口罩可以防止呼吸道病毒的传播. 帮助呼吸道病毒传播的其他措施包括洗手, respiratory etiquette, and avoiding others when you are sick.

Lisa Maragakis, M.D., M.P.H.这位感染预防专家回答了有关口罩的问题.

What are the different types of masks?

The CDC provides an overview of various types of masks and respirators. In general, 你能做的最重要的事情就是选择一个合适的口罩, 在被建议或被要求这样做的情况下，始终正确地佩戴它.

Cloth Masks

In non-health care settings, 如果一直正确佩戴，多层织物口罩是阻隔呼吸道飞沫的极好屏障, covering the nose and mouth.

Procedural and Surgical Masks

这是一种宽松的口罩，用来遮住口鼻. 医疗级外科或程序口罩提供良好的保护，由于其过滤和流体阻力. A simple “knot and tuck” technique 可用于改善矩形外科或手术口罩的贴合度.

N95s and Other Respirators

N95口罩的过滤水平高于布口罩、外科口罩或手术口罩. 然而，在正常情况下，它们并不是保护人们免受病毒侵害的必要条件. In order to be optimally effective, respirators must be fit-tested and worn properly, tightly fitted against the person’s face.

N95 respirators, Dräger呼吸器和动力空气净化呼吸器(papr)由医疗专业人员使用，用于照顾COVID-19等病毒感染患者, and when performing high-risk or aerosol-generating procedures.

Face Shields

面罩是一块固定在发带上的坚硬透明塑料. The plastic piece covers the face, extending below the chin.

牙医和牙科保健员在接近推荐十大正规网赌平台的口腔工作时有时会戴口罩. Doctors, nurses and technologists might use face shields, together with face masks, 当执行可能将血液或其他物质推进空气中的程序时.

你不应戴面罩代替口罩或戴透明的类似盾牌的口罩, 哪些与面罩不同，面部周围有间隙，因此不能提供与戴口罩相同的保护.

Most people do not need a face shield in public settings.

还有绑腿、头巾和带呼吸阀的口罩呢?

这三种类型的面罩都不如合适的口罩好用. A good mask has a double layer of washable, 透气织物，有助于防止穿戴者将可能感染的飞沫传播到空气中. 缠在脸上的大手帕不如面具好用，因为它的底部是打开的. A gaiter (a tube of thin, 弹性针织织物(可以围在脖子上，拉起来遮住鼻子和嘴巴)通常太薄，无法提供足够的保护. 同样，带有呼吸阀的口罩可以让液滴逸出到空气中.

Johns Hopkins Medicine does not permit bandanas, gaiters or masks with exhalation valves to be worn by patients, staff members or visitors at our locations.

How do I properly wear a cloth mask?

Anytime you wear a mask, make sure:

• 在戴上或摘下口罩之前，用肥皂或洗手液洗手.
• It is worn consistently and appropriately. A mask that is frequently pulled down to breathe or talk, or is worn under the nose, is not effective.
• 口罩贴合你的脸，没有缝隙——重要的是，你吸入和呼出的大部分空气都流经口罩，而不是通过口罩两侧的缝隙, top or bottom.
• 你的布口罩是由几层紧密编织的织物制成的，很适合你的鼻子和嘴巴，是一个有效的过滤器.
• 该口罩有一个灵活的鼻梁，贴合脸部，防止眼镜起雾.
• It stays in place while talking and moving, 所以它可以穿着而不会打滑，所以它不需要你经常触摸它.
• 这款口罩戴起来很舒服，你不需要在需要戴的时候调整它.

Learn more about how to properly wear a face mask.

How do I wash my cloth face mask?

• 由织物制成的口罩，如棉质，可以用热水在你的常规洗衣店清洗.
• Disposable, 蓝色外科口罩不能洗涤或清洁，当口罩明显被弄脏或损坏时，应扔掉.
• 洗完织物口罩后，将其放入烘干机，调高温度烘干.
• 如果你对香水敏感，你可以考虑使用无香味的洗衣粉, so it is easier to wear masks.
• You can also hand-wash your mask, using hot, soapy water. 擦拭面膜至少20秒，然后用烘干机高温烘干.
• Store clean masks in a clean place when you are not using them.

How often should I clean my face mask or covering?

You should clean your mask after every wearing. This reduces the risk of spreading the coronavirus or other germs.

How many face masks do I need?

It’s a good idea to have at least two. This way, you will have a fresh mask if one is in the wash.

Face Masks and COVID-19

Do I need to wear a face mask if I currently have COVID-19?

Yes. 如果您感染了冠状病毒，并且无法完全远离家中的其他人, droplets from your nose or mouth could infect another person. 尽可能远离他人，在你的医生说可以安全停止戴口罩之前，在其他人身边戴上口罩.

如果我已完全接种疫苗并接种了加强疫苗，我是否需要戴口罩?

尽管充分接种疫苗和/或增强免疫可以降低感染或传播冠状病毒的机会, it does not eliminate it entirely. If you are infected with the coronavirus and do not know it, 口罩可以防止你的呼吸道飞沫和颗粒感染他人. 查看你所在地区的口罩建议，以帮助你决定是否需要戴口罩.

如果我周围的人感染COVID-19的风险更大，我需要戴口罩吗?

It is important to protect other people from getting COVID-19. Even if you are fully vaccinated and have a booster, wearing a mask provides an extra layer of protection, 特别是当你周围的人可能更容易感染COVID-19时. Likewise, 风险较大的人应强烈考虑戴口罩，以帮助保护自己.