healthHealth and Medicine

CDC Recommends Vaccinated People Wear Masks Again As Delta Variant Spreads


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockJul 27 2021, 17:57 UTC

The concern is the spread of the Delta variant, the fact transmission is much faster, and reports of a rise in breakthrough infections. Image credit: FamVeld/

The Center for Disease Control (CDC) has changed its recommendation on fully vaccinated people wearing masks, given the spread of the COVID-19 Delta variant in the United States. Back in May, fully vaccinated people were told by the CDC that they could stop wearing masks outdoor and in most indoor settings if they choose.

The announcement yesterday is a reversal of this position as the US has seen an increase in the number of cases over the month of July. The CDC's recommendation is that fully vaccinated people should wear a mask in "public indoor settings in areas of substantial or high transmission." The concern is the spread of the Delta variant, the fact transmission is much faster, and reports of a rise in breakthrough infections. Two months ago, the variant made up 3 percent of COVID-19 cases in the US. Today it's more than 85 percent of all cases.


In particular, large areas of the South and Midwest are seeing sharp increases in both cases and hospitalizations. The situation is particularly concerning in Alabama, Louisiana, and Missouri. The number of people in Intensive Care is reportedly at a breaking point in these areas, with the vast majority of patients being between 30 and 60 years old, much younger on average than previous waves.

The agency also recommends fully vaccinated people test 3-5 days after coming into contact with somebody with suspected or confirmed COVID-19, and to wear a mask in public indoor settings for 14 days or until they test negative.

The CDC reports that more than 95 percent of the patients in hospital due to COVID-19 across the US are unvaccinated. This shows the high efficacy of the vaccine but is also a reminder that as long as the virus is allowed to spread rapidly across a population, even vaccinated people are at risk. This is why wearing masks in crowded, poorly ventilated, indoor spaces it is now being recommended again. 

The CDC is also expected to recommend that everyone, regardless of their vaccination status, wear masks in K-12 schools due to numbers in poorly ventilated buildings.


For more information about COVID-19, check out the IFLScience COVID-19 hub where you can follow the current state of the pandemic, the progress of vaccine development, and further insights into the disease. 

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