Human Parainfluenza Virus in Homeless Shelters before and during the COVID-19 Pandemic, Washington, USA

Area of Science:

• Epidemiology
• Virology
• Public Health

Background:

• The COVID-19 pandemic created unique challenges for infectious disease control in congregate settings.
• Homeless shelters are high-risk environments for respiratory virus transmission.

Purpose of the Study:

• To investigate the epidemiology of human parainfluenza virus (HPIV) in homeless shelters.
• To analyze HPIV genetic diversity and transmission patterns during the COVID-19 pandemic in Washington State.

Main Methods:

• Retrospective analysis of respiratory specimens collected from 23 homeless shelters in Washington, USA, between 2019 and 2021.
• Genomic sequencing of detected HPIV strains.
• Epidemiological data analysis to identify transmission clusters.

Main Results:

• Human parainfluenza virus was detected in the studied homeless shelter population.
• Two distinct clusters of HPIV infections were identified, primarily affecting children.
• Genetic analysis revealed that these clusters were linked by shelter of origin, suggesting localized transmission.

Conclusions:

• Homeless shelters experienced HPIV circulation during the COVID-19 pandemic.
• Evidence suggests localized transmission events within shelters, particularly impacting children.
• The findings underscore the need for shelter-specific public health interventions to mitigate HPIV spread.