Post-Exposure Prophylaxis with SA58 (anti-COVID-19 monoclonal antibody) Nasal Spray for the prevention of symptomatic Coronavirus Disease 2019 in healthy adult workers: A randomized, single-blind, placebo-controlled clinical study (preprint)

BACKGROUND This study has assessed a new Anti-COVID-19 Monoclonal Antibody Nasal Spray (SA58) for post-exposure prophylaxis (PEP) against symptomatic coronavirus disease 2019 (COVID-19). METHODS We conducted an efficacy study in adults aged 18 years and older within three days of exposure to a SARS-CoV-2 infected individual. Recruited participants were randomized in a ratio of 3:1 to receive SA58 or placebo. Primary endpoints were laboratory-confirmed symptomatic COVID-19 within study period. FINDINGS A total of 1,222 participants were randomized and dosed (SA58, n=901; placebo, n=321). Median of follow-up was 2.25 days and 2.79 days for SA58 and placebo, respectively. Adverse events occurred in 221 of 901 (25%) and 72 of 321 (22%) participants with SA58 and placebo, respectively, with no significant difference (P=0.49). All adverse events were mild in severity. Laboratory-confirmed symptomatic COVID-19 developed in 7 of 824 participants (0.22 per 100 person-days) in the SA58 group vs 14 of 299 (1.17 per 100 person-days) in the placebo group, resulting in an estimated efficacy of 80.82% (95%CI 52.41%-92.27%). There were 32 SARS-CoV-2 RT-PCR positives (1.04 per 100 person-days) in the SA58 group vs 32 (2.80 per 100 person-days) in the placebo group, resulting in an estimated efficacy of 61.83% (95%CI 37.50%-76.69%). A total of 21 RT-PCR positive samples were sequenced. 21 lineages of SARS-CoV-2 variants were identified, and all were the Omicron variant BF.7. INTERPRETATION SA58 Nasal Spray showed favorable efficacy and safety in preventing SARS-CoV-2 infection or symptomatic COVID-19 in healthy adult workers who had exposure to SARS-CoV-2 within 72 hours.

Prevalence of redetectable positive SARS-CoV-2 nucleic acid in recovered COVID-19 patients: a systematic review and meta-analysis (preprint)

Background: The prevalence of positive SARS-CoV-2 nucleic acid in recovered COVID-19 patients has attracted attention. We aimed to investigate the repositive rate of SARS-CoV-2 and the clinical features of discharged COVID-19 patients. Methods: In this systematic review and meta-analysis, we searched PubMed, Embase, Web of Science, China National Knowledge Internet, Wanfang Data, China BioMedical Literature, VIP, and Google Scholar. Fixed or random-effect models were used to determine effect estimates. Results: Eleven studies were included. The pooled positive rate of viral RNA in discharged patients was 11% (95% CI 7-15; I2=90.4%). The median days from discharge to repositivity were 7 to 8 days. Coughing was the most common clinical symptom, occurring in 16% (95% CI 11-20; I2=0%) of patients at readmission. Chest CT and laboratory indicators of positive retest (PR) patients showed significant recovery trends. The prevalence of comorbidities between the PR patients and the negative retest patients were not significant (OR 0.86 [95% CI 0.38–1.95]; p=0.002; I2=76.5%). No close contacts were positive for SARS-CoV-2 RNA. Conclusion: PR patients were uncommon. The repositive result was likely due to the incomplete clearance of virus from a previous disease course. PR patients were less likely to be contagious. However, close monitoring and quarantine after discharge from the hospital are necessary. Registration: The protocol has been registered on PROSPERO, registration ID: CRD42021239650 Keywords: COVID-19, SARS-CoV-2, discharged patients, positive retest rate