Scientists are investigating a poorly-understood immune mechanism in the body that they hope could help efforts to curb COVID-19.
At the moment, people who think they have had the virus might get a serological test to check for antibodies.
These proteins help fight off infection and may prevent them from getting the disease again in the future — but there are signs that with COVID-19 they could fade away within weeks.
This leaves the other instrument in the body’s toolkit — T lymphocytes — a type of white blood cell responsible for the second part of the immune response.
With little yet known about how they operate against COVID-19, scientists are racing to fill in the gaps in our knowledge.
One hypothesis is that these T cells might help give people a level of cross-immunity protection from COVID-19 because they “remember” previous infections by other viruses in the same family, four of which cause common colds.
“The immune system is complex,” said Andreas Thiel, who co-authored a study that looked at the presence of T cells able to react to the new coronavirus, both among those with confirmed infections and healthy people.
The research, published last week in the journal Nature, found that at least a third of adults that had never had COVID-19 have these T cells.
“These most likely originate from previous infections with endemic coronaviruses,” Thiel, a professor at Berlin-Brandenburg Center for Regenerative Therapies, told AFP.
But he cautioned that much more research was needed to find out whether their presence would necessarily mean immunity.