The study, published in the British Medical Journal, suggests that having the vacunación contra la gripe during pregnancy does not have an impact on child health.

Pregnant mothers and their children are particularly vulnerable to serious illness during gripe and seasonal epidemics. Many countries encourage all pregnant women to have the flu vaccination to protect themselves and their unborn child. However, uptake remains low due to the safety concerns of parents, despite a large body of evidence demonstrating the safety and effectiveness of the flu vaccination for newborn health.

Few studies have looked into the impact of the vaccine on older child health. In this study, researchers in Canada and the USA looked into the relation between the 2009 flu vaccination and child health outcomes in the first five years of life. Of the large study group of 104,249 children, 31,295 (30%) were born to vaccinated mothers.

The researchers found that there was no increased risk for cáncer, infections, chronic diseases, hospital admissions or death for the children of vaccinated mothers. They did find that the rate of childhood gastrointestinal infections was slightly lower in children born to vaccinated mothers. They also found that childhood asma was slightly higher in these children. However, they stress that the links between these risks and the vaccination were very small and may be due to other unaccounted factors.

The findings are consistent with similar studies and reflect the safety of the vaccination. The researchers hope that the results will reassure concerned mothers and increase uptake of the vaccination.

"Especially in this era of 'anti-vaxx' anxiety and misinformation, it is our duty to be clear: vaccination of pregnant women saves lives," they said. Further research is necessary in various settings and with different vaccine formulations to develop “the evidence base on longer-term paediatric outcomes following influenza vaccination during pregnancy."

This study was published in the British Medical Journal.