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Receipt of pertussis vaccine during pregnancy across 7 Vaccine Safety Datalink Sites
Preventive Medicine 67 (2014) 316–319
Contents lists available at ScienceDirect
Preventive Medicine journal homepage: www.elsevier.com/locate/ypmed
Brief Original Report
Receipt of pertussis vaccine during pregnancy across 7 Vaccine Safety Datalink Sites Elyse O. Kharbanda a,⁎, Gabriela Vazquez-Benitez a, Heather Lipkind b, Allison L. Naleway c, Nicola P. Klein d, T. Craig Cheetham e, Simon J. Hambidge f,g, Claudia Vellozzi h, James D. Nordin a a
HealthPartners Institute for Education and Research, Minneapolis, MN, United States Department of Obstetrics and Gynecology, Yale University, New Haven, CT, United States Center for Health Research, Kaiser Permanente Northwest, Portland, OR, United States d Vaccine Study Center, Kaiser Permanente of Northern California, Oakland, CA, United States e Kaiser Permanente of Southern California, Pasadena, CA, United States f Kaiser Permanente Institute for Health Research, Denver, CO, United States g Denver Health Community Health Services, Denver, United States h Immunization Safety Office, Division of Healthcare Quality and Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States b c
a r t i c l e
i n f o
Available online 18 June 2014 Keywords: Pertussis Pregnancy Vaccine coverage
a b s t r a c t Objective. In response to widespread pertussis outbreaks and infant deaths, in 2010, the California Department of Health (CDPH) and in 2011 the Advisory Committee on Immunization Practices (ACIP) advised that the tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine be administered during pregnancy. The goals of this study were to describe Tdap coverage among pregnant women following these recommendations. Methods. In this observational cohort study, we utilized electronic medical record and claims data from seven Vaccine Safety Datalink sites to identify pregnancies and Tdap administrations. All Tdap doses were classified as pre-pregnancy, during pregnancy or post-pregnancy/postpartum. For pregnancies ending in a live birth, we evaluated factors associated with Tdap vaccination. Results. Among 289,141 live births at the California VSD sites, receipt of Tdap during pregnancy increased substantially in the years 2010, 2011, and 2012, when coverage was 15.9, 30.0 and 19.5%, respectively. Among 82,398 women with live births at the Oregon, Washington, Colorado, Wisconsin and Minnesota VSD sites, receipt of Tdap during pregnancy first increased in 2012, at 16.0%. Women receiving early prenatal care and other vaccine(s) during pregnancy had higher Tdap coverage. Conclusion. We observed substantial increases in Tdap coverage during pregnancy following CDPH and ACIP recommendations. © 2014 Elsevier Inc. All rights reserved.
Introduction Bordetella pertussis is a highly contagious bacterium that infects the human respiratory tract. While most pertussis infections in children and adults are asymptomatic or result in mild illness, infants with pertussis can experience apnea, respiratory failure, neurologic complications, and death (Gall, 2012). Two tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines were licensed in the United States in 2005 for routine use in non-pregnant adolescents and adults (Broder et al., 2006; Kretsinger et al., 2006). While starting in 2006 the American Academy of Pediatrics endorsed the use of Tdap for ⁎ Corresponding author at: HealthPartners Institute for Education and Research, PO Box 1524, MS 21111R, Minneapolis, MN 55425, United States. Fax: +1 952 967 5022. E-mail address: [email protected] (E.O. Kharbanda).
http://dx.doi.org/10.1016/j.ypmed.2014.05.025 0091-7435/© 2014 Elsevier Inc. All rights reserved.
pregnant adolescents (Anon., 2006); more often cocooning or vaccinating parents and other close contacts was recommended to prevent pertussis transmission and severe illness in newborns (Anon., 2011; Kretsinger et al., 2006). In 2010, in response to a statewide pertussis outbreak with infant deaths (CDC, 2010; Winter et al., 2012), the California Department of Health (CDPH) advised that Tdap be administered to previously unvaccinated pregnant women (CDPH, n.a). In 2011, the Advisory Committee on Immunization Practices (ACIP) followed with similar recommendations for pregnant women across the United States. In 2012, ACIP further revised recommendations that Tdap be administered to all pregnant women during every pregnancy, even if previously vaccinated (Anon., 2013). To date there is limited data on receipt of Tdap during pregnancy. The aim of this report was to describe Tdap coverage for pregnancies occurring from 2007 to 2102 at seven geographically diverse integrated health care systems within the Vaccine Safety Datalink (VSD).
E.O. Kharbanda et al. / Preventive Medicine 67 (2014) 316–319
Materials and methods The VSD is a collaborative effort between the Center for Disease Control and Prevention's Immunization Safety Office and 9 large medical care organizations in the U.S. and includes data on approximately 2.5 million women of reproductive age (Baggs et al., 2011). For this report, data on Tdap coverage was available from seven VSD sites: Group Health Cooperative (WA), Kaiser Permanente Northwest (OR) and (WA), Kaiser Permanente Northern California (CA), Southern California Kaiser Permanente (CA), HealthPartners (MN), Marshfield Clinic (WI), and Kaiser Permanente Colorado (CO). Pregnancies ending between 1/1/2007 and 11/15/2012 were identified using a validated algorithm (Naleway et al., 2013). The algorithm utilizes claims, administrative, and birth data to a) identify pregnancies, b) determine pregnancy outcomes and c) estimate gestational age at pregnancy outcome (Naleway et al., 2013). This algorithm has been used in prior studies of vaccine safety (Kharbanda et al., 2013; Nordin et al., 2013) and vaccine coverage during pregnancy (Naleway et al., 2014). To be included in this report, pregnant women 14–49 years of age were required to have continuous insurance coverage from 6 months prior to pregnancy through 6 weeks after pregnancy end with no more than a 30-day gap. Women with ectopic pregnancies, gestational trophoblastic disease, and pregnancies whose outcome could not be determined with available data were excluded. Women with live births and no medical visits recorded throughout pregnancy were also excluded. Identification of Tdap administrations Receipt of Tdap from 1/1/2005 to 12/31/2012 was identified from electronic medical record and claims data. All Tdap doses were then classified as: Pre-pregnancy (1/1/2005 through 7 days after the last menstrual period (LMP); During pregnancy (8 days after LMP through 7 days before pregnancy end); and Post-pregnancy/Postpartum (6 days before pregnancy end through 42 days after pregnancy end). Categories were assigned to avoid prepregnancy and postpartum vaccines being misclassified as occurring during pregnancy (Kharbanda et al., 2012). Analysis For pregnancies in the cohort, we report the proportion receiving Tdap pre-pregnancy, during pregnancy, and post-pregnancy/postpartum. We then
317
describe Tdap coverage by pregnancy outcome, year, age, and socioeconomic status. Among pregnancies ending in a live birth, we evaluated Tdap coverage by year, age, socio-demographic factors, health care utilization and pregnancy risk, stratified by California versus other VSD sites. All data were analyzed using SAS/STAT software, Version 9.3 (SAS Institute Inc). This study was approved by the Institutional Review Boards at all participating sites and the Centers for Disease Control and Prevention.
Results Of 535,851 pregnancies at seven VSD sites over six years with continuous insurance enrollment, we excluded 15,157 (2.8%) based on pregnancy outcome and 2994 (0.6%) for having no medical claims throughout pregnancy. The final study cohort included 517,700 pregnancies with end dates between 1/1/07 and 11/15/2012. Pregnancy outcomes were: live birth (71.7%), spontaneous abortion (14.8%), therapeutic abortion (13.0%) and stillbirth (0.4%). Across all pregnancies, 25.3% received Tdap before pregnancy, 7.1% during pregnancy and 10.8% within six weeks of pregnancy end. Receipt of Tdap during pregnancy increased steadily in 2010 and 2011 but then decreased in 2012 (Table 1). Of 289,141 pregnancies from the CA VSD sites with a live birth, receipt of Tdap during pregnancy increased markedly from 0.3% in 2007 to 30.4% in 2011 but decreased to 19.5% in 2012. Pre-pregnancy receipt of Tdap increased steadily each year, by 2011 35.3% and by 2012 53.8% of women with live births in CA had received Tdap prior to pregnancy. In 2011, 15.9% of pregnancies did not receive Tdap in any period (pre-pregnancy, during pregnancy or postpartum); this decreased to 14.6% in 2012. Among those vaccinated during pregnancy, receipt of Tdap at ≥20 week gestation increased from 12.3% in 2007 to 69.4% in 2012. Of 82,398 pregnancies occurring in the WA, OR, MN, WI and CO VSD sites and ending in a live birth, receipt of Tdap during pregnancy increased from 0.8% of pregnancies in 2007 to 16.1% in 2012. Pre-pregnancy and postpartum Tdap administration also increased substantially over time. The proportion who did not receive Tdap in any period decreased consistently from 87.3% in 2007 to 17.4% in
Table 1 Receipt of Tdap among all pregnancies in cohorte.
Pregnancy outcome Live birth SAB, SB or TABa Year 2007 2008 2009 2010 2011 2012 Site California VSD sites Other VSD sitesb Maternal age b18 18–24 25–34 ≥35 Socioeconomic statusc Medium/high Low Missing total, all pregnancies a b c d e
Postpartumd (%)
Did not receive Tdap (%)
9.5 1.2
14.4 1.6
53.8 67.2
3.2 8.6 16.8 26.5 40.1 56.1
0.5 0.7 1.0 9.2 17.1 13.7
2.3 6.4 13.4 18.9 14.2 8.8
94.0 84.5 69.3 47.0 30.1 22.6
407,239 110,461
23.6 31.5
8.3 3.0
10.7 11.2
58.2 55.2
12,488 90,069 286,516 128,627
46.6 28.4 23.7 24.8
4.3 6.0 7.8 6.8
5.7 8.5 11.8 10.6
45.7 58.3 57.5 58.4
314,364 142,354 60,982 517,700
26.2 23.2 25.8 25.3
7.4 9.3 1.1 7.1
13.0 9.9 1.5 10.8
54.3 58.7 71.7 57.6
N
Pre-pregnancy (%)
371,539 146,161
23.5 30.0
84,278 84,827 84,581 89,888 91,445 82,681
Pregnancy (%)
SAB = Spontaneous abortion, SB = Stillbirth, TAB = Therapeutic abortion. Other VSD sites located in: Colorado, Minnesota, Oregon, Washington and Wisconsin. Low socioeconomic status defined as living in data census tract having 20% or more of the population living at less than 150% of the federal poverty level. Within 42 days of end of pregnancy/postpartum for live births. Row percents may add to N100 as women may have received Tdap in more than one period (e.g., pre-pregnancy and postpartum).
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E.O. Kharbanda et al. / Preventive Medicine 67 (2014) 316–319
Table 2 Receipt of Tdap during pregnancy, live births in California Vaccine Safety Datalink (VSD) sites and other VSD sitesa. Received Tdap during pregnancy Other VSD sitesa
California VSD sites
Year 2007 2008 2009 2010 2011 2012 Maternal age b18 years 18–24 25–34 ≥35 years Socioeconomic statusb Medium/high Low Missing Prenatal care index Adequate/plus Intermediate Inadequate Missing Care in 1st trimester Yes No Missing Delivery b37 weeks Yes No Pregnancy risk Comorbiditiesc No comorbidities Complicationsd No complications Other vaccine in pregnancye Yes No Total
Number of pregnancies
N (%) vaccinated
Number of pregnancies
N (%) vaccinated
48,398 48,828 48,434 48,321 49,227 45,933
155 (0.3) 214 (0.4) 410 (0.8) 7672 (15.9) 14,765 (30.0) 8946 (19.5)
13,488 14,161 13,965 14,089 14,229 12,466
108 (0.8) 171 (1.2) 192 (1.4) 219 (1.6) 318 (2.2) 2000 (16.0)
5647 43,903 171,095 68,496
419 (7.4) 4546 (10.4) 19,615 (11.5) 7582 (11.1)
1238 11,980 51,381 17,799
29 (2.3) 473 (3.9) 1849 (3.6) 657 (3.7)
186,821 102,283 37
19,926 (10.7) 12,232 (12.0) –
69,406 12,962 30
2472 (3.6) 536 (4.1) –
223,015 56,227 9780 119
26,770 (12.0) 4635 (8.2) 749 (7.7) –
42,485 23,862 16,003 48
1598 (3.8) 952 (4.0) 458 (2.9) –
273,121 15,316 704
30,802 (11.3) 1339 (8.7) 21 (3.0)
68,883 6999 6516
2605 (3.8) 185 (2.6) 218 (3.3)
23,196 265,945
1981 (8.5) 30,181 (11.3)
5991 76,407
165 (2.8) 2843 (3.7)
51,672 237,469 84,581 204,560
5440 (10.5) 26,722 (11.3) 9771 (11.6) 22,391 (10.9)
13,012 69,386 23,094 59,304
488 (3.8) 2520 (3.6) 842 (3.6) 2166 (3.7)
113,516 175,625 289,141
20,543 (18.1) 11,619 (6.6) 32,162 (11.1)
38,442 43,956 82,398
1778 (4.6) 1230 (2.8) 3008 (3.7)
a
Other VSD sites located in: Colorado, Minnesota, Oregon, Washington and Wisconsin. Low socioeconomic status defined as living in a census tract having 20% or more of the population living at less than 150% of the federal poverty level. c Comorbidities included pulmonary disease, hypertension or other heart disease, diabetes, renal or neurologic conditions diagnosed from 6 months prior to last menstrual period through end of pregnancy. d Pregnancy complications included gestational diabetes, gestational hypertension and hemorrhage in early pregnancy. e Other vaccines included: inactivated influenza vaccines (95.9%), hepatitis A/hepatitis B (1.4%), human papillomavirus vaccine (1.1%), and other (1.6%). b
2012. Among those vaccinated during pregnancy, receipt of Tdap at ≥20 week gestation increased from 16.7% in 2007 to 91.7% in 2012. Tdap coverage among live births, by sociodemographc, healthcare utilization and pregnancy risk is shown in Table 2.
Discussion Administering Tdap during the third trimester of pregnancy is likely to be the most effective strategy for preventing severe pertussis infections in newborns (Anon., 2013; Peters et al., 2012; Terranella et al., 2013) and thus the CDPH and ACIP recommendation has been broadly endorsed (A.C.O.G. Committee Opinion No. 566, 2013). In this study, we observed a marked response to recommendations to administer Tdap during pregnancy to women not previously vaccinated across seven geographically diverse integrated health delivery systems. At the CA VSD sites, increases in Tdap coverage during pregnancy began in 2010, following the CDPH recommendations; at the other VSD sites, increases were first observed in 2012, following the 2011 ACIP recommendations. The decline in Tdap coverage during pregnancy in CA in 2012 was likely because more than half of women that year had received Tdap prior to pregnancy. Thus, based on recommendations at the time, these women were not eligible to receive another Tdap dose.
We observed larger increases in receipt of Tdap among women receiving adequate prenatal care, those with medical care in their first trimester, and among full term births. These associations likely represent pregnancies with more contact with prenatal providers and thus increased opportunities to vaccinate. Tdap is now the second vaccine, following influenza, specifically recommended for routine use during pregnancy. For influenza, providers and women were initially hesitant regarding vaccination during pregnancy (Ahluwalia et al., 2010). However, since the H1N1 influenza pandemic, where pregnant women were disproportionately affected, vaccine uptake has increased remarkably (Henninger et al., 2013). Similarly, the marked increase in Tdap administration during pregnancy at the CA sites in 2010 may have reflected fears related to the ongoing pertussis outbreak (Winter et al., 2012). Several limitations to this report should be noted. First, the data presented are novel but do not reflect the current ACIP recommendations. Second, our sample is limited to women with continuous insurance enrollment receiving care within large integrated health care systems. Women who were uninsured prior to becoming pregnant and those with fragmented care may be less likely to receive Tdap. In addition, Tdap administration outside the healthcare system or administration of Tdap that did not generate a medical claim may have been missed. Furthermore, for women who did not receive Tdap
E.O. Kharbanda et al. / Preventive Medicine 67 (2014) 316–319
during pregnancy, details regarding whether the vaccine was offered during routine prenatal care were not available. Previously, our team reported on vaccines administered to pregnant women within the VSD from 2007 through 2009 (Naleway et al., 2014). The current report expands on this work by including pregnancies from 2010 through 2012, highlighting the response to the 2010 CDPH and 2011 ACIP recommendations. Conflicts of interest Dr. Nicola Klein receives research support from GlaxoSmithKline, Sanofi Pasteur, Novartis, Pfizer and Merck. Dr. Allison Naleway receives research support from GlaxoSmithKline. Dr. Cheetham receives research support from Merck. The remaining co-authors have no financial conflicts of interest to report.
Acknowledgments Findings of this study represent those of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention. This study was funded by the Centers for Disease Control and Prevention, Contract 200-2012-53526. Dr. Claudia Vellozzi is employed by the funder and a collaborator on this research. Dr. Vellozzi assisted with study design, interpretation of findings and the decision to submit this article for publication. This paper did undergo the CDC clearance process. References A.C.O.G. Committee Opinion No. 566, 2013. Update on immunization and pregnancy: tetanus, diphtheria, and pertussis vaccination. Obstet. Gynecol. 121 (6), 1411–1414 (Jun). Ahluwalia, I.B., Jamieson, D.J., Rasmussen, S.A., D'Angelo, D., Goodman, D., Kim, H., 2010. Correlates of seasonal influenza vaccine coverage among pregnant women in Georgia and Rhode Island. Obstet. Gynecol. 116 (4), 949–955 (Oct). Anon., 2006. Prevention of pertussis among adolescents: recommendations for use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Pediatrics 117 (3), 965–978 (Mar). Anon., 2011. Updated recommendations for use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine (Tdap) in pregnant women and persons who have or anticipate having close contact with an infant aged b12 months—Advisory Committee on Immunization Practices (ACIP), 2011. MMWR Morb. Mortal. Wkly Rep. 60 (41), 1424–1426 (Oct 21).
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Anon., 2013. Updated recommendations for use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine (Tdap) in pregnant women—Advisory Committee on Immunization Practices (ACIP), 2012. MMWR Morb. Mortal. Wkly Rep. 62 (7), 131–135 (Feb 22). Baggs, J., Gee, J., Lewis, E., et al., 2011. The Vaccine Safety Datalink: a model for monitoring immunization safety. Pediatrics 127 (Suppl. 1), S45–S53 (May). Broder, K.R., Cortese, M.M., Iskander, J.K., et al., 2006. Preventing tetanus, diphtheria, and pertussis among adolescents: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccines recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm. Rep. 55 (RR-3), 1–34 (Mar 24). CDC, 2010. Notes from the field: pertussis—California, January–June 2010. Morb. Mortal. Wkly. Rep. 59 (26), 817. CDPH, a. Broadens recommendations for vaccinating against pertussis: immunization key to controlling whooping coughhttp://www.cdph.ca.gov/Pages/PH10-048.aspx (Accessed December 2, 2013). Gall, S.A., 2012. Prevention of pertussis, tetanus, and diphtheria among pregnant, postpartum women, and infants. Clin. Obstet. Gynecol. 55 (2), 498–509 (Jun). Henninger, M., Crane, B., Naleway, A., 2013. Trends in influenza vaccine coverage in pregnant women, 2008 to 2012. Perm. J. 17 (2), 31–36 (Spring). Kharbanda, E.O., Vazquez-Benitez, G., Shi, W.X., et al., 2012. Assessing the safety of influenza immunization during pregnancy: the Vaccine Safety Datalink. Am. J. Obstet. Gynecol. 207 (3 Suppl.), S47–S51 (Sep). Kharbanda, E.O., Vazquez-Benitez, G., Lipkind, H., Naleway, A., Lee, G., Nordin, J.D., 2013. Inactivated influenza vaccine during pregnancy and risks for adverse obstetric events. Obstet. Gynecol. 122 (3), 659–667 (Sep). Kretsinger, K., Broder, K.R., Cortese, M.M., et al., 2006. Preventing tetanus, diphtheria, and pertussis among adults: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine recommendations of the Advisory Committee on Immunization Practices (ACIP) and recommendation of ACIP, supported by the Healthcare Infection Control Practices Advisory Committee (HICPAC), for use of Tdap among health-care personnel. MMWR Recomm. Rep. 55 (RR-17), 1–37 (Dec 15). Naleway, A.L., Gold, R., Kurosky, S., et al., 2013. Identifying pregnancy episodes, outcomes, and mother–infant pairs in the Vaccine Safety Datalink. Vaccine 31 (27), 2898–2903. Naleway, A.L., Kurosky, S., Henninger, M.L., et al., 2014. Vaccinations given during pregnancy, 2002–2009: a descriptive study. Am. J. Prev. Med. 46 (2), 150–157 (Feb). Nordin, J.D., Kharbanda, E.O., Benitez, G.V., et al., 2013. Maternal safety of trivalent inactivated influenza vaccine in pregnant women. Obstet. Gynecol. 121 (3), 519–525 (Mar). Peters, T.R., Banks, G.C., Snively, B.M., Poehling, K.A., 2012. Potential impact of parental Tdap immunization on infant pertussis hospitalizations. Vaccine 30 (37), 5527–5532. Terranella, A., Asay, G.R., Messonnier, M.L., Clark, T.A., Liang, J.L., 2013. Pregnancy dose Tdap and postpartum cocooning to prevent infant pertussis: a decision analysis. Pediatrics 131 (6), e1748–e1756 (Jun). Winter, K., Harriman, K., Zipprich, J., et al., 2012. California Pertussis Epidemic, 2010. J. Pediatr. 161 (6), 1091–1096.
Contents lists available at ScienceDirect
Preventive Medicine journal homepage: www.elsevier.com/locate/ypmed
Brief Original Report
Receipt of pertussis vaccine during pregnancy across 7 Vaccine Safety Datalink Sites Elyse O. Kharbanda a,⁎, Gabriela Vazquez-Benitez a, Heather Lipkind b, Allison L. Naleway c, Nicola P. Klein d, T. Craig Cheetham e, Simon J. Hambidge f,g, Claudia Vellozzi h, James D. Nordin a a
HealthPartners Institute for Education and Research, Minneapolis, MN, United States Department of Obstetrics and Gynecology, Yale University, New Haven, CT, United States Center for Health Research, Kaiser Permanente Northwest, Portland, OR, United States d Vaccine Study Center, Kaiser Permanente of Northern California, Oakland, CA, United States e Kaiser Permanente of Southern California, Pasadena, CA, United States f Kaiser Permanente Institute for Health Research, Denver, CO, United States g Denver Health Community Health Services, Denver, United States h Immunization Safety Office, Division of Healthcare Quality and Promotion, Centers for Disease Control and Prevention, Atlanta, GA, United States b c
a r t i c l e
i n f o
Available online 18 June 2014 Keywords: Pertussis Pregnancy Vaccine coverage
a b s t r a c t Objective. In response to widespread pertussis outbreaks and infant deaths, in 2010, the California Department of Health (CDPH) and in 2011 the Advisory Committee on Immunization Practices (ACIP) advised that the tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine be administered during pregnancy. The goals of this study were to describe Tdap coverage among pregnant women following these recommendations. Methods. In this observational cohort study, we utilized electronic medical record and claims data from seven Vaccine Safety Datalink sites to identify pregnancies and Tdap administrations. All Tdap doses were classified as pre-pregnancy, during pregnancy or post-pregnancy/postpartum. For pregnancies ending in a live birth, we evaluated factors associated with Tdap vaccination. Results. Among 289,141 live births at the California VSD sites, receipt of Tdap during pregnancy increased substantially in the years 2010, 2011, and 2012, when coverage was 15.9, 30.0 and 19.5%, respectively. Among 82,398 women with live births at the Oregon, Washington, Colorado, Wisconsin and Minnesota VSD sites, receipt of Tdap during pregnancy first increased in 2012, at 16.0%. Women receiving early prenatal care and other vaccine(s) during pregnancy had higher Tdap coverage. Conclusion. We observed substantial increases in Tdap coverage during pregnancy following CDPH and ACIP recommendations. © 2014 Elsevier Inc. All rights reserved.
Introduction Bordetella pertussis is a highly contagious bacterium that infects the human respiratory tract. While most pertussis infections in children and adults are asymptomatic or result in mild illness, infants with pertussis can experience apnea, respiratory failure, neurologic complications, and death (Gall, 2012). Two tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines were licensed in the United States in 2005 for routine use in non-pregnant adolescents and adults (Broder et al., 2006; Kretsinger et al., 2006). While starting in 2006 the American Academy of Pediatrics endorsed the use of Tdap for ⁎ Corresponding author at: HealthPartners Institute for Education and Research, PO Box 1524, MS 21111R, Minneapolis, MN 55425, United States. Fax: +1 952 967 5022. E-mail address: [email protected] (E.O. Kharbanda).
http://dx.doi.org/10.1016/j.ypmed.2014.05.025 0091-7435/© 2014 Elsevier Inc. All rights reserved.
pregnant adolescents (Anon., 2006); more often cocooning or vaccinating parents and other close contacts was recommended to prevent pertussis transmission and severe illness in newborns (Anon., 2011; Kretsinger et al., 2006). In 2010, in response to a statewide pertussis outbreak with infant deaths (CDC, 2010; Winter et al., 2012), the California Department of Health (CDPH) advised that Tdap be administered to previously unvaccinated pregnant women (CDPH, n.a). In 2011, the Advisory Committee on Immunization Practices (ACIP) followed with similar recommendations for pregnant women across the United States. In 2012, ACIP further revised recommendations that Tdap be administered to all pregnant women during every pregnancy, even if previously vaccinated (Anon., 2013). To date there is limited data on receipt of Tdap during pregnancy. The aim of this report was to describe Tdap coverage for pregnancies occurring from 2007 to 2102 at seven geographically diverse integrated health care systems within the Vaccine Safety Datalink (VSD).
E.O. Kharbanda et al. / Preventive Medicine 67 (2014) 316–319
Materials and methods The VSD is a collaborative effort between the Center for Disease Control and Prevention's Immunization Safety Office and 9 large medical care organizations in the U.S. and includes data on approximately 2.5 million women of reproductive age (Baggs et al., 2011). For this report, data on Tdap coverage was available from seven VSD sites: Group Health Cooperative (WA), Kaiser Permanente Northwest (OR) and (WA), Kaiser Permanente Northern California (CA), Southern California Kaiser Permanente (CA), HealthPartners (MN), Marshfield Clinic (WI), and Kaiser Permanente Colorado (CO). Pregnancies ending between 1/1/2007 and 11/15/2012 were identified using a validated algorithm (Naleway et al., 2013). The algorithm utilizes claims, administrative, and birth data to a) identify pregnancies, b) determine pregnancy outcomes and c) estimate gestational age at pregnancy outcome (Naleway et al., 2013). This algorithm has been used in prior studies of vaccine safety (Kharbanda et al., 2013; Nordin et al., 2013) and vaccine coverage during pregnancy (Naleway et al., 2014). To be included in this report, pregnant women 14–49 years of age were required to have continuous insurance coverage from 6 months prior to pregnancy through 6 weeks after pregnancy end with no more than a 30-day gap. Women with ectopic pregnancies, gestational trophoblastic disease, and pregnancies whose outcome could not be determined with available data were excluded. Women with live births and no medical visits recorded throughout pregnancy were also excluded. Identification of Tdap administrations Receipt of Tdap from 1/1/2005 to 12/31/2012 was identified from electronic medical record and claims data. All Tdap doses were then classified as: Pre-pregnancy (1/1/2005 through 7 days after the last menstrual period (LMP); During pregnancy (8 days after LMP through 7 days before pregnancy end); and Post-pregnancy/Postpartum (6 days before pregnancy end through 42 days after pregnancy end). Categories were assigned to avoid prepregnancy and postpartum vaccines being misclassified as occurring during pregnancy (Kharbanda et al., 2012). Analysis For pregnancies in the cohort, we report the proportion receiving Tdap pre-pregnancy, during pregnancy, and post-pregnancy/postpartum. We then
317
describe Tdap coverage by pregnancy outcome, year, age, and socioeconomic status. Among pregnancies ending in a live birth, we evaluated Tdap coverage by year, age, socio-demographic factors, health care utilization and pregnancy risk, stratified by California versus other VSD sites. All data were analyzed using SAS/STAT software, Version 9.3 (SAS Institute Inc). This study was approved by the Institutional Review Boards at all participating sites and the Centers for Disease Control and Prevention.
Results Of 535,851 pregnancies at seven VSD sites over six years with continuous insurance enrollment, we excluded 15,157 (2.8%) based on pregnancy outcome and 2994 (0.6%) for having no medical claims throughout pregnancy. The final study cohort included 517,700 pregnancies with end dates between 1/1/07 and 11/15/2012. Pregnancy outcomes were: live birth (71.7%), spontaneous abortion (14.8%), therapeutic abortion (13.0%) and stillbirth (0.4%). Across all pregnancies, 25.3% received Tdap before pregnancy, 7.1% during pregnancy and 10.8% within six weeks of pregnancy end. Receipt of Tdap during pregnancy increased steadily in 2010 and 2011 but then decreased in 2012 (Table 1). Of 289,141 pregnancies from the CA VSD sites with a live birth, receipt of Tdap during pregnancy increased markedly from 0.3% in 2007 to 30.4% in 2011 but decreased to 19.5% in 2012. Pre-pregnancy receipt of Tdap increased steadily each year, by 2011 35.3% and by 2012 53.8% of women with live births in CA had received Tdap prior to pregnancy. In 2011, 15.9% of pregnancies did not receive Tdap in any period (pre-pregnancy, during pregnancy or postpartum); this decreased to 14.6% in 2012. Among those vaccinated during pregnancy, receipt of Tdap at ≥20 week gestation increased from 12.3% in 2007 to 69.4% in 2012. Of 82,398 pregnancies occurring in the WA, OR, MN, WI and CO VSD sites and ending in a live birth, receipt of Tdap during pregnancy increased from 0.8% of pregnancies in 2007 to 16.1% in 2012. Pre-pregnancy and postpartum Tdap administration also increased substantially over time. The proportion who did not receive Tdap in any period decreased consistently from 87.3% in 2007 to 17.4% in
Table 1 Receipt of Tdap among all pregnancies in cohorte.
Pregnancy outcome Live birth SAB, SB or TABa Year 2007 2008 2009 2010 2011 2012 Site California VSD sites Other VSD sitesb Maternal age b18 18–24 25–34 ≥35 Socioeconomic statusc Medium/high Low Missing total, all pregnancies a b c d e
Postpartumd (%)
Did not receive Tdap (%)
9.5 1.2
14.4 1.6
53.8 67.2
3.2 8.6 16.8 26.5 40.1 56.1
0.5 0.7 1.0 9.2 17.1 13.7
2.3 6.4 13.4 18.9 14.2 8.8
94.0 84.5 69.3 47.0 30.1 22.6
407,239 110,461
23.6 31.5
8.3 3.0
10.7 11.2
58.2 55.2
12,488 90,069 286,516 128,627
46.6 28.4 23.7 24.8
4.3 6.0 7.8 6.8
5.7 8.5 11.8 10.6
45.7 58.3 57.5 58.4
314,364 142,354 60,982 517,700
26.2 23.2 25.8 25.3
7.4 9.3 1.1 7.1
13.0 9.9 1.5 10.8
54.3 58.7 71.7 57.6
N
Pre-pregnancy (%)
371,539 146,161
23.5 30.0
84,278 84,827 84,581 89,888 91,445 82,681
Pregnancy (%)
SAB = Spontaneous abortion, SB = Stillbirth, TAB = Therapeutic abortion. Other VSD sites located in: Colorado, Minnesota, Oregon, Washington and Wisconsin. Low socioeconomic status defined as living in data census tract having 20% or more of the population living at less than 150% of the federal poverty level. Within 42 days of end of pregnancy/postpartum for live births. Row percents may add to N100 as women may have received Tdap in more than one period (e.g., pre-pregnancy and postpartum).
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Table 2 Receipt of Tdap during pregnancy, live births in California Vaccine Safety Datalink (VSD) sites and other VSD sitesa. Received Tdap during pregnancy Other VSD sitesa
California VSD sites
Year 2007 2008 2009 2010 2011 2012 Maternal age b18 years 18–24 25–34 ≥35 years Socioeconomic statusb Medium/high Low Missing Prenatal care index Adequate/plus Intermediate Inadequate Missing Care in 1st trimester Yes No Missing Delivery b37 weeks Yes No Pregnancy risk Comorbiditiesc No comorbidities Complicationsd No complications Other vaccine in pregnancye Yes No Total
Number of pregnancies
N (%) vaccinated
Number of pregnancies
N (%) vaccinated
48,398 48,828 48,434 48,321 49,227 45,933
155 (0.3) 214 (0.4) 410 (0.8) 7672 (15.9) 14,765 (30.0) 8946 (19.5)
13,488 14,161 13,965 14,089 14,229 12,466
108 (0.8) 171 (1.2) 192 (1.4) 219 (1.6) 318 (2.2) 2000 (16.0)
5647 43,903 171,095 68,496
419 (7.4) 4546 (10.4) 19,615 (11.5) 7582 (11.1)
1238 11,980 51,381 17,799
29 (2.3) 473 (3.9) 1849 (3.6) 657 (3.7)
186,821 102,283 37
19,926 (10.7) 12,232 (12.0) –
69,406 12,962 30
2472 (3.6) 536 (4.1) –
223,015 56,227 9780 119
26,770 (12.0) 4635 (8.2) 749 (7.7) –
42,485 23,862 16,003 48
1598 (3.8) 952 (4.0) 458 (2.9) –
273,121 15,316 704
30,802 (11.3) 1339 (8.7) 21 (3.0)
68,883 6999 6516
2605 (3.8) 185 (2.6) 218 (3.3)
23,196 265,945
1981 (8.5) 30,181 (11.3)
5991 76,407
165 (2.8) 2843 (3.7)
51,672 237,469 84,581 204,560
5440 (10.5) 26,722 (11.3) 9771 (11.6) 22,391 (10.9)
13,012 69,386 23,094 59,304
488 (3.8) 2520 (3.6) 842 (3.6) 2166 (3.7)
113,516 175,625 289,141
20,543 (18.1) 11,619 (6.6) 32,162 (11.1)
38,442 43,956 82,398
1778 (4.6) 1230 (2.8) 3008 (3.7)
a
Other VSD sites located in: Colorado, Minnesota, Oregon, Washington and Wisconsin. Low socioeconomic status defined as living in a census tract having 20% or more of the population living at less than 150% of the federal poverty level. c Comorbidities included pulmonary disease, hypertension or other heart disease, diabetes, renal or neurologic conditions diagnosed from 6 months prior to last menstrual period through end of pregnancy. d Pregnancy complications included gestational diabetes, gestational hypertension and hemorrhage in early pregnancy. e Other vaccines included: inactivated influenza vaccines (95.9%), hepatitis A/hepatitis B (1.4%), human papillomavirus vaccine (1.1%), and other (1.6%). b
2012. Among those vaccinated during pregnancy, receipt of Tdap at ≥20 week gestation increased from 16.7% in 2007 to 91.7% in 2012. Tdap coverage among live births, by sociodemographc, healthcare utilization and pregnancy risk is shown in Table 2.
Discussion Administering Tdap during the third trimester of pregnancy is likely to be the most effective strategy for preventing severe pertussis infections in newborns (Anon., 2013; Peters et al., 2012; Terranella et al., 2013) and thus the CDPH and ACIP recommendation has been broadly endorsed (A.C.O.G. Committee Opinion No. 566, 2013). In this study, we observed a marked response to recommendations to administer Tdap during pregnancy to women not previously vaccinated across seven geographically diverse integrated health delivery systems. At the CA VSD sites, increases in Tdap coverage during pregnancy began in 2010, following the CDPH recommendations; at the other VSD sites, increases were first observed in 2012, following the 2011 ACIP recommendations. The decline in Tdap coverage during pregnancy in CA in 2012 was likely because more than half of women that year had received Tdap prior to pregnancy. Thus, based on recommendations at the time, these women were not eligible to receive another Tdap dose.
We observed larger increases in receipt of Tdap among women receiving adequate prenatal care, those with medical care in their first trimester, and among full term births. These associations likely represent pregnancies with more contact with prenatal providers and thus increased opportunities to vaccinate. Tdap is now the second vaccine, following influenza, specifically recommended for routine use during pregnancy. For influenza, providers and women were initially hesitant regarding vaccination during pregnancy (Ahluwalia et al., 2010). However, since the H1N1 influenza pandemic, where pregnant women were disproportionately affected, vaccine uptake has increased remarkably (Henninger et al., 2013). Similarly, the marked increase in Tdap administration during pregnancy at the CA sites in 2010 may have reflected fears related to the ongoing pertussis outbreak (Winter et al., 2012). Several limitations to this report should be noted. First, the data presented are novel but do not reflect the current ACIP recommendations. Second, our sample is limited to women with continuous insurance enrollment receiving care within large integrated health care systems. Women who were uninsured prior to becoming pregnant and those with fragmented care may be less likely to receive Tdap. In addition, Tdap administration outside the healthcare system or administration of Tdap that did not generate a medical claim may have been missed. Furthermore, for women who did not receive Tdap
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during pregnancy, details regarding whether the vaccine was offered during routine prenatal care were not available. Previously, our team reported on vaccines administered to pregnant women within the VSD from 2007 through 2009 (Naleway et al., 2014). The current report expands on this work by including pregnancies from 2010 through 2012, highlighting the response to the 2010 CDPH and 2011 ACIP recommendations. Conflicts of interest Dr. Nicola Klein receives research support from GlaxoSmithKline, Sanofi Pasteur, Novartis, Pfizer and Merck. Dr. Allison Naleway receives research support from GlaxoSmithKline. Dr. Cheetham receives research support from Merck. The remaining co-authors have no financial conflicts of interest to report.
Acknowledgments Findings of this study represent those of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention. This study was funded by the Centers for Disease Control and Prevention, Contract 200-2012-53526. Dr. Claudia Vellozzi is employed by the funder and a collaborator on this research. Dr. Vellozzi assisted with study design, interpretation of findings and the decision to submit this article for publication. This paper did undergo the CDC clearance process. References A.C.O.G. Committee Opinion No. 566, 2013. Update on immunization and pregnancy: tetanus, diphtheria, and pertussis vaccination. Obstet. Gynecol. 121 (6), 1411–1414 (Jun). Ahluwalia, I.B., Jamieson, D.J., Rasmussen, S.A., D'Angelo, D., Goodman, D., Kim, H., 2010. Correlates of seasonal influenza vaccine coverage among pregnant women in Georgia and Rhode Island. Obstet. Gynecol. 116 (4), 949–955 (Oct). Anon., 2006. Prevention of pertussis among adolescents: recommendations for use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Pediatrics 117 (3), 965–978 (Mar). Anon., 2011. Updated recommendations for use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine (Tdap) in pregnant women and persons who have or anticipate having close contact with an infant aged b12 months—Advisory Committee on Immunization Practices (ACIP), 2011. MMWR Morb. Mortal. Wkly Rep. 60 (41), 1424–1426 (Oct 21).
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