- Jennifer Middleton, MD, MPH
According to the Centers for Disease Control and Prevention (CDC), pregnant women with influenza infection are more likely to be hospitalized than non-pregnant women of the same age. It seems intuitive that influenza vaccination would help reduce these hospitalizations, but data demonstrating as such has only been published in the last week. A large multi-center retrospective study found that influenza vaccination reduces influenza-related hospitalizations among pregnant women by 40%.
Organizations from several countries, including the CDC, comprise the Pregnancy Influenza Vaccine Effectiveness Network (PREVENT), who conducted this retrospective study that reviewed over 19,000 hospitalization records from Australia, Canada, Israel, and the western United States (US). A significant limitation to the study is that, overall, only 6% of pregnant women admitted for flu-like illness had documented influenza virus testing; among these women, 13% with confirmed influenza had been vaccinated, compared with 22% with confirmed influenza who had not been vaccinated. The authors note that vaccine uptake was low across all studied countries, with the US having the highest vaccination rates at just 50%. (The authors' findings correlate with CDC data from the 2016-17 influenza season, when 53.6% of pregnant US women were vaccinated.)
Given the many documented benefits of influenza vaccine in pregnancy, we need to improve vaccination rates. Safety concerns, especially in pregnancy, continue to be a major barrier to vaccination. The CDC has a website devoted to allaying these safety concerns that cites multiple studies demonstrating the vaccine's safety and efficacy in pregnancy. The American College of Obstetricians and Gynecologists (ACOG) and the American Academy of Family Physicians (AAFP) both also strongly recommend influenza vaccination in pregnancy; ACOG has an online fact sheet for patients as does AAFP's familydoctor.org.
Studies also cite low rates of physician recommendation as a factor in suboptimal influenza vaccination rates in pregnant women, even though physician recommendation to vaccinate correlates with higher vaccination rates. Even though many family physicians do not provide direct obstetric care, we can still work with our pregnant patients to encourage influenza vaccination. FPM has a resource describing "How to Talk to Reluctant Patients About the Flu Shot," and the latest issue of AFP includes the CDC's Advisory Committee on Immunization Practices (ACIP) update for 2018-2019. There's also an AFP By Topic on Influenza with more references and patient handouts.