PHILADELPHIA _ Up to 70% of KN95 masks do not meet the U.S. standards for effectiveness, according to a new study by ECRI, a Pennsylvania-based patient safety organization.
The findings suggest an increased risk of contracting COVID-19 for health care workers and patients at hospitals that imported the masks from China to deal with massive shortages of protective equipment during the early days of the pandemic. (N95 masks meet the U.S. standards for effectiveness.)
Public health experts have already criticized KN95 masks for featuring ear loops instead of straps that go around the head and neck. This feature prevents the mask from sealing effectively against the wearer's face, experts say.
ECRI researchers looked at nearly 200 KN95 masks from 15 manufacturers, including models purchased by some of the country's largest health care systems, and found that 60% to 70% of the imported masks do not filter 95% of aerosol particles. They tested the masks by attaching them to a machine, which then blew particles at the mask. Researchers then counted the particles
