Setting up isolation facilities and wards

This page describes the guidelines and best practices in setting up quarantine and isolation facilities to ensure infection prevention and control

This is summarized mainly from the NCDC Guidelines for setting up isolation facilities and wards.

For a quick checklist for setting up of isolation wards please see this document.

Who should be placed in quarantine and who in isolation wards?

Quarantine refers to separation of individuals who are not yet ill but have been exposed to COVID-19 and therefore have a potential to become ill. Isolation refers to separation of individuals who are ill and suspected or confirmed of COVID-19. All suspect cases detected in the containment/buffer zones (till a diagnosis is made), need to be hospitalized and kept in isolation in a designated facility till such time they are tested negative.

How should we isolate the patients who are suspected or confirmed cases of COVID19?

Ideally, patients can be isolated in individual isolation rooms or negative pressure rooms with 12 or more air-changes per hour. In resource constrained settings, all positive COVID-19 cases can be cohorted in a ward with good ventilation. Similarly, all suspect cases should also be cohorted in a separate 2 ward. However under no circumstances these cases should be mixed up. A minimum distance of 1 meter needs to be maintained between adjacent beds. All such patients need to wear a triple layer surgical mask at all times.

Ventilation, filtration, and air distribution systems and disinfection technologies have the potential to limit airborne pathogen transmission through the air and thus break the chain of infection. Hence, it is important to ensure proper airflow management of isolation rooms/facilities.

Theoretical aerobiology of transmission of droplets and small airborne particles produced by an infected patient with an acute infection (courtesy Yuguo Li). Image from position paper by ASHRAE.

Should isolation wards be restricted to negative pressure rooms?

The main goal of a negative pressure room is to contain contagions within a single room and prevent illness from spreading to other areas of the hospital. Containing pathogens to a single room can reduce the likelihood of spreading contamination to other patients, staff or sterile equipment. Negative pressure isolation rooms are commonly used for patients with airborne infections (like COVID-19). In resource constrained settings very often rooms with separate air-conditioning may not be available. Under these circumstances ensuring natural airflow and ventilation can help limit the spread of infection.

What to do if isolation ward is connected with the central air-handling unit?

The use of highly efficient particle filtration in centralized air-conditioning systems reduces the airborne load of infectious particles. This strategy reduces the transport of infectious agents from one area to another when these areas share the same central conditioning system through supply of recirculated air. When appropriately selected and deployed, single-space high-efficiency filtration units (either ceiling mounted or portable) can be highly effective in reducing/lowering concentrations of infectious aerosols in a single space.

If recirculation of air from isolation rooms to other rooms is unavoidable, HEPA filters should be installed in the exhaust duct leading from the isolation rooms to the general ventilation system. This could also be augmented by standard UV filters which could be set up by an electrician and may not be prohibitively expensive.

What to do if not air-conditioning is available for the isolation ward?

Many buildings are fully or partially naturally ventilated. They may use operable windows and rely on intentional and unintentional openings in the building envelope. The ability to actively manage risk in such buildings is reduced due to lack of control over airflow patterns. Generally speaking, designs that achieve higher ventilation rates will reduce risk. Artificial airflow, under lack of natural ventilation, could also be created through putting up 3-4 exhaust fans driving air out of the room.

Is maintenance of appropriate levels of temperature and humidity a requirement?

Yes, humidity levels of 40%-60% should be maintained within the isolation wards/rooms.

Mid-range humidity levels has been correlated with improved immunity against respiratory infections. Some scientific literature reflects that most unfavorable conditions for survival for microorganisms arise when the RH (relative humidity) is between 40% and 60%. Introduction of water vapor to the indoor environment to achieve the mid-range humidity levels associated with decreased infections requires proper selection, operation, and maintenance of humidification equipment. Very dry environments where RH falls below 40% is associated with three factors that increase infections:

1) infectious aerosols emitted from a primary host shrink rapidly to become droplet nuclei, and these dormant yet infectious pathogens remain suspended in the air and are capable of traveling great distances. When they encounter a hydrated secondary host, they rehydrate and are able to propagate the infection.

2) many viruses and bacteria are anhydrous resistant and actually have increased viability in low-RH conditions, which may lead to secondary infections in COVID patients.

3) ambient RH below 40% impairs mucus membrane barriers and other steps in immune system protection.

For further details please read ASHRAE Position Paper on infectious aerosols.

More details can be obtained along CDC Guidelines for environmental infection control in healthcare facilities.