ABSTRACT
ObjectiveTo observe the clinical course and explore the risk factors for SARS-CoV-2 RNA negative conversion duration （NCD） in asymptomatic and mild-symptomatic patients infected with the SARS-CoV-2 Omicron variant. MethodsClinical data were collected from 244 confirmed cases of corona virus disease （COVID-19） with Omicron variant infection admitted to a temporal makeshift hospital in Shanghai from April 9， 2022 to May 20， 2022. Demographic and clinical data were analyzed， with a primary focus on the time of COVID-19 nucleic acid conversion. Univariate and multivariate Cox regression analysis were used to determine identify risk factors associated with NCD. ResultsThe median duration of negative RNA conversion was 9 days （ranged 7‒12 days）. The percentage of patients with positive nucleic acid results on the 5th， 7th， 10th， and 14th days after confirmed infection was 68.4%， 47.1%， 20.1%， and 5.7%， respectively. Kaplan-Meier curves indicated a median nucleic acid conversion time of 12 days （ranged 10‒14 days） for patients with hypertension， 9 days （ranged 7‒11 days） in patients without hypertension， and 11 days （ranged 9‒13 days） for patients aged ≥60 years， and 9 days （ranged 7‒11 days） for patients aged <60 years. Multivariate Cox regression analysis showed that only hypertension was an independent risk factor of NCD （RR=1.60； 95% CI： 1.03‒2.49， P=0.036）. ConclusionIn asymptomatic or mildly symptomatic patients infected with the Omicron variant， 20.1% patients continue to exhibit positive viral nucleic acid on the 10th days of infection. The independent risk factor associated with the conversion of SARS-CoV-2 nucleic acid to negative is hypertension.
ABSTRACT
ObjectiveTo determine the epidemiological characteristics of COVID-19 in Shaanxi Province. MethodsEpidemiological analysis was conducted on the confirmed cases of COVID-19 （n=245） from January 23rd， 2020 through February 21st， 2020 based on the official data announced by Shaanxi Province. The effects of local population migration， prevention and control measures on the epidemic were explored. ResultsAs of February 21st， 2020， a total of 245 COVID-19 cases had been notified in Shaanxi Province， with a cumulative incidence rate of 0.63 per 100 000， of which imported cases accounted for 47.34%. The high incidence was observed between January 31st and February 5th. Xi’an had the largest number of COVID-19 cases， followed by Ankang， Hanzhong and Xianyang， totally accounting for 81.20% of the cases in the province. In terms of social factors， daily morbidity was positively correlated with Baidu migration scale index 14 days before. On January 25th， the provincial health emergency response was launched， and on January 31st， it was further upgraded for quarantine. On February 20th， the provincial prevention and control system was implemented by classified areas. There were no emerging local cases after February 21st and no confirmed cases for 28th consecutive days as of March 19th. Local cases and close contacts were cleared to zero on March 27th. ConclusionThe COVID-19 epidemic in Shaanxi Province is mainly concentrated in Guanzhong area and southern Shaanxi， with a widespread pattern in all cities. The prevention and control measures have effectively contained the epidemic， with a declining incidence. However， quarantine of suspected cases and close contacts remains crucial for routine prevention and control strategy.