Shortened quarantine ...

[NoGoldenCalves]

So, the CDC has reduced the recommended quarantine time for isolation. It seems ... suspect. 

[twitter] https://twitter.com/JoshuaPotash/status/...4975705088 [/twitter]

One concern (other than we cannot really take the CDC at their word) is that the longer isolation time was based on a distribution of infectious periods in the population, and they chose a mark which protected against (I believe) upwards of 99% of that range, a standard that was much stronger than "the majority of SARS-CoV-2 transmission occurs early in the course of illness." What percentage of infected people are still infectious beyond five days?

Also, should "the majority of SARS-CoV-2 transmission" be the focus? We know that about half (last I looked, this may be dated) of cases happened while folks were presymptomatic. But I imagine that the isolation period helped boost the proportion of cases where transmission occurs early in part because ... many people isolated once they knew they were infected. Now it seems that people may venture back out with masks that don't fully protect others while still infectious, even if they appear to be over it. 

They also continue to say to wear nothing more than a "well-fitting mask" instead of N95s or KN95s or better. 

Am I wrong for thinking this is another tremendous misstep by the CDC?

[M_T]

More concerning to me is that they've shortened their recommended quarantine time to 5 days + 5 days wearing a mask (yeah, right), at the same time they are saying Omicron is a highly infectious disease. Furthermore, you're excused from quarantine if it is "not feasible" (not "not possible", only "not feasible"). And that's for those that have minimal or no immunity.

Remember, 5 days after exposure was the median of when symptoms tended to appear. That's just when you get to go out again.

It seems the CDC is throwing in the towel and not recommending anything that will effectively reduce the spread. And in particular, not reduce the R rate, letting it sweep through the country. If you get sick, they've covered their rear by having some recommendation, and they'd say that someone must have disobeyed it. So it's that person's fault, not theirs. How could anyone prove that everyone around them followed this recommendation?

"For all those exposed, best practice would also include a test for SARS-CoV-2 at day 5 after exposure" Did you notice, they don't say the tests that most would take only detect COVID about half the time?

[M_T]

Interesting article out of CNN
  "CDC changes to quarantine, isolation advice took local health officials by surprise"
(I spotted it in the San Jose Mercury News, but chose to link the original.)

Sure makes it sound like it was pushed down onto the CDC from above.  (Where is the public outcry?)

[NoGoldenCalves]

CDC director says that 85-90% of viral transmission happens in the first 5 days. So they are okay with 10-15% of oopsies with this new quarantine period with no test out.

https://twitter.com/CBSMornings/status/1...3077726219

[M_T]

It isn't clear to me where those numbers come from. But changing the isolation & quarantine recommendations will surely increase that "10-15%" if 100% of those who know they are infected go out into public after 5 days.

[M_T]

Another misleading aspect of this 85-90% claim:

Consider all the people that you have close contact with in the 14 days (or whatever length). What % of them did you first have close contact with within 5 days? Who do you have close contact outside of family and coworkers?

If the average were (say) 85% of close contacts are first exposed within 5 days, then wouldn't that mean that the 15% that were after 5 days are essentially all getting sick? Ie, anyone exposed 5 days to end of the period would likely be infected.

The point is that this statistic (% of infections before/after 5 days) is meaningless without knowing the % of people exposed before/after 5 days.

[NoGoldenCalves]

Really great points, MT. I was also thinking that because people are unlikely to isolate or quarantine the first couple of days, for no other reason than they just don't know, the number of infections in the first five days is skewed higher because after that point is when people start to isolate and quarantine. If everyone ran around without isolating or quarantining when they found out they're infected or have been exposed then of course the numbers would stretch out for that reason, as well.

[ChrisGreene]

I just listened to a podcast called the Osterholm Update. 

https://www.cidrap.umn.edu/about-us/cidr...lm-phd-mph

A paraphrasing of his words: I'd rather have a health care worker 5 days out of an infection with an N95 mask on than being alone in a hospital bed with nobody to care for me.

I read the shortened quarantine as a response that we can't really sustain so many people out of the workforce. A cost/benefit analysis well beyond my understanding or pay grade.

[M_T]

The health care workers quarantine/isolation was reduced previous to the reduction for the general population. I didn't hear much complaint about it.

I guess the CDC figured that the people standing in line in front & behind you at the store (or, next to you at bowl or basketball game) really need to be out of isolation early.