H1N1 influenza virus vaccination programs for pregnant women may have been controversial – but recent results are very reassuring.
The recent H1N1 Influenza pandemic across many parts of the World raised a great deal of concern particularly amongst
the pregnant population. Pregnant women form one of the most at risk groups in H1N1 influenza, showing increased
morbidity and mortality. Vaccination programs were put in place to provide H1N1 Influenza Virus vaccination to protect pregnant women during their antenatal care.
National campaigns to vaccinate at risk groups were met with major concerns because of uncertainty of the side
effects of the vaccine on the pregnant mother and unborn baby.
A lot of women did not heed the call to get vaccinated. Since the pandemic in 2009 a lot of efforts have gone into
gathering data about safety and outcomes following H1N1 vaccination during pregnancy.
Several studies have been published proving the efficacy and safety of the vaccines.
These studies have shown that among thousands of women, there was no increased risk to the mother or baby.
There were other unexpected advantages of H1N1 vaccination during pregnancy.
Read more here:
Objective To describe a large study on pregnancy outcome after vaccination against H1N1 during the 2009/10 pandemic.
Setting The Swedish Medical Birth Register was used for the analysis. Information on vaccination and pregnancy week
when vaccination was made was obtained from antenatal care documents.
Population All women who gave birth during 2009 and 2010 in Sweden.
Outcome measures Stillbirth, congenital malformations, preterm birth, low birthweight, small for gestational age.
A total of 18 612 vaccinated women having 18 844 infants were studied. The risk for stillbirth, preterm
birth and low birthweight was lower than in the comparison groups whereas the risk for small for gestational age and
a congenital malformation (after vaccination during the first trimester) did not differ from the comparison groups.
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This Swedish study by Källén B, Olausson P. on the outcomes of H1n1 vaccination during pregnancy is the largest study
so far involving over 18,000 pregnant women who were vaccinated. The results confirmed earlier but smaller earlier
studies from Canada and elsewhere.
The study demonstrated benefits of vaccination other than protection against the H1n1 influenza virus. Women who were vaccinated had better pregnancy outcomes than those who did not get vaccinated. The was no clear explanation of the basis for the beneficial effect of the vaccine.
An intriguing question must arise as to whether unexplained fetal deaths in pregnancy are due to sub-clinical viral infections that may be less likely after H1n1 vaccination!
Those women who were vaccinated had bigger babies compared to non vaccinated women.
This study will go a long way to reassuring pregnant women who have been hesitant about vaccination against the influenza virus. The study also provides ammunition for health care providers as they go out to counsel women in their care about the importance of H1N1 vaccination during pregnancy.
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