No risk of autism associated with H1N1 influenza vaccine

According to a census in Sweden, children born to women who received the H1N1 flu vaccine during pregnancy during 2009-2010 were not likely to develop autism.

Baby exposed to “Swine flu” Pregnant vaccines did not increase the risk of developing autism spectrum disorders (ASD) or autism disorders (AD) compared to those born to unvaccinated women, Stockholm said. Reported by Jonas F. Ludvigsson, MD, Karolinska Institute.

Analysis of first semester exposure-the period during which the vaccine could potentially have the greatest impact on fetal neurodevelopment-there was no association between vaccination and risk of autism, the researchers write ing Internal medicine annual report..

“Both of our main analyzes… and some additional analyzes all show that H1N1 influenza vaccination during pregnancy is not linked to autism in offspring,” Ludvigsson said. Was MedPage today on mail.

To Accompanying editorial, Statens Serum Institut and Anders Hviid, MSc, DrMedSci of the University of Copenhagen, Denmark, say the study is “a rare and welcome contribution to a much more comprehensive perinatal safety assessment”. It was.

Despite the weak biological relevance that influenza vaccines may have in the development of fetal development, Hviid has set out in a further observational study examining the effects of vaccination not only during pregnancy and immediately after childbirth, but also until late childhood Emphasized the need. This is important for determining safety, but also for denying skepticism about vaccines that could derail vaccination programs.

“A comprehensive and proactive approach to vaccine safety is more needed than ever before with the advent of the COVID-19 vaccine,” Hviid wrote.

A suggested link between the MMR vaccine and the risk of autism is: Withdraw Wakefield and others. InvestigationSeveral studies have overturned the proposition that vaccination increases the risk of autism. Still, some investigating influenza and H1N1 vaccines during pregnancy were unable to completely dismiss the hypothesis, Ludvigsson said.

Ludvigsson et al. use Swedish national registration data to conduct a population-based cohort study to investigate the risk of autism in children of mothers who were swine flu vaccinated between 2009 and 2010 during pregnancy. Did.

The Ludvigsson group collected data on Swedish singleton births, where many of the population were vaccinated in a pandemic vaccination campaign against swine flu. They linked vaccination data to national patient registries, including participants from seven Swedish healthcare areas.

In their primary analysis, the researchers compared the risk of autism spectrum disorders in children exposed to the swine flu vaccine in utero to unexposed children. The secondary outcome was autism. The researchers also compared the risks associated with vaccination in early pregnancy with other gestational ages and conducted a sensitivity analysis to examine maternal epilepsy and neurological and mental illness.

This group controls maternal age at birth, BMI, birth history, smoking, country of birth, disposable income, medical area, comorbidities, baby sex, and prenatal investigation time.

In a cohort of over 69,000 study participants, nearly 40,000 infants were prenatally exposed to the H1N1 vaccine. Mothers of infants exposed to the vaccine were older at birth, had higher disposable income, had higher BMI, smoked, or were less likely to have been born outside Sweden.

At an average of 7 years of follow-up, 1.0% (394) of prenatally exposed children with the H1N1 vaccine were diagnosed with autism spectrum disorder, compared with 1.1% (330) of unexposed children. I understand.

Children exposed to swine flu vaccination did not have an increased risk of ASD compared to unexposed children (adjusted hazard ratio 0.95, 95% CI 0.81-1.12). There were also no secondary outcomes or an increased risk of AD in children prenatally exposed to the vaccine (aHR 0.96, 95% CI 0.80-1.16). The sensitivity analysis did not change the risk estimate.

Ludvigsson et al. acknowledged that the lack of information on H1N1 infection in pregnant women could limit the analysis and could result in additional unmeasured confounding.

The researchers also said that understanding the safety of vaccines in the pregnant population was important, especially during the COVID-19 pandemic.

“All vaccination studies are important now, as we will have a better understanding of how the vaccine affects or does not affect fetal development,” Ludobigson said. “This is important in anticipation of the upcoming covid-19 vaccine when thousands, if not millions, of pregnant women are likely to be vaccinated against covid-19.”