The need for a third dose of the Pfizer vaccine between six and 12 months after a person is fully vaccinated will "likely" be needed, the CEO of Pfizer said in comments released Thursday.
"A likely scenario is that there will be likely a need for a third dose, somewhere between six and 12 months and then from there, there will be an annual revaccination," Pfizer CEO Albert Bourla told CNBC's Bertha Coobs on "CVS Health Live."
Bourla said the third dose would be necessary to combat coronavirus variants.
"It is extremely important to suppress the pool of people that can be susceptible to the virus," Bourla explained. "The fact that there are people that are protected, this is what creates the new variants."
Bourla added some diseases, like polio, only require one vaccine dose whereas the flu requires a shot every year.
"The COVID virus looks more like the influenza virus, than the polio virus. The duration of immunity was unknown until yesterday," Bourla said in the interview recorded on April 1.
Bourla was referring to data released earlier this month suggesting the Pfizer and BioNTech COVID-19 vaccine is 91% effective for up to at least six months after getting a second dose.
Pfizer said at the time the data confirmed that the mRNA vaccine is 95.3% effective against severe COVID-19 as defined by the FDA and 100% effective against what the U.S. Centers for Disease Control and Prevention defines as severe disease.
The company said 12,000 participants have followed up after their second dose to assure that the vaccine is effective for up to six months.
The study also found that the vaccine was 100% effective against the variant that was first discovered in South Africa. However, that study into the B1.351 variant only involved 800 participants.
Pfizer and BioNTech previously announced back in February that it would begin studying a third dose of the COVID-19 vaccine in an effort to protect people against emerging variants.
Other studies have also shown the effectiveness of the vaccines. A study from the CDC at the end of March said both the Pfizer and Moderna shots were highly effective at 90% after two doses.
Erin McHugh contributed to this report.