(Newswire.net— October 29, 2020) — The risk of re-infection with COVID-19 still remains high in those who have had the disease with milder symptoms, claims Professor Dr. Natalia Freund, a virologist and head of the Human Body Reactions Laboratory at Tel Aviv University.
For the Radio Quarantine podcast, she spoke about the work she and her team have published these days, in which they present very interesting conclusions about the reaction of the human body to a coronavirus infection; specifically how and to what extent it stimulates the production of antibodies and how it affects the risk of re-infection.
This study has two parts: In the first, which started after the outbreak of the coronavirus in Israel, scientists tried to find the correlation between the severity of the disease and the intensity of antibody production in the infected.
“We know that many people can become infected and remain asymptomatic or have mild symptoms, while there are those with complications, some of which even die. And here the question arises what is the response of the immune system and antibodies. Do people with mild symptoms have a large number of antibodies in advance, so the disease does not become complicated or vice versa?” Dr. Freund said.
The second question was to see if the research team could characterize the antibody response to the disease in more detail and possibly isolate antibodies that neutralize the disease, to learn how the body fights the coronavirus, and possibly see if therapy could be made based on those findings.
Natalia Freund further says that she and her colleagues were surprised at first by what they discovered.
“To our surprise, we found that people who had mild symptoms or none at all did not have antibodies to the coronavirus. Their reaction was very weak in terms of neutralizing the virus. At first glance, that is illogical, but if we think a little better, we see that there is actually logic. When the virus causes serious damage to the body, which happens in seriously ill people, it also causes a great reaction of the immune system,” Dr. Freund said.
The immune system reacts to the infection, not the other way around. So, where there is a strong presence of the virus, the body produces a lot of antibodies. Therefore, in patients who had a serious illness, who ended up in the hospital or even on a respirator, and who are now well and no longer have the virus in them – they now have high levels of antibodies, which is a consequence of the intensity of the infection.
On the other hand, for those who had no symptoms or just mild ones, the intensity of the infection was not so high as to cause a significant immune reaction.
This brings us to the problem of re-infection where we see that there is a possibility that those who have had mild symptoms can be re-infected more easily.
Professor Freund emphasizes that this research was done on blood samples taken only six months after the infection and that the long-term consequences of the infection on the immune system are not yet known. In the short term, her team’s conclusion is that those with milder symptoms have a higher risk of re-infection.