SARS-CoV-2 seropositivity and subsequent infection risk in healthy young adults: a prospective cohort study

April 15, 2021

Andrew G Letizia, Yongchao Ge, Sindhu Vangeti Carl Goforth Dawn L Weir Natalia A Kuzmina et al

The Lancet Respiratory Medicine

In order to determine the infection risk in young adults, researchers evaluated protection by seropositivity against reinfection of SARS-CoV-2 in a largely male, healthy, cohort of Marines ages 18-20. They utilized the COVID-19 Health Action Response for Marines (CHARM) longitudinal prospective cohort study to identify infection and immune response. PCR testing was conducted from May 11 to August 24, 2020 at one site and from August 24 to November 2, 2020 at another site. The amount of SARS-CoV-2 IgG antibodies and serum virus neutralizing activity were measured. Overall, results showed that those with COVID-19 antibodies had reduced incidence of reinfection by 82%. Additionally, those that were seropositive and infected had lower antibody levels and were less likely to have neutralizing antibodies in comparison to those who were seropositive and not infected. Researchers concluded that antibodies are protective but may not entirely prevent reinfection. They also discussed that it is unclear if transmission is likely among those vaccinated and those who have already been infected with COVID-19 before; however, they found that some reinfected people may be able to transmit the infection as much as those who are infected for the first time. In conclusion, reinfection is possible at one-fifth the rate of naïve infection, and vaccination may be necessary even in young adults who are seropositive.

Letizia AG, Ge Y, Vangeti S, Goforth C, Weir DL, Kuzmina NA, Balinsky CA, Chen HW, Ewing D, Soares-Schanoski A, George MC, Graham WD, Jones F, Bharaj P, Lizewski RA, Lizewski SE, Marayag J, Marjanovic N, Miller CM, Mofsowitz S, Nair VD, Nunez E, Parent DM, Porter CK, Santa Ana E, Schilling M, Stadlbauer D, Sugiharto VA, Termini M, Sun P, Tracy RP, Krammer F, Bukreyev A, Ramos I, Sealfon SC. SARS-CoV-2 seropositivity and subsequent infection risk in healthy young adults: a prospective cohort study. Lancet Respir Med. 2021 Apr 15:S2213-2600(21)00158-2. doi: 10.1016/S2213-2600(21)00158-2.

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