Epidemiological characteristics of COVID-19: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational epidemiological studies
PubMed 32594937 · doi:10.1017/S0950268820001430
What was done
A systematic review and meta-analysis searched MEDLINE, Embase, Google Scholar, and article bibliographies from December 1, 2019, to March 11, 2020, without language restrictions. Quantitative studies evaluating confirmed COVID-19 patients were included to synthesize case fatality rate (CFR), incubation period, and time intervals from symptom onset to first clinical visit, intensive care unit (ICU) admission, recovery, and death. Two independent reviewers extracted the data.
What was found
From 1,675 non-duplicate studies identified, 43 were included in the meta-analysis: - Pooled mean incubation period: 5.68 days (99% CI: 4.78, 6.59). - Pooled mean days from symptom onset to first clinical visit: 4.92 (95% CI: 3.95, 5.90). - Pooled mean days to ICU admission: 9.84 (95% CI: 8.78, 10.90). - Pooled mean days to recovery: 18.55 (95% CI: 13.69, 23.41). - Pooled mean days to death: 15.93 (95% CI: 13.07, 18.79). - Pooled CFR among confirmed COVID-19 patients: 0.02 (95% CI: 0.02, 0.03).
Why it matters
This synthesis provided foundational estimates of COVID-19 incubation and clinical timelines during the initial pandemic phase, informing clinical triage timelines and quarantine durations.
Limits
The review covers only the earliest phase of the pandemic (up to March 11, 2020), which is subject to early testing constraints, right-censoring of active cases, and under-ascertainment of mild infections. The total number of individual patients, statistical heterogeneity, and study quality are not reported in the abstract.
Cited by
- supports In COVID-19 cases, death typically occurs days after the infectious transmission window has already passed.