BACKGROUND AND PURPOSE:

Previous studies have examined potential adverse effects of the pandemic A(H1N1) vaccine on pregnancy and birth outcomes.

• No link has been found between the A(H1N1) vaccine and major pregnancy and birth adverse outcomes during pregnancy or in the perinatal period
• Guidelines recommend that all pregnant women should be offered the flu vaccine
• Limited data on potential effects beyond the perinatal period
• This study by Hviid et al. (JAMA Pediatrics, 2017) sought to determine if vaccination with A(H1N1) flu vaccine during pregnancy increased the risk for early childhood morbidity in offspring

METHODS:

• Register-Based Cohort Study
• Live-born singleton children born in Denmark between November 2, 2009-March 31, 2010 were included in the survey
• The vaccine was the monovalent inactivated AS03-adjuvanted split virion influenza A(H1N1)pdm09 vaccine (Pandemrix; GlaxoSmithKline Biologicals)

RESULTS:

• 61,359 children included with a mean follow up of 4.6 years
  • 55,048 – unvaccinated mothers
  • 349 – mothers vaccinated during the first trimester
  • 5,962 – mothers vaccinated during the second and third trimesters
• Children exposed to the vaccine in the first trimester did not have higher rates of hospitalization during early childhood than their unexposed
• Children exposed to the vaccine in the second and third trimesters did not have higher rates of hospitalization in early childhood than their unexposed counterparts
  • Rather, there was a 7% decrease in risk due to reduced risk for infectious disease-related hospitalization

CONCLUSION:

• This large, comprehensive study found no risk of increased early childhood morbidity following of exposure to the A(H1N1) flu vaccine during pregnancy
• The data support guidelines that routine influenza vaccination is recommended for all women who are or will become pregnant (in any trimester) during influenza season

Learn More – Primary Sources:

Association Between Pandemic Influenza A(H1N1) Vaccination in Pregnancy and Early Childhood Morbidity in Offspring

 

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