Influenza Vaccine

Does an MF59-Adjuvanted H7N9 Influenza Vaccine Boost Immunity in Older Adults?

An MF59-adjuvanted H7N9 influenza (influenza A/Shanghai/02/2013) vaccine (H7N9 IIV) does not significantly boost immune responses among older adults, according to new data.1

MF59 is a naturally occurring substance that is added to vaccines to help stimulate immune response. The first MF59-adjuvanted vaccine for older adults was approved in February 2020.2

“Overall, the vaccine was well tolerated,” the researchers wrote. “Two mild potentially immune mediated adverse events occurred, lichen planus and guttate psoriasis.”1

Included in this phase 2 study were 479 participants aged 65 years or older who were in stable health at the time of enrollment. The participants were randomly assigned to receive 1 of 3 vaccine doses and to 1 of 2 dose schedules:

  1. 3.75 µg of MF59-adjuvanted H7N9 IIV given as a 3-dose series on days 1, 28, and 168
  2. 3.75 µg of MF59-adjuvanted H7N9 IIV given as a 3-dose series on days 1, 57, and 168
  3. 7.5 µg of MF59-adjuvanted H7N9 IIV given as a 3-dose series on days 1, 28, and 168
  4. 7.5 µg of MF59-adjuvanted H7N9 IIV given as a 3-dose series on days 1, 57, and 168
  5. 15 µg of MF59-adjuvanted H7N9 IIV given as a 3-dose series either on days 1, 28, and 168
  6. 15 µg of MF59-adjuvanted H7N9 IIV given as a 3-dose series either on days 1, 57, and 168

 

Overall, no significant differences were found between the 2 dose schedules, and no statistically significant associations were found between the immune response rates and age, gender, or body mass index. Moreover, immune responses were only modest across all groups.

Only about 37% of participants had hemagglutination inhibition (HAI) titers of 40 or higher after the second dose, and about 49% had HAI titers of 40 or higher after the third dose.

Analysis of microneutralization (MN) assays taken after the second dose and after the third dose showed similar results to the HAI titers. However, the MN titers were nearly twice as high as the HAI titers.

“MF59-adjuvanted H7N9 IIV was only modestly immunogenic in the older adult population following three doses,” the researchers concluded. “There were no significant differences in antibody responses noted among the various antigen doses or the two dose schedules.”1

—Amanda Balbi

References:

  1. Winokur P, El Sahly HM, Mulligan MJ, et al. Immunogenicity and safety of different dose schedules and antigen doses of an MF59-adjuvanted H7N9 vaccine in healthy adults aged 65 years and older. Vaccine. Published online: January 20, 2021. https://doi.org/10.1016/j.vaccine.2020.11.051
  2. Seqirus Receives FDA Approval for FLUAD® QUADRIVALENT (Influenza Vaccine, Adjuvanted) for Adults 65 Years and Older. News release. PR Newswire. February 24, 2020. Accessed February 8, 2021. https://www.prnewswire.com/news-releases/seqirus-receives-fda-approval-for-fluad-quadrivalent-influenza-vaccine-adjuvanted-for-adults-65-years-and-older-301009593.html