Pregnant women should be vaccinated against influenza viruses. Being immunised reduces their chances of being hospitalised during pregnancy and decreases the risk of fetal anomalies. Although immunisation with inactivated flu vaccine is recommended by the World Health Organisation and national health bodies, few mothers receive the vaccine and little is known about its effect on neonates.
What is known is that natural maternal antibodies protect babies in the first few months of life but there are no data on whether vaccinating the mother also offers protection. Zaman et al (NEJM 2008;359:1556-64) now report on a trial that looked at the effectiveness of a trivalent inactivated vaccine in reducing flu in pregnant women and their offspring for 6 months after delivery.
Compared to mothers and infants not given the vaccine, babies whose mothers received the vaccination intervention had a two-thirds reduction in the risk of having laboratory- proven flu while the mothers had a one-third reduction in their likelihood of respiratory fever. The study was carried out in Bangladesh and showed that the remarkable effectiveness of the vaccine conveyed infant immunity for a longer duration than that offered by passive antibody acquisition from the mother. The “two for the price of one” benefit to mother and infant is an additional incentive, with 5 pregnant women needing to be treated to prevent one illness in her or her baby.
