Q: You’ve said we need to continue to fight this virus, but there is so much information and it seems like it keeps changing. Just what do we know now about COVID-19?
A: I certainly understand your frustration. I’m doing this full time and have a hard time keeping up with it myself. The good news is that, even though we’ve known about this virus for less than a year, much has been learned and progress has been made. It’s important to remember that in medicine, as in all science, our advice and treatment is based on the facts as we learn them, and we always have to be prepared for change when new facts are discovered. Let’s review what we’ve learned.
* Quarantines: We knew early on that this was a respiratory virus that was spread through the air. Therefore, we knew that people with the virus, or exposed to it, should isolate themselves from others until they were no longer contagious. It took a while to learn just how long that would take, but we now have good evidence that most people who catch the virus will no longer be contagious after 10 days if their fever is gone and symptoms are improving. For sicker people, this can take longer. We know that, if you’re exposed to the virus, it can take up to 14 days to know whether you are infected or not, so this is why people who are close contacts are kept in quarantine longer than people who actually have the virus. This can be very confusing, but it is what the science has told us.
It was initially thought that only people who were sick with the virus were contagious and, therefore, if they just isolated themselves and everyone avoided contact with sick people, it would be OK. This was why, very early on, many experts thought that masks would not help. However, it was soon discovered that nearly half the people with the virus did not have symptoms, but could still infect others. Since that time, scientists have recommended that everyone wear masks around others. It was initially thought that masks only prevented spread from others who had the virus, so if you wore a mask and no one else did, you weren’t protected. However, while masks are most effective on those with the virus, there is now evidence that they do protect the wearer and that the best protection of all is for everyone to wear them around others. This has been shown to prevent spread, hospitalizations and death in multiple studies, including a recent one in Tennessee by Vanderbilt showing fewer deaths in counties with mask mandates than in counties without them (https://www.vumc.org/health-policy/sites/default/files/public_files/Vanderbilt%20COVID%20Report-Masks%20and%20Deaths_Nov10.pdf).
* Ventilation: You also may have heard that masks can’t help because viruses are so small that they will go right through them, especially cloth masks. However, viruses aren’t spread by themselves. They come out of your mouth and nose on water droplets, which are big enough to be stopped by the mask, as has been shown in multiple demonstrations. When you have the virus, just the act of talking, shouting, heavy breathing during exercise and even singing will spread them further. It is also true that these droplets can remain in the air, and as they dehydrate, they get smaller. This is why being indoors, especially in poorly ventilated spaces, is much higher risk than outdoors. Also, the more people there are and the longer the time they’re together, the greater the risk, even with masks on. This is also why the greater the distance you can keep between yourself and others, the more those droplets can disperse and drop to the ground. This is also why, even though airborne spread is the main means of transmission, we still recommend keeping your hands and frequently touched surfaces sanitized on a regular basis.