WASHINGTON — In the event you have been uncovered to COVID-19, take three house exams as an alternative of two to be sure to’re not contaminated, in line with new U.S. suggestions launched Thursday.
Beforehand, the Meals and Drug Administration had suggested taking two speedy antigen exams over two or three days to rule out an infection. However the company says new research recommend that protocol can miss too many infections, and will end in individuals spreading the coronavirus to others, particularly if they do not develop signs.
The brand new steering applies to individuals with out signs who suppose they might have been uncovered. Individuals with signs can proceed utilizing two exams spaced 48 hours aside.
Thursday’s replace displays the evolving understanding of the accuracy of antigen exams, that are much less delicate than laboratory exams however have develop into the usual testing method on account of their velocity and comfort. As an alternative of detecting the coronavirus itself, they detect protein traces, often called antigens, much like speedy flu exams.
Well being officers have repeatedly cautioned that the exams can provide false negatives if taken too early. The Facilities for Illness Management and Prevention recommends individuals with out signs wait 5 days after an publicity. That is as a result of it usually takes a number of days earlier than the antigens attain ranges detectable by way of testing with a nostril swab.
All 22 house antigen exams on the U.S. market have been licensed for emergency use based mostly on preliminary information, whereas firms and researchers gathered extra definitive metrics on their accuracy.
The FDA mentioned its newest resolution displays new data on the accuracy of antigen exams. In a authorities research, including a 3rd take a look at improved accuracy from 62% to 79%.