[Analysis of the first cluster of cases in a family of COVID-19 in Gansu Province].

The epidemiological history and clinical characteristics of 7 cases of COVID-19 and 1 case of close contact in the first family aggregation epidemic of COVID-19 in Gansu Province were analyzed. The first patient A developed on January 22, 2020, with a history of residence in Wuhan, and confirmed severe cases of NCP on January 24, 2020; patient B, on January 23, 2020, diagnosed on January 31, severe cases; patient C, asymptomatic, diagnosed on January 27; patient D, asymptomatic, diagnosed on January 27; patient E, on January 24, diagnosed on January 28; patient F, asymptomatic, diagnosed on January 31; Patient G was asymptomatic and was diagnosed on January 31. In close contact, H was asymptomatic, PCR test was negative and asymptomatic, and he was discharged early. Among the 7 patients, 1 case died of (B) aggravation, and the other patients' condition was effectively controlled after active treatment. Except for the discharged cases, 5 cases were positive for COVID-19 specific IgM antibody and 1 case was negative. In this clustering outbreak, 4 patients remained asymptomatic, but PCR and IgM antibodies were positive, indicating that asymptomatic patients may be the key point to control the epidemic. Specific IgM antibody screening for patients whose pharyngeal swab nucleic acid test is negative but with ground glass-like lung lesions is very important for early detection and early isolation.

[Epidemiological characteristics of COVID-19 in Gansu province].

Objective: To understand the epidemiological characteristics of COVID-19 cases in different epidemic stages in Gansu province. Methods: Epidemiological investigation was conducted to collect the information of confirmed COVID-19 cases, including demographic, epidemiological and clinical information. Results: As of 25 February 2020, a total of 91 confirmed COVID-19 cases had been reported in Gansu. The epidemic of COVID-19 in Gansu can be divided as three different stages, i.e. imported case stage, imported-case plus indigenous case stage, and indigenous case stage. A total of 63 cases were clustered cases (69.23%), 3 cases were medical staff infected with non-occupational exposure. The initial symptoms included fever (54.95%, 50/91), cough (52.75%, 48/91), or fatigue (28.57%, 26/91), the proportion of each symptom showed a decreasing trend along with the three epidemic stages, but only the differences in proportions of fever (trend χ2=2.20, P<0.05) and fatigue (trend χ2=3.18, P<0.05) among the three epidemic stages were statistically significant. The cases with critical severe symptoms accounted for 42.85% (6/14), 23.73% (14/59) and 16.67% (3/18), respectively, in three epidemic stages, showed a decreasing trend (H=6.45, P<0.05). Also, the incubation period prolonged along with the epidemic stage (F=51.65, P<0.01), but the intervals between disease onset and hospital visit (F=5.32, P<0.01), disease onset and diagnosis (F=5.25, P<0.01) became shorter along with the epidemic stage. Additionally, the basic reproduction number (R0) had decreased from 2.61 in imported case stage to 0.66 in indigenous case stage. Conclusions: The COVID-19 epidemic in Gansu was caused by the imported cases, and about 2/3 cases were clustered ones. No medical worker was observed to be infected by occupational exposure. With the progression of COVID-19 epidemic in Gansu, the change in initial symptom and incubation period suggests, the early screening cannot only depend on body temperature monitoring.

[Analysis of the first cluster of cases in a family of novel coronavirus pneumonia in Gansu Province].

The epidemiological history and clinical characteristics of 7 cases of COVID-19 and 1 case of close contact in the first family aggregation epidemic of COVID-19 in Gansu Province were analyzed. The first patient A developed on January 22, 2020, with a history of residence in Wuhan, and confirmed severe cases of NCP on January 24, 2020; patient B, on January 23, 2020, diagnosed on January 31, severe cases; patient C, asymptomatic, diagnosed on January 27; patient D, asymptomatic, diagnosed on January 27; patient E, on January 24, diagnosed on January 28; patient F, asymptomatic, diagnosed on January 31; Patient G was asymptomatic and was diagnosed on January 31. In close contact, H was asymptomatic, PCR test was negative and asymptomatic, and he was discharged early. Among the 7 patients, 1 case died of (B) aggravation, and the other patients' condition was effectively controlled after active treatment. Except for the discharged cases, 5 cases were positive for COVID-19 specific IgM antibody and 1 case was negative. In this clustering outbreak, 4 patients remained asymptomatic, but PCR and IgM antibodies were positive, indicating that asymptomatic patients may be the key point to control the epidemic. Specific IgM antibody screening for patients whose pharyngeal swab nucleic acid test is negative but with ground glass-like lung lesions is very important for early detection and early isolation.