In recent months, masks have become a highly polarising topic. Despite intense debates online, and the sometimes violent conflicts that erupt in public about mask requirements, the science behind mask-wearing is not at all controversial.

There's extensive evidence to support wearing a mask to protect both yourself and other people, and help slow the spread of the coronavirus.

Here are some of the most common myths used to argue against mask-wearing, and why they're wrong.

Wearing a mask won't worsen a coronavirus infection

Myth: If I have the virus, wearing a mask means I'll be re-exposed to viral particles I exhale, making me sicker.

Fact: This claim was circulated in the pseudoscience documentary Plandemic, which has been thoroughly debunked by scientists.

You can't reinfect yourself if you already have the virus, and it's impossible for it to somehow "reactivate" in your body, research has shown.

"There is no science behind it, and it's totally false," microbiologist Dr. Miryam Wahrman, author of The Hand Book: Surviving in a Germ-filled World, previously told Business Insider about this claim.

More and more evidence suggests that once your body mounts an immune response to COVID-19, it's protected – for some time – from reinfection.

Masks don't reduce your oxygen levels

Myth: I can't breathe in a mask. It might be dangerous to wear one because it could limit my oxygen levels.

Fact: Masks have consistently been shown to be safe, which is why they were already used heavily by medical personnel even before the pandemic. The common rumour that they reduce the oxygen saturation level of your blood has been debunked by multiple medical doctors.

Furthermore, despite claims that a mask could exacerbate health conditions like asthma, doctors have repeatedly stated that there's no legitimate reason for a medical exemption from wearing a mask. Strategies like fitting your mask properly and choosing the right type of mask can help.

You can even work out in a mask until it becomes saturated with sweat, at which point it's less effective.

Certain types of industrial-quality sealed respirators may affect levels of oxygen intake, especially when worn for a prolonged period of time, but the most common types of protective mask, such as surgical masks and cloth masks, will not interfere with oxygen levels.

You should wear a mask even if you don't have symptoms

Myth: If I feel fine and don't have a cough or fever, I don't need to wear a mask.

Fact: As many as 40 percent of people infected with the coronavirus show no symptoms at all. These asymptomatic carriers of the virus can still spread it to other people without ever knowing they were sick in the first place.

Even people who do show signs of illness can be contagious before symptoms appear, research has shown.

This could be particularly crucial for young people as schools struggle to reopen this fall, since there is some evidence children are more likely to spread the virus without symptoms than adults.

That makes it especially important to have a consistent and comprehensive policies on mask-wearing to help slow the spread of the virus as people return to public life.

Masks protect the people around you

Myth: Only people who are afraid of getting sick should wear masks. If I'm healthy or brave, I don't have to.

Fact: The primary benefit of wearing a mask is to prevent the people around you from getting sick, which is why it's so important for everyone to do it, according to research.

Masks work by blocking potentially-contagious respiratory particles from flying out into the surrounding air (and onto other people) every time you cough, sneeze, breathe, or speak. They can also prevent you from breathing in some particles expelled by other people.

Inconsistent messaging about masks from health officials early on in the pandemic may have contributed to this myth, leading some people to believe healthy people don't need masks.

But based on the latest research, the most effective scenario for reducing coronavirus infection is when everyone involved wears a mask.

In a recent study from the CDC, masks helped to stop an outbreak at a hair salon in Missouri. Even though two employees were asymptomatic carriers of the virus, not a single one of 139 clients got sick, since clients and stylists all wore masks.

Neck gaiters don't increase your risk of viral infection

Myth: Research found that neck gaiters, the fleece wraps that runners often use, are worse for coronavirus risk than no mask at all.

Fact: A study from Duke University researchers swept the internet this month, reportedly finding that people who wear neck gaiters would be safer wearing no mask at all.

But these results were framed out of context. The study was not looking at the effectiveness of masks. In fact, researchers were studying how to measure a mask's effectiveness.

This is a key distinction since, as the researchers themselves note, the results were not intended to be comprehensive, but just to demonstrate that the methodology could work for larger-scale studies on masks to help compare their effectiveness.

It's true that some masks may be more effective than others, but more research is needed to understand how neck gaiters measure up in terms of effectiveness.

The science is clear that wearing a mask can help reduce the spread of the virus

Myth: Wearing a mask is an issue of politics, freedom, or just "virtue-signalling", and doesn't make a practical difference in whether or not people get sick.

Fact: The research is unambiguous. Masks work to reduce the spread of infectious viral particles, thereby preventing additional cases of the virus. Recent research from the UK found the getting the entire population to wear masks could be enough to slow the virus without resorting to lockdowns.

The more people wear masks, the more effectively a community can control the disease.

Health officials in the US, which has struggled to contain the coronavirus, are urging the public to wear masks after models have suggested doing so could save thousands of lives.

Masks don't replace other precautions like social distancing and hand-washing

Myth: If I wear a mask, I can be close to other people or in large groups without worrying.

Fact: While the research is clear that masks work, masks alone aren't enough. Health experts continue to recommend other precautions to slow the spread of the virus, such as washing your hands frequently and maintaining at least a 6-foot (2-metre) distance from others whenever possible.

Research has shown that these preventative measures, when combined, can significantly reduce the rate of transmission and save lives.

This article was originally published by Business Insider.

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