RESUMEN
BackgroundStudies on the Omicron variant infection have generally been restricted to descriptions of its initial clinical and epidemiological characteristics. We investigated the timeline-related advancement in individuals with Omicron variant. MethodsWe conducted a retrospective, single-centered study including 226 laboratory-confirmed cases with Omicron variant between April 6th and May 11th, 2022 in Shanghai, China. Final date of follow-up was May 30, 2022. ResultsAmong 226 enrolled patients, the median age was 52 years old, and 118 (52.2%) were female. The duration from onset of symptoms to hospitalization was 3 days (interquartile range [IQR]: 2-4 days) for symptomatic patients. Cough occurred in 168 patients (74.3%). The median interval to negative reverse-transcriptase PCR tests of nasopharynx swab was 10 days ([IQR]: 8-13 days). No radiographic progressions were found in 196 patients on the 7th day after onset of symptoms. The median duration of fever in all participants was 5 days (IQR: 4-6 days). The median PCR conversion time of Paxlovid-treated patients was 8 days (IQR: 7-10 days) compared with that of Lianhuaqingwen (10 days, IQR: 8-13 days) (p=0.00056). Booster vaccination can significantly decrease the severity of Omicron infection when compared with unvaccinated, partially or fully vaccinated patients (p=0.009). The median time of PCR conversion in individuals aged under 14 recovered significantly faster than older patients (median 8 days versus 11 days, P < 0.0001). In multivariate logistic analysis, erythrocyte sedimentation rate (ESR) (OR=1.05) was independently related to the severity of the infection. ConclusionsThe majority clinical symptoms of Omicron infection were not severe. Early and aggressive administration of Paxlovid can significantly reduce the PCR conversion time. Booster vaccination should also be highly recommended in population over 14 years old.