Understand different transmission modes of COVID-19 and take action
As we mark the one-year anniversary of the COVID-19 pandemic, immunisation programs all over the world promise us a return to the busy and crowded norm we have left behind. Are you looking forward to going back into public buildings such as shops, restaurants, hairdressers and even schools and work? I know I am. However, even with the robust vaccination measures in place, many of us cannot help but feel nervous about being in close contact with others. Although we are looking forward to going back out into public domains, it is certain that it will have to come with additional new precautions.
Modes of SARS-CoV-2 / COVID-19 transmission
To ensure protection from SARS-CoV-2 / COVID-19, it’s helpful if you understand the different transmission modes and take action. Inhaling small airborne droplets has been established as a third route of infection, in addition to more widely recognised transmission via larger respiratory droplets and direct contact with infected people or contaminated surfaces. It was only in October of 2020, The Centers for Disease Control and Prevention (CDC) issued an update , highlighting increasing evidence of COVID-19 transmission in enclosed spaces through airborne exposure. Social distancing, hand washing, and the use of masks and personal protective equipment (PPE) have been established to protect us from disease that can spread through close contact; however effective preventative measures against transmission via aerosols is still to be implemented.
Although the air sampling data for viral particles is currently incomplete, several hospital-based studies showed positive indication of airborne transmission, with the highest viral loads found in personal samplers worn by team members in the presence of a patient receiving oxygen via nasal cannulas.
Effective monitoring for viral DNA and RNA
The Environmental Express® Vira-Pore viral sampling cassette, featuring the ZePore™ filter, has been specifically designed and validated for the collection of airborne RNA from coronavirus and therefore, by analogy, could be used for sampling RNA from other viruses such as SARS-CoV-2, the virus that causes COVID-19, Influenza A, H1N1, and H5N1.
The Vira-Pore is the only scientifically validated air sampling cassette in the market that collects viral particles, while maintaining the stability of the RNA throughout sampling, transport, and storage. Once at the lab, the viral RNA can be analysed using reverse transcription polymerase chain reaction (RT-PCR).
Engineering controls to minimise disease transmission
Using engineering controls in public buildings and public transport, in parallel with effective application of other controls, could be an important and additional measure to help you reduce the likelihood of disease transmission that protects not only healthcare workers and hospital patients, but also your workers and the public.
Implement sufficient ventilation
Ventilation controls how quickly room air is replaced with outside air over time. Good ventilation practices are already in place in many hospital settings, however, similarly effectively measures may not be available in other types of public buildings. In response to the pandemic, we have seen several large emergency hospital wards created within exhibition centres. While these facilities usually have adequate mechanical ventilation for exhibition or conference use, it is unclear if that would also be sufficient for patient management and infection control purposes.
The SARS-CoV-2 virus, which has been shown to be stable in airborne particles with a half-life of more than one hour, produces a high likelihood of an infected person sharing air with susceptible occupants in public buildings and other shared spaces. It would, therefore, be beneficial to implement monitoring solutions that can help identify the risk in such a setting.
Avoid air recirculation
The recirculation of air is a common cost-saving measure implemented in numerous buildings, but it can pose the risk of transporting airborne contaminants, including infectious virus particles, from one space to another that are connected by the same ventilation system. Placing particulate filters and disinfection equipment in recirculated air streams can reduce this risk, provided they are purposefully designed. During a pandemic, however, it is advisable to stop the recirculation of air as much as practically possible.
Air cleaning options
When it is not feasible to improve ventilation or prevent air recirculation, filtering or ultraviolet germicidal irradiation (UVGI) can be used to remove or deactivate potential viral contamination. The “upper-room” system, which gained popularity in the 1980s, involves mounting UV lamps on ceilings and walls of the upper part of the room. It has been estimated to reduce the risk of infection by an amount equivalent to doubling the ventilation rate of that space. Portable consumer air cleaning devices may also be beneficial in smaller rooms.
Until vaccination programs can effectively reduce the transmission rate of COVID-19 infections to below 1.0, continue to follow isolation, quarantine, social distancing, and hand hygiene guidelines. In addition, it is good to know that scientists and policymakers are working on several other monitoring and preventative measures that can be implemented to ensure your workplace and other public spaces are made safer for all of us.
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