Comparative Reactogenicity of Enhanced Influenza Vaccines in Older Adults.


We analysed data from a randomized controlled trial on the reactogenicity of three enhanced influenza vaccines compared to standard-dose inactivated influenza vaccine.

Reported reactions were generally mild and short-lived. Systemic reactions occurred in similar proportions of participants by vaccine. Some local reactions were slightly more frequently reported among recipients of the MF59-adjuvanted vaccine and the high-dose vaccine compared to standard dose recipients. Participants reporting feverishness one day after vaccination had mean-fold-rises in post-vaccination hemagglutination inhibition titers that were 1.85-fold higher (95% CI: 1.01, 3.38) for A(H1N1) compared to those who did not report feverishness.

We enrolled community-dwelling older adults in Hong Kong, and randomly allocated them to receive 2017/18 northern hemisphere formulations of: standard-dose vaccine (FluQuadri, Sanofi Pasteur); MF59-adjuvanted vaccine (FLUAD, Seqirus); high-dose vaccine (Fluzone High Dose, Sanofi Pasteur); or recombinant-hemagglutinin vaccine (Flublok, Sanofi Pasteur). Local and systemic reactions were evaluated at Days 1, 3, 7 and 14 after vaccination.

Some acute local reactions were more frequent following vaccination with MF59-adjuvanted and high-dose influenza vaccines compared to standard-dose inactivated influenza vaccine, while systemic symptoms occurred at similar frequencies in all groups. The association between feverishness and immunogenicity should be further investigated in a larger population.

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