The public may require annual vaccines to protect against SARS-CoV-2, Pfizer (NYSE:PFE) CEO Albert Bourla said today.
“It is extremely important to suppress the pool of people that can be susceptible to the virus,” Bourla said in a CNBC interview.
While the details of Pfizer-BioNTech boosters are not yet clear, COVID-19 boosters will likely be based on an mRNA platform.
Adenovirus-vectored vaccines from AstraZeneca and Johnson & Johnson are currently in limited use, given concerns that they could cause rare but serious blood clotting problems.
The mRNA vaccines from Moderna and Pfizer/BioNTech also have a head start, and U.S. officials expect 600 million doses of the vaccines to be delivered by the end of July.
It will be “a stretch for adenoviral-vector vaccines to have any material uptake,” in the U.S., said Navin Jacob, a senior equity research analyst at UBS. “And you can’t really give boosters with the adenoviral-vector vaccines because of the potential for attenuation of efficacy because of antibodies that are created against the vector,” Jacob added.
Early data from Pfizer and Moderna suggest that mRNA vaccines offer a durable immune response with antibodies persisting at least six months after vaccination.
Pfizer and Moderna are both developing versions of their vaccines to optimize protection against more-transmissible variants.
Moderna CEO Stéphane Bancel recently announced that the company was exploring developing a vaccine to protect against both COVID-19 and influenza.
Speaking broadly about immunity from vaccines, Dr. Shahrokh Shabahang, CIO of Aditx Therapeutics, said there is “no reason for us to think that SARS-CoV-2 defies all rules of infectious diseases and immunity.”
While the public may be familiar with flu vaccines, comparing immunity to SARS-CoV-2 and the flu “confuses the issue,” Shabahang said. “Flu is not one disease. It’s a syndrome made up of multiple symptoms caused by multiple infectious agents,” he added.
In addition to the four flu strains (A, B, C and D), other viruses, including HIV, can cause flu-like illness.
The public can confuse the seasonal nature of flu infections and the variable risk SARS-CoV-2 variants pose.
Ultimately, though, more data are needed to understand the durability of immunity from SARS-CoV-2, COVID-19 vaccines and how SARS-CoV-2 variants will inform vaccination strategies.
“The only way to really understand if someone has long-term immunity is looking at memory cells,” Shabahang said.
“If we’re just looking at antibody levels or saying we need to give boosters every year based on the fact that we’re doing that for flu or the fact that antibody levels wane over time, that’s not a good way to evaluate long term immunity,” Shabahang concluded.