Pfizer's combination Covid, flu vaccine will move to final-stage trial after positive data

Pfizer on Thursday said its combination vaccine candidates targeting Covid and the flu will move to a final-stage trial in the coming months after showing positive initial results in an early to mid-stage study.

That moves the pharmaceutical giant and its German partner BioNTech one step closer to winning a potential regulatory approval for a combination shot for Covid and the flu. Earlier this year, Pfizer said it hopes to launch a vaccine targeting those two respiratory viruses in 2024 or later.

Pfizer and other vaccine makers like Moderna and Novavax believe combination shots will simplify the process for people to protect themselves against respiratory viruses that typically surge around the same time of the year.

"This vaccine has the potential to lessen the impact of two respiratory diseases with a single injection and may simplify immunization practices," Annaliesa Anderson, Pfizer's head of vaccine research and development, said in a release. 

Pfizer CEO Albert Bourla said during an investor call earlier this month that he believes the convenience offered by combination vaccines will "unlock a significant potential by improving the vaccination rates." 

Covid vaccine rates in the U.S. were bleak last year, and could look the same this year.

The trial measured the safety, tolerability and efficacy of Pfizer's combination vaccine candidates among adults ages 18 to 64. The trial also compared the combination vaccines to a licensed influenza vaccine and Pfizer's bivalent Covid shot, which targets the omicron variants BA.4 and BA.5 and the original strain of the virus. 

The results showed that "lead" formulations of Pfizer's combination vaccine demonstrated robust immune responses to influenza A, influenza B and Covid strains, according to Pfizer. The safety profiles of the combination vaccine candidates were also consistent with the company's Covid vaccine.

Pfizer and BioNTech are also developing a vaccine that targets both Covid and RSV. Meanwhile, both Moderna and Novavax are developing their own combination shots.