Neutralizing antibodies correlate with protection from SARS-CoV-2 in humans during a fishery vessel outbreak with high attack rate

Abstract

The development of vaccines against SARS-CoV-2 would be greatly facilitated by the identification of immunological correlates of protection in humans. However, to date, studies on protective immunity have only been performed in animal models and correlates of protection have not been established in humans. Here, we describe an outbreak of SARS-CoV-2 on a fishing vessel associated with a high attack rate. Predeparture serological and viral RT-PCR testing along with repeat testing after return to shore was available for 120 of the 122 persons on board over a median follow-up of 32.5 days (range 18.8 to 50.5 days). A total of 104 individuals had an RT-PCR positive viral test with Ct <35 or seroconverted during the follow-up period, yielding an attack rate on board of 85.2% (104/122 individuals). Metagenomic sequencing of 39 viral genomes suggested the outbreak originated largely from a single viral clade. Only three crewmembers tested seropositive prior to the boat's departure in initial serological screening and also had neutralizing and spike-reactive antibodies in follow-up assays. None of these crewmembers with neutralizing antibody titers showed evidence of bona fide viral infection or experienced any symptoms during the viral outbreak. Therefore, the presence of neutralizing antibodies from prior infection was significantly associated with protection against re-infection (Fisher's exact test, p=0.002).

SARS-CoV-2–Specific Neutralizing Antibody Responses in Norwegian Health Care Workers After the First Wave of COVID-19 Pandemic: A Prospective Cohort Study

“…Virus neutralizing antibodies can potentially prevent reinfection with SARS-CoV-2 [ 17–19 ]. Therefore, we further assessed in vitro protective immunity against SARS-CoV-2 in HCW with positive or intermediate results by screening RBD ELISA (n = 76) using the MN assay to confirm infection.…”

“…Importantly, virus neutralizing antibodies can potentially prevent reinfection with SARS-CoV-2 [ 17–19 ]. We developed neutralization assays to investigate protective antibodies against the live SARS-CoV-2 virus in HCW, which most studies have not reported [ 3–11 , 13 , 20–22 , 26 , 32–41 ].…”

Attenuated influenza virions expressing the SARS-CoV-2 receptor-binding domain induce neutralizing antibodies in mice

“…Fourth, although we demonstrated high SARS-CoV-2 neutralizing antibody titers at three weeks post vaccination, we did not perform experiments to examine the durability of these titers over longer timeframes. Finally, while the presence of neutralizing titers against SARS-CoV-2 is correlated with protection against infection in animal models [48,49] and preliminarily in human studies [50], we did not directly test if the neutralizing antibodies elicited by ΔNA(RBD)-Flu are protective against viral challenge.…”

A human coronavirus evolves antigenically to escape antibody immunity

“…We focused our studies on the viral spike protein because it is the main target of neutralizing antibodies (Tortorici and Veesler, 2019), and because anti-spike antibodies are the immune parameter best established to associate with protection against coronavirus infection in humans (Addetia et al, 2020;Callow, 1985;Callow et al, 1990;Lumley et al, 2020;Polack et al, 2020).…”