- Email: [email protected]
Pertussis vaccines: WHO position paper—Recommendations
Vaccine 29 (2011) 2355–2356
Contents lists available at ScienceDirect
Vaccine journal homepage: www.elsevier.com/locate/vaccine
Conference report a r t i c l e
i n f o
Keywords: Pertussis Vaccine Position paper Recommendations
a b s t r a c t This article presents the WHO recommendations on the use of pertussis vaccines excerpted from the recently published Pertussis vaccines: WHO position paper. This document replaces the WHO position paper entitled Pertussis vaccines: WHO position paper published in the Weekly Epidemiological Record in January 2005. Footnotes to this paper provide a limited number of core references; their abstracts as well as a more comprehensive list of references may be found at http://www.who.int/immunization/documents/positionpapers/en/index.html. Grading tables which assess the quality of scientific evidence for key conclusions are also available through this link and are referenced in the position paper. In accordance with its mandate to provide guidance to Member States on health policy matters, WHO issues a series of regularly updated position papers on vaccines and combinations of vaccines against diseases that have an international public health impact. These papers are concerned primarily with the use of vaccines in large-scale immunization programmes; they summarize essential background information on diseases and vaccines, and conclude with WHO’s current position on the use of vaccines in the global context. This updated paper reflects the recent recommendations of WHO’s Strategic Advisory Group of Experts on immunization, or SAGE.
Pertussis vaccines: WHO position paper—Recommendations
2. Primary vaccination and booster doses in children
The main aim of pertussis vaccination is to reduce the risk of severe pertussis in infants. The worldwide priority is to achieve ≥90% coverage with 3 doses of high quality pertussis vaccine in infants, particularly where pertussis poses a serious health threat to infants and young children [1].
WHO recommends a 3-dose primary series, with the first dose administered at age 6 weeks; subsequent doses should be given 4–8 weeks apart, at age 10–14 weeks and 14–18 weeks. The last dose of the recommended primary series should be completed by the age of 6 months. All infants, including those who are HIV-positive, should be immunized against pertussis. Although administration of aP vaccine at birth and at age 1 month has been shown to induce antibody responses in infants at the age of 2 months [4], further studies are needed to confirm this finding, and neonatal immunization against pertussis is not recommended by WHO. The duration of protection following primary immunization varies considerably depending upon factors such as local epidemiology, immunization schedule and choice of vaccine [5]. Therefore, a booster dose is recommended for children aged 1–6 years, preferably during the second year of life. When given in the second year of life, this booster will improve protection following primary immunization if a less effective vaccine (wP or aP) is used, thus preventing early accumulation of susceptible individuals. The timing of this booster should also provide an opportunity for catch-up vaccination and allow for the use of a combination vaccine containing both pertussis and Hib antigens. The booster should be given ≥6 months after the last primary dose. Completion of this schedule (primary series plus booster) is expected to ensure protection against pertussis for ≥6 years. Children whose vaccination series has been interrupted should resume the series without repeating previous doses. Children aged 1–7 years or older who have not previously been immunized should receive 3 doses of wP vaccine or aP vaccine with intervals of 2 months between the first dose and the second; there should be a 6–12 month interval between the second and third doses.
1. Choice of vaccines Protection against severe pertussis in infancy and early childhood can be obtained after a primary series of vaccination with wP or aP vaccine [2]. Although local and systemic reactogenicity are more commonly associated with wP-containing vaccines, both aP-containing and wP-containing vaccines have excellent safety records [3]. The aPcontaining vaccines continue to be significantly more expensive than wP-containing vaccines, and for many countries there is insufficient marginal benefit to consider changing from wP-containing vaccine to aP-containing vaccine. However, in countries where the higher nonserious reactogenicity of wP would be an impediment to high vaccination coverage, the use of aP vaccine may be a mechanism to help improve acceptability. In these cases, aP vaccine should replace the wP vaccine in the national childhood immunization programme, either for the booster dose only or for the entire vaccination series.
Abbreviations: aP, acellular pertussis vaccine; Hib, Haemophilus influenzae type B; WHO, World Health Organization; wP, whole-cell pertussis vaccine. 0264-410X/$ – see front matter doi:10.1016/j.vaccine.2010.11.059
2356
Conference report / Vaccine 29 (2011) 2355–2356
3. Boosters of pertussis vaccine in adolescents and adults
6. Vaccine interchangeability and combinations of vaccines
Although vaccination can prevent pertussis in adolescents and adults there is insufficient evidence to support the addition of booster doses in these age groups in order to achieve the primary goal of reducing severe pertussis in infants. Decisions concerning such programmes should be based on the incidence and cost-effectiveness data; embarking on a strategy to vaccinate adolescents and adults presupposes there is high coverage of routine immunization in infants. However, the duration of protection after a single booster dose in adolescence, as well as programme costs and implications, merit further investigation. Only aP-containing vaccines should be used for vaccination in those aged >6 years.
Although data on the interchangeability of pertussis vaccines are limited, WHO has concluded that changing among or within the wP and aP vaccine groups is unlikely to interfere with the safety or immunogenicity of these vaccines. Surveillance should be implemented in countries that introduce combinations of vaccines, especially when aP-containing combinations are used.
4. Vaccinating pregnant women and household contacts There is insufficient evidence to recommend vaccinating pregnant women against pertussis. Although several countries have recommended that close household contacts and caregivers be vaccinated (known as cocooning), the significant programmatic difficulties and unproven effectiveness of this strategy have led WHO to conclude that there is inadequate evidence to recommend it. The relative merits of neonatal vaccination versus maternal vaccination should be investigated. When results are available WHO will review studies of maternal vaccination using aP-containing vaccines. 5. Vaccinating health-care workers Vaccinating health-care workers, primarily to prevent nosocomial transmission to infants and immunocompromised persons, may be cost effective if high coverage rates are obtained. In most settings, however, high coverage is unlikely without measures to both enhance access to, and compliance with, recommendations. Countries with demonstrable nosocomial transmission are encouraged to implement such vaccination especially among staff in maternity and paediatric units if it is economically and logistically feasible.
7. Surveillance Careful epidemiological surveillance of pertussis, particularly laboratory-confirmed disease, is to be encouraged worldwide to monitor the disease burden and the impact of immunization. Of particular interest are surveys comparing age-specific incidences of pertussis in countries with different policies on vaccine booster doses. Outbreak studies may also offer valuable information and should be encouraged. Existing research platforms – including the Child Health Epidemiology Reference Group, the Pneumonia Etiology Research for Child Health project and the Neonatal Sepsis Etiology Trial – should be expanded so that a better understanding of the true burden of pertussis in infants can be gained. References [1] Pertussis vaccines: WHO position paper. Wkly Epidemiol Rec 2010;85:385–400. [2] Grading of scientific evidence: Table I efficacy and effectiveness, with key references; http://www.who.int/entity/immunization/pertussis grad efficacy.pdf. [3] Grading of scientific evidence: Table II safety, with key references; http://www.who.int/entity/immunization/pertussis grad safety.pdf. [4] Wood N, McIntyre P, Marshall H, Roberton D. Acellular pertussis vaccine at birth and one month induces antibody responses by two months of age. Pediatr Infect Dis J 2010;29:209–15. [5] Grading of scientific evidence: Table III duration of protection, with key references; http://www.who.int/entity/immunization/pertussis grad duration.pdf.
WHO Publication World Health Organization, Department of Immunization, Vaccines and Biologicals, 20 Avenue Appia, 1211 Geneva 27, Switzerland E-mail address: [email protected] 8 November 2010 Available online 1 December 2010
Contents lists available at ScienceDirect
Vaccine journal homepage: www.elsevier.com/locate/vaccine
Conference report a r t i c l e
i n f o
Keywords: Pertussis Vaccine Position paper Recommendations
a b s t r a c t This article presents the WHO recommendations on the use of pertussis vaccines excerpted from the recently published Pertussis vaccines: WHO position paper. This document replaces the WHO position paper entitled Pertussis vaccines: WHO position paper published in the Weekly Epidemiological Record in January 2005. Footnotes to this paper provide a limited number of core references; their abstracts as well as a more comprehensive list of references may be found at http://www.who.int/immunization/documents/positionpapers/en/index.html. Grading tables which assess the quality of scientific evidence for key conclusions are also available through this link and are referenced in the position paper. In accordance with its mandate to provide guidance to Member States on health policy matters, WHO issues a series of regularly updated position papers on vaccines and combinations of vaccines against diseases that have an international public health impact. These papers are concerned primarily with the use of vaccines in large-scale immunization programmes; they summarize essential background information on diseases and vaccines, and conclude with WHO’s current position on the use of vaccines in the global context. This updated paper reflects the recent recommendations of WHO’s Strategic Advisory Group of Experts on immunization, or SAGE.
Pertussis vaccines: WHO position paper—Recommendations
2. Primary vaccination and booster doses in children
The main aim of pertussis vaccination is to reduce the risk of severe pertussis in infants. The worldwide priority is to achieve ≥90% coverage with 3 doses of high quality pertussis vaccine in infants, particularly where pertussis poses a serious health threat to infants and young children [1].
WHO recommends a 3-dose primary series, with the first dose administered at age 6 weeks; subsequent doses should be given 4–8 weeks apart, at age 10–14 weeks and 14–18 weeks. The last dose of the recommended primary series should be completed by the age of 6 months. All infants, including those who are HIV-positive, should be immunized against pertussis. Although administration of aP vaccine at birth and at age 1 month has been shown to induce antibody responses in infants at the age of 2 months [4], further studies are needed to confirm this finding, and neonatal immunization against pertussis is not recommended by WHO. The duration of protection following primary immunization varies considerably depending upon factors such as local epidemiology, immunization schedule and choice of vaccine [5]. Therefore, a booster dose is recommended for children aged 1–6 years, preferably during the second year of life. When given in the second year of life, this booster will improve protection following primary immunization if a less effective vaccine (wP or aP) is used, thus preventing early accumulation of susceptible individuals. The timing of this booster should also provide an opportunity for catch-up vaccination and allow for the use of a combination vaccine containing both pertussis and Hib antigens. The booster should be given ≥6 months after the last primary dose. Completion of this schedule (primary series plus booster) is expected to ensure protection against pertussis for ≥6 years. Children whose vaccination series has been interrupted should resume the series without repeating previous doses. Children aged 1–7 years or older who have not previously been immunized should receive 3 doses of wP vaccine or aP vaccine with intervals of 2 months between the first dose and the second; there should be a 6–12 month interval between the second and third doses.
1. Choice of vaccines Protection against severe pertussis in infancy and early childhood can be obtained after a primary series of vaccination with wP or aP vaccine [2]. Although local and systemic reactogenicity are more commonly associated with wP-containing vaccines, both aP-containing and wP-containing vaccines have excellent safety records [3]. The aPcontaining vaccines continue to be significantly more expensive than wP-containing vaccines, and for many countries there is insufficient marginal benefit to consider changing from wP-containing vaccine to aP-containing vaccine. However, in countries where the higher nonserious reactogenicity of wP would be an impediment to high vaccination coverage, the use of aP vaccine may be a mechanism to help improve acceptability. In these cases, aP vaccine should replace the wP vaccine in the national childhood immunization programme, either for the booster dose only or for the entire vaccination series.
Abbreviations: aP, acellular pertussis vaccine; Hib, Haemophilus influenzae type B; WHO, World Health Organization; wP, whole-cell pertussis vaccine. 0264-410X/$ – see front matter doi:10.1016/j.vaccine.2010.11.059
2356
Conference report / Vaccine 29 (2011) 2355–2356
3. Boosters of pertussis vaccine in adolescents and adults
6. Vaccine interchangeability and combinations of vaccines
Although vaccination can prevent pertussis in adolescents and adults there is insufficient evidence to support the addition of booster doses in these age groups in order to achieve the primary goal of reducing severe pertussis in infants. Decisions concerning such programmes should be based on the incidence and cost-effectiveness data; embarking on a strategy to vaccinate adolescents and adults presupposes there is high coverage of routine immunization in infants. However, the duration of protection after a single booster dose in adolescence, as well as programme costs and implications, merit further investigation. Only aP-containing vaccines should be used for vaccination in those aged >6 years.
Although data on the interchangeability of pertussis vaccines are limited, WHO has concluded that changing among or within the wP and aP vaccine groups is unlikely to interfere with the safety or immunogenicity of these vaccines. Surveillance should be implemented in countries that introduce combinations of vaccines, especially when aP-containing combinations are used.
4. Vaccinating pregnant women and household contacts There is insufficient evidence to recommend vaccinating pregnant women against pertussis. Although several countries have recommended that close household contacts and caregivers be vaccinated (known as cocooning), the significant programmatic difficulties and unproven effectiveness of this strategy have led WHO to conclude that there is inadequate evidence to recommend it. The relative merits of neonatal vaccination versus maternal vaccination should be investigated. When results are available WHO will review studies of maternal vaccination using aP-containing vaccines. 5. Vaccinating health-care workers Vaccinating health-care workers, primarily to prevent nosocomial transmission to infants and immunocompromised persons, may be cost effective if high coverage rates are obtained. In most settings, however, high coverage is unlikely without measures to both enhance access to, and compliance with, recommendations. Countries with demonstrable nosocomial transmission are encouraged to implement such vaccination especially among staff in maternity and paediatric units if it is economically and logistically feasible.
7. Surveillance Careful epidemiological surveillance of pertussis, particularly laboratory-confirmed disease, is to be encouraged worldwide to monitor the disease burden and the impact of immunization. Of particular interest are surveys comparing age-specific incidences of pertussis in countries with different policies on vaccine booster doses. Outbreak studies may also offer valuable information and should be encouraged. Existing research platforms – including the Child Health Epidemiology Reference Group, the Pneumonia Etiology Research for Child Health project and the Neonatal Sepsis Etiology Trial – should be expanded so that a better understanding of the true burden of pertussis in infants can be gained. References [1] Pertussis vaccines: WHO position paper. Wkly Epidemiol Rec 2010;85:385–400. [2] Grading of scientific evidence: Table I efficacy and effectiveness, with key references; http://www.who.int/entity/immunization/pertussis grad efficacy.pdf. [3] Grading of scientific evidence: Table II safety, with key references; http://www.who.int/entity/immunization/pertussis grad safety.pdf. [4] Wood N, McIntyre P, Marshall H, Roberton D. Acellular pertussis vaccine at birth and one month induces antibody responses by two months of age. Pediatr Infect Dis J 2010;29:209–15. [5] Grading of scientific evidence: Table III duration of protection, with key references; http://www.who.int/entity/immunization/pertussis grad duration.pdf.
WHO Publication World Health Organization, Department of Immunization, Vaccines and Biologicals, 20 Avenue Appia, 1211 Geneva 27, Switzerland E-mail address: [email protected] 8 November 2010 Available online 1 December 2010