Lower respiratory tract infections


Factsheet: Lower respiratory tract infection hospitalisations (0–4 years) (July 2022) View interactive report Download report PDF
Metadata: Lower respiratory tract infection hospitalisations Download report PDF

Poor indoor and outdoor air quality increases the risk of lower respiratory tract infections among children

Lower respiratory tract infections (LRTI) refer to infections of the windpipe (trachea), lungs, and airways (bronchi, bronchioles). These include pneumonia, bronchitis and bronchiolitis. Household crowding [1] second-hand smoke exposure [2], indoor dampness and mould [3], and outdoor air pollution [4] increase the risk of lower respiratory tract infections in young children.

LRTI is responsible for a large burden of avoidable mortality and morbidity among young children under five years old globally. Compared with other developed countries, New Zealand has high rates of LRTI hospitalisation among young children [5]. Each year, a small number of children in New Zealand die from lower respiratory tract infections. Between 2001 and 2018, 173 children under five years of age died from lower respiratory tract infections, an average of 10 deaths every year.


The COVID-19 pandemic

In March 2020, the New Zealand Government pursued an elimination strategy for COVID-19. New Zealand moved to Alert Level 4 (Lockdown) on 25 March 2020, along with temporary border closures, quarantine requirements, community testing, school closures, and contact tracing. These public health measures appeared to have affected lower respiratory tract infection (LRTI) hospitalisation rates in children 0–4 years in 2020.


Number of LRTI hospitalisations decreased dramatically in 2020

In 2020, there were 2856 LRTI hospitalisations in children under five years old, a 71% decrease since 2019 (9939 hospitalisations) (Figure 1).

Figure 1: Number of lower respiratory tract infection hospitalisations in children aged 0–4 years, 2001–2020


Usual winter LRTI hospitalisation peak was down by 85%

The number of LRTI hospitalisations during the 2020 winter season was very low compared to previous years since 2001. There were 272 hospitalisations in August 2020, down from 1817 in August 2019 (Figure 2). This dramatic decrease in LRTI hospitalisations is likely related to the strict public health measures implemented during the COVID-19 pandemic.

Figure 2: Number of lower respiratory tract infection hospitalisations in children aged 0–4 years, by month, 2018–20


Information about this data

Lower respiratory tract infection hospitalisations

Source: National Minimum Dataset, Ministry of Health

Definition: Acute and semi-acute hospitalisations with pneumonia (ICD-10AM J12–J16, J18), bronchitis (J20), bronchiolitis (J21) or unspecified acute lower respiratory tract infection (J22) as the primary diagnosis, for children aged 0–4 years.  Analyses excluded overseas visitors and transfers within and between hospitals. Rates have been presented per 100,000 children.  



1. Baker MG, McDonald A, Zhang J, Howden-Chapman P. 2013. Infectious diseases attributable to household crowding in New Zealand: A systematic review and burden of disease estimate. Wellington: He Kainga Oranga/ Housing and Health Research Programme, University of Otago. 

2. U.S. Department of Health and Human Services. 2007. Children and Secondhand Smoke Exposure. Excerpts from The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health.

3. Fisk W, Eliseeva E, Mendell M. 2010. Association of residential dampness and mold with respiratory tract infections and bronchitis: a meta-analysis. Environmental Health 9(1): 72. doi: 10.1186/1476-069X-9-72

4. Mehta S, Shin H, Burnett R, et al. 2013. Ambient particulate air pollution and acute lower respiratory infections: a systematic review and implications for estimating the global burden of disease. Air Qual Atmos Health 6: 69–83.

5. Trenholme AA, Byrnes CA, McBride C, et al. 2013. Respiratory health outcomes 1 year after admission with severe lower respiratory tract infection. Pediatric Pulmonology 48: 772–79

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