Yellow fever vaccination during pregnancy and spontaneous abortion: a case-control study.
OBJECTIVE
To assess a possible association between Yellow fever (YF) vaccine (inadvertently) administered during early pregnancy and spontaneous abortion.


METHODS
A hospital-based case-control study conducted in a Brazilian town after a YF vaccine campaign that followed an epidemic of dengue. The study included 39 women who attended a university hospital with spontaneous abortion (cases) and 74 pregnant women attending the antenatal clinic of that hospital (controls).


RESULTS
The crude odds ratio (relative risk estimate) of this association was 2.49, which dropped to 2.29 (95% CI 0.65-8.03) when adjusted for several confounders by multiple logistic regression. Dengue and exposure to organophosphate insecticide fogging during pregnancy were not associated with spontaneous abortion.


CONCLUSIONS
This study, although small and with low power, provides some evidence that women vaccinated with YF vaccine during early pregnancy have an increased risk of having spontaneous abortion. Based on these findings a sensible recommendation should be to avoid YF vaccination of pregnant women unless their risk of acquiring YF outweighs the risk of vaccine-related abortion.
Nishioka
S de A
Sde A
Centro de Ciências Biomédicas, Universidade Federal de Uberlândia, Brazil. Snishioka@hc.ufu.br
Nunes-Araújo
F R
FR
Pires
W P
WP
Silva
F A
FA
Costa
H L
HL
D000022:Abortion, Spontaneous / Q000453:epidemiology / Q000209:etiology*; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D016015:Logistic Models; D016017:Odds Ratio; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012307:Risk Factors; D014765:Viral Vaccines / Q000009:adverse effects*; D015005:Yellow fever virus / Q000276:immunology*
D014765:Viral Vaccines