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The emergence of new, more infectious variants of the coronavirus has raised a troubling question: Will the current crop of COVID-19 vaccines prevent these variants from causing disease?
A study published Wednesday in the journal Nature suggests the answer is yes.
The research was fairly straightforward. Scientists took blood from volunteers who had received the Johnson & Johnson COVID-19 vaccine and looked at levels of neutralizing antibodies, the type of antibodies that prevent a virus from entering cells.
“What we have shown is that the neutralizing antibodies are reduced by about five times to the B.1.351 variant,” says Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston. In the new nomenclature proposed by the World Health Organization, B.1.351 is now called Beta. It first appeared in South Africa.
“It’s very similar to what other researchers have shown with other vaccines,” he says. “But what we’ve also shown is that there are many other types of immune responses other than neutralizing antibodies, including binding antibodies, functional FC antibodies, and T cell responses.”
And it’s this latest immune response, the T-cell response, that Barouch says is critically important. Because T cells, especially CD-8 T cells, play a crucial role in preventing disease.
“These are the killer T cells,” says Barouch. “These are the types of T cells that can essentially find and destroy infected cells and help clear the infection directly.”
They do not prevent infection; they help prevent an infection from spreading.
“T cell responses are actually not reduced – at all – to variants,” says Barouch. Not just the Beta variant, but also the Alpha and Gamma variants.
This may help explain why the Johnson & Johnson vaccine prevented serious illness when tested on volunteers in South Africa, where worrying variants are circulating.
“The data is very solid,” says Alessandro Sette, immunologist at the La Jolla Institute of Immunology. “Dan Barouch’s data really shows that there is no appreciable decrease in [CD8 T-cell] reactivity.”
Sette’s laboratory obtained similar results with the Pfizer-BioNTech and Moderna COVID-19 vaccines. The same goes for Marcela Maus of Massachusetts General Hospital. While it will require studies in people to be sure the vaccines will work against the variants, “Anything that generates a T-cell immune response to SARS-CoV-2, I would say, shows promise as potentially protective,” Maus says. .
What is not yet clear is how long the T cell response will last, but several labs are working to answer this question.