Even though pregnant women and newborns are considered to be at especially high risk during influenza outbreaks, antivaxxer-fueled concerns about vaccination safety have kept the uptake too low, according to a recent study.
The report in the BMJ points out that many countries, including the United States, recommend that all pregnant women receive the annual flu vaccine because of that high risk. Yet even with substantial data demonstrating safety in newborn infants, concerns have been raised about longer term health effects in children.
“The lack of information on longer term health outcomes in children following influenza vaccination during pregnancy may be a potential barrier to achieving higher uptake and has been identified as an evidence gap for maternal immunization policy globally,” states the article.
To investigate that, University of Ottawa–led researchers looked at any association between exposure to the 2009 H1N1 “swine flu” vaccine during pregnancy and health problems in early childhood.
The retrospective cohort study used a population-based birth registry linked to health administrative databases in Ontario, Canada. Included were more than 100,000 live births from November 2009 through October 2010. The children were followed until 5 years of age to gauge rates of immune-related (infectious diseases, asthma), nonimmune-related (neoplasms, sensory disorders), and nonspecific morbidity outcomes (urgent or inpatient health services use, pediatric complex chronic conditions).
About 30% (31,295) of the children were exposed to the pH1N1 influenza vaccination in utero, but researchers detected no significant associations with upper or lower respiratory infections, otitis media, any infectious diseases, neoplasms, sensory disorders, urgent and inpatient health services use, pediatric complex chronic conditions, or mortality.
A weak association was observed between prenatal pH1N1 vaccination and increased risk of asthma (adjusted hazard ratio 1.05, 95% CI, 1.02-1.09) and decreased rates of gastrointestinal infections (adjusted incidence rate ratio 0.94, CI, 0.91-0.98), however.
“No associations were observed between exposure to pH1N1 influenza vaccine during pregnancy and most five-year pediatric health outcomes,” the study authors conclude. “Residual confounding may explain the small associations observed with increased asthma and reduced gastrointestinal infections. These outcomes should be assessed in future studies.
“Especially in this era of ‘anti-vaxx’ anxiety and misinformation, it is our duty to be clear: vaccination of pregnant women saves lives,” the researchers add.
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