Fewer infants hospitalized for respiratory infections followed counter-COVID-19 measures in New Zealand

Abstract

In March 2020, a national elimination strategy for coronavirus disease was introduced in New Zealand. Since then, hospitalizations for lower respiratory tract infection among infants <2 years of age and cases of respiratory syncytial or influenza virus infection have dramatically decreased. These findings indicate additional benefits of coronavirus disease control strategies.

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In New Zealand, the incidence of hospitalization of infants with lower respiratory tract infection (LRTI) is high. LRTIs disproportionately affect Māori and Pacific Islander children and are predominantly caused by respiratory syncytial virus (RSV) (1).

The first case of coronavirus disease (COVID-19) in New Zealand was identified on February 28, 2020. Subsequently, the government pursued an elimination strategy, commencing with a national lockdown on March 25, along with strict international border controls, mandatory 14-day isolation of all international arriving passengers, intensive community testing, school closures, and contact tracing. This strategy seems to have largely succeeded, although recent small clusters of cases in the Auckland region demonstrate continuing vulnerabilities (2).

Kidz First Children’s Hospital serves an urban population of ≈550,000 persons in South Auckland, where 50% of infants are of Māori or Pacific Islander ethnicity. Since 2007, clinicians have performed nasopharyngeal sampling for respiratory virus PCR when clinically indicated and have participated in the SHIVERS (Southern Hemisphere Influenza Vaccine Effectiveness Surveillance) program of multiplex PCR virus surveillance (2). Since March 2020, additional COVID-19 PCR testing has been routinely performed for hospitalized children with respiratory illness. ....

After COVID-19 lockdown measures were implemented, we observed a marked reduction in hospitalizations of infants for respiratory illness at Kidz First Hospital; the reduction was sustained after gradual easing of the national lockdown beginning on April 27, 2020. To confirm the decrease, we examined respiratory viral PCR test results and infant LRTI hospitalization data from January 1, 2015, through August 31, 2020. ...