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Meta-Analysis
. 2021 Apr 8;10(1):101.
doi: 10.1186/s13643-021-01648-y.

The incubation period during the pandemic of COVID-19: a systematic review and meta-analysis

Wafa Dhouib  1 , Jihen Maatoug  2 , Imen Ayouni  2 , Nawel Zammit  2 , Rim Ghammem  2 , Sihem Ben Fredj  2 , Hassen Ghannem  2
Affiliations
Meta-Analysis

The incubation period during the pandemic of COVID-19: a systematic review and meta-analysis

Wafa Dhouib et al. Syst Rev. .

Abstract

Background: The aim of our study was to determine through a systematic review and meta-analysis the incubation period of COVID-19. It was conducted based on the preferred reporting items for systematic reviews and meta-analyses (PRISMA). Criteria for eligibility were all published population-based primary literature in PubMed interface and the Science Direct, dealing with incubation period of COVID-19, written in English, since December 2019 to December 2020. We estimated the mean of the incubation period using meta-analysis, taking into account between-study heterogeneity, and the analysis with moderator variables.

Results: This review included 42 studies done predominantly in China. The mean and median incubation period were of maximum 8 days and 12 days respectively. In various parametric models, the 95th percentiles were in the range 10.3-16 days. The highest 99th percentile would be as long as 20.4 days. Out of the 10 included studies in the meta-analysis, 8 were conducted in China, 1 in Singapore, and 1 in Argentina. The pooled mean incubation period was 6.2 (95% CI 5.4, 7.0) days. The heterogeneity (I2 77.1%; p < 0.001) was decreased when we included the study quality and the method of calculation used as moderator variables (I2 0%). The mean incubation period ranged from 5.2 (95% CI 4.4 to 5.9) to 6.65 days (95% CI 6.0 to 7.2).

Conclusions: This work provides additional evidence of incubation period for COVID-19 and showed that it is prudent not to dismiss the possibility of incubation periods up to 14 days at this stage of the epidemic.

Keywords: COVID-19; Contact tracing; Coronavirus; Infectious disease incubation period.

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Conflict of interest statement

The authors declare that they have no competing interests

Figures

Fig. 1
Fig. 1
PRISMA study flow diagram for search up to 1 December 2020
Fig. 2
Fig. 2
Overall and detailed risk of bias assessment among the 42 studies
Fig. 3
Fig. 3
Forest-plot for mean incubation period in days
See this image and copyright information in PMC

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