We already know a few things…
- If you wear a mask, you’re protecting those around you (whether you know it or not). A mask reduces the distance and the number of droplets when talking, sneezing, or coughing. With 40% of cases being asymptomatic, universal mask wearing is especially important because you may be spreading the disease even if you feel great
- A mask can protect the wearer by blocking particles from coming into the nose and mouth. For example, after universal mask wearing was implemented in Boston hospitals, infections decreased among health care workers.
The New England Journal of Medicine recently published another possible reason to wear a mask. This is NOT peer-reviewed science, it is an educated guess (hypothesis). Meaning the scientists used previous studies to make this guess. However, for the TOP medical journal (and I mean TOP) to publish a hypothesis means there is legitimate weight behind this guess.
What are they guessing? Universal mask wearing reduces the severity of COVID19 among those who do wear a mask.
Why? In epi, there is this concept called “dose-response”. For COVID19, this means the more virus particles you are exposed to, the more severe your symptoms/outcomes will be. And vice versa. So, if someone sneezes directly on your face you will get much sicker than touching COVID19 on a surface.
SOO, their thought process is that if you wear a mask, you filter out a lot of virus particles (dependent on mask type), and then your disease/symptoms will be less severe. In fact, this allows more people to get the asymptomatic disease MORE (compared to symptomatic disease). This is good because even among asymptomatic and mild cases of COVID19 you can develop antibodies. We get closer to herd immunity.
We have seen this, anecdotally, in a few instances:
- Argentinian cruise ship, where people were provided masks, asymptomatic infection was 81% (compared to 20% in earlier cruise ship investigations)
- US food processing plants, people were provided with masks each day, 95% were asymptomatic and 5% experienced mild-to-moderate symptoms during recent outbreaks
- Countries with population-wide masking have fared beer in terms of COVID19 rates and deaths
- Syrian hamster models (i.e. not humans) this hypothesis has shown to work
This is an educated guess. Now, other epidemiologists will (hopefully) test this guess to see if it is true. IF this is hypothesis is true, it’s a game changer, especially in the US while we wait for a vaccine with less-than-ideal testing and response.
Hamster study: https://www.pnas.org/content/117/28/16587