I know that the PCR test can have positive results for months. Is it also true for the at-home COVID tests? I think those are the antigen tests, right?
I tested positive a week ago Sunday, so this is day nine and I just took a test and there’s still a faint line.
From what I gather, there’s not a whole lot of value in continuing to test at-home after detection. You may test positive for a week or two, but if your schedule to end isolation is based on when your symptoms end, not the test results.
You can actually show positive test results from the lateral flow tests for up to a month, and these tests have a significant degree of false positive results to owing to the relatively poor specificity. The general guidance based upon correlated lateral flow testing and plaque assays (for what it is worth because the threshold of viral infectiousness is still undetermined) is that you are not contagious after five days of no symptoms. This isn’t universally true—there are immune compromised people who have hosted and been determined to be intermittently contagious many months after the initial infection—but is a good rule of thumb for most people who do not have an immunological condition. Realistically there is so much asymptomatic or barely symptomatic spread of the SARS-CoV-2 virus that if you just wait until symptoms abate (or five days after first positive detection, which is the CDC guidance) then you are probably not contributing to general contagion more than someone who is not testing at all.
Polymerase chain reaction (PCR) testing can show ‘positive’ for many months because it literally takes fragments of RNA and amplifies them, and RNA fragments from viral infections can continue to circulate in your bloodstream for months or even years without breaking down or being attacked by antigens, and the cycle threshold for SARS-CoV-2 detection (the number of cycles of PCR amplification) has been set so absurdly high that even just a few fragments can result in a positive result. Given how wide the contagion has been, PCR is virtually worthless without sequencing to confirm that the detection is a currently circulating variant of the virus.
Stranger
I’m on an immunosuppressant in order to treat an autoimmune disease, so I guess I could remain contagious longer.
Yeah, I don’t know what to tell you. I’d recommend to talk with your doctor but they probably don’t know anything more than the various contradictory statements that have from from a wide array of public health officials and immunologists. If you don’t have symptoms for a few days…you’re probably fine?
Stranger
I was going to go back into the office on Tuesday, but I’ll hold off until at least Wednesday, I guess.
Yeah, doctors won’t really know much more.
Had COVID in early October, as did my wife and live in son. I had it first, hardly even knew it until one day I said “The soup is bland” which they disagreed with. A few days later my son tested positive and two days after that my wife did. I may have been over it by then. They both work so I didn’t want to use up the tests on myself, they would need them if they contracted it as they did, and couldn’t return to work until testing negative which they both did after 10 days. When I finally took a test after they were better it was negative, although I don’t know for sure that I had it.
I have heard of lingering positive test results but everyone I know who needed a negative test to return to work had one in no more than 2 weeks.