tetano
Editor, Senior Moderator
Vaccine
. 2021 Sep 28;S0264-410X(21)01171-3.
doi: 10.1016/j.vaccine.2021.09.003. Online ahead of print.
History of pandemic H1N1-containing influenza vaccination and risk for spontaneous abortion and birth defects
Celeste J Romano[SUP] 1 [/SUP], Clinton Hall[SUP] 2 [/SUP], Zeina G Khodr[SUP] 2 [/SUP], Anna T Bukowinski[SUP] 2 [/SUP], Gia R Gumbs[SUP] 2 [/SUP], Ava Marie S Conlin[SUP] 3 [/SUP]
Affiliations
Abstract
Background: One recent study suggested an association between receipt of pandemic H1N1 (pH1N1)-containing vaccines in consecutive influenza seasons and spontaneous abortion, but corroborating scientific evidence is limited. In the present study, we leveraged a population of vaccine-compliant pregnant military women to examine history of pH1N1-containing influenza vaccination and adverse pregnancy outcomes. Because seasonal influenza vaccination is compulsory for military service, safety concerns regarding repeat vaccination are particularly relevant in this population.
Methods: Pregnancies and live births from Department of Defense Birth and Infant Health Research program data were linked with military personnel immunization records to identify women vaccinated with a pH1N1-containing vaccine in pregnancy prior to 21 6/7 weeks' gestation, October 2009-April 2015. Cox and modified Poisson regression models estimated associations between vaccination with pH1N1- versus non-pH1N1-containing influenza vaccine in the season prior to the index pregnancy, and spontaneous abortion and birth defects, respectively. Cox models were calculated for two periods of follow-up: through (1) 21 6/7 weeks' gestation and (2) 28 days postvaccination.
Results: Of 26,264 pregnancies, 21,736 (82.8%) were among women who received a dose of pH1N1-containing vaccine in the prior influenza season and 4,528 (17.2%) were among women who received non-pH1N1-containing vaccine in the prior influenza season. Among 23,121 infants, 19,365 (83.8%) and 3,756 (16.2%) had mothers exposed and unexposed to pH1N1-containing vaccine in the prior influenza season, respectively. The adjusted hazard ratio (aHR) for spontaneous abortion approximated 1.0 across the complete follow-up period (95% confidence interval [CI]: 0.89-1.13) and was slightly elevated when censored at 28 days postvaccination, though the CI was imprecise (aHR: 1.19; 95% CI: 0.97-1.46). No associations with birth defects were observed.
Conclusion: This work lends additional safety evidence and support for vaccination against pH1N1 in pregnancy, regardless of the vaccine received in the prior influenza season.
Keywords: Birth defects; Influenza vaccine; Military personnel; Pregnancy; Spontaneous abortion.
. 2021 Sep 28;S0264-410X(21)01171-3.
doi: 10.1016/j.vaccine.2021.09.003. Online ahead of print.
History of pandemic H1N1-containing influenza vaccination and risk for spontaneous abortion and birth defects
Celeste J Romano[SUP] 1 [/SUP], Clinton Hall[SUP] 2 [/SUP], Zeina G Khodr[SUP] 2 [/SUP], Anna T Bukowinski[SUP] 2 [/SUP], Gia R Gumbs[SUP] 2 [/SUP], Ava Marie S Conlin[SUP] 3 [/SUP]
Affiliations
- PMID: 34598819
- DOI: 10.1016/j.vaccine.2021.09.003
Abstract
Background: One recent study suggested an association between receipt of pandemic H1N1 (pH1N1)-containing vaccines in consecutive influenza seasons and spontaneous abortion, but corroborating scientific evidence is limited. In the present study, we leveraged a population of vaccine-compliant pregnant military women to examine history of pH1N1-containing influenza vaccination and adverse pregnancy outcomes. Because seasonal influenza vaccination is compulsory for military service, safety concerns regarding repeat vaccination are particularly relevant in this population.
Methods: Pregnancies and live births from Department of Defense Birth and Infant Health Research program data were linked with military personnel immunization records to identify women vaccinated with a pH1N1-containing vaccine in pregnancy prior to 21 6/7 weeks' gestation, October 2009-April 2015. Cox and modified Poisson regression models estimated associations between vaccination with pH1N1- versus non-pH1N1-containing influenza vaccine in the season prior to the index pregnancy, and spontaneous abortion and birth defects, respectively. Cox models were calculated for two periods of follow-up: through (1) 21 6/7 weeks' gestation and (2) 28 days postvaccination.
Results: Of 26,264 pregnancies, 21,736 (82.8%) were among women who received a dose of pH1N1-containing vaccine in the prior influenza season and 4,528 (17.2%) were among women who received non-pH1N1-containing vaccine in the prior influenza season. Among 23,121 infants, 19,365 (83.8%) and 3,756 (16.2%) had mothers exposed and unexposed to pH1N1-containing vaccine in the prior influenza season, respectively. The adjusted hazard ratio (aHR) for spontaneous abortion approximated 1.0 across the complete follow-up period (95% confidence interval [CI]: 0.89-1.13) and was slightly elevated when censored at 28 days postvaccination, though the CI was imprecise (aHR: 1.19; 95% CI: 0.97-1.46). No associations with birth defects were observed.
Conclusion: This work lends additional safety evidence and support for vaccination against pH1N1 in pregnancy, regardless of the vaccine received in the prior influenza season.
Keywords: Birth defects; Influenza vaccine; Military personnel; Pregnancy; Spontaneous abortion.