The Chinese Center for Disease Control and Preven-tion recently published the largest case series to date ofcoronavirus disease 2019 (COVID-19) in mainland China(72 314 cases, updated through February 11, 2020).1ThisViewpoint summarizes key findings from this report anddiscusses emerging understanding of and lessons fromthe COVID-19 epidemic
Epidemiologic Characteristicsof the COVID-19 Outbreak
Among a total of 72 314 case records (Box), 44 672were classified as confirmed cases of COVID-19 (62%;diagnosis based on positive viral nucleic acid test resulton throat swab samples), 16 186 as suspected cases(22%; diagnosis based on symptoms and exposuresonly, no test was performed because testing capacity isinsufficient to meet current needs), 10 567 as clinicallydiagnosed cases (15%; this designation is being used inHubei Province only; in these cases, no test was per-formed but diagnosis was made based on symptoms,exposures, and presence of lung imaging features con-sistent with coronavirus pneumonia), and 889 asasymptomatic cases (1%; diagnosis by positive viralnucleic acid test result but lacking typical symptomsincluding fever, dry cough, and fatigue).1Most case patients were 30 to 79 years of age(87%), 1% were aged 9 years or younger, 1% were aged10 to 19 years, and 3% were age 80 years or older.Most cases were diagnosed in Hubei Province (75%)and most reported Wuhan-related exposures (86%;ie, Wuhan resident or visitor or close contact withWuhan resident or visitor). Most cases were classifiedas mild (81%; ie, nonpneumonia and mild pneumonia).However, 14% were severe (ie,dyspnea, respiratoryfrequency 30/min, blood oxygen saturation 93%,partial pressure of arterial oxygen to fraction of inspiredoxygen ratio <300, and/or lung infiltrates >50% within24 to 48 hours), and 5% were critical (ie, respiratoryfailure, septic shock, and/or multiple organ dysfunctionor failure) (Box).1The overall case-fatality rate (CFR) was 2.3% (1023deaths among 44 672 confirmed cases). No deaths oc-curred in the group aged 9 years and younger, but casesin those aged 70 to 79 years had an 8.0% CFR andcases in those aged 80 years and older had a 14.8% CFR.No deaths were reported among mild and severe cases.The CFR was 49.0% among critical cases. CFR was el-evated among those with preexisting comorbid condi-tions—10.5% for cardiovascular disease, 7.3% for diabe-tes, 6.3% for chronic respiratory disease, 6.0% forhypertension, and 5.6% for cancer. Among the 44 672cases, a total of 1716 were health workers (3.8%), 1080of whom were in Wuhan (63%). Overall, 14.8% of con-firmed cases among health workers were classified assevere or critical and 5 deaths were observed.1COVID-19 rapidly spread from a single city tothe entire country in just 30 days. The sheer speed ofboth the geographical expansion and the sudden in-crease in numbers of cases surprised and quickly over-whelmed health and public health services in China, par-ticularly in Wuhan City and Hubei Province. Epidemiccurves reflect what may be a mixed outbreak pattern,with early cases suggestive of a continuous commonsource, potentially zoonotic spillover at Huanan Sea-food Wholesale Market, and later cases suggestive of apropagated source as the virus began to be transmit-ted from person to person
0 Comments