CDC Study Shows Up to 7.7 Times the Risk of Miscarriage After Influenza Vaccine

The CDC has just published a seismic study (Donahue et al. 2017 Vaccine 35:5314) linking spontaneous abortions in women to flu vaccines.  The study reviewed data for the 2010-11 and 2011-12 flu seasons.   Women vaccinated with the inactivated influenza vaccine (IIV) in the 2010-2011 season were 3.7 times more likely to experience a spontaneous abortion within 28 days than women not receiving the vaccine.  Over the entire study period (2010 to 2012), the odds for a spontaneous abortion for vaccinated women were 2.0 times greater than for those women not receiving the flu vaccine.  Both figures showed a statistically significant increase in miscarriages when women received their flu shot.  Most alarmingly, in women who received the H1N1 vaccine in the previous flu season, the odds of spontaneous abortion in the 28 days after receiving a flu vaccine was 7.7 times greater.