Swine flu vaccine mostly safe
Wednesday July 11th, 2012
The swine flu vaccine is safe for women in the late stages of pregnancy - but questions remain about side-effects in the early stages, according to a major new study.
And other
research has found a small risk to adults from the flu vaccine.
Researchers said that in most cases the benefits from vaccine will far outweigh the risks.
Writing in the Journal of the American Medical Association, Danish researchers report an analysis of 53,000 babies born between 2009 and 2010. Nearly 7,000 were born to women who agreed to have the H1N1 swine flu vaccine while pregnant.
The researchers found that rates of premature birth did not seem affected by vaccination among women who received it in the last six months of pregnancy.
But there were small differences in rates of birth defects among children born to women vaccinated in the first three months <!trimester>. The researchers say these differences were not statistically significant.
Researcher Dr Björn Pasternak, of the Statens Serum Institut, Copenhagen, "Although the data provide robust evidence of safety with respect to outcomes associated with second- or third-trimester exposure, results from analyses of first-trimester exposure should be viewed as preliminary and need confirmation.
"Further research also needs to address risk of specific birth defects as well as effectiveness of H1N1 vaccination in pregnancy."
A second Canadian study links the vaccine to a slight increase in risk of developing Guillain-Barre syndrome, which causes motor weakness and slow reflexes.
The findings come from a study of more than four million people vaccinated in Quebec. Researchers said the vaccine was linked to an increase of two cases of the disease for every million people. It only affected people over the age of 50.
Researcher Dr Philippe De Wals, of Laval University, said: "In Quebec, the individual risk of hospitalization following a documented influenza A(H1N1) infection was one per 2,500 and the risk of death was 1 in 73,000. The H1N1 vaccine was very effective in preventing infections and complications.
"It is likely that the benefits of immunization outweigh the risks."
JAMA. 2012;308[2]:165-174, 184-185
Tags: Europe | Flu & Viruses | North America | Pharmaceuticals
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