The omicron variant of the coronavirus strikes quick. Signs sometimes seem just some days after an infection, with viral ranges peaking lower than 5 days after the pathogen first turns into detectable.
However for some individuals, the virus appears to linger, with at-home checks coming again constructive day after day, even after different individuals within the family return to work or college. So why do some individuals take a look at constructive for the virus for 10 or 12 and even 14 days — and are they nonetheless infectious after so lengthy?
“It’s an amazing query — it’s one which I get requested on a regular basis,” mentioned Dr. Peter Chin-Hong, an infectious illness specialist on the College of California, San Francisco.
Additionally it is one with out a simple reply. Though speedy antigen checks, which detect proteins on the skin of the coronavirus, can flag individuals carrying excessive ranges of the virus, they aren’t good predictors of infectiousness.
Research recommend that whereas most individuals cease testing constructive on antigen checks someday throughout the first 10 days of their sicknesses, a notable subset of individuals proceed to check constructive for longer, for causes that scientists don’t fully perceive.
In some instances, these individuals should still be shedding infectious virus, however in others, the checks could also be selecting up viral particles from a waning an infection, consultants say, making it tough to know interpret the outcomes.
“Some individuals will not be infectious on the finish of their course even when nonetheless antigen-positive, whereas others could also be infectious even when antigen-negative,” mentioned Dr. Yonatan Grad, an immunologist and infectious illness professional on the Harvard T.H. Chan College of Public Well being.
Certainly, scientists disagreed on the very best plan of action for individuals who take a look at constructive for greater than 10 days. Whereas some say that essentially the most prudent path is to proceed to isolate, others argue that extended isolation is pointless for many in any other case wholesome individuals.
Given the uncertainty, some consultants have suggested that take a look at outcomes on the finish of an an infection be considered as only one doubtlessly helpful piece of knowledge thought-about in live performance with different elements, together with a affected person’s signs and immune standing. Alongside these traces, Chin-Hong beneficial “utilizing the speedy take a look at as a information however not the be-all and end-all.”
What We Know
Research carried out earlier than the emergence of omicron demonstrated that folks with COVID-19 had been probably to unfold the virus within the few days earlier than and after creating signs.
The Facilities for Illness Management and Prevention cited these findings when explaining its choice to shorten its isolation tips late final 12 months. Whereas the previous tips beneficial that sufferers isolate for 10 days, the present suggestions say that many individuals can go away isolation after 5 days, though they need to put on a masks by means of Day 10.
