Friday 2 September 2016

Korea contamination: Middle East respiratory syndrome coronavirus in the room..

Remember that MERS-CoV outbreak in South Korea from May 2015? 

It was the biggest outbreak of MERS-CoV to occur outside the Arabian peninsula, killing 20% of those known to be infected. As with all the noticeable MERS-CoV transmission events, it occurred within, and was undoubtedly facilitated by, a hospital setting. 

Back in March 2016, a paper came out looking at routes of infection within in 2 South Korean hospitals (Chungbuk National University Hospital, Hallym University Kangnam Sacred Heart Hospital) among 4 female patients (3 with prior underlying diseases, 1 of whom died) who had developed pneumonia.[1]

Some interesting findings from this study included:
  • Infectious virus could be grown from 3 patients up to 18-22 days after symptom onset (RNA to the 25th day in 1 patient's sputum, suggesting a good correlation between RNA positivity and risk of infection in this small study). The 4th patient shed viral RNA to day 23 after onset but no infectious virus could be isolated. This case also had no underlying diseases so perhaps viral loads were just lower.
  • MERS-CoV RNA could be detected by RT-PCR in hospital rooms 2-5 days after the occupant had died or last tested positive. Anteroom floor and desk samples and medical equipment like X-Ray machines and thermometers were also found to be RNA positive.
    Some of these locations were not directly accessible to the patients and so were likley to have been contaminated via droplets or by healthcare workers.
  • A swabbed air inlet ventilation duct tested positive for MERS-CoV RNA hinting at airborne viral movement
  • Infectious MERS-CoV virus was able to be grown from some items and surfaces including bed sheet, bed rails, intravenous fluid hangers and a table.

All in all, this study highlights how effectively an environmentally stable respiratory virus can deposit itself around the room of a productively shedding patient. 

When you add in:
  • poor or inconsistent infection control
  • room overcrowding
  • family members given some responsibility for care [3]
  • that MERS-CoV is not very good at passing from human-to-human in the community have a clear explanation for why MERS outbreaks occur entirely in relation to healthcare settings. These settings are where you find close and prolonged contact between infected cases and health care workers and family and friends. You also find those cases contained in multi-bed, flat-surface filled boxes (rooms), ready-made to be contaminated by virus-laden droplets.

While the finding of virus everywhere is not a surprise, it is important to have thorough studies like this that can be referenced in protocols which aim to improve infection control and prevention processes.

Common sense alone is not evidence.

  1. Persistent Environmental Contamination and Prolonged Viral Shedding in MERS Patients During MERS-CoV Outbreak in South Korea
  2. Middle East respiratory syndrome coronavirus: how tough is it?
  3. 2015 MERS outbreak in Korea: hospital-to-hospital transmission

No comments:

Post a Comment

Note: only a member of this blog may post a comment.