Benign Clinical and Epidemiological Outcomes-Associated Factors of COVID-19 from a Solved Epidemic with a Low Case Fatality Rate

Background: Since December 2019, COVID-19 has been confirmed in more than18.8 million patients and leads to 0.70 million deaths worldwide. The mortality and disease severity predictors of COVID-19 have been investigated in many studies. However, they are based on early or partial datasets from high epidemic areas. Here, we retrospect benign clinical and epidemiological outcomes-associated factors from a solved epidemic in a low epidemic area. Methods: All 98 laboratory-confirmed COVID-19 patients in a local epidemic (Zhuhai, China) from January 17, 2020 to March 10, 2020 were enrolled. Data were updated until all patients having final outcomes. Results: Patients were all hospitalized. The case fatality rate was 1.0%. There were no local secondary infection cases. The median age was 46.3 years. Underlying diseases were found in 33.7% patients. The severe/critical rate was 19.4%. The mean period from disease onset to admission was 4.4 days. Compared with serious/critical cases, mild/common cases on admission were much younger, lacks of comorbidities and normal in functions of vital organs and indicators of secondary bacterial infections. The lymphocyte counts in serious/critical cases began to be significantly lower 3 days before their identification dates. The absence of lymphopenia before the eighth day from disease onset can exclude the possibility of 78.5% to be serious/critical ill. Most patients (88.8%) received antiviral treatments. Early antiviral treatment significantly shortened the viral RNA-negative conversion time. The delayed antiviral treatment was associated with critical patients.Conclusions: Younger age, lack of aging-related diseases and early hospitalization of all patients to conduct antiviral treatment and prevention of secondary epidemic were the important benign clinical and epidemiological outcomes-associated factors of COVID-19. In combating COVID-19, the active intervention strategies are crucial in low epidemic areas and the continuous monitoring of lymphocytes may be useful to sort patients reasonably in high epidemic areas.