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Monitoring respiratory infections in covid-19 epidemics

BMJ 2020; 369 doi: (Published 04 May 2020) Cite this as: BMJ 2020;369:m1628

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  1. Ka Hung Chan, early career research fellow1,
  2. Pak-wing Lee, masters student2,
  3. Crystal Ying Chan, doctoral student3,
  4. Kin Bong Hubert Lam, associate professor1,
  5. Pak-leung Ho, clinical associate professor4
  1. 1Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
  2. 2Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
  3. 3JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong SAR, China
  4. 4Carol Yu Centre for Infection and Department of Microbiology, University of Hong Kong, Hong Kong SAR, China
  1. Correspondence to: K H Chan kahung.chan{at} or P Ho plho{at}

Ka Hung Chan and colleagues argue that monitoring influenza-like illness could be a complementary approach to assessing the effectiveness of general infection control measures against covid-19

Key messages

  • Compartmental modelling studies on covid-19 should not be relied on as the only approach for monitoring the pandemic or assessing the effectiveness of infection control measures

  • Simple and rapid assessment of influenza-like illness using widely available surveillance data could be a cost effective and complementary approach to compartmental modelling

  • But the potential confounding due to changes in behaviours of patients and healthcare providers must be carefully considered

  • The proposed methods will be particularly useful for countries in which testing capacity for covid-19 and expertise in infectious disease modelling are limited

  • The timely, stringent, and community-wide epidemic response in Hong Kong seemed to effectively control local outbreaks of covid-19 as well as the underlying transmission of influenza and other respiratory infections

The covid-19 epidemic has grown rapidly from a local outbreak in China to a pandemic with over 2.5 million confirmed cases and 166 000 deaths worldwide (as at 20 April 2020).1 Despite the strong connection with mainland China, the number of confirmed cases in Hong Kong Special Administrative Region has been relatively low (n=1025; 13.8 per 100 000 population as of 20 April, compared with 1651 per 100 000 in New York City and 214.7 per 100 000 in London),1 perhaps attributable to its extensive infection control response.

Limitations of compartmental modelling studies and the severe shortfall of covid-19 testing capacity worldwide, especially in low and middle income countries, have necessitated alternative options to appraise the performance of infection control strategies. Common respiratory infections (such as influenza) share similar transmission pathways (primarily through droplets and fomites) with covid-19,2 so most infection control measures should have qualitatively similar effects on these diseases, even though covid-19 is …

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