Why do some people seem to have greater immunity to Covid-19 than others? Why is it that some people have been infected more than once and others have managed to escape in the last two years?
Although there are usually individuals who can naturally generate a more effective immune response, a new study suggests that ‘super-immunity’ may also be part of the answer. Professor Paul Wilmes, a microbiologist at the Luxembourg Centre for Systems Biomedicine (LCSB) at the University of Luxembourg and spokesperson for the Covid-19 Task Force of Research Luxembourg, explains everything around super-immunity.
Super-immunity, also known as hybrid immunity, is built up through the combination of a full vaccination and infection with Covid-19. Successive exposures to Covid-19 appear to be the key to the development of super-immunity. He adds that the order of vaccination and infection does not seem to make much difference. So if a person has had an infection first and then been vaccinated, it is possible that this super-immunity to Covid could develop.
The reason some people develop super-immunity is due to a type of white blood cell known as a ‘memory B cell’. As part of our adaptive immune system, memory B cells are generated in response to a virus, either by infection or vaccination. They can circulate in the bloodstream for decades, ready to reactivate and trigger an antibody response the next time the individual comes into contact with the virus. The more memory B cells an individual has, the more protected he or she is against the virus, hence the importance of a full vaccination against Covid-19.
While super-immunity is not a new concept for researchers and scientists, the pandemic has brought it under much closer scrutiny. Professor Wilmes says that super-immunity has been assumed to exist for other infectious diseases. What we are seeing for the first time in human history with Covid-19, however, is our ability to track immunity conferred by infection and vaccination in real time.
Professor Wilmes thus assumes that, given its apparent robustness, super-immunity will make a major contribution to herd immunity. The emergence of super-immunity could be one of the signals that we are moving from pandemic to endemic. Of course, there are many other factors to consider, including the continued evolution of the virus itself.
