On Oct. 16, 2024, the U.S. Food and Drug Administration (FDA) announced it had updated the label for FLUBLOK (Influenza Vaccine) to include data from a new safety study involving pregnant individuals 18 years and older, in time to inform those hoping to comply with U.S. Centers for Disease Control and Prevention (CDC) recommendations to receive their annual flu vaccine ideally before the end of October. The results from the study of more than 48,000 pregnant individuals across multiple flu seasons were published in American Journal of Obstetricians and Gynecologists (AJOG) Global Reports and demonstrated that FLUBLOK safety is consistent with a standard-dose flu vaccine and pregnancy-related outcomes in the general population.

This study was a post-licensure, observational, retrospective safety surveillance study of 48,781 pregnant individuals, including those with chronic conditions. In the study, patients were immunized with either FLUBLOK Quadrivalent (30.7%; n=14,981) or with a comparator standard-dose quadrivalent inactivated influenza vaccine (67.3%; n=33,800) during the Northern Hemisphere influenza seasons 2018-2019 and 2019-2020. Immunization occurred within 28 days prior to pregnancy or during pregnancy. The efficacy of FLUBLOK (quadrivalent) is relevant to FLUBLOK (trivalent) because both vaccines are manufactured using the same process and have overlapping compositions.

Per the CDC, pregnant and postpartum (up to two weeks after the end of pregnancy) individuals are at higher risk for severe illness and complications from flu, particularly during the second and third trimesters. The American College of Obstetricians and Gynecologists (ACOG) recommends full vaccination during pregnancy, as this is when the risk of severe illness is highest. The CDC, Advisory Committee on Immunization Practices (ACIP) and ACOG recommend that individuals who are or will become pregnant during flu season receive an inactivated or recombinant vaccine as soon as it is available, as pregnant persons with influenza may be at increased risk for adverse pregnancy outcomes, including preterm labor and delivery.

With over 125 years of heritage in helping protect global public health, Sanofi is one of the world leaders in vaccines, helping to vaccinate more than 500 million people annually. As one of the largest providers of influenza vaccines to the United States with a wide range of options, Sanofi meets immunization needs across the lifespan, from children as young as six months of age through adults 65 years of age and older.

FLUBLOK is a vaccine indicated for immunization for the prevention of disease caused by influenza A and B strains represented by antigens contained in the vaccine. FLUBLOK is given to people 18 years of age and older.