Wait, do we really have to wear masks? Short answer: yes. Long answer: Absolutely yes.

It’s the debate that’s been going on since Covid-19 first reached the United States. Are masks and social distancing really necessary? Some people seem to think that it’s not, which is honestly ridiculous. There is so much proof that it is necessary, so I’m going to show it to anyone who doubts it.

According to the American Institute of Physics, the Contagion Airborne Transmission (CAT) inequality model can show how, based on how the virus spreads, masks and social distancing are effective. 

The article starts with researchers from Johns Hopkins University and the University of Mississippi employing basic concepts of fluid dynamics and factors in airborne transmission to propose the CAT inequality model. Not all factors are known, including environment variables and amount of particles needed to trigger an infection. However, it can still be used to assess relative risks. 

Airborne transmitted diseases, like influenza, can spread through the air on dust, fibers, and other microscopic particles. They can also be spread through expiratory droplets. Influenza can also be spread through secondary objects, or fomites, such as door handles or tissues. Little is known about which route is most important, though airborne transmission is harder to protect against.

When a virus like Covid-19 enters the body, the body fights off the virus. It is first fought off with innate immunity, a defense that activates immediately upon infection. It’s nonspecific and rapid. If that proves to be unsuccessful, then adaptive immunity (aka acquired immunity) develops after exposure. It is very specific, though slower. The B-cells of the immune system bind and neutralize the pathogen, while T-cells eliminate any infected cells. There are also B and T memory cells that help recognize the pathogen if a host ever gets reinfected, speeding up the immune response. However, the Covid-19 virus is new. People getting infected do not have these memory cells and the immune system needs more time to react and defend themselves. Time that the virus takes to wreak havoc on the host’s body.

These researchers are able to determine the precautions necessary to prevent transmission. According to their research, increasing physical distance does increase protection. Author Rajat Mittal says doubling your distance generally doubles your protection. The scientists have also found masks to be protective. A simple cloth mask can provide significant protection and reduce the spread of Covid-19.

Physical activity that increases breathing rate and volume of people are still issues when it comes with transmission, which is why reopening schools, malls, and gyms have hard implications.

The CAT inequality model is inspired by the Drake equation in astrobiology. The Drake equation is a formula that gives us an idea about how many alien societies exist and are detectable. The equation estimates the number of transmitting societies in the Milky Way galaxy through a factorization.

Similar to the Drake equation, the model develops a factorization based on the idea that airborne transmission occurs when a person inhales a viral dose. It includes variables added at each of the three stages of airborne transmission, including breathing rates, number of virus-carrying droplets expelled, the environment, and exposure time. This model could also apply to airborne transmission of other respiratory infections like the flu, tuberculosis, and the measles.

Researchers are continuing to look closer at face mask efficiency and transmission details in high-density of outdoor spaces. However, the CAT inequality model shows that a person is less likely to inhale a viral dose if they wear a protective mask and keep their distance.

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