By Edsel Maurice T. Salvana, MD, DTM&H, FPCP, FIDSA, MANILA BULLETIN
As the country tries to open up after a prolonged lockdown, many employees and employers are diligently preparing their workplaces to minimize the risk of spreading COVID-19. What are the best practices to ensure we can resume work safely? Can we ever go “back to normal?” What is the best way to beat the virus at its own game?
How the virus moves from one person to anotherUnderstanding how Covid-19 spreads is key to controlling its transmission. Since SARS-CoV-2 (the virus that causes COVID-19) is a respiratory virus-like influenza, the most common route of transmission is from respiratory droplets. These are released when someone sneezes or coughs. Droplets can also be generated and released when someone is talking—but this is much less efficient than an explosive cough or sneeze. Droplets typically travel about three feet before they drop to the ground, although some may travel longer distances if there is wind or ventilation. This is the rationale behind keeping a physical distance of three to six feet from each other—chances are much less that any expelled respiratory droplets will be inhaled or swallowed. Inhalation of respiratory droplets is by far the most efficient and common way for COVID-19 to spread. The best ways to prevent droplet transmission are by consistent physical distancing and by wearing a mask.
Another path of transmission is through contact with infectious secretions. When someone sneezes, surfaces can be contaminated with respiratory droplets. If someone touches these surfaces, the droplets can transfer the infectious virus on to a person’s hands. If the person does not wash his hands and then inadvertently touches his eyes, nose, or mouth, live virus can be transferred. This route of transmission can be affected by the surface that the droplet lands on, as well as the environmental temperature which can eventually inactivate the virus the longer it stays exposed. The best ways to prevent contact transmission are by frequent handwashing and appropriate disinfection of surfaces.
The transmission number
To measure how easily a virus replicates itself and infects other people, scientists use a number called the reproductive number, abbreviated as R0 or “r-naught.” This is a theoretical number that reflects on average how many people a person with a contagious disease can infect. An R0 of one means one person infects another person before he or she recovers—the epidemic continues, but the new case numbers will remain steady over time. An R0 of two or above will result in exponential growth—one person infects two (or more), those two infect four, the four infect sixteen, and so on. The R0 of COVID-19 has been calculated to be as high as 5.7—and the exponential increase in cases seen in the US and Brazil bears this out.
When the Philippine government implemented the lockdown in March, it was working with reported data from Wuhan, China where the R0 was shown to be as high as 3.8, but post-lockdown it went down to 0.3. An R0 of less than one can result in the termination of an epidemic, although this is hard to achieve. A lockdown was the only intervention that showed any good evidence of working.
The epidemic in Italy at that time stood out as a stark warning that using usual thresholds of deciding when to lock down were not enough to mitigate the exponential growth that has characterized this virus. The Philippine government, with a much smaller healthcare capacity than Italy, decided to act. We were the first developing country to shut down its capital, at only 52 cases. Eight weeks later, the R0 has been brought down from about 3, to near 1.0. Not perfect, but potentially tens of thousands of Filipino lives were saved (Figure 1).
Figure 1. R0 of COVID-19 in the Philippines over time. Courtesy of Epimetrics.
Keeping R0 at or below 1As we begin to ease ECQ, we also release physical controls on the virus. The potential for R0 to suddenly surge is always present, but the virus may be kept at bay with interventions to interrupt transmission. For those returning to work, it will be essential to rely on actions that limit the potential for the virus to transfer from one person to another.
The following measures can help limit the spread of the virus in the workplace.
Don’t go to work if you feel sick. While absenteeism is generally frowned upon, now is not the time to tough it out when you feel under the weather. That cough or cold could just be the usual respiratory infection, but it could also be Covid-19. In order to lessen the chance of transmission, stay home if you feel ill. Employers should allow flexible work arrangements for those at risk and for those who have symptoms that might be due to Covid-19. Staying home when you feel sick is the right thing to do.
Wear a mask. A cloth mask should be enough if you don’t have any symptoms. The main reason for wearing the mask is so that you do not transmit virus in case you are infected with Covid-19 but have not yet developed symptoms. Wearing a mask is an act of solidarity—you are doing it for other people and not just yourself. If you have overt respiratory symptoms, use a surgical mask and contact a healthcare professional. Leave the N95 masks for healthcare workers. These need to be specially fitted and can be very uncomfortable.
When wearing a mask, cover both your nose and mouth. Do not touch the front part of the mask, and adjust it using the ear loops. If you accidentally touch the front of the mask, wash your hands immediately.
When you are done wearing the mask, remove it by the ear loops or ties. If it is a washable cloth mask, soak it in water with detergent immediately. Always wash your hands right after handling a used mask. Avoid touching your face.
Maintain physical distancing. “Six feet apart or six feet under,” goes the saying. It sounds morbid but staying at least three to six feet from one another precludes respiratory droplet transmission.
Wash your hands. Even if you get your hands contaminated with Covid-19, the virus still has to get into your body. Washing your hands with soap and water will inactivate the virus, because soap strips off the lipid coating of the virus, which is necessary for it to infect human cells.
Select the right test for the right people. There is no perfect swab or blood test that can pick out asymptomatic carriers. Testing may be requested and carried out at some workplaces with employees’ consent, with the employer shouldering the cost. There is no required test for returning to work as long as you have not been sick in the last 14 days. Just screening of returning workers for symptoms using health questionnaires or similar tools eliminates about 85 percent of the potential for transmission. Beyond testing, engineering the workplace to be Covid-19- proof is the best way to deal with undetected asymptomatic carriers.
Arrange transport that enables social distancing. This may be the most challenging for those who take public transport. While DOTr has come up with guidelines, the ideal for workers who need to be physically present is still onsite housing. Other options include dedicated company shuttles, using bicycles, or walking when feasible. More and more public transport providers are accepting contactless payment systems, and more innovations, with hope, will be incorporated to decrease the risk of spread.
Transitioning to a safer work environment is essential in this time of COVID-19. We know a lot more about this virus than we used to, and we can use that knowledge to protect ourselves. The only way forward is to learn to safely live with this virus until an effective vaccine is found. Life needs to go on—we just have to manage the risk of infection and protect ourselves and our loved ones as best we can.
Edsel Maurice T. Salvana, MD, DTM&H, FPCP, FIDSA is an internationally-recognized infectious diseases specialist and molecular biologist at the University of the Philippines and the Philippine General Hospital. He is the director of the Institute of Molecular Biology and Biotechnology at the National Institutes of Health at UP Manila. He has spoken and written extensively on the COVID-19 outbreak, and serves on the Technical Advisory Group of the Inter-Agency Task Force for the Management of Emerging Infectious Diseases (IATF-EID).
