Thread by @DavidLat

1/ Here's the latest chapter in my #COVID19 drama.

On Saturday, I tested POSITIVE on a #PCR test.

Was I reinfected?

(Note: this is a multi-tweet THREAD; please read ALL tweets in the thread.)

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

2/ As some of you might recall, I had a brutal case of #COVID19 in the fall. I spent 17 days hospitalized at @NYULangone, including almost a week in the ICU on a ventilator.

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

3/ But the idea of having #COVID19 again surprised me, for a number of reasons.

First, reinfection is rare. And I was tested at the same time for #COVID antibodies, and I was still positive.

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

4/ Second, my #COVID19 antibodies, while still positive, were lower than the last time (2.3, down from 3.2).

In reinfection, you might have expected my antibodies to climb again.

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

5/ Third, I had no symptoms and felt great -- and still feel great today.

(But some reinfected patients are asymptomatic the second time around, like this Hong Kong man.)

bit.ly/3l7b9MQ #COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

6/ Fourth, my husband, from whom I have not been quarintining, recently got both rapid and #PCR tests for #COVID19, and he was negative on both.

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

7/ But at the same time, #PCR tests for #COVID19 have a fairly low false positive rate.

So I was still unnerved. When I wasn't holing up at home, I went out for more tests.

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

8/ On Monday, I went to @CityWideUrgent1 and got a rapid antigen test: NEGATIVE.

(Btw, the wait was "only" 3 hours, shorter than @CityMD, and you can wait indoors if you like.)

#COVID19 #COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic #CityMD

9/ But rapid tests are less reliable/sensitive than #PCR tests. So while I was at @citywideurgent1 on Monday, I had another PCR test for #COVID19 (but results would take a few days).

#COVID19 #COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

10/ Through one of my doctors at @NYULangone, I set up another #PCR test for #COVID19, which I took on Tuesday.

#COVID #COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

11/ The @NYULangone testing center, by the way, was incredibly efficient: I was in and out in SIX MINUTES!!!

But you need to already have a doctor at NYU Langone who can order the test for you; you can't just walk in.

#COVID19 #COVID #Covid_19 #COVID__19

12/ A protip from the @NYULangone nurse who administered my #COVID19 test: try humming, lips closed, when the swab goes up your nose, and it will be less uncomfortable. (This totally worked for me.)

#COVID #Covid_19 #COVID__19 #coronavirus

13/ Today, on Wednesday afternoon, both of my #PCR tests for #COVID19 came back.

First, I got the @citywideurgent1 test result: NEGATIVE!

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

14/ Second, I got the #PCR test result from @NYULangone: also NEGATIVE!

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

15/ So, in sum, my one positive #PCR test for #COVID19, taken on Saturday at @BellevueHosp, was followed by a negative antigen test on Monday and two negative PCR tests on Monday and Tuesday.

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic

16/ I presented all this information to an infectious disease doctor who does #COVID19 research, and this doctor opined that the first result was likely a false positive.

#COVID #Covid_19 #COVID__19 #coronavirus #CoronavirusPandemic #falsepositive

17/ False positives on #PCR tests for #COVID19 are rare, but not impossible.

(Btw, some journalist should write about this and interview some of us. It's scary thinking you have it again!)

#COVID #Covid_19 #COVID__19 #coronavirus

bit.ly/2JfG3p3

18/ For example, last month @UofAlabama football coach Nick Saban got a #falsepositive (although he now seems to have #COVID19 for real, unfortunately -- I wish him a speedy recovery).

#COVID #Covid_19 #COVID__19 #coronavirus

nyti.ms/3fHy8gI

19/ The #PCR test for #COVID19 is very sensitive, so sometimes it picks up trace amounts of RNA that wouldn't grow if cultured and wouldn't infect anyone ("non-infectious positive").

#COVID #Covid_19 #COVID__19 #coronavirus #falsepositive

20/ And sometimes the #PCR test for #COVID19 yields a false positive because of cross-contamination, reagent contamination, and the like.

#COVID #Covid_19 #COVID__19 #coronavirus #falsepositive

21/ But again, a #falsepositive on a #PCR test for #COVID19 is rare.

If you've never had #COVID and test positive, you probably have it, especially if you have symptoms. And you should act like you have it and quarantine.

#Covid_19 #COVID__19 #coronavirus

22/ In my case, I probably wouldn't have doubted the positive result if I hadn't already had #COVID.

Reinfection can happen, but it's rare. See @apoorva_nyc's stories for @NYTimes on the general subject of immunity.

Anyway....

nyti.ms/2UAQztD

23/ This #Thanksgiving, I have something else to be thankful for, on top of the family, friends, and followers who supported me during my illness.

I DON'T HAVE #COVID19 AGAIN!!!

#COVID #Covid_19 #COVID__19 #coronavirus #Thanksgiving2020 #HappyThanksgiving

24/ Some tests turn up "positive" results even if the patient isn't sick or contagious because they run too many "amplification cycles."

See this @MITmedical article (via @Ottstorage).

bit.ly/2JaLANN

25/ Some have argued that rapid antigen tests, which are less sensitive than #PCR tests, might be more useful in dealing with #COVID19 from a public-health perspective.

See this @NYTimes article by @apoorva_nyc (via @TFC3Tweets).

nyti.ms/3647qvi