June 8 (UPI) -- Pregnant women who are vaccinated against the flu do not increase their baby's risk for certain health problems, including asthma, infections, or hearing or vision loss, a study published Tuesday by JAMA found.
Rates of asthma, sensory impairment and neoplasms, or cancer-like growths, were similar among children born to women who received the flu shot during pregnancy and those whose mothers were unvaccinated, the data showed.
This remained the case from infancy through roughly age 4 years, the researchers said.
"We now have many studies from different countries ... showing that influenza vaccination during pregnancy does not increase the chances of having pregnancy complications or adverse birth outcomes," study co-author Deshayne B. Fell told UPI in an email.
"This study adds to what we know about longer-term safety of influenza vaccination during pregnancy, and can reassure pregnant individuals, as well as their care providers," said Fell, an associate professor of epidemiology and public health at the University of Ottawa in Canada.
Although vaccination against the flu is recommended for pregnant women, many choose not to get the shot because they fear potential side effects for themselves and health complications for their babies, research suggests.
This is despite multiple studies that have found the vaccine, which is developed each flu season based on virus strains expected to be in circulation, to be safe for women and their babies, Fell said.
As a result of these concerns, however, nearly 40% of pregnant women in the United States decided against vaccination during the 2019-20 flu season, according to the Centers for Disease Control and Prevention.
For this study, Fell and her colleagues analyzed health data for more than 28,000 children born in the Canadian province of Nova Scotia between October 2010 and March 2014.
Just over 90% of the children included in the study were delivered at full term, and more than 10,000, or 36%, were born to mothers who had received the flu shot while pregnant, the researchers said.
Among the more than 10,000 children of mothers vaccinated while pregnant, nearly 7,000 suffered from infections, 113 were diagnosed with asthma, 30 experienced sensory impairment and 12 developed neoplasms from infancy through age 4 years.
Of the more than 18,000 children born to unvaccinated mothers, nearly 12,000 suffered from infections, 162 were diagnosed with asthma, 63 experienced sensory impairment and 17 developed neoplasms during early life, the researchers said.
The similar rates of these complications among babies born to vaccinated and unvaccinated mothers suggest that the annual shot is safe for mothers and their newborns, according to the researchers.
"Influenza vaccination during pregnancy has been shown to protect pregnant people from getting the flu [and it] also protects newborn infants from getting the flu in the first several months of life," Fell said.
"Since infants under 6 months of age can have serious complications if they get infected with flu, a major benefit of vaccinating pregnant people is the ability to protect newborn babies from getting the flu after they are born," she said.