Basics of Infection Prevention and Control with Special Reference to Human Respiratory Coronaviruses

By Dr. Syed Sattar (5), Dr. Bahram Zargar (2)

February 24, 2020

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Background

Coronaviruses often cause self-limiting respiratory infections similar to the ‘common cold’. However, infections by certain types of such viruses can lead to potentially fatal pneumonia. In less than the past two decades, three such highly pathogenic coronaviruses have emerged as zoonotic (originating in animals) agents for humans. The first among these was in 2003, the virus that caused a pandemic (world-wide epidemic) of the severe acute respiratory syndrome (SARS). Then, another virus was incriminated as the cause of the Middle-East Respiratory Syndrome (MERS) with the main health impact on Saudi Arabia. COVID-19 is the latest virus to have emerged out of China in December 2019.

The three above-mentioned viruses together have caused much disruption to our healthcare systems, economy and travel. COVID-19 alone has led to well over 75,000 clinical cases with at least 2,000 fatalities including several in healthcare personnel. China, the epicenter of the current outbreak, has put in place unprecedented measures to stem virus spread, while the World Health Organization (WHO) has also been active from the very outset to mobilize international efforts against the virus. Nevertheless, the pandemic rages on!

Virus Spread

Sneezing and coughing can generate virus-laden respiratory droplets, which can transmit the infection to those close by. Such droplets may fall out of the air and contaminate environmental surfaces for further spread, possibly by hands. Smaller airborne particles (droplet nuclei) may remain suspended in air for longer periods with the potential to be carried by air currents over longer distances. While the relative importance of droplet nuclei as vehicles for virus spread remains unknown, the ability of the virus to survive in air for several hours points to the potential for airborne transmission.

Viruses shed in feces may also lead to the contamination of environmental surfaces and direct and/or contamination of hands. The main portals of virus entry into the body are believed to be the nose and the mouth. The incubation period is about two weeks. Those infected can pass the virus on to other susceptible persons (secondary cases).

In terms of the fatality rate, data from China in particular suggests that about 2% of those with a severe infection die from it; those 80 years or older show a higher degree of susceptibility to the virus. It is not known if the survivors remain refractory to reinfection by the virus and for how long.

Approaches to IPAC

As of now, no vaccines or drugs are available against coronaviruses in general. Therefore, public education and general IPAC precautions remain the only options to counter the spread of such pathogens. Notably, those in healthcare professions are at a higher risk of exposure to the viruses due to their closer interactions with clinically and sub-clinically infected patients. Basic IPAC strategies include:

Properly and frequently wash visibly-soiled hands by lathering them well with plain (without any antimicrobial ingredients) soap and water by rubbing them together for at least 20 seconds. Rinse the lathered hands thoroughly with clean running water and then dry them well with a clean cloth or paper towel; warm-air hand dryers may be used, if available.
In between handwashings, or when access to soap and water is unavailable, sanitize hands by rubbing them for 20 seconds with a handrub containing 60-80% ethanol (volume for volume). Such handrubs need not contain any additional antimicrobial agents.
Regular hand hygiene is a generic means to interrupt virus transfer to the portals of entry and also to keep other surfaces and objects from contamination.
Wear a face mask to avoid inhalation of droplets and airborne virus particles.
Stay away from public places during the infectious phase of the infection.
Avoid travel to an area with known cases of the virus.
As much as possible, avoid close contact with a known case of the infection for no less than 14 days (incubation period of the viruses). Use proper personal protective equipment (PPE) when such contact in avoidable.
Handle all known or suspected clinical specimens from cases of COVID-19 and other pathogenic coronavirus infections to prevent laboratory-associated cases of infection. The use of a face mask, gloves and manipulations of the specimens in a biosafety cabinet are among the basic precautions in this regard.

Concluding Remarks

COVID-19 will most certainly not be the last such virus to confront humanity. In fact, many ongoing climatic and societal changes are poised to favour the emergence of viruses and other human pathogens. In the meantime, we are learning crucial lessons every time a new pathogen emerges. For example, the SARS and MERS viruses have taught us better ways to counter COVID-19. Finally, we must revive the practice of IPAC as generic and effective approaches to counter existing and emerging pathogens while efforts are underway to develop safer and effective vaccines and drug.

NOTE

Over the past five decades, Dr. Sattar has been studying the environmental fate of a wide variety of human pathogens including respiratory and enteric viruses. He also researches the role of disinfectants and hand hygiene agents to interrupt the spread of pathogens by environmental surfaces, hands and indoor air.

Specifically, Dr. Sattar has studied the impact of indoor air temperature and relative humidity on the survival of human respiratory coronavirus 229E, a common surrogate for highly pathogenic coronaviruses. He has also studied how well 229E survives on environmental surfaces and human hands as well as the ability of disinfectants and hand hygiene agents to inactivate it.

Several of the test protocols developed by his research team now form the basis of national and international standards. Dr. Sattar has published three books, over 200 peer-reviewed papers and has delivered nearly 380 invited lectures in some 40 countries worldwide. He is an advisor to the WHO.