There is no evidence that face masks weaken the immune system. Evidence shows that masks are effective in preventing the transmission of COVID-19.
With the outbreak of the COVID-19 pandemic, the World Health Organization (WHO) and other health experts advised people to maintain social distance and wear a face mask. Since then, there has been considerable debate around the usefulness of face masks, with numerous viral posts stating that face masks compromise a person's immune system. However, this is incorrect. In fact, face masks, washing hands, social distancing, and vaccination are effective measures to reduce the spread of infectious diseases. None of these measures weaken the immune system. WHO encourages face masks as a part of a "comprehensive approach" to reduce COVID-19 transmission and save lives. The Centers for Disease Control and Prevention (CDC) explains that face masks can help reduce the emission of respiratory droplets from asymptomatic or presymptomatic people, who could be infectious. The American Lung Association has also debunked this false claim, saying, "There is absolutely no scientific evidence that mask-wearing or physical distancing weakens the immune system." On the other hand, researchers at the National Institutes of Health (NIH) suggest that humidity created inside the face mask may lessen the severity of COVID-19. The moisture created by the masks hydrates the respiratory tract, creating proteins called interferons that strengthen the immune system and fight against the virus, adding additional protection against COVID-19. This study tested four common types of masks— an N95 mask, a three-ply disposable surgical mask, a two-ply cotton-polyester mask, and a heavy cotton mask. All four masks increased the humidity level of inhaled air in differing degrees. The immune system can weaken for many reasons. According to the Conversation, lack of sleep, low vitamin D levels, lack of physical activity, certain medications and the overuse of antibiotics, a diet rich in processed foods, and reduced consumption of fruits and vegetables can weaken the immune system. The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19, including symptoms, prevention, and available treatment, please refer to the World Health Organization or your national healthcare authority.