Some people may become immune to COVID-19 for unexpected reasons, according to a new study, according tomedia BGR. A new study of coronavirus immunity provides the same conclusions that similar papers have provided over the past few months. They believe that immunity may be unexpectedly improved from the common cold. When the researchers looked for answers to questions around COVID-19 immunity, they found that the immune response to other human coronavirus infections produced T-cells that could identify the COVID-19 virus and react quickly.
These T-cells can roam the body for years and defend against new coronaviruses for long periods of time. It is not known how long COVID-19 immunity will last, a crucial detail for future pandemics and vaccine management policies.
Four known human coronaviruses cause the common cold, and a study has said that any infection from these viruses could teach the immune system to recognize new coronaviruses and prevent them from causing complications. Researchers from the Duke-Singapore Graduate School of Medicine explain that T-cells created by the immune system to beat the common cold enhance the immune response to COVID-19. The team found that people infected with SARS in 2003 still had circulating T-cells about 17 years later.
T-cells roam the body, always looking for specific pathogens that they train to remember. After secondary exposure, they can create more T-cells, which are then neutralized with infected cells. T-cells can also “recruit” B cells to make new antibodies.
Research a few weeks ago suggested that COVID-19 antibodies may disappear from the blood stream three months after infection. But the researchers also point out that the immune system also “trains” T-cells, which persist. These cells cannot be detected through antibody testing, but their presence can be identified by more complex tests. Some promising candidates offer the same dual defense mechanism, improving antibodies that block the virus and T-cells that remember what happened.
The latest study, published in the journal Science, comes from researchers at the La Jolla Institute of Immunology, who proved the same phenomenon as early as May. Around the same time, a study by The University Hospital of Challit in Germany showed the importance of T cells in COVID-19 immunity.
Scientists at the La Jolla Institute of Immunology believe that people who have never been exposed to COVID-19 may have a better immune response to the virus because of previous colds. These episodes train a generation of T cells that can also identify SARS-CoV-2 and initiate rapid response. “This may help explain why some people show milder symptoms of the disease, while others become seriously ill,” study co-author Alessandro Sette said in a press release. However, it is not clear how pre-existing immunity affects the prognosis of COVID-19.
Sette and his team studied blood samples taken from 25 people between 2015 and 2018, when the COVID-19 virus had not yet appeared in humans. The researchers found that T-cells in these samples could identify the new coronavirus and the four known human coronaviruses that cause the common cold.
While this is good news for patients with COVID-19, more research is needed to determine what protection previous exposure to known coronaviruses can provide against COVID-19. More research could also explain whether there is any correlation between exposure to one of the four mild coronaviruses and the evolution of COVID-19 infection. Also, it will be interesting to see if this cross-reactive T-cell reaction can explain why some people do not develop symptoms and recover faster than others.