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COVID-19

Concomitant Administration of Seasonal Influenza and COVID-19 mRNA Vaccines does not Negatively Affect Immunogenicity

Strategic Insights

— 1 min read

A recent study published in the Emerging Microbes & Infections journal has shed light on the concomitant administration of seasonal influenza and COVID-19 mRNA vaccines. The research, conducted by a team of scientists at the Icahn School of Medicine at Mount Sinai, aimed to understand the impact of mRNA COVID-19 vaccines administered concomitantly on the immune response to influenza vaccines. The study found that the concomitant administration of seasonal influenza and mRNA COVID-19 vaccines did not negatively affect immunogenicity, and in some cases, even enhanced the antibody induction for certain viral strains.

Key Takeaways:

  • The study involved 128 volunteers, vaccinated during the 22-23 influenza season, and divided into three groups: FLU vaccine only, FLU vaccine with mRNA bivalent COVID-19 vaccines administered in the same arm, and FLU vaccine with mRNA bivalent COVID-19 vaccines administered in different arms.
  • The researchers observed that the mRNA bivalent COVID-19 vaccines administered concomitantly with seasonal influenza vaccines had a slight increase in side effects, which is expected due to the known reactogenicity of mRNA vaccines.
  • Antibody levels were high at 4 weeks post-vaccination, and differences were found only for the H3N2 virus when administered in different arms compared to the other groups at day 28 post-vaccination.
  • The study found that subjects who received the FLUCOVID vaccine in different arms tended to have better antibody induction than those receiving FLU vaccines for H3N2 virus in the absence of pre-existing immunity.
  • The researchers concluded that their data supports the concomitant administration of seasonal influenza and mRNA COVID-19 vaccines.

Statistics:

  • 128 volunteers participated in the study.
  • 46 participants (35% of the total) received the FLU vaccine only.
  • 42 participants (33% of the total) received the mRNA bivalent COVID-19 vaccines concomitantly with seasonal influenza vaccines in the same arm.
  • 40 participants (31% of the total) received the mRNA bivalent COVID-19 vaccines concomitantly with seasonal influenza vaccines in different arms.
  • Antibody levels were high at 4 weeks post-vaccination (95% confidence interval: 83.2-99.9).

Sources:

  • NewsRx. Studies in the Area of COVID-19 Reported from Icahn School of Medicine at Mount Sinai (Concomitant Administration of Seasonal Influenza and Covid-19 Mrna Vaccines). Vaccine Weekly. August 13, 2025; p 458.
  • Emerging Microbes & Infections. Concomitant Administration of Seasonal Influenza and Covid-19 Mrna Vaccines. 2024;13(1).

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