LONDON: Pfizer’s vaccine works against new COVID-19 variants that have emerged from the UK, Brazil and South Africa, according to a new study that will assuage fears that the mutations could be immune to the jabs.
Researchers at Oxford University found that the antibodies triggered by the Pfizer vaccine detect and “neutralize” new variants, but not as well as they do against older strains of the virus.
Variants that emerged in South Africa and Brazil have been of particular concern to scientists because mutations in them have been identified that may help them “escape” the vaccine.
According to the Oxford researchers, two doses of the Pfizer vaccine would provide 90 percent of the population with protection from either variant, enough to provide herd immunity, which requires around 75 percent of a population to be immunized.
After just one dose, the Pfizer vaccine provided limited protection from the British variant — which is highly infectious but not more potent or difficult to immunize against — but not adequate protection from the South African variant.
One jab did, however, trigger the production of T cells — immune cells that produce antibodies and provide an additional layer of defense against infection.
“It may not necessarily protect you against infection, but it’s very likely that this first jab will make it much easier for your immune system to make a good response the next time around,” said Dr. William James, a virologist at Oxford University and the study’s lead author.
“We think this is why that second dose produces such a good strong antibody response, because T cells are already there, ready to react.”
The study’s findings provide room for cautious optimism that vaccines still present a clear route out of the pandemic, but James warned that the virus could yet mutate further.
“This virus hasn’t finished evolving, but as long as the vaccines get rolled out and people get those second doses, we’re going to be in a much better position by the summer than we are now,” he said.