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A provocative study suggests that certain colds may leave antibodies against the new coronavirus, perhaps explaining why children are more protected than adults. It’s been a big puzzle of the pandemic: Why are children so much less likely than adults to become infected with the new coronavirus and, if infected, less likely to become ill? A possible reason may be that many children already have antibodies to other coronaviruses, according to researchers at the Francis Crick Institute in London. About one in five of the colds that plague children are caused by viruses in this family. Antibodies to those viruses may also block SARS-CoV-2, the new coronavirus causing the pandemic. In a study published Friday in Science, the group, led by George Kassiotis, who heads the Retroviral Immunology Laboratory at the institute, reports that on average only 5 percent of adults had these antibodies, but 43 percent of children did.
Researchers who did not participate in the study were intrigued by the finding. H. Benjamin Larman, an immunologist at Johns Hopkins School of Medicine, called it a “well-done study that puts forward a compelling theory which is supported by their data.” Stephen J. Elledge, a genetics professor at Harvard Medical School and Brigham and Women’s Hospital, had a similar response. He and others have found many people have antibodies to common colds caused by other coronaviruses; in laboratory studies, these antibodies also block the new coronavirus. In March, as the pandemic was just beginning, Dr. Kassiotis and his colleagues decided to develop a highly sensitive antibody test. To assess it, they examined blood samples taken before the pandemic from over 300 adults and 48 children and adolescents, comparing them with samples from more than 170 people who had been infected with the new coronavirus. The scientists expected samples taken before the pandemic to have no antibodies that attacked the new coronavirus. Those were to be the controls for the test the scientists were developing. Instead, they found that many children, and some adults, carried one antibody in particular that can prevent coronaviruses, including the new one, from entering cells. This antibody attaches itself to a spike that pokes out of coronaviruses. While the tip of the spike is unique to the new coronavirus, the base is found in all coronaviruses, Dr. Kassiotis said. In lab tests, antibodies to the base of the spike prevented the new coronavirus from entering cells in order to reproduce.
Now the researchers are planning to expand their study to monitor thousands of children and adults. Some have antibodies that can block the new coronavirus in lab tests. Others do not. “If they have the pandemic strain, are they protected?” Dr. Kassiotis asked. Will they get sick, he wondered, or will the infection be all but undetectable? Dr. Elledge and his colleagues at Harvard developed their own highly specific, sensitive and exhaustive antibody test, VirScan. It is able to detect a diverse collection of antibodies with that are directed at any of more than 800 places on the new coronavirus, including the antibody that Dr. Kassiotis and his colleagues studied. After examining blood taken from 190 people before the pandemic emerged, Dr. Elledge and his colleagues concluded that many already had antibodies, including the one targeting the base of the spike — presumably from infections with related coronaviruses that cause colds...
Cited study published in Science (Nov. 6, 2020):
Via Juan Lama
