'Not clear yet' if Covid vaccine booster shots are needed, AstraZeneca CEO says

July 30, 2021: -On Thursday, AstraZeneca is not yet sure if the third dose of its Covid-19 vaccine will be required for the protection against the virus, CEO Pascal Soriot told CNBC.

“There are two dimensions to this immunity, antibodies that decline over time, but the second, critical dimension of vaccination is the T-cells. They tend to protect people against harmful disease, but they also ensure durability,” Soriot says.

“With the technology we use, we have very high production of T-cells. We’re hoping we can have vaccines that are durable and protect us for a long period. So if we will need a third booster or not is clear yet; only time will tell,” Soriot added.

T-cells are a kind of white blood cell that play different roles in defending the body against an invading virus. For example, they may attack the pathogen or support other white blood cells in producing antibodies.

Antibodies prevent viruses from invading cells but don’t last as long as T-cells.

Soriot further said that the only way to be sure whether a booster dose would be needed was to watch whether the vaccine’s efficacy declined over time.

“We know that has a decline of antibodies we haven’t seen a decline of efficacy yet, but it’s a bit early to judge; only time will tell, and I hope the T-cells will provide this durable, long-term protection.”

On Wednesday, Pfizer CEO Albert Bourla told CNBC that the company was “very, very confident” that the third dose of its vaccine would provide enough immunity to protect against the faster-spreading delta variant of Covid.

Bourla commented after a study found the effectiveness of the Pfizer-BioNTech vaccine came down by an average of 6% every two months and that the vaccine was effective amid one week and two months after receiving the second dose of that shot.

On Wednesday, Bourla also told CNBC that the vaccine’s efficacy dropped to around 84% four to six months after the second dose.