Early-Stage Government Control of COVID-19 Limits Spreading and Reduces Fatality by Narrowing the Outbreak-Phase Duration: An Epidemiological Study

Background: The novel pandemic SARS-CoV-2 has led to 414,179 confirmed cases as of Mar 25, leaving unprecedented pressure on the whole world. Around the globe, several countries achieved preliminary success by focusing on both persistent strict domestic controls and vigilance against exogenous imported cases, as early preventive measures. Considering that most countries are still at an early stage of disease spread, evaluating the effectiveness of control measures conducted before outbreak out of control is pivotal for the global epidemic prevention and constraint.Methods: Eight representative countries were selected and divided into quick-acting and delayed-acting groups according to government control measures at the early stage. Logarithmic lagging growth ratio and outbreak-phase duration were introduced to analyze dynamics of confirmed cases and outbreak period. We compared the dynamics of confirmed cases, outbreak-phase duration, infected population and case-fatality ratio between two groups. Data were collected from WHO and Chinese Centers for Disease Control (updated to 22 Mar).Findings: Early-stage government control slowed the growth of confirmed cases and narrowed outbreak phase. However, delayed-acting representative countries like US were still caught in outbreak phase. We found outbreak-phase duration positively correlated with the size of infected population. Besides, case-fatality ratio rose in the presence of an outbreak phase. Therefore, Early-stage government control may have effective consequences of reduced infected population and low case-fatality ratio by narrowing the outbreak-phase duration.Interpretation: Our results revealed that government interventions with stringent regulations at an early stage had strong positive effect on controlling disease spread and decreasing fatality caused by COVID-19. Narrowed outbreak-phase duration might be an essential target for epidemic disease control. Thus, strict measures should be quickly implemented at early stage, especially in countries at potential risk of outbreak.Funding Statement: No funding.Declaration of Interests: There is no conflict of interest.