The effect of pre-existing coronavirus antibodies on SARS-CoV-2 infection outcomes in exposed household members

Abstract

AbstractBackground/RationaleWe investigated the effect of pre-existing antibodies against SARS-CoV-2 and seasonal human coronaviruses on infection outcomes in Omicron BA1/2 exposed household members from January to March 2022.MethodsData from a prospective household study in the Netherlands were used including 63 households with 195 household members exposed to a SARS-CoV-2 Omicron BA1/2 index case. The protocol included repeated nose-throat swab and saliva RT-PCR testing, paired serology, and self-reported daily symptom scoring by household members. Infection outcomes included the occurrence of secondary infections, symptom severity, and CT-value trajectories. We studied the effect of baseline binding antibody levels for SARS-CoVs and seasonal coronaviruses (hCoV) NL63, 229E, HKU1 and OC43 spike protein, on SARS-CoV-2 infection outcomes.Results132 of 195 (68%) exposed household members developed a SARS-CoV-2 infection. Among exposed household members, higher levels of SARS-CoV-2 and beta hCoV antibodies (HKU1 and OC43) at baseline, were associated with a reduced risk of secondary infection (adjusted Odds ratio 0.61; 95% Confidence interval 0.44-0.84 and aOR 0.72; 95%CI 0.56-0.92, respectively). No significant differences between antibody levels and symptom burden or CT-value trajectories were observed.ConclusionsOur study suggests that prior SARS-CoV-2 and beta hCoV antibodies provide some protection against Omicron BA.1/BA.2 infection, while effects on symptom burden or CT-value could not be demonstrated. The results highlight the relatively limited, but not negligible role of cross-protective antibodies, especially when facing immune escape variants of SARS-CoV-2.