(Positive)ly fine

You know what I was most afraid about with getting Covid? Extended social isolation.  And, voila, here I am :-(.  I’m not completely isolated.  I spend a decent amount of time with my kids out on the deck each day.  I’ve been zooming for various things (including class), but, my God is my extreme extrovert psyche not cut out for this!!  Alas, every day since February 7 I start with a rapid Covid test and every day that sample line turns dark pink in no time.  Ugh.

The thing is I feel totally fine.  Just the slightest bit of extra mucous, but, not something I think I’d really even think twice about under normal circumstances.  And I think my energy level was roughly back to normal by this past weekend.  Today, I realized there was no reason not to fully resume my exercise regimen and I ran my normal distance in just ever-so-slower than my usual time (I realized that any other illness I would not have an everyday test of viral load and I would have assumed I had recovered and resumed normal exercise).  But those damn pink lines!  

Anyway, this of course caused me to to more research on lingering Covid.  Among, other things, staying positive this long is not unusual at all.  And really does suggest the CDC’s– let yourself out of isolation after five days if you are symptom free– is far more about expediency than actually preventing the spread of Covid. 

Some good stuff I came across:

How long should I isolate if I have covid?

The coronavirus has the tricky feature of being transmissible even before the infected person has symptoms. In general, the peak period of virus shedding starts about a day or two before symptoms appear and continues two or three days after.

Even though a person is less likely to transmit the virus later in the course of illness, it’s still possible. Research shows that people continue to shed virus that can be cultured in a laboratory — a good test of the potential to pass along the virus — for about eight days on average after testing positive.

In another report, researchers at the University of Massachusetts Chan Medical School found that 30 percent of patients were still testing positive on a rapid antigen test 10 days after their infection was confirmed through a sensitive PCR molecular test.

And this was especially handy from NPR, “Still testing positive after day 10? How to decide when to end your COVID isolation” (at this point I feel like surely I’ll still be testing positive on day 10)

Testing to get out of isolation is tempting because it promises a straightforward answer. Unfortunately — and perhaps unsurprisingly — the science is not entirely settled.

“We don’t have anything that says definitely you are contagious or definitely you’re not,” says Dr. Emily Landon, an infectious disease specialist at UChicago Medicine. “The best thing we have are these rapid antigen tests.”

Unlike PCR tests, which search for genetic material from the virus, rapid antigen tests work by looking for the proteins that are packed inside the virus. A positive test generally correlates with the presence of infectious virus. Scientists can determine that by taking samples from someone who’s been infected and trying to grow the virus in a lab — what’s known as a viral culture…

Generally, most people who get infected are not still testing positive on an antigen test 10 days after symptom onset.

“If you have enough virus in your system to be turning one of these tests positive, that means your body probably hasn’t yet fully cleared the infection,” says Hay.

But there is no perfect study that shows how likely it is thata positive test on a rapid test translates into shedding enough virus that you could actually infect another person, says Dr. Geoffrey Baird, chair of the department of laboratory medicine and pathology at the University of Washington School of Medicine.

“The answer to that is clear as mud,” he says.

Indeed, infectious disease experts tend to differ about how much stock to put in a rapid test result when someone knows they’re infected and deciding whether it’s safe to rejoin the outside world.

After all, Baird points out that these tests were never designed to function as get-out-of-isolation cards. Relying on the result to tell whether you’re truly still infectious is dicey, he says.

“There’s actually a lot more discrepancy than anyone would be happy with,” he says.

A positive antigen test could essentially be picking up leftover viral “garbage,” which can include “dead viruses, mangled viruses … viruses that are 90% packed together but not really going to work,” says Baird. And the amount can vary depending on each person’s immune system, the variants, the stage of the infection, and so on…

In fact, a study co-authored by Landon followed health care workers at the University of Chicago who had been infected but were feeling mostly better and went to get tested after five days. They found that more than half of them still tested positive on antigen tests after six days.

This tracks with other research. For example, one study analyzing data from a testing site in San Francisco during the January omicron surge suggests that many people were still testing positive after five days. And research done by the CDC shows about half of people were still testing positive on the antigen test between five and nine days after symptom onset or diagnosis.

“You’d be erring on the side of caution if you followed the test and said, ‘I’m not going to leave my isolation until after my test is negative,'” she says.

Preliminary data from scientists at Harvard and MIT shows that about 25% of symptomatic people with COVID-19 had virus that could be cultured after eight days after symptom onset or their first test.

On the more encouraging side, there’s this:

Some research has aligned more closely with the CDC isolation guidance, which assumes most people will no longer be infectious after five days. A preprint study of close to 100 vaccinated college students at Boston University suggests that a majority were no longer infectiousafter five days.

“Only about 17% of those who we looked at still had what looks like viable COVID out past five days,” says Dr. Karen Jacobson, an infectious disease specialist at the Boston University School of Medicine and one of the study’s authors. A very small number did have virus that could be cultured eight days after symptom onset.

Her study found that a negative rapid antigen test on day five is a “perfect” indicator of whether the virus could be cultured in a lab. In other words, anyone who had a negative test on day five or later after their initial diagnosis had no more detectable virus.

“The flip side was that if you had a positive rapid [test], about half of the people still had culturable virus and half did not,” says Jacobsen. “The way that we’ve started to frame it, and I think many others have, is that if you’re positive, you particularly need to take this very seriously.”

At the end the day, if you’re still testing positive but you feel fine and are symptom-free, the decision to go out in the world comes down to context. If you’re going to spend time with people who are high-risk, think twice, says Landon.

“If you are thinking about going to the nursing home to visit your grandmother, this is not the time to do it,” she says.

But if there’s something essential you need to do, don’t feel trapped in your house. Go do it but keep your mask on, she adds.

And here’s the cool scientific study on all this.

Anyway, so, presumably it’s only about 50-50 at this point that I’d still be infecting people with my positive test.  Of course, we’ve made it 8 days with me not infecting any of the other five household members (ventilation plus N95 when in common areas absolutely works!), so I’m sure not going to blow that now.  Charts C and E above really make it seem like it is pretty damn safe to come out after 10 days, regardless of the testing status, as eyeballing it only about 5% of people seem to have culturable (i.e., infectious) virus, regardless of testing at that point.  So, I don’t know what I’ll do when I’m still positive at day 10 (I know what my wife will want me to do), but this sure is damn frustrating.