Doctors explain why and when to wear a mask according to CDC guidelines

of Center for Disease Control and Prevention Has changed its policy and advised to cover her face with a mask or cloth whenever it was difficult to maintain social distance, regardless of whether she had COVID-19 symptoms. For clarity, the CDC does not say that you need to wear a mask everywhere you go, but indicates that you are in a gathering place, such as a grocery store, public transport, or a ride share .

Changes in recommendations Growing evidence COVID-19 can be transmitted by human breath and normal speech, but the fact that people do not effectively cover sneezing or coughing.

Stealth virus

The middle name of COVID-19 must be “stealth”. People may drop out Virus for 1-3 days Symptoms called asymptomatic infection before showing symptoms such as coughing, sneezing, and no fever. Ah Singapore Studies It suggests that 10% of infections are due to pre-onset spread.

Study of 3,711 passengers and crew members Diamond princess Cruise ships have shown that nearly one in five COVID-19 carriers have no symptoms. Some of these people transmit the virus through “asymptomatic infections”. The proportion of infected people who do not develop symptoms One third For the general public who is younger and healthier than general cruise ships.

The ability of a virus to spread from one person to the next is so demanding that people be physically separated from each other. But people still have to go out to get the necessities where the people gather.

If a person is not coughing or sneezing, how can the virus spread? One way is by contact. The virus inhabits the mucous membranes of the throat and nose. Every time people touch their faces 2.5 minutes, On average, it’s easy to see how a virus can be reached. The virus is then spread on commonly used surfaces, such as door knobs, subway plastic handles, or the hands of someone else. Steel and plastic The surface can hold live virus for 3 days.

Another route of transmission is by asymptomatic individuals. Breathing, speaking, call out Or sing. These activities Aerosolize virusAirborne virus particles-also known as droplet nuclei-are so small that they can float in the air. 3 hours. Coughing and sneezing create greater water and virus transmission splashAnd production Aerosolized virus.

Common medical devices such as nebulizer machines for asthmatics and CPAP machines for sleep apnea can aerosolize the virus. However, the concentration of aerosolized virus is low in large, well-ventilated spaces and rarely found outdoors. Infectious aerosolized viruses become more of a concern in places such as poorly ventilated small rooms. Everywhere, such as the home patient’s bedroom, some nursing homes, classrooms, Doctor. Hospital rooms are generally well ventilated.

Another important determinant of infection is exposure time. Therefore, the risk is much lower at 5 minutes compared to exposures of 30 minutes or more. People consider the risks of radiation exposure in much the same way. How close you are to the source, concentration of exposure, and exposure time.

DIY and surgical masks protect you and others

If you sneeze or cough, wearing a face cover or a surgical mask where people gather, the purpose of all of us is first and foremost to protect others. These covers block many of the large droplets that could otherwise reach people 18 feet away. Just released the study Show it surgical mask It can also reduce the amount of aerosolized virus produced by people breathing and talking.

The big questions are: These DIY or surgical mask Do you protect the wearer? Same study Investigation Indicate that these masks prevent the aerosolized virus from being shed by the user, possibly reducing the respiration of the virus. But they are not perfect. Because these covers do not fit snugly on the face, aerosolized viruses and large droplets can be inhaled through the gap between the face and the mask when inhaling.

In addition, some virus particles are so small that they can be sucked from the cloth or paper used to create these masks. People should not be fooled by a false sense of security when considering these types of things. mask Protects them from aerosolized viruses, especially in poorly ventilated spaces that are frequently visited by others. The best way is to avoid such space or stay in it for as short a time as possible.

The important thing

The likelihood of catching COVID-19 from anyone walking outdoors is very low. We recommend wearing a face cover. Mass transit And the ride share with others.

Maintain wherever you are Physical distance At least 6 feet without physical contact. If a nearby person is sneezing or coughing and not wearing a mask, keep at least 20 feet away. When you go out, wear your face cover and get your business done as soon as possible.

You do not need an N-95 mask if you are wearing public face coverings and maintaining physical distance when going to public indoor areas or riding public transport. Healthcare professionals must care for COVID-19 patients at very close distances for long periods of time. If they do not have an N-95 mask, the risk is very high for them. If you have an N-95 mask, donate it to a local hospital or first responder.

This article was republished from conversation Under Creative Commons license. Read Original work.