text: "I know a lot of people think, 'I had COVID, so I don't need to get a shot,'" said senior author John Alcorn, Ph.D., professor of pediatrics at the University of Pittsburgh School of Medicine and UPMC Children's Hospital of Pittsburgh. "But this study suggests that some patients, particularly young people, don't have particularly good antibody memory after infection, indicating that immune boosting with vaccination is important for these people."
  Comparing patients, the researchers found that some people had high antibody levels while others had much lower responses, and these differences weren't explained by time since infection. But when the researchers broke the participants into different age groups, they found something surprising: Patients under the age of 30 produced lower antibody levels compared with all other age groups.
  "Some people, particularly young people, don't respond particularly well in terms of immune memory to prior infection. These people may not be well protected from a second infection," explained Alcorn. "But we now have a tool—vaccines—that can reinduce immune responses and boost protection. This study puts more evidence behind the recommendation that people who had COVID-19 should get vaccinated."
  It's not clear why young people had the poorest immune responses, Alcorn said. Other studies have shown that COVID-19 disease severity is linked with higher antibody levels, so the researchers suspected that low antibody responses in patients under 30 could be because these patients weren't as sick as their older peers.
  "But people aged under 30 and those aged 31 to 45 had the same symptom duration, but their antibody levels were significantly different," said Alcorn. "These findings suggest that disease severity could influence a person's level of protection, but it doesn't explain everything."
  Alcorn and his team plan to follow up with the same patients to measure how neutralizing antibody levels change over longer periods of time. Because some of these patients have now received a COVID-19 vaccine, the researchers will also compare antibody levels in those who have or haven't been immunized.
  More information: Bo Zhai et al, SARS-CoV-2 Antibody Response is Associated with Age in Convalescent Outpatients, medRxiv (2021). DOI: 10.1101/2021.11.08.21265888
  Citation: Young adults have lowest antibody levels after COVID-19 infection, suggesting vaccination still key (2021, November 9) retrieved 26 January 2022 from https://medicalxpress.com/news/2021-11-young-adults-lowest-antibody-covid-.html