While worldwide research focuses on two pathways of development: a possible vaccine and the behaviour of the COVID-19 virus in the human body, scientists from the Duke-NUS School of Medicine, in close collaboration with the Yong School of Medicine Loo Lin of the National University of Singapore (NUS), the Singapore General Hospital (SGH) and the National Center for Infectious Diseases (NCID), has published a study showing that people infected (and recovered) with the syndrome acute respiratory tract (SARS) that ravaged China and part of the world in 2003 still possess T cells, crucial for the fight against infections. Now they suggest that these same cells are present in people cured of the new coronavirus.

The T lymphocytes or T cells together with antibodies are an integral part of the human response immune against viral infections because of its ability to attack and kill directly to infected cells. They are created by the bone marrow, a substance that is found inside our bones and contains the stem cells of the blood that, later, become red blood cells, white blood cells or platelets.

To carry out this study, the results of which were published this July 15 in the journal ‘Nature’, the team evaluated several subjects recovered from covid-19 and discovered the presence of these types of cells specific for SARS-CoV-2 in all of them, showing that they play an important role in overcoming the disease.

Compared to patients who had recovered from SARS 17 years ago after the 2003 outbreak, this same group of researchers found that they still possessed the same type of memory cells specific to the virus and showed a type of cross-immunity to current SARS- CoV-2.

We tested that 50% of healthy uninfected individuals also had SARS-CoV-2 specific T cells

“Our team also tested healthy uninfected individuals and found SARS-CoV-2-specific T cells in more than 50% of them. This could be due to cross-reactive immunity gained from exposure to other coronaviruses, such as those that cause the common cold or currently unknown animal coronaviruses,” says Professor Antonio Bertoletti, author of this study, and continues: “It is important to understand that this could explain why some people can better control the infection.”

Meanwhile, research associate professor Tan Yee Joo adds that they have also started “follow – up studies on covid -19 in recovered patients to determine if their T-cell immunity persists for an extended period of time.” “This is very important for vaccine development and to answer the question about reinfection,” he concludes.

The team will now conduct a larger study of exposed and uninfected subjects to examine whether T cells can protect against the new coronavirus or alter the course of infection. Furthermore, according to the Duke-NUS School of Medicine, they will also explore the potential therapeutic use of SARS-CoV-2-specific T cells.