Even in the worst COVID-19 cases, the body launches immune cells to fight back: study

Even the sickest COVID-19 patients produce T cells to battle the virus, a new study reveals.

The research, published in Science Immunology, provides more proof that any vaccine for the deadly virus will have to bring T cells along to work with antibodies.

"This is key to understanding how the immune response fights the virus," said Alessandro Sette, a professor at La Jolla Institute for Immunology, who co-led the study, in a statement. "You want vaccine approaches to be grounded in observations from rather diverse settings to ensure that the results are generally applicable."

Researchers tracked 10 COVID-19 patients with very severe symptoms. All of them were admitted to the ICU and put on ventilators as part of their care. Two eventually died from the disease.

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By closely examining their immune responses, it was clear that all 10 patients produced T cells targeting SARS-CoV-2, the virus that causes COVID-19. The T cells worked hand-in-hand with antibodies to try to halt the infections.

"Activating these cells appears to be at least as important as the production of antibodies," said Erasmus MC virologist Rory de Vries, who co-led the study.

As of Friday afternoon, there were more than 2.7 million infections and at least 129,114 deaths in the United States from COVID-19.