Discussion
infection, death
INFECTIOUS DISEASES, SARS-COV-2 INFECTION, ASYMPTOMATIC COVID-19, DISEASE, INFECTION
During our study period, the Omicron BF.7 sublineage caused several outbreaks in Beijing. Our preliminary results in healthy adult workers within 72 h of contact with SARS-CoV-2-infected individuals showed that SA58 Nasal Spray was highly effective in preventing symptomatic COVID-19 and SARS-CoV-2 infection caused by Omicron BF.7 sublineage, which variants have shown significant escape of immunity in previous studies [The median incubation period of SARS-CoV-2 was estimated to be five days, with most cases developing symptoms within 11.5 days of infection [There were 99 SARS-CoV-2 RT–PCR positive participants at baseline (Our study has several limitations. First, our study participants were confined to healthy workers generally young and healthy, which limits the generalizability of our study results to other populations, namely the elderly living in long-term care facilities, healthcare personnel who have frequent contacts with patients at increased risk of severe outcomes, and people who have underlying medical conditions. These populations have a higher risk of severe disease or death following SARS-CoV-2 infection and are more likely to benefit from PEP with mAbs. In the future, studies need to be conducted in these high-risk populations to expand the target population for SA58. Second, concurrent practices may impact on the observed effect of SA58. For example, in an attempt to block transmission and to quickly stop the potential outbreak, our infected study participants were managed at isolation facilities for highly infectious diseases, which lowers the risk of infection and may distort associations between treatment and disease outcome. Further assessment of SA58 in participants continuously exposed to SARS-CoV-2 in real-world situation is needed. Third, our study ended prematurely on December 9, 2022, two days after the Chinese government lifted its COVID-19 containment policy on December 7, 2022 [