Factors influencing the time to COVID-19 antigen tests negative conversion among students at a Chinese university: a retrospective analysis.

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause repeated infections. China experienced an outbreak of COVID-19 (coronavirus disease 2019) after the Chinese government changed its COVID-19 policy in December 2022. However, little is known about the influencing factors, such as a history of previous infection and vaccine dose, and whether these factors affect the time at which the antigen test results become negative for SARS-CoV-2. Boarding colleges and universities are prone to outbreaks caused by COVID-19. Therefore, we investigated the factors influencing the time of COVID-19 antigen tests conversion at one university from April to June 2023.

METHODS

This study included college students from one university in Guangzhou who tested positive for the COVID-19 antigen and collected information such as sex, history of previous COVID-19 infection, vaccination dose, symptom onset date, and antigen tests conversion date for retrospective analysis. Chi-square tests or t-tests were used to compare differences between groups.

RESULTS

A total of 255 college students were included in this study. In addition to fever, the most common symptoms were sore throat, nasal symptoms and fatigue. The average time to antigen tests negative conversion of patients with their first infection was 6.12 ± 1.83 days, and that of patients with their second infection was 4.70 ± 1.43 days. The difference between the groups was statistically significant (P < 0.001). The average time to antigen tests negative conversion was 6.21 ± 1.92 days in patients with more than 3 symptoms except fever, which was significantly greater than that in patients with 0-1 (5.54 ± 1.79 days) or 2-3 symptoms (5.45 ± 1.78 days) (P < 0.05). There was no significant difference in time to antigen tests negative conversion according to sex, health observation location or vaccination dose (P > 0.05).

CONCLUSION

In college students, a history of SARS-CoV-2 infection as well as the number of symptoms were significantly associated with the time to COVID-19 antigen tests conversion.