WE are all in the long-haul stretch of the Covid-19 endless marathon and we see fatigue and hopelessness setting in as repeated movement control orders (MCOs) and tighter restrictions are imposed. We need to be science-based with our daily SOPs, rather than resort to harsh measures. Heftier fines, extended MCOs, increased public blaming are counterproductive and also harmful to the poor and those who have lost their livelihood. We have to walk this fine balance between harm from Covid-19 and destroying lives from tight SOPs that limit employment.
I would like to offer some evidence-based suggestions on the few key SOPs that work, or do not work, for members of the public. Our ‘mantra’ for Covid-19 prevention should be three things – masks, ventilation, and prevent crowding (physical distancing). These are the key measures and all SOPs should be focused around them. All these three relate to airborne transmission, which is the primary mechanism for Covid-19 spread.
Stop temperature scanning
We are all used to the routine temperature checks required at all premises. Some of us have been cautious about their value in detecting individuals with possible Covid-19. Mekjavic and Tipton have written a detailed review of available data on the value of infrared thermographic screening for Covid-19. The key points from all the studies reviewed suggest that:
1. A measurement of skin (forehead) temperature does not provide an accurate assessment of core body temperature that is raised in a fever.
2. Not all who have Covid-19 have a fever, especially in early stages while still infectious. Hence a normal temperature check may provide false reassurance. We are aware that pre-symptomatic and currently asymptomatic individuals are important in Covid-19 transmissions.
3. The reliability of infrared thermometers is an issue and may vary by as much as 2 degrees Celsius. One study comparing forehead temperature of 1,000 people with different infrared thermometers gave variable temperatures ranging from 31 degrees Celsius to 35.6 degrees Celsius. Another study showed an over 80 per cent false negative (missed the fever) using infrared thermometers.
One of the authors of the review, Prof Mike Tipton said, “Using a surface temperature scanner to obtain a single surface temperature, usually the forehead, is an unreliable method to detect the fever associated with Covid-19.”
Hence infrared thermometer screening is inaccurate and provides false reassurance. In addition, we have seen locations where you have to come very close to the device, often touching it, to get a reading (high risk). Queuing for a temperature check also slows movements and reduces physical distancing. It is best that we stop this activity (SOP).
Al fresco dining
Ventilation is key to reducing Covid-19 risk, especially in buildings. Here we are focusing on F&B (food and beverage) outlets. While takeaway food is a good option we also need to get back to sit-down dining to enable some to make a living. Lipinski and colleagues have reviewed the data on ventilation strategies to reduce the risk of disease transmission in high-occupancy buildings. The data is clear that recirculating ventilation and systems that move indoor air around produce turbulent air flows with stale air and hence are of high risk.
What is preferred are displacement ventilation systems that remove contaminated indoor air and supply fresh air from outside constantly. The US Centers for Disease Control and Prevention (CDC) have good guidance on improving ventilation in buildings and considerations for restaurants. The CDC suggests that restaurants prioritise outdoor dining with a good two-metre spacing between tables. Small outdoor bubbles for dining are not safe as they restrict airflow. Any indoor dining should significantly restrict patrons, have two-metre spacing between groups and have displacement ventilation – increase fresh outdoor air by opening windows and doors, and place fans at a window to draw room air to the outdoors and draw fresh air into the room (avoid placing fans that cause contaminated air to flow directly from one person over to another).
Hence all shops and restaurants should be open-air and non-air-conditioned. We can make this happen by allowing tables and chairs to be put on the five-footway and perhaps even the road (at night). Strictly limit indoor patrons, keep all doors and windows open, and use fans judiciously as mentioned above.
The current single entry into a shop, with tape to cordon off all other entries, may be harmful – we can still do handphone scanning for entry at multiple sites. Restaurant bathrooms remain a high-risk location and should be avoided by patrons. Other useful tips include avoiding reusable menus or other items where surface spread may happen, enabling strict booking times, and limited eating times to reduce crowding. Do not use straws for drinks as they pose a high contamination risk.
Some members of the public have expressed concern with the opening of night markets but they are definitely a much safer place to eat than a shopping complex or closed air-conditioned restaurant.
Improve mask quality and fit
Despite the widespread usage of masks, we still have many issues with mask use, especially poor usage. In addition, there is a growing call for the general public to replace cloth masks with medical/surgical masks. There have been a number of good reviews looking at all the evidence for mask use, cloth mask effectiveness compared to medical/surgical masks, face shields, etc; they include work by Chu et al, Howard et al, Clapp et al, Edelstein and Ramakrishnan, and The Royal Society and the British Academy.
The key points from all the studies reviewed support that:
1. Masks are effective in reducing transmission of infected Covid-19 respiratory particles to others (both protect others and protect us).
2. When compliance to mask wearing by the public is high, spread of the virus is effectively reduced.
3. Cloth masks are effective if made with multiple layers and hybrid construction (following World Health Organisation guidelines for three layers: outer layer of non-absorbent material, such as polyester or polyester blend; middle layer of non-woven non-absorbent material, such as polypropylene; inner layer of absorbent material, such as cotton). Cloth masks could provide 70 to 90 per cent filtration efficiency with a good fit and aluminium nose bridge.
4. An improper fit of a mask can result in a significant decrease in the filtration efficiency. This applies to both medical/surgical masks and cloth masks. Medical/surgical masks with ear loops are poor (38 per cent filtration efficiency) compared to those with ties (72 per cent efficiency). See Figure 1 from The Royal Society and The British Academy and Figure 2 from Clapp et al. Note that the effective N95 respirator-type masks, used in hospitals, are not discussed here.
The ‘Evaluation of Cloth Masks and Modified Procedure Masks as Personal Protective Equipment for the Public during the Covid-19 Pandemic’ by researchers from the US Centers for Disease Control and Prevention Epicenters Program (Clapp et al) stated as a conclusion, “While modifications to improve medical procedure mask fit can enhance the filtering capability and reduce inhalation of airborne particles, this study demonstrates that the FFEs of consumer-grade masks (cloth masks) available to the public are, in many cases, nearly equivalent to or better than their non-N95 respirator medical mask counterparts.”
Hence it is important that those wearing medical/surgical masks with ear loops work to improve the fit of those masks. The time has come to provide standard guidelines on commercial cloth mask manufacture as in a number of countries. It is better for us to use quality reusable cloth masks, rather than pollute the environment with single-use medical/surgical masks (with the plastic in these masks they can last 300 to 400 years). Finally, no amount of mask usage is of value if the nose is exposed or the mask placed on the chin.
Open parks, trails to the public
Outdoor activities are relatively safe (not contact sports), provided unrelated persons maintain some physical distancing. Nature parks and jungle trails are safe locations for the public to go to. The current restrictions on forest reserves and jungle trails works against the public, who require some outlets for recreation.
Not all areas are covered in this brief write up but I hope the data and evidence quoted here support improvements in our SOPs and efforts towards improved control of the pandemic locally.
Datuk Dr Amar-Singh HSS is a senior consultant paediatrician.