Impact assessment of non-pharmaceutical interventions against coronavirus disease 2019 and influenza in Hong Kong: an observational study
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Abstract
Background A range of public health measures have been implemented to suppress local transmission of coronavirus disease 2019 (COVID-19) in Hong Kong. We examined the effect of these interventions and behavioural changes of the public on the incidence of COVID-19, as well as on influenza virus infections, which might share some aspects of transmission dynamics with COVID-19. Methods We analysed data on laboratory-confirmed COVID-19 cases, influenza surveillance data in outpatients of all ages, and influenza hospitalisations in children. We estimated the daily effective reproduction number ( R t ) for COVID-19 and influenza A H1N1 to estimate changes in transmissibility over time. Attitudes towards COVID-19 and changes in population behaviours were reviewed through three telephone surveys done on Jan 20–23, Feb 11–14, and March 10–13, 2020. Findings COVID-19 transmissibility measured by R t has remained at approximately 1 for 8 weeks in Hong Kong. Influenza transmission declined substantially after the implementation of social distancing measures and changes in population behaviours in late January, with a 44% (95% CI 34–53%) reduction in transmissibility in the community, from an estimated R t of 1·28 (95% CI 1·26–1·30) before the start of the school closures to 0·72 (0·70–0·74) during the closure weeks. Similarly, a 33% (24–43%) reduction in transmissibility was seen based on paediatric hospitalisation rates, from an R t of 1·10 (1·06–1·12) before the start of the school closures to 0·73 (0·68–0·77) after school closures. Among respondents to the surveys, 74·5%, 97·5%, and 98·8% reported wearing masks when going out, and 61·3%, 90·2%, and 85·1% reported avoiding crowded places in surveys 1 (n=1008), 2 (n=1000), and 3 (n=1005), respectively. Interpretation Our study shows that non-pharmaceutical interventions (including border restrictions, quarantine and isolation, distancing, and changes in population behaviour) were associated with reduced transmission of COVID-19 in Hong Kong, and are also likely to have substantially reduced influenza transmission in early February, 2020. Funding Health and Medical Research Fund, Hong Kong.
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It is unclear whether observed patterns in infectious and maternal deaths reflected true reductions in infectious disease burden or changes in death attributions associated with lockdown-related disruptions to MCCD functions.
“making it unclear whether observed patterns reflected true reductions in infectious disease burden, as reported in other settings41–45, or changes in death attributions associated with lockdown-related disruptions to MCCD functions.”
From Attributed causes of excess mortality during the COVID-19 pandemic in a south Indian city (2023) · cites this paper as [41]
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- Authors
- Cowling, B. J., Ali, S. T., Ng, T. W. Y., Tsang, T. K., Li, J. C. M., Fong, M. W., Liao, Q., Kwan, M. Y., Lee, S. L., Chiu, S. S., Wu, J. T., Wu, P., & Leung, G. M.
- Affiliations
- University of Hong Kong (HK)
- Queen Mary Hospital (CN)
- Corresponding author
- Wu, Peng
- ORCID
- Venue
- The Lancet Public Health
- Publisher
- Elsevier BV
- Published
- 2020-05
- Volume
- 5
- Issue
- 5
- Pages
- e279-e288
- ISSN
- 2468-2667 (ISSN-L)
- PMC
- PMC7164922
- OpenAlex
- W3017190864
- Cited by
- 1,258
- References
- 21
- Citations by year
- 2026: 33 · 2025: 53 · 2024: 103 · 2023: 149 · 2022: 223 · 2021: 392 · 2020: 305
- FWCI
- 42.46
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- The Lancet Public Health (publishedVersion, cc-by)
- medRxiv (acceptedVersion, cc-by-nd)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Funders
- Sanofi
- Food and Health Bureau
- Sanofi Pasteur
- Health and Medical Research Fund
- Topics
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Health Sciences › Medicine › Epidemiology › Influenza Virus Research Studies
- Social Sciences › Sociology and Political Science › COVID-19 Prevention and Impact
- Keywords
- H1N1 influenza, non-pharmaceutical interventions, social distancing, school closures, masking, effective reproduction number, influenza transmission, border restrictions, quarantine and isolation, Hong Kong, COVID-19 pandemic, influenza surveillance, community transmission, pandemic preparedness and response, public health measures
- MeSH terms
- Betacoronavirus, COVID-19, SARS-CoV-2, Adult, Child, Cross-Sectional Studies, Hong Kong, Hospitalization, Humans, Influenza, Human, Health Knowledge, Attitudes, Practice, Pneumonia, Viral, Incidence, Coronavirus Infections, Risk Assessment, Influenza A Virus, H1N1 Subtype, Pandemics
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