A major study aimed at uncovering the crucial role that human antibodies and other immune defences play in the seriousness of Covid-19 cases was launched by British scientists.
Antibody studies may explain the defense of children against diseases, or why viruses cause life-threatening effects.
The findings may support the assumption of some scientists that antibodies induced by common colds could protect children from the disease. Alternatively, the study may confirm the concerns of other researchers that some immune responses to the virus could cause deadly inflammatory reactions that may impede attempts to manufacture anti-Covid vaccines.
“It may reveal that cross-reacting antibodies explain why children are less likely to suffer from extreme Covid-19, or could indicate that life-threatening effects are induced by patients’ own immune responses.”
Most of the work of the groups will concentrate on antibodies, essential proteins for immune defense that bind to viruses to inhibit their action. Scientists started looking for antibodies against the virus in patients and healthy individuals when Covid-19 first emerged and, to their surprise, they found them not only in samples obtained from newly infected individuals, but in specimens collected before the pandemic started.
“We found that a small number of people — about 6% of the UK population — already had antibodies that could identify the new virus, although they were never exposed to it,” Kassiotis said. We noticed that cross-reactivity between common cold coronaviruses and the latest pandemic strain had to take place.
Coronaviruses cause the Covid-19 virus to be attached to about a fifth of UK common colds and antibodies induced by them. “These antibodies can actually protect against Covid-19.” In comparison, children get them five or six times a year because, Kassiotis said, they constantly reinfect each other at school . As a result, about 60% of them have coronavirus antibodies, 10 times the level of adults.
“In general , children do not get serious Covid-19 and I believe defense is provided by cross-reacting antibodies caused by recurrent colds of the coronavirus,” Kassiotis said.
“Crucially, when kids leave school, coronavirus antibody levels tend to drop steeply and that raises a concern: during the lockdown, UK kids could have lost immunity.” The pandemic strain, not the seasonal cold variety, may be the next coronavirus to spread among them, “said Kassiotis. This also implies the lockdown maz have done more harm than good.
The new Crick-Imperial-UCL research will examine samples from thousands of individuals to see whether they have Covid antibodies and also evaluate whether they have any other immune reactions, including responses in T-cells, that may have been caused by coronaviruses. It will also study how people do as the pandemic progresses to see how well they are covered by antibodies.
Kassiotis said that when the disease hits, several different kinds of antibodies are produced by the immune system of the body. Others lock on parts shared by all coronaviruses — and it may be possible to design a vaccine to protect against all coronaviruses by concentrating on those parts.
“But there are other facets of the immune response of the body to Covid-19 that may have a somewhat different effect.” After the pandemic started, we started to see critically sick, infected children with extreme inflammation and multi-organ failure, “Levin said.” We were puzzled because their illness emerged not at the height of their infection, but many weeks later — when the virus was gone, but we were puzzled. We were afraid the antibodies might actually be causing the damage.
Levin added that the culprit could be a phenomenon called antibody-dependent disease enhancement. The antibodies first created by your immune system can actually make the disease worse when you encounter a slightly different strain of the virus. Triggering the production of antibodies can increase the effect of the disease, as vaccines try to do, unless those antibodies are effective against all three dengue
Levin said he was worried that the recently recognized Covid-19-related childhood inflammatory disorder could be caused by antibodies that later cause inflammation and organ damage. If so, a related issue could be caused by coronavirus antibodies triggered by a vaccine.
We need to understand whether the antibodies produced by children against common cold coronaviruses and Covid-19 are protective against serious disease, or whether certain children and adults create antibodies that may make the disease worse.