Important update: Healthcare facilities
CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more
UPDATE
Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.
UPDATE
The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.

Interactive Home Ventilation Tool

Interactive Home Ventilation Tool
Updated Feb. 9, 2022

Small particles that people breathe out can contain virus particles, including the virus that causes COVID-19.  If a guest visits your home, improving ventilation (air flow) can help prevent virus particles from accumulating in the air. Good ventilation, along with other preventive actions, like staying 6 feet apart and correctly wearing masks, can help prevent you from getting and spreading COVID-19.

We need your feedback! Help us improve this tool by taking a quick survey after using the tool below.

How can I decrease the level of virus particles during and after a guest visits my home?

Select the options below to see how particle levels change as you adjust ventilation settings.

(To create additional scenarios, including to adjust the length of the visit and size of the home, see the expanded model from the National Institute of Standards and Technology.)

The risk of getting COVID-19 varies according to individual susceptibility and the number of virus particles to which a person is exposed. The fewer virus particles in the air, the better.

Portable air filter
Image of a room
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Greater than 99 percent particle reduction
90% particle reduction
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Greater than 99 percent particle reduction
90 percent particle reduction
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0 percent particle reduction
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