What are the guidelines for administering the flu shot to pregnant patients?

Guidelines for Administering Flu Shot to Pregnant Patients

All pregnant women should receive the inactivated influenza vaccine during any trimester of pregnancy to protect both the mother and infant from influenza-related complications. 1, 2

Rationale for Vaccination During Pregnancy

• Pregnant women, particularly in their second and third trimesters, are at higher risk for severe illness and complications from influenza 1
• Influenza vaccination during pregnancy provides protection not only to the mother but also to infants during their first months of life when they are too young to be vaccinated 1, 2
• Maternal influenza immunization has been shown to reduce laboratory-confirmed influenza disease in both mothers and infants 2
• Infants born to vaccinated mothers have shown up to 72% reduction in laboratory-confirmed influenza hospitalizations in the first few months of life 2

Vaccine Type and Timing

• Only inactivated influenza vaccine (IIV) or recombinant influenza vaccine (RIV) should be used during pregnancy 1
• Live attenuated influenza vaccine (LAIV) is contraindicated during pregnancy but can be used postpartum 1
• The vaccine can be safely administered during any trimester of pregnancy 1, 2
• Ideally, vaccination should occur before the end of October, but it can be given throughout the influenza season (typically October through May) 3
• Early vaccination (during July and August) can be considered for women in their third trimester during these months to provide protection for the infant during the first months of life 1

Safety Profile

• Multiple studies have not found an association between influenza vaccination and adverse pregnancy outcomes, including spontaneous abortion (miscarriage) 1, 2
• A 5-year retrospective cohort study with over 10,000 women found that influenza vaccination in the first trimester was not associated with increased rates of major congenital malformations 2
• A systematic review and meta-analysis of 15 studies showed no association between congenital defects and influenza vaccination in any trimester 2
• One observational study initially suggested an association between H1N1pdm09-containing vaccine and risk of miscarriage when the same vaccine had been received the previous season, but a larger follow-up study did not confirm this association 1, 2

Clinical Practice Recommendations

• The American College of Obstetricians and Gynecologists and the Advisory Committee on Immunization Practices (ACIP) strongly recommend influenza vaccination for all pregnant women 1, 3
• No special precautions or observation periods are needed when administering influenza vaccines to pregnant women 2
• Vaccination is also safe for breastfeeding mothers and does not affect the safety of mothers or their infants 1, 2
• Healthcare providers should strongly recommend and offer influenza vaccination to pregnant patients, as women who are offered the vaccine by a provider are significantly more likely to be vaccinated (71% vs. 14%) 4

Common Pitfalls and Caveats

• Some providers may hesitate to administer vaccines during the first trimester due to unfounded concerns about safety; however, current evidence supports vaccination during any trimester 1, 2
• Waiting until later in pregnancy may leave women unprotected during early pregnancy 2
• Concerns about thimerosal (a mercury-containing preservative in some multidose vials) are unfounded; no scientific evidence exists that thimerosal-containing vaccines cause adverse events among children born to women who received influenza vaccine during pregnancy 5
• Providers should be aware that pregnant women with medical conditions that increase their risk for complications should be vaccinated regardless of the stage of pregnancy 1