This cohort study shows that a series of multifaceted public health interventions was temporally associated with improved control of the COVID-19 outbreak in Wuhan. Findings may inform public health policy in other countries and regions.

It is unknown whether a combination of public health interventions can improve control of the COVID-19 outbreak. This cohort study sought to evaluate the association of public health interventions with the epidemiological features of the COVID-19 outbreak in Wuhan by 5 periods according to key events and interventions.

The authors extracted individual-level data on 32, 583 laboratory-confirmed COVID-19 cases reported between December 8, 2019, and March 8, 2020 from the municipal Notifiable Disease Report System, including patients’ age, sex, residential location, occupation, and severity classification.

They examined the impact of nonpharmaceutical public health interventions (including cordons sanitaire, traffic restriction, social distancing, home confinement, centralized quarantine, and universal symptom survey) on rates of laboratory-confirmed COVID-19 infections (defined as the number of cases per day per million people), across age, sex, and geographic locations within 5 periods: December 8 to January 9 (no intervention), January 10 to 22 (massive human movement due to the Chinese New Year holiday), January 23 to February 1 (cordons sanitaire, traffic restriction and home quarantine), February 2 to 16 (centralized quarantine and treatment), and February 17 to March 8 (universal symptom survey). T

Findings among 32,583 laboratory-confirmed COVID-19 cases include:

• The median patient age was 56.7 years (range, 0-103; interquartile range, 43.4-66.8).
• 16,817 (51.6%) were women.
• The daily confirmed case rate peaked in the third period and declined afterward across geographic regions and sex and age groups, except for children and adolescents, whose rate of confirmed cases continued to increase.
• The daily confirmed case rate over the whole period in local health care workers was higher than that in the general population.
• The proportion of severe and critical cases decreased from 53.1% to 10.3% over the 5 periods.
• The severity risk increased with age.
• The effective reproduction number fluctuated above 3.0 before January 26, decreased to below 1.0 after February 6, and decreased further to less than 0.3 after March 1.

In summary, this report provides evidence that a series of multifaceted public health interventions was temporally associated with improved control of the COVID-19 outbreak in Wuhan, China.