COVID-19 outbreaks in residential care homes in Hong Kong and effectiveness of vaccine against severe outcomes

Tracking SARS-CoV-2 RNA in the air: Lessons from a COVID-19 outbreak in an infirmary unit

BACKGROUND

The duration and magnitude of SARS-CoV-2 air dispersal during nosocomial outbreaks remain uncertain. This study evaluates the impact of mobile modular high-efficiency particulate air filter units (MMHUs) on SARS-CoV-2 air dispersal.

METHODS

We investigated a nosocomial COVID-19 outbreak in an infirmary unit. The viral load (VL) of SARS-CoV-2 in air samples was correlated with the VL in nasopharyngeal swabs with or without MMHU. These samples underwent whole-genome sequencing and phylogenetic analysis.

RESULTS

Upon outbreak declaration (August 2, 2024, day 0), 44 (69.8%) of 63 patients acquired COVID-19 in Ward 2B (19 male) and 2C (25 female) by day 4. The VL of SARS-CoV-2 remained detectable in air until day 11 (2B) and day 20 (2C). The VL of air samples was significantly correlated with the VL in nasopharyngeal swabs collected on days 5, 7, 10, and 13 in 2C (r = -0.975, P = .004). Using MMHU, the mean daily ratio of SARS-CoV-2 RNA (copies/1,000 L of air/patient) in 2B was 5 times lower than in 2C from days 5 to 10. Whole-genome sequencing revealed all 41 tested strains belonged to the Omicron variant, KP.3.1.1, phylogenetically related to the prevailing community strains.

CONCLUSIONS

Using MMHU mitigates the duration and magnitude of SARS-CoV-2 air dispersal during nosocomial outbreak.

Revisiting Vaccine Hesitancy in Residential Care Homes for the Elderly for Pandemic Preparedness: A Lesson from COVID-19

Residents in residential care homes for the elderly (RCHEs) are at high risk of severe illnesses and mortality, while staff have high exposure to intimate care activities. Addressing vaccine hesitancy is crucial to safeguard vaccine uptake in this vulnerable setting, especially amid a pandemic. In response to this, we conducted a cross-sectional survey to measure the level of vaccine hesitancy and to examine its associated factors among residents and staff in RCHEs in Hong Kong. We recruited residents and staff from 31 RCHEs in July-November 2022. Of 204 residents, 9.8% had a higher level of vaccine hesitancy (scored ≥ 4 out of 7, mean = 2.44). Around 7% of the staff (n = 168) showed higher vaccine hesitancy (mean = 2.45). From multi-level regression analyses, higher social loneliness, higher anxiety, poorer cognitive ability, being vaccinated with fewer doses, and lower institutional vaccination rates predicted residents' vaccine hesitancy. Similarly, higher emotional loneliness, higher anxiety, being vaccinated with fewer doses, and working in larger RCHEs predicted staff's vaccine hesitancy. Although the reliance on self-report data and convenience sampling may hamper the generalizability of the results, this study highlighted the importance of addressing the loneliness of residents and staff in RCHEs to combat vaccine hesitancy. Innovative and technology-aided interventions are needed to build social support and ensure social interactions among the residents and staff, especially amid outbreaks.