(CNBC) Pfizer and BioNTech announced Thursday they are developing a Covid-19 booster shot intended to target the delta variant as concerns rise about the highly transmissible strain that is already the dominant form of the disease in the United States.
The companies said although they believe a third shot of their current two-dose vaccine has the potential to preserve the “highest levels” of protection against all currently known variants, including delta, they are “remaining vigilant” and developing an updated version of the vaccine.
“As seen in real world evidence released from the Israel Ministry of Health, vaccine efficacy has declined six months post-vaccination, at the same time that the Delta variant is becoming the dominate variant in the country,” the companies said in a written statement.