vaccines’ safety and health professionals have a positive influence on the parents, even in those who thought that vaccination was not safe [27]. This great influence of the context and the means of communication were corroborated by groups of immunization experts worldwide, specifically by SAGE in April, 2013 [28]. The characterization of missed opportunities for vaccination in our setting is not identical to the ones found in other regions of the world which would allow to orient more these strategies toward the appropriate knowledge of the current vaccination schedules, deepening it in children over 12 months old that turned out to be those who showed more risk of having delays in the influenza vaccination schedule. In this way, the actions and programs aimed to improving vaccination coverage among the population will be able to be oriented and assessed, to diminish in this way the morbi-mortality caused by vaccination-preventable diseases, achieving more equity in the population’s health.
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[13]
[14] [15]
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[18] [19]
[20]
[21]
Conflicts of interest
[22]
The authors declare that they have no conflicts of interest. [23]
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Vaccine journal homepage: www.elsevier.com/locate/vaccine
Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old A. Gentile a,∗ , M. Juárez a , S. Hernandez b , A. Moya c , J. Bakir a , M. Lucion a a b c
Epidemiology, R. Gutiérrez Children’s Hospital, Buenos Aires, Argentina Infectology, “Prof. A. Posadas” National Hospital, Buenos Aires, Argentina Infectology, Misericordia Nuevo Siglo Hospital, Córdoba, Argentina
a r t i c l e
i n f o
Article history: Received 13 January 2015 Received in revised form 5 June 2015 Accepted 12 June 2015 Available online xxx Keywords: Influenza vaccines Immunization/utilization Immunization programs/organization and administration Infants
a b s t r a c t Introduction: In Argentina respiratory disease is the third leading cause of death in children under 5 years. In 2011 influenza vaccination was included in the National Calendar for children between 6 and 24 months (two doses schedule). Influenza vaccine coverage for second dose was 46.1% in 2013. The aim was to determine the proportion of delayed schedules and missed opportunities, to assess the characteristics of missed opportunities for vaccination and to explore the perception of influenza disease and vaccination from the parents of children between 6 and 24 months in different regions of Argentina in 2013. Methods: Analytical observational multicenter cross-sectional study. Structured surveys were carried out to the children’s parents who were between 6 and 24 months of age during the influenza virus vaccination season (April–October 2013). Chi-Square test was used to assess association and differences between proportions and categorical variables. A logistic regression model was built to identify delay predictor variables in the vaccination schedules. Missed opportunities for vaccination were characterized through the estimation of proportions. Results: 1350 surveys were conducted in the three centers. We detected 65% (884/1340) of delayed influenza vaccination schedules, 97% of them associated with missed opportunities of vaccination. The independent protective factors associated with a decreases risk of delayed schedules were: (a) perception of the importance of influenza vaccination (OR = 0.42(0.18–0.94); p = 0.035), (b) having less than one year of age (OR = 0.75(0.59–0.96); p = 0.022), (c) to have received information in pediatric visits or in any media (OR = 0.71(0.56–0.90); p = 0.004). There was 38% of MOIV in 1st dose and 63.4% in 2nd dose. The main cause of MOIV in 1st dose was not detecting the need for vaccination (39%) and in 2nd dose the unknowledge of the vaccination schedule (35.3%). No cultural reasons were detected. Conclusions: High frequency of delayed vaccination schedules and missed opportunities were detected. Parents had little concern about the safety of influenza vaccine. © 2015 Elsevier Ltd. All rights reserved.
1. Introduction The acute lower respiratory tract infections (ALRTI) represent an important cause of morbimortality, specially in children under 5 years of age, elder people over 65 years old and those with certain conditions that increase the risk to develop complications and severe forms of presentation [1]. In Argentina, respiratory diseases caused 787 deaths in children under 5 years old in 2012, representing the third most common cause of mortality in this group. 77% of these deaths occurred before infants turned one year old [2].
∗ Corresponding author. Tel.: +54 1149649019; fax: +54 91130887431. E-mail address: angelagentile@fibertel.com.ar (A. Gentile).
The high infection rates and the costs related with the morbimortality, particularly in high risk population, make seasonal influenza a disease of great importance in Public Health. The influenza virus is so far, the only respiratory virus preventable by means of a vaccine that has proved to be safe and effective in children older than 6 months old. Young children without medical history have a hospitalization rate associated with influenza virus comparable to the ones of high risk patients and described vaccine efficacy of the influenza vaccine to prevent hospitalizations is approximately 70% [3–7]. In 2011, Argentina introduced mandatory influenza virus vaccination to all children between 6 and 24 months to the National Immunization Program, by means of a two-dose schedule administered with a month interval. According to the aims of the World
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Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065
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Health Organization, in the so-called “Decade of Vaccines”, by the year 2020, at least 90% of national coverage and 80% in each district should be achieved for all the vaccines included in immunization programs. In 2013, the achieved coverage for the second dose was of 46.1% [3]. In this context, it is important to note that there are still barriers to achieve good vaccination coverage, including accessibility, growing complexity of vaccination schedules, fear of side effects, professionals’ lack of knowledge about vaccines and other missed opportunities for vaccination (MOV) [8–10]. The aims of this study were to determine the proportion of delayed schedules and missed opportunities, as well as to assess the characteristics of the missed opportunities for vaccination, the perception of seriousness of influenza disease and the information obtained by the parents about influenza disease, of children between 6 and 24 months old examined in the reference hospitals in different regions of Argentina in 2013. 2. Material and methods Analytical observational cross-sectional study. Structured surveys were administered to parents of children who were between 6 and 24 months of age during the influenza virus vaccination season (from April to October 2013) and who consulted on an outpatient basis in any of the three selected centers. The surveys were conducted at the end of the Influenza Virus Vaccination Campaign. To select the survey respondent, a non-probabilistic convenience sampling was carried out. The questionnaires were performed from Monday to Friday, in different parts of day to avoid possible bias related with the attitudes of the health care workers and the different characteristics of the population aim of this search. The inclusion criteria were: children between 6 and 24 months old, who went to the offices of the 3 health centers (“Ricardo Gutiérrez Children’s Hospital”, “Misericordia-Nuevo Siglo Hospital”, “Prof. Dr. A. Posadas National Hospital”) and who have vaccination cards or medical history in the health center to ascertain the vaccination status at the time of the survey. Exclusion criteria were: to be a sibling of a participant in this study or the parents’ refusal to answer the survey and to have a true contraindication to vaccinate. For the sample size estimation, reliability of 95% was considered, foreseeing an error of 5%, an expected proportion of 20% and accuracy of 2%, resulting in a necessary minimum n of 1332 surveys. Sociodemographic variables were investigated: age, gender, location, social status according to the Graffar’s modified method (Appendix 1). Supplementary material related to this article can be found, in the online version, at http://dx.doi.org/10.1016/j.vaccine.2015.06. 065 Variables related with the vaccination: • Delayed schedules: children who did not receive the influenza vaccine within 30 days of either turning 6 months of age during the flu vaccination interval in Argentina or within 30 days after the start of the recommended flu vaccination interval in Argentina for those already 6–24 months of age at the start of that interval or failure to receive the second dose between 30 and 60 days following the first dose. • Missed opportunity for vaccination (MOV): regarded as every visit of the individual to the health care center, who needed to be vaccinated and that, though true contraindications did not exist, they did not receive the necessary vaccines [11]. • Perception of the disease: the perception of seriousness was considered according to the parents’ assessment to the disease from which they were protecting their children.
• Vaccination importance: questions about the importance parents gave to the influenza vaccine were made, measured using Likert scales with the following categories: very important (5)/important (4)/somewhat important (3)/not important (2)/unnecessary (1). For the data analysis, a general description was first carried out, estimating the mean and standard deviation for the continuous variables and proportions for categorical data, with 95% confidence interval. To assess association and differences between the variables, the Chi-Square test was used for proportions and categorical variables. An alpha type I error of 5% was accepted. Due to the study design, the odds ratio with an interval of trust of 95% was used as an association measure. A logistic regression model was built to identify delay predictor variables in the vaccination schedules. To construct the model, the univariate analysis of each of the variables was first carried out by means of simple logistic regression. The age variable was introduced in models as categorical (6–11 months, 12–23 months). To construct the model, the multiple logistic regression was used. Variables were added in a staggered manner including those with p < 0.2 and/or biologically plausible. Missed opportunities for vaccination were characterized through the estimation of proportions.
3. Results 1350 surveys were carried out in the 3 health centers mentioned above with the following distribution: Prof. A. Posadas Hospital: 474 (35.37%); R. Gutiérrez Children’s Hospital: 454 (33.88%); Misericordia Nuevo Siglo Hospital: 412 (30.75%). Parents of children between 8 and 29 months were surveyed at the end of the influenza vaccine campaign (October 2013), with a median of 14 months of age. 55% of the children came from Buenos Aires province, 36% belonged to socioeconomic level IV (relative poverty according to modified Graffar method), 60% had made a consult for acute pathology and 54% had the shots given in public hospitals. The main population features are shown in Table 1. In the consult previous to the survey, 63.1% (494) of the patients had been asked about their vaccination status and the doses that they received were determined by reviewing the vaccination record card or health record. As for the vaccination status: 29.9% (404) had received only one influenza vaccine dose and 43.4% (582) had completed the two-dose vaccination schedule, that is, they were appropriately vaccinated for the age. 26.9% (364) of the survey respondent did not receive any dose.
3.1. Delayed vaccination schedules In the 65.8% (884) of the survey respondents, delayed vaccination schedules were detected and 54% showed delay in both doses of influenza vaccine (Chart 1).ln 97.9% of the delayed schedules, the delay occurred as a consequence of a missed opportunity for vaccination; in only two cases there was a true contraindication for influenza vaccination present. Different factors that could act as protectors and could avoid the occurrence of delay in both vaccination doses were assessed (Table 2). Multivariate analysis reflected, as independent predictors, considering influenza vaccination useful (OR = 0.42; CI95% = 0.18–0.94; p = 0.035), age less than one year (OR = 0.75; CI95% = 0.59–0.96; p = 0.022) and to having seen or heard messages about vaccines during the pediatric visit or in any means of communication (OR = 0.71; CI95% = 0.56–0.90; p = 0.004).
Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065
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Table 1 Socio-demographic features of the polled population. Features of the surveyed population
n (%)
CI95%
Age
<12 months ≥12 months
465 (34.7) 875 (65.3)
32.16–37.33 62.67–67.84
Gender
Female
671 (50.1)
47.40–52.82
Origin
City of Buenos Aires Buenos Aires Córdoba
187 (13.9) 741 (55.3) 412 (30.8)
12.17–15.95 52.59–57.98 28.30–33.31
Graffar
II (median-high) III (median) IV (relative poverty) V (critical poverty)
47 (3.4) 349 (26.1) 845 (63.1) 99 (7.4)
2.62–4.68 23.73–28.50 60.40–65.64 6.07–8.95
Chief complaint
Acute pathology Health control Patient companion Vaccine control
807 (60.3) 240 (17.9) 233 (17.4) 59 (4.4)
57.58–62.89 15.93–20.11 15.43–19.56 3.40–5.68
Vaccination sitea
Public hospital Private hospital Health center Private vaccination place
732 (54.6) 9 (0.7) 684 (51.1) 5 (0.4)
51.9–57.3 0.33–1.32 48.3–53.7 0.14–0.92
a
8.9% (120/1340) of the patients vaccinated in more than one site.
3.3. Perception of influenza disease and influenza vaccine As for the awareness and parents’ perception about the disease caused by the influenza virus, 84.7% mentioned knowing about the disease and 62.8% thought it was serious. Regarding the influenza vaccine: 33.7% (451) mentioned it was very important, 58.5% that it was important, 3.6% that it was unnecessary and 4.2% did not have a formed opinion in this matter. 95.3% of the parents considered that influenza vaccination was useful: 69.8% due to the risk of catching the illness, 20.5% for the increase of cases, 2.4% because it was a provision from the Ministry of Health, 0.8% for other reasons and 6.3% did not know the cause. 17.6% of the surveyed had searched information about influenza vaccination, 51.6% had seen some kind of message about preventable diseases by means of vaccines: 32.7% on television, 33.8% in the pediatric visit, 9.1% in advertisements, 4.5% on the radio, 4.1% on the Internet and 0.1% on other means of communication.
Chart 1. Delayed schedule distribution according to the number of doses where the delay took place.
3.2. Missed opportunities for vaccination (MOV)
3.4. Perception of influenza disease, influenza vaccine and missed opportunities
38% (510) of MOV were associated with the first influenza dose and 63.4% (848) of MOV were associated with the second influenza dose. The main cause of MOV was lack of awareness of the schedule (29.1%), followed by not detecting the necessity to vaccinate (28.7%). The MOV causes are detailed in Chart 2. It was significant the difference among the main causes of MOV according to the time of occurrence. Not detecting the necessity to vaccinate meant 39% in the first dose and 22.8% in the second one (p = 0.000), whereas the unawareness of vaccination schedules represented 19.3% for the first dose and 35.3% for the second one (p = 0.000).
Considering influenza vaccination useful (OR = 0.39; CI95% = 0.18–0.80; p = 0.010) and thinking that vaccination is important or very important (OR = 0.52; CI95% = 0.20–0.96; p = 0.041) resulted in MOV protection independent predictors in the first dose. While searching information about influenza vaccine (OR = 0.72; CI95% = 0.53–0.97; p = 0.034) and considering influenza vaccination useful (OR = 0.44; CI95% = 0.20–0.96; p = 0.041), were MOV protection factors in the second dose. On the other hand, knowing about the influenza disease (OR = 0.93; CI95% = 0.62–1.93; p = 0.733) and/or considering it serious (OR = 1.14; CI95% = 0.86–1.52; p = 0.337) were not associated
Table 2 Factors possibly involved in the occurrence of delayed schedules. Variable
OR
To have searched information about influenza vaccine To consider vaccination useful To be under one year of age To know about influenza disease To consider influenza a serious disease To see/hear messages about the influenza
0.8034 0.4179 0.7581 0.8238 1.7276 0.714
95% CI 0.5935–1.0876 0.216–0.8086 0.5972–0.9623 0.6174–1.0993 1.1777–2.5342 0.5658–0.901
p 0.157 0.01 0.023 0.188 0.005 0.005
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4 45.00% 40.00%
38.90% 35.27%
35.00% 30.00% 25.00% 20.00%
22.80% 19.29% 15.91% 13.58%
15.00% 8.46% 10.00% 6.65% 5.00% 0.98% 1.07%
2.95% 2.49%
1.77% 1.66 %
0.00% Not detecng Unawareness the necessity of schedule to vaccinate
Not having the card
Postpone the appointment
6.10% 4.87%
Temporary lack of vaccines
7.01% 4.53%
2.76% 1.19%
Difficulty with Cultural reasons Mild disease the vaccinaon center schedule
Other false Convalescence contraindicaons
MOV 1° dose MOV 2° dose Chart 2. Causes of missed opportunities for vaccination according to the time of occurrence.
with a MOV. Similarly, the fact that the vaccination record card was not checked during the previous consult, did not behave as a protection factor (OR = 1.42; CI95% = 1.11–1.81; p = 0.004). 4. Discussion There are two measures in Public Health that have had an extraordinary impact on health worldwide: water purification and vaccination. Immunization is one of the most efficient interventions of Public Health [12]. While vaccines represent an expense, fundamentally they are an investment. The final goal of vaccination is to eliminate diseases and its mid-term objective is to achieve primary prevention of these at an individual as well as community level. Both objectives can be achieved by means of a wide universal immunization program achieving high coverage in target populations and with an exhaustive epidemiological surveillance that acts as a monitor of these strategies. In Argentina influenza vaccination is available free for children between 6 and 24 years old. However, there exist barriers to achieve good coverage, which is particularly evident in the case of the influenza vaccine [13]. These situations demand a wide focus, which studies not only what is inherent to the program itself, but also the health staff, parents and caregivers’ attitudes. This extended view allows recognizing differences between vaccinated and unvaccinated children and those who are incompletely vaccinated [14]. The first group demands local actions, since they can be located and they represent a risk for both the vaccinated children and the ones incompletely vaccinated. The second ones demand actions essentially programmatic. Half of the polled cases showed delayed vaccination schedules for both influenza vaccine doses, nearly all due to MOVs. The necessity to promote the schedule and the importance of vaccination show themselves as a protection factor and set the need that, both the pediatricians and health authorities are responsible for promoting these prevention messages. We use a pretty strict definition for delay immunization schedules so in the absence of outreach and active notification, it is likely to result in a very high measured rate of delayed vaccination. In addition, it likely contributes to the observation that children less than 12 months of age, whose visits are more frequent, were a protective factor against delayed vaccination [15,16]. In our research, one of the most prominent barriers was the missed opportunities for vaccination. In a multi-centered study, it
was found that within the MOV causes, false contradictions (three times more frequent during the consult due to the disease than in a healthy child consult) were highlighted, the missed opportunity for vaccination for not giving all the corresponding vaccines simultaneously at the same visit and the physician’s inappropriate consulting about the child’s immune status [17], showing that postponing schedules and the MOV are important factors that reduce vaccination coverage [18]. Reducing MOV is fundamental in this setting to improving influenza vaccination coverage. Identifying sources of MOV and developing potential solutions with subsequent reassessment and, if indicated, making further refinements is necessary to achieving this goal [19,20]. In addition, the lack of perception of the vaccination necessity and the unawareness of the schedules were highlighted, particularly, in a vaccine such as influenza, of a recent introduction to the national schedule. As for the omission of the influenza vaccine prescription, it is well-known that vaccination schedules are not static but they are being modified according to the new vaccines availability and the evolution of the epidemiological situation of the different preventable diseases through vaccination, knowledge updating turns out to be a fundamental variable [21]. The described barriers causing low coverage during the introduction of new vaccines are: limited staff, unsatisfactory training, lack of topic presence in the community, lack of disease seriousness perception, vaccination schedule complexity, obstacles to accessibility, fear to vaccination adverse side effects and missed opportunities for vaccination (MOV), among others [8,9]. On an interesting study by Bosch-Capblanch et al. [22], it is shown the inequity among the different countries regarding the vaccination coverage and the need for programmatic efforts to identify unvaccinated children, generally undetected by the implemented routine systems. In this study, great relevance is given to the parents or habitual caregivers’ attitudes and their vaccination status in relation with the children’s vaccination. The survey results suggest that delayed or incomplete immunizations are not due to parental concern with vaccine or lack of awareness of severity of disease but instead with their lack of familiarity with the recommended schedule. Parents are not expected to know the recommended vaccination schedule. Instead, it appears that system issues as a lack of outreach, incomplete health records, not flagging vaccines due at visits, availability of vaccine
Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065
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(identified in 8%) and provider variables (awareness of recommended childhood vaccine schedules, failure to review vaccine records, and ordering and administration of recommended vaccine (s) at all visits) are the main sources of low uptake of influenza, and likely other, vaccine in this setting [23–25]. As regards the influenza vaccine, as we could prove in this study, the disease seriousness perception is high in the population, but it did not concur with the achieved coverage. Similarly, there still exists the paradox of having been a highly requested social vaccine after the influenza pandemic which took place in 2009, and of currently being one of the vaccines with the least coverage in the regular vaccination schedule, especially in the age group from 6 to 18 months old [3], and specially regarding the second dose. In this sense, operations research designs would be useful to adjust the strategies connected to the subject [26]. In the polled population, parents’ hesitation about the vaccines safety was not detected. This profile is different from the one described in Europe or North America. However, it is remarkable the communication about the benefits and risks of vaccination. Many parents have doubts about these topics, mainly about the vaccines’ safety and health professionals have a positive influence on the parents, even in those who thought that vaccination was not safe [27]. This great influence of the context and the means of communication were corroborated by groups of immunization experts worldwide, specifically by SAGE in April, 2013 [28]. The characterization of missed opportunities for vaccination in our setting is not identical to the ones found in other regions of the world which would allow to orient more these strategies toward the appropriate knowledge of the current vaccination schedules, deepening it in children over 12 months old that turned out to be those who showed more risk of having delays in the influenza vaccination schedule. In this way, the actions and programs aimed to improving vaccination coverage among the population will be able to be oriented and assessed, to diminish in this way the morbi-mortality caused by vaccination-preventable diseases, achieving more equity in the population’s health.
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[18] [19]
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[21]
Conflicts of interest
[22]
The authors declare that they have no conflicts of interest. [23]
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Please cite this article in press as: Gentile A, et al. Influenza vaccine: Delayed vaccination schedules and missed opportunities in children under 2 years old. Vaccine (2015), http://dx.doi.org/10.1016/j.vaccine.2015.06.065