Monday, April 21, 2014

MERS, HCWs, And Infection Control


Credit CDC


# 8505



Although there is a good deal we don’t know about the current outbreaks of MERS-CoV in healthcare settings in both Jeddah, Saudi Arabia and in the UAE, one thing is glaringly obvious: 


Healthcare workers are being infected at a disturbing rate.   Somewhere between 20%-25% of all known cases have reportedly been HCWS.


A fact that has apparently unnerved some medical staff, as over the past week we’ve seen stories indicating that some doctors, nurses, paramedics and healthcare facilities have refused to treat suspected MERS cases (see  KSA: Red Crescent Orders Ambulances & ERs To Accept MERS Cases). 


The CDC’s interim guidance for MERS-CoV infection control is very stringent, and it is based on a number of considerations:

  • Suspected high rate of morbidity and mortality among infected patients
  • Evidence of limited human-to-human transmission
  • Poorly characterized clinical signs and symptoms
  • Unknown modes of transmission of MERS-CoV
  • Lack of a vaccine and chemoprophylaxis


The World Health Organization’s recommended infection control guidelines are not quite as exacting (no doubt due to the wide disparity of resources available among nations), but nonetheless – if consistently observedought to provide reasonable protection to HCWs. 


For the past couple of months the WHO has included this reminder in every MERS update (bolding mine):


Infection prevention and control measures are critical to prevent the possible spread of MERS-CoV in health care facilities. Health-care facilities that provide for patients suspected or confirmed to be infected with MERS-CoV infection should take appropriate measures to decrease the risk of transmission of the virus from an infected patient to other patients, health-care workers and visitors. Health care workers should be educated, trained and refreshed with skills on infection prevention and control.

It is not always possible to identify patients with MERS-CoV early because some have mild or unusual symptoms. For this reason, it is important that health-care workers apply standard precautions consistently with all patients – regardless of their diagnosis – in all work practices all the time.

Droplet precautions should be added to the standard precautions when providing care to all patients with symptoms of acute respiratory infection. Contact precautions and eye protection should be added when caring for probable or confirmed cases of MERS-CoV infection. Airborne precautions should be applied when performing aerosol generating procedures.


Last year, when the first MERS HCW infections began to show up, we looked at the history of `sub-optimal’ compliance with infection control protocols, including during the 2009 H1N1 pandemic (see nCoV: PPE Adherence & Infection Control)


Admittedly, PPEs can be hot, uncomfortable, and a considerable bother to put on and take off properly, so lapses in infection control are not uncommon, at least during normal times..


The $64 question is why we are seeing so many HCWs infected with the MERS virus when they’ve been repeatedly warned to observe stricter infection control protocols?

While we don’t know, a few possibilities include:

  • Recommended infection control practices are not being applied fully and consistently.  (I’ve seen media reports complaining of lack of PPEs in hospitals and ambulances, including this one  h/t Sharon Sanders on FluTrackers)
  • Asymptomatic patients or staff are able to transmit the virus (known to happen with influenza, but unproven with MERS and not seen with SARS).
  • The virus has become more easily transmittable between humans in recent weeks (always a possibility, but unproven)
  • As we’ve seen with some influenza viruses (see PPEs & Transocular Influenza Transmission), the virus can be contracted via the ocular route (possible, but again, unproven). (Note: I’ve seen a lot of pictures of Saudi medical staff wearing surgical masks, but less commonly any eye protection)
  • Or, a combination of factors, not necessarily limited to this list.


Answers to these, and other pressing questions, can only come from detailed epidemiological investigations into these outbreaks.  Something that, presumably, is being done but whose details have not been publicly released. 


SARS – another novel coronavirus that thrived (albeit, briefly) in health care environments  – was brought under control only after hospitals figured out how to prevent its transmission in the workplace. 


Which makes figuring out how, and why, this virus seems to be transmitting so well in hospitals a major priority.


For those not intimately familiar with the different levels of infection control, the CDC defines `Standard Precautions’ as:


 Standard precautions” are a set of basic steps care providers use to protect their patients and themselves
from infection.  These basic steps include: 

  1. Practicing appropriate hand hygiene before and after contact with a patient, after contact with the
    surfaces or objects around the patient, and after removing gloves (if used). 
  2. Wearing disposable gloves when the care provider may have contact with blood, feces, urine, or
    any other body fluids.
  3. Wearing a gown to prevent contamination of the provider’s clothing with blood or body fluids.
  4. Using a face mask, face shield, and/or goggles if splashing of blood or body fluids might occur. 
  5. Cleaning of care equipment between patients.  


The next layer of infection control is `Droplet Precautions’, which add the requirement of wearing a face mask (surgical mask) anytime when in a room with a person who has a respiratory infection.

These precautions are used in addition to standard precautions listed above.

`Airborne Precautions’ are the most stringent, and add placing the patient in an airborne infection isolation room (AIIR) if available, and the following PPEs:

    • Wear a fit-tested N-95 or higher level disposable respirator, if available, when caring for the patient; the respirator should be donned prior to room entry and removed after exiting room
    • If substantial spraying of respiratory fluids is anticipated, gloves and gown as well as goggles or face shield should be worn


And lastly, the World Health Organization provides these guidance documents on dealing with MERS in the healthcare, and home environment.


Technical guidance - infection prevention and control

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