Table 1.

Epidemiological characteristics of human CoVs

	SARS-CoV	MERS-CoV	Commonly circulating human CoVs (229E, NL63, OC43, HKU1)
Basic reproductive number, mean (95% CI), or prevalence of infection (for commonly circulating human CoVs)	Beijing: 1·88 overall,1 0·94 after generation 1 (excluding SSE).1 Hong Kong: 1·70 (0·44–2·29)* overall,2 2·7 (2·2–3·7) in the early phase (excluding SSE),3 range 0·14–1 in the later phase (excluding SSE).3 Singapore: 1·63 overall1 or 1·83 (0·47–2·47)* overall,2 range 2·2–3·6 in the early phase (including SSE).4 Toronto 0·86 (0·24–1·18)* overall.2 Worldwide: 0·95 (0·67–1·23) overall.5	Middle East: 0·47 (0·29–0·80) overall.6 Saudi Arabia: 0·45 (0·33–0·58) overall.7 Middle East and South Korea: 0·91 (0·36–1·44) overall.5 South Korea: range 2·0–8·1 in early phase (including SSE).8	229E and OC43 in USA:9 annual infection attack rates of 2·8% to 26·0% in prospective cohorts. Guangzhou, China:10 CoVs detected in 2·25% of adults and children with fever and upper respiratory infection symptoms, among which 60% were OC43, 17% were 229E, 15% were NL63, and 7·8% were HKU1. UK:11 CoVs detected in all age groups, most frequently in children aged 7–12 months (4·86%)
Incubation period, days, mean (SD) or mean (95% CI)	Hong Kong:12 4·6 (3·8–5·8). Hong Kong:13 4·4 (4·6). Beijing:13 5·7 (9·7). Taiwan:13 6·9 (6·1)	Saudi Arabia:14 5·0 (4·0–6·6). South Korea:14 6·9 (6·3–7·5).	OC43 and other common human CoVs:15 range 2–4. common human CoVs:16 range 2–5. Common human CoVs:17 range 3–4.
Serial interval, days, mean (SD)	Singapore:4 8·4 (3·8).	Saudi Arabia:7 6·8 (4·1). South Korea:18 12·4 (2·8).	··
Seroprevalence among non-cases	Hong Kong, among close contacts:19 around 0%.	Qatar:20 0·21% (10 of 4719) among healthy blood donors, 0·74% (1 of 135) among individuals who are close contacts of cases but not sick. Arabian Peninsula:21 0·15% (15 of 10 365) among general population, 6·2% (68 of 1090) among individuals exposed to camels.	OC43 and 229E:22 86–100%. HKU1, S-protein-based ELISA:23 0% in children aged <10 years, to a plateau of 21·6% in adults aged 31–40 years.
Case-hospitalisation probability, mean (95% CI)	Around 100%.12	South Korea:24 around 100%.	OC43 in Canada:25 12·6% among older and disabled adults in a long-term care facility. 229E and OC43 in USA:9 prevalence of 3·3–11·1% in a hospitalised cohort. Brazil:26 11% among children aged <3 years attending the paediatric emergency room with acute lower respiratory infection and hospitalised.
Case-fatality proportion	Worldwide (WHO): 9·6% among probable cases. mainland China:27 6·4% among probable cases. Hong Kong:12 17% among laboratory-confirmed cases.	Worldwide (WHO): 34·5% among laboratory-confirmed cases. South Korea:24 20·4% among laboratory-confirmed cases.	··

CoV=coronavirus. SARS=severe acute respiratory syndrome. MERS=Middle East respiratory syndrome. SSE=superspreading event.

^*Data are mean (IQR).