COVID-19 cases in the US have declined since January's spike, and all states have since removed their statewide mask mandates. However, Philadelphia is reinstating its indoor masking requirement beginning April 18 due to a rise in reported infections. The Transportation Security Administration announced earlier this week it was extending the federal mask mandate for public transit by two weeks, which includes airplanes, buses and trains. It's now set to expire May 3.
The Centers for Disease Control and Prevention and the World Health Organization agree that properly wearing a face mask over your nose and mouth is proven to slow the spread of COVID-19, which has killed more than 986,000 Americans.
Since the start of the pandemic, there have been many misconceptions about face masks, from who needs to wear them to which are the best kind, so we're addressing the most common here, backed by information from experts. For more, get the latest about at-home COVID-19 tests.
Myth 1: You don't need a mask if you're fully vaccinated or have recovered from COVID-19
While the CDC and WHO have eased masking recommendations, they both still recommend everyone wear masks while in areas of high transmission. This includes those who are fully vaccinated since COVID-19 vaccines are not 100% effective and anyone can carry and spread the disease.
The CDC says everyone ages 2 and older should wear a mask indoors in public in areas where the COVID-19 community level is high, regardless of vaccination status. The CDC also notes that if you or someone you live with is at an increased risk for severe illness, you should speak to your healthcare provider about wearing a mask at medium COVID-19 community levels.
Myth 2: Cloth masks are useless
Though a cloth covering alone may not completely prevent someone from spreading the coronavirus, it still reduces the likelihood. If a cloth mask is all you have, it can still work as a physical barrier by absorbing respiratory droplets that carry the coronavirus.
"Any mask is better than no mask," CDC director Dr. Rochelle Walensky said at a COVID-19 briefing. Her agency recommends well-fitted masks, which can include multiple layers of cloth masks.
Still, the most protective masks are N95 respirators, which block 95% of tiny particles, including viruses, and they're much easier to find now than they were at the start of the pandemic. If you're worried that using N95 masks will mean frontline workers won't have access to them, that's not such a concern anymore.
Read more: The Best Face Masks to Stop COVID-19
Myth 3: Only people sick with COVID-19 need to wear face masks
If you're not experiencing COVID-19 symptoms, it doesn't necessarily mean you're not infected: The CDC cites more than a dozen studies indicating that asymptomatic or presymptomatic people can still spread the virus.
If you're going out in public or will be around people who aren't part of your household, wear a face mask to protect them, even if you're vaccinated. You could be sick without realizing it, either because you're asymptomatic, presymptomatic or blaming mild symptoms on other causes, such as allergies. People who are mildly affected can still spread the virus to others, including those at higher risk of developing severe forms of COVID-19.
Scientists and medical experts generally agree that COVID-19 is an airborne virus: Wearing a mask forms a barrier that traps virus-containing droplets emitted by the wearer. In other words, if you're not wearing a mask and you breathe in the same air as an infected person who also isn't wearing a mask, your risk of acquiring the coronavirus increases dramatically.
Myth 4: Wearing a mask only protects you from infecting others
According to the CDC, while the primary function of masks is to block the release of "exhaled respiratory particles into the environment," several studies have illustrated that cloth masks can also reduce the wearer's exposure to infectious droplets through filtration -- including particles less than 10 microns.
"Multiple layers of cloth with higher thread counts have demonstrated superior performance compared to single layers of cloth with lower thread counts," the agency wrote in a release, "in some cases filtering nearly 50% of fine particles less than 1 micron."
Some materials, like polypropylene, may enhance filtration by generating static electricity that enhances the capture of charged particles.
Beyond the material and number of layers of your mask, improving its fit can improve filtration, as well. "Examples include but are not limited to mask fitters, knotting-and-tucking the ear loops of medical procedure masks, using a cloth mask placed over a medical procedure mask, and nylon hosiery sleeves," the CDC stated.
Myth 5: Wearing a mask is dangerous because of carbon dioxide
When worn properly, masks completely cover your nose and mouth -- from the bridge of the nose (above the nostrils) down below the chin, without gaps on the sides.
Some people have suggested that surgical masks trap exhaled carbon dioxide and cause the wearer to breathe in more CO2. This myth received much attention after a June 2021 letter in the Journal of the American Medical Association suggested high levels of carbon dioxide in children wearing surgical masks. JAMA retracted the report two weeks later, citing problems with the study's methodology, data and conclusions.
WHO confirms that the prolonged use of surgical masks doesn't lead to CO2 intoxication or lack of oxygen. And research from the American Thoracic Society demonstrated that face masks do not generate dangerous levels of carbon dioxide, even in patients with severe lung disease.
As Fast.ai notes, COVID-19 particles are 100 nanometers in diameter while carbon dioxide molecules are just 0.33 nanometer, exponentially smaller and nearly impossible to block with a mask.
Myth 6: You don't need to socially distance while wearing a mask
People wear masks when in public or with strangers to reduce their chances of getting or spreading the coronavirus. However, the WHO says the use of masks alone isn't enough to provide a sufficient amount of protection. Unlike N95 masks, which undergo a certification process, there's no regulatory body governing the materials or production of cloth masks.
Along with wearing a mask properly, you should continue to practice physical distancing, wash your hands frequently and avoid touching your face. The CDC still recommends staying at least 6 feet away from people whenever possible, even when masked.
Myth 7: Wearing face masks weakens your immune system
The weakened immune system myth stems from the idea that the human immune system is strengthened by exposure to bacteria and other pathogens.
The American Lung Association says there's no scientific evidence that wearing a mask weakens the immune system. However, even young and healthy people, without preexisting conditions, can catch and spread COVID-19: As of Jan. 12, 18 to 34-year-olds were the demographic with the highest number of reported cases in California, according to the state Department of Public Health.
Washing your hands and wearing a mask won't negatively impact your immune system, especially in adults. In fact, researchers at the National Institutes of Health published a study in February suggesting that face masks may actually help your immune system. The humidity created by masks hydrates the respiratory tract, creating proteins called interferons that bolster your immune system, adding additional protection against COVID-19.
Myth 8: You don't need to wear a mask outside
Research has demonstrated that the odds of spreading COVID-19 outdoors are as much as 19 times lower than spreading it indoors, but you should still wear a mask in outside areas where physical distancing isn't possible. For example, if you're hiking on a busy trail, going to an outdoor concert or enjoying an amusement park.
You don't have to wear a mask outdoors if you're running in a secluded area or if you're spending time in your own backyard with the people you live with. If you plan on going to a crowded outdoor area, however, you should (and may be required to) mask up.
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.