Would suspect a true reinfection. Whether it is waning immune reponse, or antigenic drift that allows for change in the virus surface proteins is yet to be clarified.

I don't know the particulars of Gaviria's case, obviously, but it's becoming quite clear that CV-19 reinfection is definitely happening. My wife (who is a nurse in Seattle) has already seen this happen in her own practice.

Needless to say, this is almost certainly bad news for a "herd immunity" strategy.

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I feel bad for the guy. He actually got really sick the first time and was in hospital for some time in UAE. Hopefully it stays asymptomatic. He has won a few races after his first bout but does not seem to be in top shape.

Most likely reinfection. Prior to this variant of the virus, there were four variants that were lumped into the category of the common cold. You can get any of these four variants multiple times so I would be surprised if the COVID-19 variant was somehow different.

Just so nobody misunderstands me, I am not trying to play devil’s advocate with COVID here. However, it is possible that Gaviria actually got a false positive. All tests may produce false positives. And when you are trying to do screening for a rare outcome, you can get a lot of false positives even with a very good test. Michael Matthews may have been in this situation, since he got an initial positive test and then he returned a couple of negative ones. I recall at least one female pro having a false positive also, but I forget her name.

There’s not really a way around this aside from re-testing, preferably with a gold standard test if you have one. Right now, I think the PCR test is effectively the gold standard. I would assume that Gaviria will get a follow up test.

If you read the academic literature summarizing the test performance of PCR tests (I.e. sensitivity and specificity), you may see the article discuss this fact, and some articles will probably mention something about the pre-test probability of the disease playing a role in interpreting the test result. This is what that means. If someone showed up in the ER with shortness of breath and other COVID symptoms, and you could rule out a non-COVID cause (e.g. pre-existing COPD), but they tested negative for COVID, you probably would assume that’s a false negative. That person’s pre-test probability of Covid is very high. (A synonym may be the prior probability.) Gaviria is the opposite case, in that he’s currently asymptomatic, and he has had symptomatic COVID before, so he should be expected to have some immune response (keeping in mind that there is documented evidence of reinfection, and who knows, maybe he’s asymptomatic now because of that immune response). And all that gets modified by the current situation in Italy, which is worsening (although Spain is worse, so the same situation in the Vuelta would be more likely a true positive).

Basically, it’s complicated, and there’s some math involved, but Gaviria could be a false positive. If I had been writing the rules, I would think about allowing someone back in the race if they produced a negative follow up PCR test, although they still need to isolate in the interim. Naturally, he could really be infected also. And no, I don’t know what the ratio of true positives to false positives is, because I don’t know the correct prior probability of having COVID in the Giro d’Italia, nor do I know the actual sensitivity and specificity of the specific PCR test the Giro is using. Also, I assume this one is a PCR test and not a rapid test, which has lower sensitivity and will produce more false negatives. Actually, there’s a case that the Giro could have decided to screen people daily with the rapid tests, and if someone in your team has a positive, the entire team needs to get a PCR test.

I am not sure if I said here that I thought the Giro should have taken Vaughters’ suggestion for an exit plan seriously. I stand by that statement. Right now, it looks like the Giro may be able to make it to Milan in reasonable safety, so I’m happy to be wrong there, but they and the Vuelta do need to think about an exit plan if enough positive tests come up. I am honestly not confident the organizers of either race would be willing to pull the plug if the situation demanded it.

According to Cycling News he didn't get really sick the first time and is asymptomatic now. The first time he had a fever for 2 days and then felt fine. They just wouldn't let him out until he had 3 negative tests.

To add onto the above, when he was positive in March, so little was known about Covid. His case was considered mild, per cyclingnews. I recently read that trying to get a negative test after a true positive, is often not worth the time or energy. This is due to some people testing positive for up to roughly 3 months after a true positive infection. This doesn’t mean these folks are active spreaders of Covid, but nonetheless are positive. The 10 day quarantine after someone first shows symptoms, but no longer has a fever is the better judge than retesting until negative. It’s very possible Gaviria falls in this category, and why the hospital didn’t let him go, with the limited Covid knowledge at the time.

If Nick Saban wasn't Nick Saban, he would be in his second week of quarantine and feeling lucky he was asymptomatic but because he is in the position he is in, he was able to confirm the false positive with about 6 consecutive negative tests.

Without getting into the mechanics of whether he is spreading the virus in the peloton or not, but it would really suck if he's relatively feeling fine and this is the same thing from March just having traces in his body and that this has largely been the case since April. While it may explain why he is not in the same form as in the past, he is still able to finish entire grand tour stages and contest for the sprint.

But this would be an example of a young person feeling 'fine' (at least as far as the general population) but not being able to participate in his profession in case he is a hazard to society. He may indeed be a hazard to society or he may not be. Whether further racing is a hazard to himself or not is another layer of question.

Just to be clear, I was only referring to Gaviria’s initial lengthy hospital stay, for only mild symptoms and that they wanted him to test negative, repeatedly, before release. It’s been more than 3 months, since then, so for him to quarantine again, makes sense. It’s very possible he exhibits some of the signs described below and why it took him a while to test negative.


On August 3, 2020, CDC updated its isolation guidance based on the latest science about COVID-19 showing that people can continue to test positive for up to 3 months after diagnosis and not be infectious to others. Contrary to media reporting today, this science does not imply a person is immune to reinfection with SARS-CoV-2, the virus that causes COVID-19, in the 3 months following infection. The latest data simply suggests that retesting someone in the 3 months following initial infection is not necessary unless that person is exhibiting the symptoms of COVID-19 and the symptoms cannot be associated with another illness.

So based on what you wrote from CDC,

• Gavaria, had no reason to go get tested
• because he was feeling fine and rolling around Italy in a protour peloton exerting himself for 4-6 hrs per day. This is way beyond most normal humans.
• But due to his profession he MUST get tested even if he feels fine
• As a result of the testing required by his profession he got a postive test but has no symptoms
• According to the CDC he may not be infectious to others (if its the original reminants)
• I am not sure it is implied but he may be infectious to others if this is a new bout of infection?

I guess the last bullet is of most interest. If he is infectious to others with a new infection then in fairness he should not be able to go to work. If it is the old thing showing up and he's not feeling sick and not infecting others, it truly sucks that he can't go to work. I am pondering these things as an employer for when I open my office back up and employees come back to the office. But I think employers have no choice....if you test positive and asymptotic (no matter what the scenario), don't come to work

I suspect the main thing with this is more that tests are still in short supply. For the average person, the clinics are probably thinking that you should just isolate yourself, it’s a waste of a good test. If we do have enough tests, we can reduce the burden on people by doing repeated follow ups. With pro athletes in general, because we are asking them to be in close quarters, we really should provide repeated testing. The same should go for anyone who really has no choice but to work close by others - medical personnel obviously, but really it should extend to the people working in nursing homes or senior living, the people working in grocery stores or Amazon warehouses, other ‘essential’ personnel who we might not think are important in some sense.

CDC uses the 3 month reference point when not to retest, if a person is asymptotic. He is well past 3 months now: March -> October (6 to 7 months). So, he should be quarantined if he now tested positive, with current guidance. Time will tell if 3 months could really mean 3 months plus “x” more months. Maybe future tests will be developed to determine if one is positive and infectious versus positive and not infectious. Hopefully he wasn’t a false positive, either!

This is almost certainly not residual from March. I would suspect he has been tested all along. When racing retarted. Prior to Tirreno-Adriatico. As part of the Giro protocol. This must be a positive test relative to prior negatives. Now, true vs. false positive a different story. Will need to wait for more details.

But again, documtented reinfections are beginning to emerge globally. And he is in a hot spot with numbers going up in Italy, and positive cases/infections in the Peloton. Pre-test probabilitiy high, and a test with good specificity make this likely.

If this is indeed true, hope and pray reinfection not more severe.

EDIT: Now, human error exists. Maybe there was a mix-up. Will just have to see.

With so many infections worldwide it's not surprising that it's happening, but there are few trully confirmed cases of re-infection. In those cases the re-infection could be detected by comparing DNA of both infections, and there being differences between them. There are only a few dozen of such cases, and in nearly all the person's immune system was compromised. There's only one known fatality so far of a re-infection which was a 89 year old women with cancer who had radiation therapy and chemo between the two infections.

If re-infections were threatening herd immunity there would be tens of thousands, if not hunderds of thousands, re-infections known by now.

Maybe Gaviria was asymptomatic in both cases, and indeed truly re-infected. Such cases aren't bad news either, as his immune system clearly deals with it effectively. It would interesting to know if he indeed was asymptomatic both times, and if his levels were high enough to be considered contagious.

I believe false positives with PCR-tests are rare, so rare that a positive should be treated as such. Maybe if in the next couple of days he would test negative you could allow him back in the race, but that would still mean he would miss a few days, so it's not a possibility. Even if the chance of a re-infection is rare too. Why take the risk, from an organisers point of view?
Kruiswijk tested postive but was asymptomatic, and felt great, however he tweeted a few days ago that he did develop symptoms a few days after the positive test.