Dataset Information

Evaluating the hazard of foetal death following H1N1 influenza vaccination; a population based cohort study in the UK GPRD.

ABSTRACT:

Background

To evaluate the risk of foetal loss associated with pandemic influenza vaccination in pregnancy. Retrospective cohort study. UK General Practice Research Database Pregnancies ending in delivery or spontaneous foetal death after 21 October 2009 and starting before 01 January 2010.

Methodology/principal findings

Hazard ratios of foetal death for vaccinated compared to unvaccinated pregnancies were estimated for gestational weeks 9 to 12, 13 to 24 and 25 to 43 using discrete-time survival analysis. Separate models were specified to evaluate whether the potential effect of vaccination on foetal loss might be transient (for ~4 weeks post vaccination only) or more permanent (for the duration of the pregnancy). 39,863 pregnancies meeting our inclusion criteria contributed a total of 969,322 gestational weeks during the study period. 9,445 of the women were vaccinated before or during pregnancy. When the potential effect of vaccination was assumed to be transient, the hazard of foetal death during gestational weeks 9 through 12 (HR(unadj) 0.56; CI(95) 0.43 to 0.73) and 13 through 24 (HR(unadj) 0.45; CI(95) 0.28 to 0.73) was lower in the 4 weeks after vaccination than in other weeks. Where the more permanent exposure definition was specified, vaccinated pregnancies also had a lower hazard of foetal loss than unvaccinated pregnancies in gestational weeks 9 through 12 (HR(unadj) 0.74; CI(95) 0.62 to 0.88) and 13 through 24 (HR(unadj) 0.59; CI(95) 0.45 to 0.77). There was no difference in the hazard of foetal loss during weeks 25 to 43 in either model. Sensitivity analyses suggest the strong protective associations observed may be due in part to unmeasured confounding.

Conclusions/significance

Influenza vaccination during pregnancy does not appear to increase the risk of foetal death. This study therefore supports the continued recommendation of influenza vaccination of pregnant women.

SUBMITTER: Sammon CJ

PROVIDER: S-EPMC3541601 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Evaluating the hazard of foetal death following H1N1 influenza vaccination; a population based cohort study in the UK GPRD.

Sammon Cormac J CJ Snowball Julia J McGrogan Anita A de Vries Corinne S CS

PloS one 20121210 12

<h4>Background</h4>To evaluate the risk of foetal loss associated with pandemic influenza vaccination in pregnancy. Retrospective cohort study. UK General Practice Research Database Pregnancies ending in delivery or spontaneous foetal death after 21 October 2009 and starting before 01 January 2010.<h4>Methodology/principal findings</h4>Hazard ratios of foetal death for vaccinated compared to unvaccinated pregnancies were estimated for gestational weeks 9 to 12, 13 to 24 and 25 to 43 using discre ...[more]

PMID: 23341865

Similar Datasets

Project description:BackgroundNon-neutralizing antibodies inducing complement-dependent lysis (CDL) and antibody-dependent cell-mediated cytotoxicity (ADCC) activity may contribute to protection against influenza infection. We investigated CDL and ADCC responses in healthy adults randomized to receive either non-adjuvanted or AS03-adjuvanted monovalent A(H1N1)pdm09 vaccine (containing 15 µg/3.75 ?g of hemagglutinin, respectively) on a 2-dose schedule 21 days apart.MethodsWe conducted an exploratory analysis of a subset of 106 subjects having no prior history of A(H1N1)pdm09 infection or seasonal influenza vaccination enrolled in a previously reported study (NCT00985673). Antibody responses against the homologous A/California/7/2009 (H1N1) vaccine strain and a related A/Brisbane/59/2007 (H1N1) seasonal influenza strain were analyzed up to Day 42.ResultsBaseline seropositivity determined with hemagglutination inhibition (HI), CDL and ADCC antibody titers against viral strains was high; A/California/7/2009 (HI [40.4-48.1%]; CDL [34.6-36.0%]; ADCC [92.1-92.3%]); A/Brisbane/59/2007 (HI [73.1-88.9%]; CDL [38.0-42.0%]; ADCC [86.8-97.0%]). CDL seropositivity increased following vaccination with both adjuvanted and non-adjuvanted formulations (A/California/7/2009 [95.9-100%]; A/Brisbane/59/2007 [75.5-79.6%]). At Day 21, increases in CDL and ADCC antibody geometric mean titers against both strains were observed for both formulations. After 2 doses of AS03-adjuvanted vaccine, vaccine responses of 95.8% (?9-fold increase from baseline in CDL titers) and 34.3% (?16-fold increase from baseline in ADCC titers) were seen against A/California/7/2009; and 22.4% and 42.9%, respectively, against A/Brisbane/59/2007. Vaccine responses after 2 doses of the non-adjuvanted vaccine were broadly similar.ConclusionsBroadly comparable non-neutralizing immune responses were observed following vaccination with non-adjuvanted and AS03-adjuvanted A(H1N1)pdm09 formulations; including activity against a related vaccine strain.

Dataset Information

Evaluating the hazard of foetal death following H1N1 influenza vaccination; a population based cohort study in the UK GPRD.

Background

Methodology/principal findings

Conclusions/significance

Publications

Evaluating the hazard of foetal death following H1N1 influenza vaccination; a population based cohort study in the UK GPRD.

Similar Datasets

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