What do we know so far about face masks and their ability to prevent COVID-19?
What do we know so far about face masks and their ability to prevent COVID-19?
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According to the World Health Organization (WHO), wearing masks is part of an overall strategy to suppress the transmission of COVID-19, along with maintaining at least 2 meters (6 feet) distance and frequently washing your hands. A recent study conducted by the U.S. Centers for Disease Control and Prevention found that by wearing two masks, people's protection against the virus in the air dramatically increased. The study demonstrated that wearing any kind of mask provides significantly more protection against infectious COVID-19 aerosols than not wearing a mask. When dummies wearing two masks - like cloth face masks over surgical masks - were exposed to infectious aerosols, their level of protection was roughly 92%. The CDC now recommends fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face. However, the U.S. CDC does not recommend wearing two disposable masks at one time or another mask on top of a KN95 or N95 mask. There are generally two kinds of face masks that are available: medical masks and non-medical (or fabric) masks. Medical masks can protect people from getting infected as well as prevent people who are infected from spreading disease to others. Therefore, WHO recommends medical masks to be worn by health workers, care givers of patients infected with COVID-19, anyone who has mild symptoms of COVID-19, people with other health conditions which make them more susceptible to COVID-19, as well as people who are 60 years or older because they have a higher risk of getting infected with COVID-19. The WHO advises that non-medical masks should be worn in areas where there is high transmission of COVID-19, crowded places where at least 2 meters (6 feet) physical distancing is not possible, on public transport, in shops and other closed areas. COVID-19 can spread from people without symptoms, as they may not know that they are infected but are equally capable of spreading the virus. Hence, masks should be worn in public settings. The U.S. CDC warns that masks with exhalation valves or vents may not help prevent the spread of COVID-19 from the person wearing such a mask to others, therefore these masks should not be used for that purpose. The U.S. CDC also does not recommend face shields as substitutes for masks because of the large gaps below and alongside the face. Ideally, face shields should be used in combination with face masks. Wearing a face mask protects others from you when you cough, sneeze, talk, or just breathe, particularly indoors or when standing close to someone. Face masks also protect the wearer by preventing people from touching their mouth and nose, as well as reducing the amount of virus inhaled from other people nearby and reducing the risks of severe illness. In addition to social distancing measures (maintaining 6 feet or 2 meters between people), face masks are recommended to prevent the spread of COVID-19, even in hot climates. There is no evidence that surgical masks or cloth masks lower oxygen levels at all. It is important to use a mask that allows you to breathe comfortably while talking and walking and that fits well on your face. For safety, there are exceptions to wearing masks for children under the age of 2, for people with certain medical conditions or who have trouble breathing, and for anyone who is unconscious or unable to remove the mask without assistance. Mask wearing is a fundamental element of pandemic response for respiratory illnesses because masks act as a physical barrier from the release of infectious respiratory droplets that may come from your mouth or nose when you speak, sing, sneeze or cough.
According to the World Health Organization (WHO), wearing masks is part of an overall strategy to suppress the transmission of COVID-19, along with maintaining at least 2 meters (6 feet) distance and frequently washing your hands. A recent study conducted by the U.S. Centers for Disease Control and Prevention found that by wearing two masks, people's protection against the virus in the air dramatically increased. The study demonstrated that wearing any kind of mask provides significantly more protection against infectious COVID-19 aerosols than not wearing a mask. When dummies wearing two masks - like cloth face masks over surgical masks - were exposed to infectious aerosols, their level of protection was roughly 92%. The CDC now recommends fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face. However, the U.S. CDC does not recommend wearing two disposable masks at one time or another mask on top of a KN95 or N95 mask. There are generally two kinds of face masks that are available: medical masks and non-medical (or fabric) masks. Medical masks can protect people from getting infected as well as prevent people who are infected from spreading disease to others. Therefore, WHO recommends medical masks to be worn by health workers, care givers of patients infected with COVID-19, anyone who has mild symptoms of COVID-19, people with other health conditions which make them more susceptible to COVID-19, as well as people who are 60 years or older because they have a higher risk of getting infected with COVID-19. The WHO advises that non-medical masks should be worn in areas where there is high transmission of COVID-19, crowded places where at least 2 meters (6 feet) physical distancing is not possible, on public transport, in shops and other closed areas. COVID-19 can spread from people without symptoms, as they may not know that they are infected but are equally capable of spreading the virus. Hence, masks should be worn in public settings. The U.S. CDC warns that masks with exhalation valves or vents may not help prevent the spread of COVID-19 from the person wearing such a mask to others, therefore these masks should not be used for that purpose. The U.S. CDC also does not recommend face shields as substitutes for masks because of the large gaps below and alongside the face. Ideally, face shields should be used in combination with face masks. Wearing a face mask protects others from you when you cough, sneeze, talk, or just breathe, particularly indoors or when standing close to someone. Face masks also protect the wearer by preventing people from touching their mouth and nose, as well as reducing the amount of virus inhaled from other people nearby and reducing the risks of severe illness. In addition to social distancing measures (maintaining 6 feet or 2 meters between people), face masks are recommended to prevent the spread of COVID-19, even in hot climates. There is no evidence that surgical masks or cloth masks lower oxygen levels at all. It is important to use a mask that allows you to breathe comfortably while talking and walking and that fits well on your face. For safety, there are exceptions to wearing masks for children under the age of 2, for people with certain medical conditions or who have trouble breathing, and for anyone who is unconscious or unable to remove the mask without assistance. Mask wearing is a fundamental element of pandemic response for respiratory illnesses because masks act as a physical barrier from the release of infectious respiratory droplets that may come from your mouth or nose when you speak, sing, sneeze or cough.
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What our experts say
According to the World Health Organization (WHO), wearing masks is part of an overall strategy to suppress the transmission of COVID-19, along with maintaining at least 2 meters (6 feet) distance and frequently washing your hands.
A recent study conducted by the U.S. Centers for Disease Control and Prevention found that by wearing two masks, people's protection against the virus in the air dramatically increased. The study demonstrated that wearing any kind of mask provides significantly more protection against infectious COVID-19 aerosols than not wearing a mask. When dummies wearing two masks - like cloth face masks over surgical masks - were exposed to infectious aerosols, their level of protection was roughly 92%.
The CDC now recommends fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face. However, the U.S. CDC does not recommend wearing two disposable masks at one time or another mask on top of a KN95 or N95 mask.
There are generally two kinds of face masks that are available: medical masks and non-medical (or fabric) masks. Medical masks can protect people from getting infected as well as prevent people who are infected from spreading disease to others. Therefore, WHO recommends medical masks to be worn by health workers, care givers of patients infected with COVID-19, anyone who has mild symptoms of COVID-19, people with other health conditions which make them more susceptible to COVID-19, as well as people who are 60 years or older because they have a higher risk of getting infected with COVID-19.
The WHO advises that non-medical masks should be worn in areas where there is high transmission of COVID-19, crowded places where at least 2 meters (6 feet) physical distancing is not possible, on public transport, in shops and other closed areas. COVID-19 can spread from people without symptoms, as they may not know that they are infected but are equally capable of spreading the virus. Hence, masks should be worn in public settings.
The U.S. CDC warns that masks with exhalation valves or vents may not help prevent the spread of COVID-19 from the person wearing such a mask to others, therefore these masks should not be used for that purpose. The U.S. CDC also does not recommend face shields as substitutes for masks because of the large gaps below and alongside the face. Ideally, face shields should be used in combination with face masks.
Wearing a face mask protects others from you when you cough, sneeze, talk, or just breathe, particularly indoors or when standing close to someone. Face masks also protect the wearer by preventing people from touching their mouth and nose, as well as reducing the amount of virus inhaled from other people nearby and reducing the risks of severe illness.
In addition to social distancing measures (maintaining 6 feet or 2 meters between people), face masks are recommended to prevent the spread of COVID-19, even in hot climates. There is no evidence that surgical masks or cloth masks lower oxygen levels at all. It is important to use a mask that allows you to breathe comfortably while talking and walking and that fits well on your face. For safety, there are exceptions to wearing masks for children under the age of 2, for people with certain medical conditions or who have trouble breathing, and for anyone who is unconscious or unable to remove the mask without assistance.
Mask wearing is a fundamental element of pandemic response for respiratory illnesses because masks act as a physical barrier from the release of infectious respiratory droplets that may come from your mouth or nose when you speak, sing, sneeze or cough.
According to the World Health Organization (WHO), wearing masks is part of an overall strategy to suppress the transmission of COVID-19, along with maintaining at least 2 meters (6 feet) distance and frequently washing your hands.
A recent study conducted by the U.S. Centers for Disease Control and Prevention found that by wearing two masks, people's protection against the virus in the air dramatically increased. The study demonstrated that wearing any kind of mask provides significantly more protection against infectious COVID-19 aerosols than not wearing a mask. When dummies wearing two masks - like cloth face masks over surgical masks - were exposed to infectious aerosols, their level of protection was roughly 92%.
The CDC now recommends fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face. However, the U.S. CDC does not recommend wearing two disposable masks at one time or another mask on top of a KN95 or N95 mask.
There are generally two kinds of face masks that are available: medical masks and non-medical (or fabric) masks. Medical masks can protect people from getting infected as well as prevent people who are infected from spreading disease to others. Therefore, WHO recommends medical masks to be worn by health workers, care givers of patients infected with COVID-19, anyone who has mild symptoms of COVID-19, people with other health conditions which make them more susceptible to COVID-19, as well as people who are 60 years or older because they have a higher risk of getting infected with COVID-19.
The WHO advises that non-medical masks should be worn in areas where there is high transmission of COVID-19, crowded places where at least 2 meters (6 feet) physical distancing is not possible, on public transport, in shops and other closed areas. COVID-19 can spread from people without symptoms, as they may not know that they are infected but are equally capable of spreading the virus. Hence, masks should be worn in public settings.
The U.S. CDC warns that masks with exhalation valves or vents may not help prevent the spread of COVID-19 from the person wearing such a mask to others, therefore these masks should not be used for that purpose. The U.S. CDC also does not recommend face shields as substitutes for masks because of the large gaps below and alongside the face. Ideally, face shields should be used in combination with face masks.
Wearing a face mask protects others from you when you cough, sneeze, talk, or just breathe, particularly indoors or when standing close to someone. Face masks also protect the wearer by preventing people from touching their mouth and nose, as well as reducing the amount of virus inhaled from other people nearby and reducing the risks of severe illness.
In addition to social distancing measures (maintaining 6 feet or 2 meters between people), face masks are recommended to prevent the spread of COVID-19, even in hot climates. There is no evidence that surgical masks or cloth masks lower oxygen levels at all. It is important to use a mask that allows you to breathe comfortably while talking and walking and that fits well on your face. For safety, there are exceptions to wearing masks for children under the age of 2, for people with certain medical conditions or who have trouble breathing, and for anyone who is unconscious or unable to remove the mask without assistance.
Mask wearing is a fundamental element of pandemic response for respiratory illnesses because masks act as a physical barrier from the release of infectious respiratory droplets that may come from your mouth or nose when you speak, sing, sneeze or cough.
Context and background
There has been a lot of debate about how effective wearing face masks are in preventing the transmission of COVID-19. Part of the reason for this is the confusion that occurred in February and March of 2020 when the World Health Organization (WHO) and the United States Centers for Disease Control and Prevention (U.S. CDC) advised the public not to wear masks. This guidance was based on several important points:
1) These agencies did not think there was enough proof that the general public should be wearing masks unless they were infected with COVID-19 or they were around people infected with COVID-19. This is because it wasn't known yet that people could still spread COVID-19 even if they had no symptoms; 2) There was a shortage of masks for doctors and healthcare professionals ; 3) The difference in the types of masks and materials that were available; and 4) The research that is still in progress about how COVID-19 spreads (like through droplets, surfaces, etc.).
However, the research has evolved since the beginning of the pandemic, and we now have evidence that masks are effective at preventing the spread of COVID-19. This is why once the international scientific community had reached that consensus, the WHO, the U.S. CDC, and other health organizations changed their recommendations and now advise people to wear masks while in public settings.
It is common to change policies as new information becomes available. Because COVID-19 is a new virus, we are still learning more every day and changing and improving our recommendations.
There has been a lot of debate about how effective wearing face masks are in preventing the transmission of COVID-19. Part of the reason for this is the confusion that occurred in February and March of 2020 when the World Health Organization (WHO) and the United States Centers for Disease Control and Prevention (U.S. CDC) advised the public not to wear masks. This guidance was based on several important points:
1) These agencies did not think there was enough proof that the general public should be wearing masks unless they were infected with COVID-19 or they were around people infected with COVID-19. This is because it wasn't known yet that people could still spread COVID-19 even if they had no symptoms; 2) There was a shortage of masks for doctors and healthcare professionals ; 3) The difference in the types of masks and materials that were available; and 4) The research that is still in progress about how COVID-19 spreads (like through droplets, surfaces, etc.).
However, the research has evolved since the beginning of the pandemic, and we now have evidence that masks are effective at preventing the spread of COVID-19. This is why once the international scientific community had reached that consensus, the WHO, the U.S. CDC, and other health organizations changed their recommendations and now advise people to wear masks while in public settings.
It is common to change policies as new information becomes available. Because COVID-19 is a new virus, we are still learning more every day and changing and improving our recommendations.
Resources
- Facial Skin Temperature and Discomfort When Wearing Protective Face Masks: Thermal Infrared Imaging Evaluation and Hands Moving the Mask (IJERPH)
- Effects of wearing N95 and surgical facemasks on heart rate, thermal stress and subjective sensations (IAOEH)
- Does Wearing a Face Mask Reduce Oxygen—and Can It Increase CO2 Levels? Here's What Experts Say (Health)
- Face masks for the public during the covid-19 crisis (BMJ)
- From the Frontlines: The Truth About Masks and COVID-19 (ALA)
- Does prolonged wearing of a facemask cause harm? (Vanderbilt)
- Partly false claim: Continually wearing a mask causes hypercapnia (Reuters)
- Killer COVID-19 Masks? The Truth About Trapped Carbon Dioxide (Hartford Healthcare)
- What People With Asthma Need to Know About Face Masks and Coverings During the COVID-19 Pandemic (AAFA)
- Severe Acute Respiratory Infections Treatment Centre (WHO)
- Will an air cleaner or air purifier help protect me and my family from COVID-19 in my home? (U.S. EPA)
- Air purifiers: A supplementary measure to remove airborne SARS-CoV-2 (BE)
- Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2 (U.S. CDC)
- Considerations for Wearing Masks: Help Slow the Spread of COVID-19 (U.S. CDC)
- Masks Do More Than Protect Others During COVID-19: Reducing the Inoculum of SARS-CoV-2 to Protect the Wearer (Journal of General Internal Medicine)
- Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 (U.S. CDC)
- Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 (U.S. CDC)
- Facial Skin Temperature and Discomfort When Wearing Protective Face Masks: Thermal Infrared Imaging Evaluation and Hands Moving the Mask (IJERPH)
- Effects of wearing N95 and surgical facemasks on heart rate, thermal stress and subjective sensations (IAOEH)
- Does Wearing a Face Mask Reduce Oxygen—and Can It Increase CO2 Levels? Here's What Experts Say (Health)
- Face masks for the public during the covid-19 crisis (BMJ)
- From the Frontlines: The Truth About Masks and COVID-19 (ALA)
- Does prolonged wearing of a facemask cause harm? (Vanderbilt)
- Partly false claim: Continually wearing a mask causes hypercapnia (Reuters)
- Killer COVID-19 Masks? The Truth About Trapped Carbon Dioxide (Hartford Healthcare)
- What People With Asthma Need to Know About Face Masks and Coverings During the COVID-19 Pandemic (AAFA)
- Severe Acute Respiratory Infections Treatment Centre (WHO)
- Will an air cleaner or air purifier help protect me and my family from COVID-19 in my home? (U.S. EPA)
- Air purifiers: A supplementary measure to remove airborne SARS-CoV-2 (BE)
- Scientific Brief: Community Use of Cloth Masks to Control the Spread of SARS-CoV-2 (U.S. CDC)
- Considerations for Wearing Masks: Help Slow the Spread of COVID-19 (U.S. CDC)
- Masks Do More Than Protect Others During COVID-19: Reducing the Inoculum of SARS-CoV-2 to Protect the Wearer (Journal of General Internal Medicine)
- Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 (U.S. CDC)
- Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and Reduce SARS-CoV-2 Transmission and Exposure, 2021 (U.S. CDC)
