Immunise to protect pregnant women and their babies

Vaccine efficacy

The immune response to influenza vaccination in pregnant women is similar to that of non-pregnant women. The efficacy (prevention of illness among vaccinated persons in controlled trials) and effectiveness (prevention of illness in vaccinated
populations) of influenza vaccines is dependent on several factors. The age and immune status of the recipient are important as well as the match between circulating viral strains and the vaccine.

Influenza vaccination during pregnancy provides “two for one” protection, reducing the maternal risk of influenza disease and associated complications and the risk for their baby during the first 6 months after birth.

A review of acute respiratory illness (ARI) and influenza vaccination during pregnancy over the 2012 and 2013 Australian influenza seasons identified that women who received an influenza vaccination during their pregnancy were 81% less likely to attend an emergency department with an ARI, and 65% less likely to be hospitalised than pregnant women who were not vaccinated. 

An increase in circulating maternal influenza antibodies after vaccination supports maximum transplacental antibody transfer to the growing baby and protection against influenza after birth. Babies born during an influenza season in 2002–2005 in the U.S. were followed until they were aged 6 months. Those born to mothers who received an influenza vaccination during pregnancy were 41% less likely to have laboratory-confirmed influenza and 39% less likely to be admitted to hospital with an influenza-like illness than babies whose mother didn’t have an influenza vaccination.

Safety of influenza vaccine in pregnant women and their babies

Inactivated influenza vaccines have been recommended for and used in pregnant women since the 1960s. No safety concerns about influenza vaccination during any trimester of pregnancy have been identified in studies of millions of vaccine doses administered to pregnant women.

Influenza vaccination during pregnancy has not been associated with any increase in pregnancy complications, or the occurrence of congenital malformations. Maternal influenza vaccination has been associated with a lower incidence of stillbirths, when vaccinated women were compared with unvaccinated women.

Poor vaccination uptake

Within New Zealand, influenza vaccination of pregnant women has been very modest. The most significant barriers to vaccination during pregnancy are a lack of information about influenza disease and potential complications, and the “two for one” benefit of maternal influenza vaccination, no recommendation from the woman’s Lead Maternity Carer or other health professionals involved in her care, and structural barriers to accessing services through general practice.96 The NIR records influenza vaccination for pregnant women. Refer to the section on Recording influenza vaccinations on the NIR.