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Meta-Analysis
. 2021 Mar 11;21(1):257.
doi: 10.1186/s12879-021-05950-x.

Serial interval and incubation period of COVID-19: a systematic review and meta-analysis

Muluneh Alene  1 , Leltework Yismaw  1 , Moges Agazhe Assemie  1 , Daniel Bekele Ketema  1 , Wodaje Gietaneh  1 , Tilahun Yemanu Birhan  2
Affiliations
Meta-Analysis

Serial interval and incubation period of COVID-19: a systematic review and meta-analysis

Muluneh Alene et al. BMC Infect Dis. .

Abstract

Background: Understanding the epidemiological parameters that determine the transmission dynamics of COVID-19 is essential for public health intervention. Globally, a number of studies were conducted to estimate the average serial interval and incubation period of COVID-19. Combining findings of existing studies that estimate the average serial interval and incubation period of COVID-19 significantly improves the quality of evidence. Hence, this study aimed to determine the overall average serial interval and incubation period of COVID-19.

Methods: We followed the PRISMA checklist to present this study. A comprehensive search strategy was carried out from international electronic databases (Google Scholar, PubMed, Science Direct, Web of Science, CINAHL, and Cochrane Library) by two experienced reviewers (MAA and DBK) authors between the 1st of June and the 31st of July 2020. All observational studies either reporting the serial interval or incubation period in persons diagnosed with COVID-19 were included in this study. Heterogeneity across studies was assessed using the I2 and Higgins test. The NOS adapted for cross-sectional studies was used to evaluate the quality of studies. A random effect Meta-analysis was employed to determine the pooled estimate with 95% (CI). Microsoft Excel was used for data extraction and R software was used for analysis.

Results: We combined a total of 23 studies to estimate the overall mean serial interval of COVID-19. The mean serial interval of COVID-19 ranged from 4. 2 to 7.5 days. Our meta-analysis showed that the weighted pooled mean serial interval of COVID-19 was 5.2 (95%CI: 4.9-5.5) days. Additionally, to pool the mean incubation period of COVID-19, we included 14 articles. The mean incubation period of COVID-19 also ranged from 4.8 to 9 days. Accordingly, the weighted pooled mean incubation period of COVID-19 was 6.5 (95%CI: 5.9-7.1) days.

Conclusions: This systematic review and meta-analysis showed that the weighted pooled mean serial interval and incubation period of COVID-19 were 5.2, and 6.5 days, respectively. In this study, the average serial interval of COVID-19 is shorter than the average incubation period, which suggests that substantial numbers of COVID-19 cases will be attributed to presymptomatic transmission.

Keywords: COVID-19; Incubation period; Meta-analysis; Serial interval.

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Conflict of interest statement

All authors declared that there is no competing interest.

Figures

Fig. 1
Fig. 1
Flow chart diagram describing the selection of studies included in the meta-analysis of serial interval and incubation period of COVID-19, 2020
Fig. 2
Fig. 2
Forest plot that shows the pooled mean serial interval of COVID-19 using available studies, 2020
Fig. 3
Fig. 3
Forest plot that shows the pooled mean incubation period of COVID-19 using available studies, 2020
Fig. 4
Fig. 4
Funnel plots to check publication bias. a The included studies to pool the mean serial interval of COVID-19. b The included studies to pool the mean incubation period of COVID-19
See this image and copyright information in PMC

References

    1. WHO . Media briefing on COVID-19. 2020.
    1. JHONS HOPKINS coronavirus resource center. COVID-19. Dashboard by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU). COVID, Coronavirus research center.
    1. The world bank . The global economic outlook during the covid-19 pandemic: a changed world. 2020.
    1. Sanders JM, Monogue ML, Jodlowski TZ, Cutrell JB. Pharmacologic treatments for coronavirus disease 2019 (COVID-19): a review. JAMA. 2020;323(18):1824–1836. - PubMed
    1. Gostic K, Gomez AC, Mummah RO, Kucharski AJ, Lloyd-Smith JO. Estimated effectiveness of symptom and risk screening to prevent the spread of COVID-19. Elife. 2020;9:e55570. doi: 10.7554/eLife.55570. - DOI - PMC - PubMed