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Review
. 2021 May 11;12(2):65-81.
doi: 10.5365/wpsar.2020.11.3.011. eCollection 2021 Apr-Jun.

Early reports of epidemiological parameters of the COVID-19 pandemic

Keeley Allen  1 , Amy Elizabeth Parry  1 , Kathryn Glass  1
Affiliations
Review

Early reports of epidemiological parameters of the COVID-19 pandemic

Keeley Allen et al. Western Pac Surveill Response J. .

Abstract

Background: The emergence of a new pathogen requires a rapid assessment of its transmissibility, to inform appropriate public health interventions.

Methods: The peer-reviewed literature published between 1 January and 30 April 2020 on COVID-19 in PubMed was searched. Estimates of the incubation period, serial interval and reproduction number for COVID-19 were obtained and compared.

Results: A total of 86 studies met the inclusion criteria. Of these, 33 estimated the mean incubation period (4-7 days) and 15 included estimates of the serial interval (mean 4-8 days; median length 4-5 days). Fifty-two studies estimated the reproduction number. Although reproduction number estimates ranged from 0.3 to 14.8, in 33 studies (63%), they fell between 2 and 3.

Discussion: Studies calculating the incubation period and effective reproduction number were published from the beginning of the pandemic until the end of the study period (30 April 2020); however, most of the studies calculating the serial interval were published in April 2020. The calculated incubation period was similar over the study period and in different settings, whereas estimates of the serial interval and effective reproduction number were setting-specific. Estimates of the serial interval were shorter at the end of the study period as increasing evidence of pre-symptomatic transmission was documented and as jurisdictions enacted outbreak control measures. Estimates of the effective reproduction number varied with the setting and the underlying model assumptions. Early analysis of epidemic parameters provides vital information to inform the outbreak response.

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Figures

Figure 1
Figure 1
Preferred reporting items for systematic reviews and meta-analysis diagram of study selection
Figure 2
Figure 2
Incubation period estimates and sample size of study (n = 28 studies, 35 estimates) published between 1 January and 30 April 2020
Figure 3
Figure 3
Estimated reproduction number and serial interval of the model (n = 23 studies, 50 estimates) published between 1 January and 30 April 2020
See this image and copyright information in PMC

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