Vincent Mor, Ph.D.
Vincent Mor, Ph.D.

Adjuvanted trivalent vaccine (Fluad) is significantly more protective against nursing home flu outbreaks than standard vaccines, according to a large new study.

Influenza outbreaks pose a threat to frail residents even in vaccinated populations, according to Vince Mor, Ph.D., of Brown University. To determine the impact of adjuvanted vaccine on the likelihood of these events, he and his colleagues compared outcomes between nursing homes that offered older residents Fluad versus those whose residents received a standard vaccine. The study took place during the 2016-2017 flu season — when Fluad was first approved for this population.

Among 777 facilities, the adjuvant group experienced a 17% reduction in suspected and laboratory-confirmed influenza outbreaks, reported Mor, a renowned nursing home researcher. The estimated reduction in outbreaks rose further — to 22% for laboratory-confirmed outbreaks — when the researchers adjusted for facility-level vaccination rates and resident characteristics.

An adjuvant is an ingredient added to vaccines to promote a better immune response. Older adults tend to have weaker immune responses compared with younger adults, and they benefit from vaccines with this added boost, according to the Centers for Disease Control and Prevention. Fluad protects against two influenza A viruses: A(H1N1) and A(H3N2), and one influenza B virus. Its quadrivalent version, approved last February, also protects against an additional B virus.

The Fluad vaccines are recommended by the CDC for adults 65 years and older, along with Fluzone High-Dose vaccine, which also is extra-protective.

Full findings were published Tuesday in the journal Clinical Infectious Diseases.