Babies born by c-section need two doses of the measles vaccine for optimal protection against the disease. A single dose of the vaccine is up to 2.6 times more likely to be completely ineffective in C-section babies, compared with those born vaginally.
Measles is a highly contagious disease spread by coughs and sneezes. It starts out with cold-like symptoms and a rash, and can lead to severe complications like blindness, seizures and death. Before the introduction of measles vaccine in 1963, major measles epidemics caused an estimated 2.6 million deaths each year.
For the study published in Nature Microbiology, researchers used data from previous studies of 1,505 children in China whose blood samples were taken every few weeks from birth to age 12. About 12 per cent of children born via C-section had no immune response to their first measles vaccination, compared to 5 per cent of children born vaginally.
The findings emphasise the importance of giving two doses of the vaccine for a long-lasting immune response. A possible reason is the development of the infant’s gut microbiome. “With a C-section birth, children are not exposed to the mother’s microbiome in the same way as with a vaginal birth,” the lead researcher explained. “We think this means they take longer to catch up in developing their gut microbiome, and with it, the ability of the immune system to be primed by vaccines against diseases including measles.”
Only 83 per cent children had received one dose of measles vaccine by their first birthday in 2022, according to the WHO, and a lot of children don’t get their second measles jab. “Vaccine hesitancy is really problematic, and measles is top of the list of diseases we are worried about because it’s so infectious,” said the study. At least 95 per cent of the children need to be fully vaccinated to keep measles under control.