Scientists have been wondering for months that past exposure to the cold-causing seasonal coronavirus may prevent people from developing severe cases of COVID-19.
Its protection explains why these cold children are less affected by SARS-CoV-2, the coronavirus that causes COVID-19.However, a new study published in the journal on Tuesday (February 9th) cellFound that antibodies against such seasonal coronaviruses did not prevent SARS-CoV-2 infection or reduce the severity of the disease.
There are four Coronavirus It circulates in the population and causes common cold symptoms — and most people have been exposed to them many times throughout their lives (especially as children) and have therefore developed. antibody Against them. Researchers have conducted a number of studies over the past year to see if these antibodies also bind to SARS-CoV-2 and protect them from infections and serious illnesses.
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“It turns out that many people have antibodies that can bind SARS-CoV-2. PandemicHowever, these antibodies did not prevent the infection, “said Scott Hensley, senior author and associate professor of microbiology at the University of Pennsylvania’s School of Medicine Perelman. Said in a statement.. Also, the antibody could not stop the serious illness.
This is different from the conclusions of similar studies published in the journal. Science In December, a small proportion of people with antibodies from previous coronavirus infections who were capable of neutralizing or disarmament SARS-CoV-2, and a proportion of children compared to adults. It turned out to be expensive.
George Casiotis, an immunologist at the Francis Crick Institute in the UK, who led another study published in Science in December, found in a new study that these antibodies couldn’t prevent infection. Said “naturally”. Antibodies that act against multiple coronaviruses are present in only a few individuals and are at very low levels, Casiotis said. Children get sick with a much more common cold than adults.This means that “antibodies to the common cold coronavirus do not stop children [from] Catch a more common cold — it would be pretty strange if you could stop catching a pandemic Virus,” He said.
That doesn’t matter, he said. Rather, researchers want to know if these antibodies can change the disease if they catch the virus, such as protecting you from severe symptoms, Casiotis told Live Science. “New research suggests[s] Not really, but I don’t think this is definitive. “
Antibody archive
In a new study, Hensley and his team analyzed serum samples collected in 2017 to determine antibody levels against seasonal antibodies in the general population. Blood samples were taken from 263 children at the Philadelphia Children’s Hospital and 168 adults from the Pennsylvania Medicine Biobank.
Most of these samples contained antibodies to the seasonal coronavirus, but the SARS-CoV-2 spike protein (the weapon the virus uses to invade human cells) or its nucleocapsid protein (the virus). Only about 20% of the antibodies contained antibodies that were also capable of binding to the weapons used to invade human cells. Protein essential for virus replication).
They then analyzed another 502 serum samples taken from people prior to the pandemic. Half of these people tested positive for SARS-CoV-2 after a pandemic hit, and half did not and were used as a control group. Similarly, they found that more than 20% of these samples contained coronavirus antibodies that could bind SARS-CoV-2. However, those who had these antibodies still developed SARS-CoV-2. Studies have found that there was no correlation between the levels of these antibodies and the severity of COVID-19 they developed.
In Part 3 of the experiment, we analyzed serum samples from 27 patients admitted with COVID-19 and found that infection increased levels of antibodies to seasonal coronavirus. Another study published in the journal in December 2020 Clinical infections Similarly, these antibodies were found to have no neutralizing effect. However, a Kassiotis study found that some of the antibodies that could bind SARS-CoV-2 could neutralize the virus.
The authors write that it is not clear whether these discrepancies are due to different test methods of the samples or other factors such as geographical differences. Kassiotis believes that researchers used less sensitive tests to identify enough people (two in the year before the pandemic, a total of 11) to have antibodies that could bind the peaplomer. I will. “These numbers are too small to draw meaningful conclusions.”
In any case, even if larger studies confirm that seasonal coronavirus antibodies are not protective, that does not mean that there are no other types of coronavirus. Immune cellsAccording to the statement, it may play a protective role, except for antibodies that remain from past cold infections that have not yet been tested. For example, T cells that respond to the original SARS-COV-1 virus attach for decades, and some also bind to SARS-CoV-2, a July 2020 study in the journal. Found.
“Antibodies from previous coronavirus infections cannot prevent SARS-CoV-2 infection, but existing memory B and T cells provide some protection or at least reduce the severity of COVID-19. There is a possibility, “said Hensley. “To test that hypothesis, we need to complete the study.”
Originally published in Live Science.
