This fall, new vaccines targeting influenza, COVID-19, respiratory syncytial virus (RSV), and pneumonia are available as part of seasonal immunization efforts, although federal guidance on COVID-19 vaccination remains limited.

For influenza, the U.S. Food and Drug Administration approved Moderna’s mRNA-based flu vaccine, MfluSiVa, on August 5. This marks the first time an mRNA flu vaccine has been authorized for use. Unlike traditional flu vaccines, which contain inactivated viruses or viral components, MfluSiVa uses synthetic messenger RNA to instruct cells to produce a viral protein, stimulating an immune response. The vaccine is approved for individuals aged 50 and older and demonstrated approximately 26.6 percent greater effectiveness in preventing flu in that group compared to standard vaccines. However, it has been associated with higher rates of side effects such as injection-site pain and muscle aches. Experts note that while the mRNA flu vaccine represents a significant technological advancement, its superiority to conventional vaccines is not yet definitive. The Massachusetts Department of Public Health and the Centers for Disease Control and Prevention (CDC) continue to recommend annual flu vaccination for everyone aged six months and older, with updated vaccine strains this year expected to provide improved protection.

COVID-19 case rates remain low in Massachusetts as of early September, though national data from the CDC indicate rising infections, particularly in Texas and Nevada. Hospitalization rates, however, remain relatively low nationwide. Clinical specialists emphasize that severe COVID-19 cases requiring hospitalization are now mostly limited to older adults—typically those in their 80s and 90s—immunocompromised individuals, or those with multiple underlying health conditions. Booster vaccinations remain recommended for people at higher risk of severe disease, while healthy younger adults may consider them optional. Several updated COVID-19 vaccines are available, including Moderna’s Spikevax and MnexSpike, Pfizer’s Comirnaty, and Novavax’s Nuvaxovid, catering to varying age groups and risk profiles. In the absence of updated CDC guidance for the 2026 fall season, Massachusetts public health authorities advise vaccination for all individuals aged six months and older, with specific booster schedules for young children and seniors.

Anticipating the seasonal rise in respiratory syncytial virus cases, which typically begins in October and lasts through March, the Massachusetts Department of Public Health recommends vaccination against RSV for pregnant people between 32 and 36 weeks gestation, infants younger than eight months whose mothers were not vaccinated, certain children aged 8 to 19 months, adults over 50 with risk factors, and all adults aged 75 and older. The maternal RSV vaccine, Pfizer’s Abrysvo, has been endorsed to help protect vulnerable newborns.

Vaccines for pneumonia, caused by bacterial infection or viral illness such as flu, COVID-19, or RSV, are also part of preventive strategies during the fall. The pneumococcal vaccine, recommended by the CDC for children aged two to five and adults over 50, helps protect against bacterial pneumonia and related conditions including meningitis.

Health experts emphasize the timing of vaccination to optimize protection, citing October as the optimal window for immunizations. “Halloween is a convenient landmark for completing vaccinations against respiratory illnesses for the season,” said infectious disease specialists, encouraging individuals to seek vaccinations before holiday activities ramp up. Boston will host free vaccine clinics citywide beginning September 23 to facilitate access to these immunizations.