Both are possible, though the former is more likely. 5 day intervals for incubation seem too short for 100% safety. I believe omicron has some data points of longer incubation already.
Another point is that there are animal reservoirs for SARS-CoV-2. We've known this since well before the zero-covid debacle, making such a plan was doomed to fail, as it did. It's likely that the virus can live in intestinal tracts of animals, including humans, for long periods without being detected and destroyed by the host's immune system. This makes the use of negative nose/throat swab tests as a guarantee of no subsequent infection a fallacy.
The way we deal with COVID is to stop testing asymptomatic people and use the plethora of effective early treatment protocols we've developed since as early as December 2019 to vastly reduce the need for hospital treatment in those that do develop symptoms.
They are also exceptionally reliable. The home test kit I used had a sub-1% false negative rate.
No, they really don't. Swabbing for RNA picks up gene fragments that may or may not be from infectious virus -- it's why we see positive tests for months after infection in some people.
Swabbing for viral protein is debatably more likely to detect the thing of interest (the virus itself, in some semblance of functioning order), but these tests also have a high false-negative rate (around 10% for the better tests I've seen; I have never heard of a test with a sub-percent FN rate, as you claim). You can be shedding live virus and these tests won't pick it up, either because you're not shedding enough, or because the antibodies in the test don't bind to the protein in your sample for whatever reason.
Either way, you're measuring a proxy for what you really care about. A true test of infection involves taking a sample and incubating in cell culture. Nobody does this, except to validate the original tests and provide clear positive and negative samples. It's slow and orders of magnitude more expensive than even PCR testing. But this is the direct test for infectious virus. Everything else is an approximation.
(Let me be clear, though: I wholeheartedly support the use of antigen tests -- even ones with low sensitivity -- over the insanity we're doing now in the US. It's just bad to misrepresent what they're actually doing.)
However, I’m not sure the value in antigen testing? Sure, when you’re traveling or have to into a higher risk situation.
But Singapore decided to freely give out antigen tests and what happened was people who tested positive showed up at the ER. And the antigen tests weren’t reliable, so PCR had to confirm. And they have a high vaccination rate so after all that testing the answer was “go home and if you get really sick, come back”.
It finally dawned on them that could just be the message anyways - if you don’t feel bad, don’t worry. If you do, you can test but don’t seek medical care unless you have severe symptoms.
That said, your point is well-taken that people can be idiots about testing positive. We do need to get over this fear and accept that the virus is endemic, and that vaccines work to prevent serious illness. We're now talking about miniscule risks that we would have rightfully shrugged off in any previous year, but folks have been terrorized, and they're desperately looking for control. Any tool that can calm that fear is a good tool.
On the "shedding" point, not necessarily. The virus can be present in but contained by the immune response from the mucosae of the upper respiratory tract in such a way that it is unable to spread into the lungs and cause COVID-19, yet not shed in large enough quantities to infect others. Given time, a healthy immune system will deal with the virus in the nose and throat, often without the host even noticing. Such a situation would set off a PCR or rapid test but not present a meaningful COVID-19 infection risk to the others. (In fact, one hypothesis for why positive cases rise soon after vaccination and booster campaigns start is because of the well understood phenomenon of reduced immune response for a short time after vaccination, giving such virus already present in the upper respiratory tract at time of vaccination the edge it needs to get into the lungs.)
And the cycle thresholds on PCR tests are often set nonsensically high making them sensitive to quantities of virus and viral debris far lower than the quantity required to meaningfully infect either the host or someone else via shedding. They can also trigger positive on not just virus but viral debris for months after recovery from COVID-19 infection. (A test can be too sensitive, especially when used as the only evidence to force someone and their contacts to isolate and in some cases not earn an income for weeks.)
> It doesn't matter if you're infected if you're not shedding the virus.
I agree, but I'm not sure if the Belgian authorities, who seem to use PCR positives as a COVID-19 diagnosis, and PCR negatives as a guarantee of safety from infection risk to others, would. The article does what most articles these days do, conflating presence of SARS-CoV-2 debris on a swab with COVID-19 disease diagnosis. It incorrectly claims 2/3rds of the 25 staff have COVID-19, when given that none seem to have symptoms of the disease it's likely a case of oversensitive tests. Let's not also forget that these tests are mostly (at least all the ones I've seen) called COVID-19 tests.
Ah ok, so that might explain why there's a significant number of people who say that they had covid without difficulty, at least of they didn't test false positive.
Thanks for explaining the nuance - I've heard a lot of this before but it's refreshing how succinctly you captured it.