Why every pregnant woman needs a flu jab

The study reported that the 1918 influenza pandemic in New Zealand caused thousands of fewer births, particularly in the 1919 year (100 years ago this year). The cause of this was estimated to largely be from miscarriages – which are well known to arise from influenza infection during pregnancy.

The study, involving researchers from University of Auckland and the University of Otago, Wellington, estimated that in the year 1919, there were 3756 fewer non-Māori and 239 fewer Māori births than in the pre-pandemic year of 1917. These declines represented a 'birth rate shock': reductions in birth rates per 1000 population of 17 percent for non-Māori and 20 percent for Māori.

The birth rate reductions in the pandemic year of 1918 (relative to 1917) were less, at 9 percent for non-Māori and 7 percent for Māori. 

Associate Professor Dr Nikki Turner, GP, director of the Immunisation Advisory Centre, and co-author in the study said that these findings highlight the importance of protection for pregnant women, including the use of flu immunisation in every pregnancy.

“In a pandemic, we should prioritise protection of pregnant women from infection using all the proven means available. These include actions to avoid contact with sick people, prioritising these women if pandemic vaccines are in short supply, and even prioritising them for access to antivirals and ventilators in hospital ICUs, if they get sick.”

She says these issues are also relevant to the flu season we have every year. Seasonal influenza in pregnant women also causes miscarriages – and there is even an increased risk of death for the women themselves.

Many changes occur in a woman’s body during pregnancy. Changes to lung function, immunity and increased heart output and oxygen consumption mean pregnant women are five times more likely to be admitted to hospital with influenza than women who are not pregnant.

“Indeed, the World Health Organization (WHO) recommends pregnant women be a high priority for vaccination. New Zealand has provided free flu vaccination for pregnant women since 2010.

“The current rate of influenza immunisation in pregnancy in NZ is low, at under half of pregnant women. So, as well as current efforts to improve childhood immunisation for protection against measles, we also need to improve immunisation in pregnancy against flu.

“Annual influenza immunisation is also important for anyone who comes in contact with pregnant women. Recent research shows that you can infect others with the flu virus even when you’re not showing symptoms yourself,” adds Dr Turner.

Free flu immunisation for pregnant women is available from April 1 each year from a GP surgery or participating pharmacist. For more information about influenza or the influenza vaccine, talk to a Lead Maternity Carer, a doctor or pharmacist, go to www.fightflu.co.nz or call 0800 IMMUNE (0800 466 863). The influenza vaccine is a prescription medicine. Talk to a doctor or nurse about the benefits and possible risks.