At a World Health Organization meeting on Wednesday, scientists presented encouraging results on immunity to the rapidly spreading Omicron variant of the coronavirus. Several laboratory studies suggest that the so-called T cells in vaccinated people may form a strong defense against the variant, which could help prevent serious illness, hospitalization and death.
The results are a welcome start to a torrent of disturbing new data on Omicron. Mutations in the variant allow it to escape numerous antibodies produced either by vaccination or by infection with previous variants. But antibodies are not the only important player in a person’s immune response to the virus.
âThe good news is that T cell responses are largely maintained at Omicron,â said Wendy Burgers of the University of Cape Town during a presentation of new research that she and her colleagues have been carrying out in recent days.
Over the past week, it has become increasingly clear that Omicron can skillfully evade antibodies, which are part of the body’s first line of defense, which is probably why infections with the variant have exploded in so many areas. Many countries.
Infections occur more frequently in two groups of people who carry antibodies: those who have received vaccines, as well as those who are not vaccinated but have recovered from a previous infection with the coronavirus.
At Wednesday’s meeting, one scientist after another presented lab results showing that the antibodies work less well against Omicron than against other variants.
But the researchers also presented data showing that mRNA vaccine boosters – Pfizer-BioNTech and Moderna – can restore antibodies to levels thought to be high enough to offer strong protection against Omicron infection. Epidemiological findings in Britain and South Africa also suggest that boosters reduce risk.
Speaking at the White House on Wednesday, Dr Anthony S. Fauci, the administration’s senior adviser on the pandemic, echoed the findings. âOur booster vaccination schedules are working against Omicron,â he said.
Many countries are sending boosters to their populations, but Omicron is spreading so quickly that it may well exceed even the best efforts. “The projected transmission rates, if confirmed, don’t leave us much time for interventions,” Phil Krause, former vaccine regulator with the Food and Drug Administration, said at the WHO meeting.
This prospect has led many scientists to hope that T cells will serve as an effective backup in the event of antibody failure. If these immune cells can fight off Omicron, they can prevent many infections from turning into serious illness.
Once a cell is infected with the coronavirus, T cells can learn to recognize fragments of viral proteins that are found on the outer surface of the cell. The T cells then either kill the infected cell or alert the immune system to launch a more powerful attack on the virus.
Alessandro Sette, immunologist at the La Jolla Institute of Immunology, and Andrew Redd of the National Institutes of Health reported that despite the many mutations in Omicron, most of the protein fragments recognized by T cells are identical to those of other variations.
These results suggest that T cells entrained by vaccines or previous infections will respond aggressively to Omicron, rather than sitting idly by. “It appears that the T cell response is largely preserved,” said Dr Sette.
Dr. Burgers and his colleagues tested this possibility by collecting T cells from 16 people vaccinated with two doses of the Pfizer-BioNTech vaccine and exposing these T cells to fragments of Omicron variant proteins. Scientists found that the T cell response to the variant was about 70% as powerful as their attack on the original form of the virus.
Some scientists have warned that the data came from studies of cells in the lab, known as in vitro experiments. It will take a few more weeks to look at actual infections in people before anyone is sure how well T cells prevent serious disease.
“We don’t yet know what these in vitro findings actually mean for the severity of the disease,” said Nora Gerhards, a virologist at Wageningen University in the Netherlands. âAnd that’s what it is. Because at the end of the day, we want to prevent a collapse of health systems in our countries. “