Biblioteca Virtual en Salud

Objective:

To investigate the relationship between vaccination doses and the duration of positive nucleic acid or antigen tests in Corona Virus Disease 2019 (COVID-19) patients during omicron epidemic.

Methods:

A cross-sectional study was conducted from December 26 to December 31, 2022 among COVID-19 patients from all community health service centers in 16 districts of Beijing municipality selected by multi-stage stratified cluster quota sampling method. A questionnaire was used to collect the basic information, vaccination doses, results of nucleic acid or antigen tests of all subjects. The subjects were divided into 5 groups according to the doses of COVID-19 vaccination the non-vaccination group, the 1, 2, 3 and 4 doses vaccination group. The relationship between vaccination doses and the duration of positive nucleic acid or antigen tests was analyzed by univariate and multivariate logistic regression models.

Results:

A total of 10 506 COVID-19 cases were included in the study with the age of (43.3±13.7) years. The duration of positive nucleic acid or antigen tests was longer than 7 days in 59.4%(276/465), 51.5%(67/130), 50.6%(355/701), 46.1% (3 464/7 520) and 39.2%(662/1 690) of non-vaccination, and 1, 2, 3, 4 dose vaccination groups, respectively ( P<0.001). Multivariate logistic regression analysis showed that compared with non-vaccination patients, the vaccination dose was an independent protective factor for duration of positive nucleic acid or antigen tests>7 days, and the OR values were 0.7 (95% CI 0.5-0.9, P=0.015), 0.6 (95% CI 0.5-0.8, P<0.001) and 0.5 (95% CI 0.4-0.6, P<0.001) for 2, 3 and 4 doses of vaccination, respectively.

Conclusion:

The vaccination doses are independently related to the duration of positive nucleic acid or antigen tests in COVID-19 patients and the risk is gradually decreases with the increasing vaccination doses.