Spike in childhood human metapneumovirus infections in Western Australia linked to reduced COVID-19 measures


Human metapneumovirus (hMPV) causes acute respiratory tract infections in kids. This virus displays differences due to the season, with a surge in an infection charges usually reported throughout the spring within the sub-tropical and temperate areas.

The non-pharmaceutical interventions (NPIs) carried out to limit the unfold of the extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of the coronavirus illness 2019 (COVID-19) pandemic, disrupted the seasonality of hMPV and different respiratory viruses in numerous components of the world, together with Western Australia (WA).

Research: A surge in human metapneumovirus paediatric respiratory admissions in Western Australia following the reduction of SARS-CoV-2 non-pharmaceutical interventions. Picture Credit score: adriaticfoto / Shutterstock.com


Like many areas worldwide, WA closed interstate and worldwide borders in early 2020. Subsequently, in mid-2020, a big discount in SARS-CoV-2 transmission was noticed.

Because of this, inner NPIs had been lowered, and enormous unmasked gatherings had been allowed. Nevertheless, state borders remained closed, and all people needed to endure two weeks of quarantine upon entry.  

Life returned to close regular contained in the closed borders for two.8 million people residing in WA. These individuals often socialized, attended massive gatherings, and will freely transfer internally.

All through this era, SARS-CoV-2 neighborhood detection was uncommon. Along with SARS-CoV-2, NPIs additionally disrupted the transmission of different respiratory viruses. For instance, no respiratory syncytial virus (RSV) and influenza virus transmission was noticed via winter in 2020; nonetheless, an out-of-season improve in RSV transmission was noticed between the summer time of 2020 and 2021. 

Though a change in RSV and influenza seasonality was noticed globally, no proof has been documented relating to the impression of COVID-19-related NPIs on hMPV. A potential laboratory surveillance report indicated a lower in hMPV incidence in 2020, adopted by a rise in its prevalence within the subtropical and temperate metropolitan areas in mid-2021. Nevertheless, these research failed to judge medical shows with seasonal variability of hMPV. 

In regards to the examine

A current Journal of Paediatrics and Child Health examine investigated the prevalence of hMPV via 2020 in WA, contemplating the implementation of NPIs as a result of COVID-19 pandemic.

This retrospective cohort examine included kids beneath sixteen years of age with respiratory-coded inpatient admissions after being dropped at the Emergency Division (ED) at Princess Margaret/Perth Youngsters’s Hospital between 2017 and 2021. Respiratory virus testing knowledge for a similar interval was obtained and matched with admitted pediatric sufferers.

All sufferers had been grouped by age and ICD-10 AM codes into bronchiolitis, wheezing, different acute decrease respiratory an infection (OALRI), and higher respiratory tract an infection (URTI).

Research findings

A complete of 44,800 ICD-10 coded respiratory ED shows had been obtained between 2017 and 2021, which included 28.9% of hospital admission. The variety of respiratory-coded admissions elevated from 2017 to 2019, decreased in 2020, and once more elevated in 2021.

Between 2017 and 2019, differences due to the season in all-cause respiratory-coded admissions had been noticed. The variety of admissions declined after the implementation of COVID-19-related NPIs in 2020, which was adopted by an out-of-season improve in respiratory-coded admissions in late 2020; notably, a surge in RSV an infection was documented. For 12 months from week 13 of 2020, no hMPV-positive admissions had been recorded following the implementation of NPIs.

Most hMPV-positive admissions occurred in 2021, which peaked in week 30. In comparison with 2017, hMPV-positive admissions elevated greater than 2.8 occasions in 2021. Equally, the proportion of whole respiratory-coded admissions associated to hMPV an infection elevated from 2% to 7% in 2021.

Within the metropolitan area, the incidence of hMPV admissions was roughly 3 times greater in 2021 than in 2017. This improve was attributed to modifications in doctor testing practices, together with a rise in hMPV testing, which may very well be attributable to SARS-CoV-2-related hospital an infection management necessities.

In comparison with the 2017-2019 interval, kids with hMPV-positive admissions had been older in 2021. The utmost incidence of hMPV an infection was noticed in kids between one and 4 years of age.

Though 2021 hMPV-positive admissions had been greater throughout all phenotypes, a most improve was noticed within the OALRI group, adopted by wheezing and URTI medical phenotypes. It’s attainable that the extended absence of hMPV might have triggered waning immunity in older people. 


After the implementation of COVID-19-related NPIs in WA, an absence of hMPV-positive admissions over 12 months was noticed. Nevertheless, within the winter of 2021, a big surge in hMPV-positive admissions was recorded.

The utmost prevalence of this an infection was noticed in kids between one and 4 years of age. Amongst all medical phenotypes, hMPV-positive OALRI admissions had been the utmost. This improve in hMPV instances may very well be pushed by COVID-19-related hospital an infection management necessities.

The shift in hMPV seasonality will change hMPV charges and related phenotypes. Sooner or later, continuous testing will assist estimate the true respiratory illness burden in kids.

Journal reference:

  • Foley, D. A., Yeoh, D. Ok., Minney-Smith, C. A., et al. (2023) A surge in human metapneumovirus paediatric respiratory admissions in Western Australia following the discount of SARS-CoV-2 non-pharmaceutical interventions. Journal of Paediatrics and Little one Well being. doi:10.1111/jpc.16445
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