
The US and German pharmaceutical giants released a statement Thursday to say they believed a third dose would boost the immune response against variants such as those first discovered in South Africa and the UK.
They are now testing the theory on a group of 144 people who received their first two doses between 6 and 12 months ago.
Today, with @BioNTech_Group, we started an evaluation of the safety and immune response of a third dose of the Pfizer-BioNTech #COVID19 vaccine against circulating virus variants. Read the release: https://t.co/5vTkVXdbDN
— Pfizer Inc. (@pfizer) February 25, 2021
"We are taking multiple steps to act decisively and be ready in case a strain becomes resistant to the protection afforded by the vaccine," Pfizer CEO Albert Bourla said in a statement.
He later told US news channel NBC a third dose could potentially raise the antibody response by as many as 20 times.
The manufacturers also maintain that the vaccine in its intended two-shot form also offers protection against the more drug-resistant variants.
Given 21 days apart, the two-shot vaccine has proven to be about 95 percent effective in protecting against the original Covid-19 strain.