Volume 28, Number 1—January 2022
Research
Effects of Nonpharmaceutical COVID-19 Interventions on Pediatric Hospitalizations for Other Respiratory Virus Infections, Hong Kong
, Benjamin J. Cowling, J.S. Malik Peiris, Eunice L.Y. Chan, Wilfred H.S. Wong, and Kwok Piu Lee
Table 2
Relative reductions in incidence rates of pediatric hospitalizations during period of NPI and incidence rate ratio during school reopenings compared with school closure periods, Hong Kong Island, January 2017–January 2021*
| Virus | Relative reduction, % (95% CI)† | Incidence rate ratio (95% CI)‡ |
|---|---|---|
| Influenza A | 99 (98–100) | NE |
| Influenza B | 99 (97–100) | NE |
| Respiratory syncytial virus | 98 (97–99) | NE |
| Adenovirus | 85 (80–88) | 1.27 (0.85–1.89) |
| Parainfluenza types 1–4 | 96 (95–97) | 1.08 (0.85–1.69) |
| Human metapneumovirus | 98 (95–99) | NE |
| Rhinovirus/enterovirus | 87 (85–89) | 1.72 (1.37–2.17) |
*NE, not estimated because <10 hospitalizations with the given virus were recorded during the NPI period; NPI, nonpharmaceutical intervention. †Estimated as 1 minus the incidence rate ratio in a Poisson regression model for virus-specific hospitalization rates, adjusted for age and calendar time, comparing the period February 2020–January 2021 (NPI period) with January 2016–2020. ‡Estimated in a Poisson regression model for virus-specific hospitalization rates, comparing the period when schools were reopened with infection control measures versus when they were closed during 2020–21, adjusted for the overall risk reduction during the NPI period as well as for age and calendar time. An incidence rate ratio >1 indicates an increased rate during the school resumption period and vice versa.