Definitely agree with you on the topic of negative tests. I wouldn't even take a PCR test after a positive home test, but it's probably required for time off work, reporting, etc. Clinically though I'm pretty sure any single positive test is sufficient to isolate given the low false positive rate.
Hi. As seems to be characteristic, I have comments ....
I was actually thinking yesterday about all those nonhuman mammals getting infected. Lots of people, including you and me, have said that we need to vaccinate everyone on Earth to cut down on production of variants. If literally billions of rodents are potential reservoirs of the virus, human public health becomes a sideshow. The variants will come from rodents. (Side note: apparently in some places 80% of white-tailed deer test positive for SARS-CoV-2.)
OTOH, somebody should be researching why rodents and ungulates can be infected and show no symptoms. Maybe we can copy their technique.
As to the mask survey, one obvious confounder (that I'm sure you've thought about) is that people who go to the trouble of getting N95 or KN95 masks are probably also taking other health precautions, because that's our priority. This was even more true back when the survey was done, before the Feds started talking more positively about high-efficiency masks.
About antigen tests and false positives: two brands that I have used claimed a 1% false positive rate, which is comparable to PCR testing. It's false negatives that are a frequent issue.
Animal variants: not all animal variants will readily pass back into humans. Public health infrastructure still matters, because it will be our way of detecting and containing new variants as they emerge.
re: why rodents and ungulates can be infected and show no symptoms, I think to a degree this is projection. They show no clinical signs (technically animals can't show symptoms) in observations so far, but maybe there is some amount of disease that we haven't managed to notice so far. Either way, the reasons for this probably have something to do with a combination of the inherent biology of these animals combined with the adaptations the virus must make to infect them. In some number of decades we may understand it well enough to bring insights into human medicine.
RE:mask survey--yes, it has some potential confounds. It's worth keeping in mind, though, that it isn't a guarantee that people who are wearing masks are taking other precautions. It may be that people wearing better masks take more risks because they think they are better protected. while this may be a confound, I leave it very much in the "may be" category. Any survey methodology is going to be imperfect, of course. That's a reason that I like to look at the totality of evidence on masks, which includes quite a lot of other types of studies. What's important to me is that these studies largely seem to agree that masks are an effective tool.
re:antigen tests, the false positive rate varies between manufacturers, but I agree it's generally low. False negative rate is harder to tease apart because often this is based on a comparison with PCR, which can detect asymptomatic infections that were never transmissible--the antigen test won't turn those up. So is that really a "false negative," for the the reasons that a person generally takes a test? My feeling is that antigen tests have their place in stopping transmission by telling people when to isolate, while PCRs are much more valuable for guiding clinical care.
Please do not misunderstand, I use masks (took off my KF94 an hour ago).
Are you going to write about the divergent vaccine news today? J&J has suspended production, presumably because supply is outrunning demand. Meanwhile, Novavax reports results indicating their vaccine is effective in adolescents, which might make it ideal for younger males. 80% prevention of infection by the Delta variant would indicate it's on-par with the mRNA vaccines.
Re: reservoirs in animals, perhaps the best thing we can do right now is support efforts to develop a pan-sarbecovirus vaccine. A few of these are already under way, and have produced what seem like promising preliminary findings.
Definitely agree with you on the topic of negative tests. I wouldn't even take a PCR test after a positive home test, but it's probably required for time off work, reporting, etc. Clinically though I'm pretty sure any single positive test is sufficient to isolate given the low false positive rate.
Sweden is abolishing the entire free PCR test infrastructure. They're just counting on anyone symptomatic to voluntarily isolate.
Hi. As seems to be characteristic, I have comments ....
I was actually thinking yesterday about all those nonhuman mammals getting infected. Lots of people, including you and me, have said that we need to vaccinate everyone on Earth to cut down on production of variants. If literally billions of rodents are potential reservoirs of the virus, human public health becomes a sideshow. The variants will come from rodents. (Side note: apparently in some places 80% of white-tailed deer test positive for SARS-CoV-2.)
OTOH, somebody should be researching why rodents and ungulates can be infected and show no symptoms. Maybe we can copy their technique.
As to the mask survey, one obvious confounder (that I'm sure you've thought about) is that people who go to the trouble of getting N95 or KN95 masks are probably also taking other health precautions, because that's our priority. This was even more true back when the survey was done, before the Feds started talking more positively about high-efficiency masks.
About antigen tests and false positives: two brands that I have used claimed a 1% false positive rate, which is comparable to PCR testing. It's false negatives that are a frequent issue.
I'll have to answer these as separate topics.
Animal variants: not all animal variants will readily pass back into humans. Public health infrastructure still matters, because it will be our way of detecting and containing new variants as they emerge.
re: why rodents and ungulates can be infected and show no symptoms, I think to a degree this is projection. They show no clinical signs (technically animals can't show symptoms) in observations so far, but maybe there is some amount of disease that we haven't managed to notice so far. Either way, the reasons for this probably have something to do with a combination of the inherent biology of these animals combined with the adaptations the virus must make to infect them. In some number of decades we may understand it well enough to bring insights into human medicine.
RE:mask survey--yes, it has some potential confounds. It's worth keeping in mind, though, that it isn't a guarantee that people who are wearing masks are taking other precautions. It may be that people wearing better masks take more risks because they think they are better protected. while this may be a confound, I leave it very much in the "may be" category. Any survey methodology is going to be imperfect, of course. That's a reason that I like to look at the totality of evidence on masks, which includes quite a lot of other types of studies. What's important to me is that these studies largely seem to agree that masks are an effective tool.
re:antigen tests, the false positive rate varies between manufacturers, but I agree it's generally low. False negative rate is harder to tease apart because often this is based on a comparison with PCR, which can detect asymptomatic infections that were never transmissible--the antigen test won't turn those up. So is that really a "false negative," for the the reasons that a person generally takes a test? My feeling is that antigen tests have their place in stopping transmission by telling people when to isolate, while PCRs are much more valuable for guiding clinical care.
Please do not misunderstand, I use masks (took off my KF94 an hour ago).
Are you going to write about the divergent vaccine news today? J&J has suspended production, presumably because supply is outrunning demand. Meanwhile, Novavax reports results indicating their vaccine is effective in adolescents, which might make it ideal for younger males. 80% prevention of infection by the Delta variant would indicate it's on-par with the mRNA vaccines.
Those are interesting stories, but I had a couple of others ahead of them. You’ll see :)
Re: reservoirs in animals, perhaps the best thing we can do right now is support efforts to develop a pan-sarbecovirus vaccine. A few of these are already under way, and have produced what seem like promising preliminary findings.