Variants don’t vex T cells from Pfizer or Moderna vaccines, study finds

T cells in COVID survivors also remain potent
T cells
T cells
Posted at 7:04 PM, Mar 04, 2021
and last updated 2021-03-04 22:30:46-05

SAN DIEGO (KGTV) -- New research suggests an important class of immune cells generated by the Pfizer and Moderna vaccines are not fooled by the four most concerning coronavirus variants.

The study by scientists at the La Jolla Institute for Immunology offers an encouraging clue that the T cells produced by the vaccines can still prevent severe disease from the trickiest known variants, even ones with mutations that might elude antibodies.

The researchers had a nearly identical finding in samples from COVID-19 survivors.

However, the scientists caution the results are based on a collection of lab tests and are not definitive clinical proof. The research was posted on a pre-print server, meaning it has not yet undergone peer review.

“It is exciting for us but I want to make sure we do not over-interpret these results,” said Dr. Alessandro Sette, one of the authors. “We still need to wear masks and be socially distanced and most importantly vaccinate as many people as possible as quickly as possible.”

Still, doctors who were not involved in the study said it offered a glimmer of hope. “I think it's great news,” said Dr. Christian Ramers of Family Health Centers of San Diego. “It reassures a lot of us that are very worried when you look at purely an antibody response.”

Unlike antibodies, T cells can’t prevent someone from being infected. They kick into gear once a virus has infiltrated a cell. But a growing body of research suggests these white blood cells play an important role in keeping the disease under control.

There are two types of T cells, helper T cells and killer T cells. The variants had “negligible effects” on both types of T cells.

“That doesn’t mean these people are protected against the virus, but it's plausible that they might be infected with a less severe disease,” Dr. Sette said.

Dr. Sette and his colleagues took genetic code from the leading four variants and rebuilt them in fragments in the lab. The researchers examined B.1.1.7, the UK variant; B.1.351, the South Africa variant; P.1, the Brazil variant; and CAL.20C, the California variant.

Then they tested the fragments against against T cells from 19 people who had been vaccinated and 11 COVID-19 survivors.

The T cell data may help explain why Johnson and Johnson’s vaccine was nearly just as effective against severe disease in South Africa as it was in the U.S., even though the South Africa variant decreased the overall efficacy in that region.