An unsung arm of the immune system appears to protect against the Omicron variant even when antibodies wane, helping to explain why a record wave of new COVID-19 cases hasn’t engulfed hospitals or led to high deaths so far.
New findings in separate studies from Erasmus University in the Netherlands and the University of Cape Town in South Africa could help explain why the wave of Omicron cases hasn’t so far caused a surge in mortality from South Africa to the U.S. and the U.K.
Unlike antibodies, T cells can target the whole of SARS-CoV-2’s spike protein, which remains largely similar even in the highly mutated Omicron variant.
The Dutch researchers looked at 60 vaccinated health-care workers and found that while their antibody responses to Omicron were lower or nonexistent compared with the Beta and Delta variants, T cell responses were largely unaltered, “potentially balancing the lack of neutralizing antibodies in preventing or limiting severe COVID-19.”
The study from the University of Cape Town’s Institute of Infectious Disease and Molecular Medicine looked at patients who had recovered from COVID-19 or been vaccinated with shots from Pfizer or Johnson & Johnson. They found that 70% to 80% of the T cell responses they assessed held up against Omicron.