Abstract: Objective To analyze the nucleic acid shedding time of Omicron variant of novel coronavirus in the elderly patients with non-severe infection, and to explore the related factors affecting the nucleic acid shedding time. Methods A total of 104 elderly patients with non-severe COVID-19 were divided into early negative group (<10 days) and late negative group (≥ 10 d) by the nucleic acid shedding time. The population information, vaccination, previous diseases, blood biochemical and inflammatory indicators, nucleic acid ORF1ab gene and N gene Ct values were collected and compared between the two groups. The Spearman rank correlation and multiple linear regression were conducted to explore the influencing factors of the nucleic acid shedding time. Results The mean time of nucleic acid shedding of Omicron variant in the early negative group was 7.26±1.54 d, compared with 12.96±2.44 d in the late negative group. There were significant differences in age, the ratio of chronic heart failure, chronic pulmonary disease and booster vaccination for COVID-19 and the first nucleic acid Ct value between the two groups (P<0.05). Spearman correlation analysis showed that the nucleic acid shedding time of Omicron was positively correlated with age, chronic heart failure and serum level of procalcitonin, but negatively correlated with the vaccination booster and the first tested nucleic acid Ct value. Multiple linear regression analysis showed that age, vaccination booster and the first tested nucleic acid Ct value were the independent influencing factors of the nucleic acid shedding time. Conclusions Age, vaccination booster for COVID-19 and the first tested nucleic acid Ct value were the independent influencing factors of nucleic acid shedding in the elderly non-severe patients infected by SARS-CoV-2 Omicron. Vaccination booster for COVID-19 in the elderly vulnerable groups can shorten the time of nucleic acid shedding.

Key words: SARS-CoV-2, aged, Omicron, nucleic acid shedding time