Becker's Clinical Quality & Infection Control

6 INFECTION CONTROL COVID-19 immunity may last years, 2 studies suggest By Erica Carbajal C OVID-19 immunity persists for at least a year, perhaps even a lifetime, according to two studies, e New York Times reported May 26. e first study, published in Nature May 24, involved 77 people who were infected with COVID-19 about a year earlier and had since recovered. Researchers focused on memory B cells, which retain a memory of the virus, and found that while the antibody levels in the participants' blood samples dropped in the months aer infection, memory B cells lingered in the bone marrow, ready to pro- duce antibodies as needed. Among the 19 participants researchers were able to obtain bone marrow samples from, 15 had detectable memory B cells about sev- en months aer infection, while four did not. is reinforces the added protection vaccines provide to those who've previously recovered from COVID-19, researchers said. e second study, published in the pre-print server bioRxiv, included 63 people who also recovered from the coronavirus about a year earlier. Most participants had mild infec- tions, and 26 had received at least one dose of mRNA vaccine. e findings showed that memory B cells evolved and strengthened overtime, with the antibodies they produced able to neutralize some of the virus variants. Further, the neutralizing ability was greatest among those who had received their shot. Findings from the two studies suggest those who've been vaccinated on top of having recovered from a prior infection will never need a booster shot, while those who've been immunized and have never had COVID-19 will likely need boosters in the future. "People who were infected and get vaccinat- ed really have a terrific response, a terrific set of antibodies, because they continue to evolve their antibodies," explained Michel Nussenzweig, MD, PhD, lead author of the bioRxiv study and immunologist at New York City-based Rockefeller University. "I expect that they will last for a long time," he told the Times.n Biopsy samples left in many gastrointestinal endoscopes after procedures, U of Utah Health finds By Mackenzie Bean A new study suggests biopsy specimens are retained in gastrointestinal endoscopes about two-thirds of the time, reported Medscape. Researchers at the University of Utah Health in Salt Lake City ex- amined endoscopes used in 50 outpatient colonoscopies and 55 esophagogastroduodenoscopy procedures, or EGD tests. The latter procedure allows clinicians to examine the inside of a pa- tient's esophagus, stomach and duodenum. Researchers found retained biopsy samples in the endoscopes after 64 percent of all procedures. Recovered tissue was sent to pathology for evaluation, which changed or added to the diag- nosis of five patients. "All of these changes were minor, and patients were already on appropriate treatment," said study author Gregory Toy, MD, an internal medicine resident at University of Utah Health, ac- cording to Medscape. "The take-home message would be that retained biopsies are much more common than most endosco- pists would think." The findings also highlight the importance of diligent endo- scope reprocessing between procedures, according to Serge Sorser, MD, a gastroenterologist at Ascension Michigan Provi- dence Hospital in Novi who was not involved in the study. Dr. Toy presented the research May 31 at the American Gas- troenterological Association's Digestive Diseases Week in San Diego, Calif. n First human case of H10N3 bird flu confirmed in China By Mackenzie Bean C hinese health officials on June 1 confirmed the world's first known human infection from a strain of bird flu called H10N3, The New York Times reported. A 41-year-old man in China's eastern Jiangsu province contracted the virus and was hospi- talized April 28. China's CDC performed genome sequencing on a virus sample from the man May 28 and determined he'd been infected with H10N3. It's not clear how the man contracted the virus. Chinese health officials said there is no evidence of human-to-human transmission, and they have not identified any other cases through contact-tracing. The development warrants close monitoring and serves as a reminder of the continued risk for pan- demic flus, health experts told the Times. Avian viruses don't typically spread to humans, but can pose a threat if they mix with human viruses and swap genetic material, Raina MacIntyre, PhD, head of the biosecurity program at the Kirby Institute at the University of New South Wales in Australia, told the Times. n

• Cover