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.