Blood tests were carried out in order to measure the antibody counts protecting against the influenza virus:
On delivery, a blood sample is taken from the umbilical cord in order to measure the quantity of influenza antibodies transmitted to the newly born. All events observed in mothers and babies during the study were recorded.
Prior to vaccination, 19% of the patients already presented H1N1 strain antibodies at levels considered to be protective. Three and six weeks after vaccination, 98% of the patients presented blood antibody counts considered to be protective. On delivery and 3 weeks after delivery, the proportion of patients with antibody counts considered to be protective were between 92% and 90%. The umbilical cord samples of newly born babies showed antibody counts considered to be protective in 95% of cases, some antibody concentrations were even higher than in the mothers (a ratio of 1.4 between neonatal babies concentrations and maternal concentrations at delivery).
"These results show that the influenza vaccine boosts the immune system in pregnant women and also protects newly-borns via transplacenta transfer ", concludes Odile Launay.
This study and an increasing number of other studies on pregnant women have confirmed the non-toxicity of the influenza vaccine during pregnancy. This year again, pregnant women are strongly recommended to take the influenza vaccine. The composition of the vaccine is modified each year to cover the major strains of the previous winter, which are the strains most likely to be present the next winter. "The H1N1 2009 virus is still around. That's why the inactivated H1N1 virus is stil
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INSERM (Institut national de la sant et de la recherche mdicale)