Dr. Weeks’ Comment: Spontaneous abortion is now linked to a flu vaccine. Ask your doctor about this underreported “side effect” and until more research is done, be careful.
Association of spontaneous abortion with receipt of inactivated influenza vaccine containing H1N1pdm09 in 2010–11 and 2011–12
Inactivated influenza vaccine is recommended in any stage of pregnancy, but evidence of safety in early pregnancy is limited, including for vaccines containing A/H1N1pdm2009 (pH1N1) antigen. We sought to determine if receipt of vaccine containing pH1N1 was associated with spontaneous abortion (SAB).
We conducted a case-control study over two influenza seasons (2010–11, 2011–12) in the Vaccine Safety Datalink. Cases had SAB and controls had live births or stillbirths and were matched on site, date of last menstrual period, and age. Of 919 potential cases identified using diagnosis codes, 485 were eligible and confirmed by medical record review. Exposure was defined as vaccination with inactivated influenza vaccine before the SAB date; the primary exposure window was the 1–28 days before the SAB.
The overall adjusted odds ratio (aOR) was 2.0 (95% CI, 1.1–3.6) for vaccine receipt in the 28-day exposure window; there was no association in other exposure windows. In season-specific analyses, the aOR in the 1–28 days was 3.7 (95% CI 1.4–9.4) in 2010–11 and 1.4 (95% CI 0.6–3.3) in 2011–12. The association was modified by influenza vaccination in the prior season (post hoc analysis). Among women who received pH1N1-containing vaccine in the previous influenza season, the aOR in the 1–28 days was 7.7 (95% CI 2.2–27.3); the aOR was 1.3 (95% CI 0.7–2.7) among women not vaccinated in the previous season. This effect modification was observed in each season.
SAB was associated with influenza vaccination in the preceding 28 days. The association was significant only among women vaccinated in the previous influenza season with pH1N1-containing vaccine. This study does not and cannot establish a causal relationship between repeated influenza vaccination and SAB, but further research is warranted.
See also these links about the flu vaccine from
Influenza vaccines are Category B or C drugs, which means that adequate and well-controlled studies on pregnant women have not been conducted and it is not known whether these vaccines can cause fetal harm when administered to a pregnant woman or if they can affect reproduction capacity.
NVIC has the current links for the 2013/2014 influenza vaccine manufacturer’s package inserts that have been licensed for use in the U.S. As a consumer, it is important to understand and read this information carefully prior to receiving a vaccine. These links are directly from the U.S. Food & Drug Administration’s website, which makes available to the public package insert information from vaccine manufacturers. Inserts contain important information regarding drug interactions, contraindications, adverse reactions, warnings and precautions.
More information regarding this year’s influenza vaccines: http://www.nvic.org/Vaccines-and-Diseases/Influenza.aspx