Effects of Nonpharmaceutical COVID-19 Interventions on Pediatric Hospitalizations for Other Respiratory Virus Infections, Hong Kong

Susan S. Chiu; Benjamin J. Cowling; J.S. Malik Peiris; Eunice L.Y. Chan; Wilfred H.S. Wong; Kwok Piu Lee


Emerging Infectious Diseases. 2022;28(1):62-68. 

In This Article

Abstract and Introduction


To determine the effects of nonpharmaceutical interventions (NPIs) for coronavirus disease on pediatric hospitalizations for infection with respiratory viruses other than severe acute respiratory syndrome coronavirus 2, we analyzed hospital data for 2017–2021. Compared with 2017–2019, age-specific hospitalization rates associated with respiratory viruses greatly decreased in 2020, when NPIs were in place. Also when NPIs were in place, rates of hospitalization decreased among children of all ages for infection with influenza A and B viruses, respiratory syncytial virus, adenovirus, parainfluenza viruses, human metapneumovirus, and rhinovirus/enterovirus. Regression models adjusted for age and seasonality indicated that hospitalization rates for acute febrile illness/respiratory symptoms of any cause were reduced by 76% and by 85%–99% for hospitalization for infection with these viruses. NPIs in Hong Kong were clearly associated with reduced pediatric hospitalizations for respiratory viruses; implementing NPIs and reopening schools were associated with only a small increase in hospitalizations for rhinovirus/enterovirus infections.


Coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first detected in Wuhan, China, in late 2019. The World Health Organization (WHO) declared the outbreak to be a pandemic on March 12, 2020. In Hong Kong, where residents share the collective trauma of the severe acute respiratory syndrome outbreaks in 2003, masking was spontaneously and voluntarily adopted by residents in late January 2020 when news of an outbreak of pneumonia with high illness and death rates in mainland China reached Hong Kong. Primary and secondary school class suspension immediately followed. Other measures of social distancing were also put in place. Such nonpharmaceutical interventions (NPIs) were associated with reduced transmission of SARS-CoV-2 in Hong Kong.[1]

The Hong Kong Special Administrative Region is made up of Hong Kong Island, Kowloon Peninsula, the New Territories, and some sparsely populated outlying islands. The only 2 public hospitals under the Hospital Authority on Hong Kong Island are Pamela Youde Nethersole Eastern Hospital (PYNEH) and Queen Mary Hospital (QMH), which manage 71.1% of all pediatric admissions on the island.[2] Since 2003, we have captured hospitalizations of children with confirmed virus infections in these 2 hospitals and documented population-based hospitalizations resulting from infections with respiratory pathogens in Hong Kong.[3–7] Our objectives with this study were to document the effects of NPIs on pediatric hospitalizations resulting from respiratory virus infections in Hong Kong in the first 12 months of the COVID-19 pandemic and the additional effects of school closure when other NPIs were implemented.

The study protocol was approved by the joint Institutional Review Board of the University of Hong Kong and the Hospital Authority Hong Kong West Cluster, as well as the Hospital Authority Hong Kong East Cluster Research Ethics Committee. The need for written consent was waived because testing for respiratory pathogens is standard and routine for all children admitted for an acute respiratory infection in the 2 study hospitals.