Anti-S antibody responses in high-risk Covid patients eligible for Sotrovimab

ABSTRACT

Introduction: Neutralising monoclonal antibodies (nMAbs), available in UK for patients meeting “high risk” criteria, reduce the risk of hospitalisation and death in unvaccinated patients with mild/moderate covid. However, in vaccinated cohorts infected predominantly with omicron variant, immune responses may be sufficiently strong that nMAbs have limited added benefit. We assessed anti-SARS COV2 anti-S antibody responses in those attending North Central London (NCL) Covid Medicines Delivery Unit (CMDU) for Sotrovimab, and stratified patients by degree of immunosuppression. Methods: Adult patients attending for Sotrovimab infusion between 20/12/21 to 20/03/22 had baseline anti-S antibody levels checked prior to administration of Sotrovimab. Data from these patients were manually extracted from patient notes and analysed in Microsoft excel. Patients were categorised into “higher risk” – Group 1 and “lower risk”- Group 2, according to degree of immunosuppression. Results: 399 patients received Sotrovimab. Serology was available for 375. 17 patients were unvaccinated (1 vaccination or less), all had antibody levels <250 iU/ml. Antibody levels for vaccinated patients can be seen in Table 1and shows undetectable antibody levels in 13% of Group 1 patients and 0% of Group 2 patients. Discussion: Patients who meet national criteria for treatment can be stratified according to degree of immunosuppression that is reflected in anti-S antibody levels. This may help define which patients would benefit most from nMAbs, and provides support for a risk stratification tool. However further data on outcomes, and neutralising efficacy of prior anti-S level on omicron variant, is needed.