The Fact News Service,
Months after recovery from mild COVID-19, when antibody levels in the blood have declined, immune cells in bone marrow remain ready to pump out new antibodies against the coronavirus, in Nature. Upon infection, short-lived immune cells are generated quickly to secrete an early wave of protective antibodies. As the immune cells die out, antibody levels decline.
But a pool of these immune cells, called long-lived plasma cells, is held in reserve after infection. Most of them migrate to the bone marrow, explained co-author Ali Ellebedy of Washington University School of Medicine in St. Louis. His team obtained bone marrow samples from 19 patients seven months after the onset of mild COVID-19. Fifteen had long-lived plasma cells secreting antibodies against the coronavirus.
Young children appear to be significant carriers of more contagious variants of the new coronavirus, such as the ones identified in the UK and in California, according to a new U.S. study. From March 2020 to April 2021, researchers at nine children’s hospitals tested a total of 2,119 COVID-19 patients age 18 or younger for so-called variants of concern, along with key mutations that help the variants become more contagious or hide from the patient’s immune system. “In total, we identified 560 of these important mutations, and 75% were children less than 12 years of age, the population that is currently not eligible for COVID-19 vaccines,” said Jennifer Dien Bard of Children’s Hospital Los Angeles.
The results provide “clear evidence” of the emergence of variants of concern in pediatric patients across diverse geographies and socioeconomic populations in the United States, the researchers said in their paper. They added that the results highlight the need for ongoing monitoring of pediatric populations “who will be among the last groups to receive vaccination and who are key to ending this pandemic.”