A survey of more than 3,000 young U.S. Marines found that those without a history of COVID-19 had a five times greater risk of infection than those previously infected, according to findings published in the journal Lancet Respiratory Medicine.
The study also found that about 10% of the young Marines who were COVID-19 survivors contracted a second infection.
However, past infections do not guarantee immunity, vaccination remains crucial, The Lancet said on Twitter, providing the link to the findings.
“Of 189 HIV-positive participants, 19 (10%) had at least one positive PCR test for SARS-CoV-2 during the 6 week follow-up (1.1 cases per person year),” the study found.
The previously infected Marines who were reinfected had lower antibody levels and fewer neutralizing antibodies, compared to previously infected Marines who were not reinfected, the study found.
“While antibodies induced by initial infection are largely protective, they do not guarantee effective SARS-CoV-2 neutralization activity or immunity to subsequent infection,” said the study.
“This analysis was performed as part of the prospective COVID-19 Health Action Response for Marines (CHARM) study. CHARM mainly included male US Marines, ages 18-20, after a 2-week unattended quarantine at home,” said the newspaper. .
A separate study published in March in The Lancet found that the majority of people who have had COVID-19 are protected from getting it again for at least six months, but older people are more prone to reinfection than younger people people. read more
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