Influenza and pertussis vaccination of women during pregnancy in Victoria, 2015–2017

To the Editor: As reported by Rowe and colleagues1 in their retrospective analysis of maternal immunisation, uptake of influenza and acellular pertussis vaccines among pregnant women remains unacceptably low. One contributing factor may be inconsistent messaging. Historically, vaccine manufacturers have included precautions about the lack of data on use in pregnancy in their product information sheets. Such precautions have been shown to lead to vaccination hesitancy and refusal among pregnant women.2,3 In contrast, the current edition of the Australian Immunisation Handbook states: “Pregnant women are routinely recommended to receive influenza vaccine … and pertussis‐containing vaccine”.4

In 2018, the Therapeutic Goods Administration asked its Advisory Committee on Vaccines to provide independent expert advice on the available safety data on influenza vaccination in pregnancy with regards to the pregnancy category of influenza vaccines. The Advisory Committee on Vaccines advised that “adoption of Australian Pregnancy Category A should be considered by sponsors for certain inactivated influenza vaccines”.5 Pregnancy Category A signals to doctors and the public that the vaccine has been used by large numbers of expectant mothers with no evidence of harm to their babies. This is in line with the Australian Immunisation Handbook: “Clinical trial data and observational studies show no increased risk of congenital defects or adverse effects in the fetuses of women who received influenza vaccine during pregnancy”.4

Following the publication of the Advisory Committee on Vaccines statement, two of the four adult influenza vaccines and one of the two acellular pertussis vaccines used to vaccinate pregnant women in Australia have changed their pregnancy category to Category A. These changes show that the Australian regulator is receptive to feedback from the medical community on how to improve immunisation rates. Hopefully, the reclassification of the pregnancy category of these vaccines will translate into increased maternal uptake and better outcomes for Australian mothers and babies.