In a recent study, “Investigation of Air Dispersal During a Rhinovirus Outbreak in a Pediatric Intensive Care Unit,” conducted at Queen Mary Hospital in Hong Kong, researchers delved into the transmission dynamics of rhinovirus within a pediatric intensive care unit (PICU). Rhinovirus is a common cause of upper respiratory tract infections, particularly affecting vulnerable pediatric patients. Understanding how rhinovirus spreads in health care settings is crucial for effective infection control.
Between March 31, 2023, and April 2, 2023, 3 patients in a 12-bed PICU at Queen Mary Hospital acquired rhinovirus. The study investigated this outbreak to determine the factors contributing to its transmission.
“Previous studies have suggested that airborne transmission, either via large or small aerosols, is a significant route of rhinovirus transmission in real-life indoor settings.
However, our study suggests that airborne transmission may not have played a significant role in the nosocomial transmission of rhinovirus in the PICU. This is supported by the fact that the air sample collected during the outbreak, where 3 hospital-acquired rhinovirus cases were cohorted together, tested negative for rhinovirus RNA.”
Top 5 Takeaways
- Study Context: The research focused on understanding the transmission of rhinovirus, a common cause of upper respiratory tract infections, within a PICU. This is particularly relevant as pediatric patients are vulnerable to such infections.
- Outbreak Investigation: Between March 31, 2023, and April 2, 2023, an outbreak of rhinovirus occurred in a 12-bed PICU involving three patients. The study aimed to uncover the factors contributing to this outbreak.
- Airborne Transmission Questioned: While prior research suggested airborne transmission as a significant route for rhinovirus, this study indicated that it may not have played a substantial role in this outbreak. Air samples collected during the outbreak tested negative for rhinovirus RNA.
- Masks and Hand Hygiene: Analysis of staff members' surgical masks revealed no presence of rhinovirus RNA, emphasizing that airborne particles might not have been the primary mode of transmission. Hand hygiene practices were well-maintained, with approximately 90% adherence among staff.
- Environmental Contamination: Only a small percentage of environmental samples tested positive for rhinovirus RNA, indicating that environmental contamination played a minor role in the outbreak.
This study highlights the complexities of rhinovirus transmission in healthcare settings and emphasizes the importance of stringent infection control measures, including hand hygiene and mask usage, in preventing nosocomial infections. Further research is needed to better understand the nuances of rhinovirus transmission in various health care environments.
One of the study's primary objectives was to assess whether air dispersal played a role in rhinovirus transmission. The researchers collected air samples from the PICU cohort area and analyzed them for rhinovirus RNA. Surprisingly, despite being significant (72,000 liters in 6 hours), the air samples tested negative for rhinovirus RNA. This finding suggests that airborne transmission may not have been a significant factor in this outbreak.
The research team examined the outer surfaces of staff members' surgical masks to gain further insights. These masks were analyzed for viral load and phylogenetic analysis. The results showed that the staff's masks did not carry rhinovirus RNA. This reinforces the idea that the primary transmission mode in this outbreak might not have been through airborne particles.
The study evaluated hand hygiene adherence in the PICU, a critical aspect of infection control. Surprisingly, the data revealed no significant differences in hand hygiene adherence before and during the outbreak. We had relatively high adherence rates in both periods, with 91.2% before the outbreak and 89.2% during the outbreak. This indicates that while hand hygiene is essential, it might not have been the primary factor driving the rhinovirus transmission.
Of all the environmental samples collected, only 1 (3.8%) tested positive for rhinovirus RNA, with a relatively low viral load (1.86 x 10^3 copies/mL). This suggests that environmental contamination played a minor role in the outbreak compared to other modes of transmission.
A case-control analysis was conducted to identify the source of the rhinovirus outbreak. Next-generation sequencing and epidemiological data identified an infected staff member as the outbreak's source. This emphasizes the importance of health care workers in preventing nosocomial infections and highlights the need for strict infection control measures among staff.
“Although a staff member is epidemiologically implicated as the source of the infection, the persistent implementation of infection control measures, particularly hand hygiene practices, universal masking by health care workers, and environmental disinfection during the COVID-19 pandemic, helped to limit the spread of rhinovirus in the PICU. The overall adherence to hand hygiene among staff was approximately 90% just before and during the nosocomial transmission of rhinovirus. In addition, only 1 out of 26 environmental samples were contaminated with rhinovirus RNA, indicating a high standard of infection control practices in the PICU.”
The findings of this study raise important questions about the transmission of rhinovirus in health care settings. While previous research had suggested the possibility of airborne transmission, this study did not find conclusive evidence of such transmission during this particular outbreak in a well-ventilated PICU.
However, it's essential to recognize that the dynamics of virus transmission can vary depending on multiple factors, including ventilation, viral load, and the behavior of individuals in the health care environment. Further research is needed to understand the nuances of rhinovirus transmission in various health care settings and under different conditions.
This study provides valuable insights into rhinovirus transmission within a pediatric intensive care unit. While airborne transmission was not conclusively documented in this particular outbreak, the research underscores the complexity of virus transmission dynamics and the importance of rigorous infection control measures, including hand hygiene and proper mask usage. Health care facilities must remain vigilant in preventing nosocomial infections and continually adapt their strategies based on the latest research findings.
The study can be found here.
