More Evidence Favoring Flu Vaccines in Pregnancy

Pregnant and considering whether or not to get a flu vaccine?  Three new studies—as well as a growing body of research related to the effects of flu on the developing fetus—suggest that vaccination is the best option.  In the studies, vaccinated women who were pregnant during flu season were much less likely to have premature or underweight babies and their babies were less likely to suffer flu after they were born.

One study, conducted by researchers at Emory University in Atlanta, looked at over 6,000 births in Georgia between 2004 and 2006. It found that when the highest rates of flu were reported in the region, women who were vaccinated were 72% less likely to have a premature baby than those who did not receive the vaccine.

If there were lower levels of flu reported locally, the vaccinated women were 56% less likely to have a premature birth.  Babies of unvaccinated women were also 69% more likely to have an underweight child--whether or not the baby was actually premature-- during periods of widespread flu infection.  These effects were only seen during flu season, making it highly unlikely that they were related to anything other than the influence of influenza.

A second study conducted by Yale researchers in New Haven found that babies whose mothers were not vaccinated were more than four times more likely to be hospitalized for flu, compared than those who did receive the vaccine.  The study included 297 babies admitted to the hospital and compared those with the flu to those admitted with other conditions.  17% of the babies with the flu had unvaccinated mothers, compared to 4% of those whose mothers had received the shot.

A third study—conducted in Bangladesh—confirmed both findings.  It found that babies born to vaccinated mothers had both a higher birth weight and their chances of coming down with flu were reduced by 63%. All three studies were presented at the annual meeting of the Infectious Disease Society of America, held this week in Philadelphia.

Because prematurity and being underweight for a baby's gestational age are linked with increased risk for numerous physical and mental problems throughout life, such large effects could have a big impact on public health.

Earlier research has also suggested a connection between schizophrenia and maternal flu infection:  one study conducted by researchers at Columbia University found that children whose mothers had the flu in the first trimester of pregnancy were seven times more likely to develop schizophrenia as adults.

None of these studies looked at vaccination for H1N1 (“swine”) flu—but that flu is already known to have put 100 American pregnant women into intensive care and killed 28 of them.  The New York Times recently told the horrifying story of a 27-year-old woman, who lost her baby, was hospitalized for four months and spent five weeks in a coma, nearly dying.

Unfortunately, only in four pregnant women currently get flu vaccines in the U.S. and there are widespread fears about side effects that are much less common than the potentially devastating effects of flu on pregnancy outcomes.