Source:  U.S. National Park Service.

Edit:  Read Post #982 first.

This is a short post for those who have been following along.  If you haven’t been following along, you should probably go back and read the last two posts on herd immunity.

If nothing else, this post illustrates why somebody needs to do this calculation with full accuracy.  Because, when you get down to it, being able to answer the question below, accurately, seems kind of important.

There’s a new, more infectious COVID variant on the loose in the U.S., commonly termed the U.K. variant.  In this post, I’m going to redo the calculation Post #979, substituting an estimate of the U.K. variant’s viral transmission rate for the previously-assumed 3.33 R-nought (R₀ ) value for the existing strains of U.S. covid.

The results will tell me whether any U.S. states have enough “herd immunity” to be have COVID new case rates continue to fall, even as the U.K. variant becomes the dominant COVID variant in the U.S.

The U.K COVID variant is rumored to raise the effective viral transmission rate from roughly 1.1 to maybe 1.5.  That means R₀ should rise proportionately, or:

• R₀ (U.K.) = 3.33 x (1.5/1.1) =  4.54.

Now plug that into the required-herd-immunity-level equation from Post #979.  Below, 0.53 is the estimate effect of current masking/distancing/restricting actions.  Solve for the effective herd immunity level H_e that will produce an effective viral transmission rate of 1, with the U.K. variant.

•  4.54 * (1 – (H + .53 – .H*.53) = 1.0
• Solve for H
• H =~ 0.54

Based on this rough calculation, any state where more than 54% of the population is immune will be protected from this new variant by the combined effect of the population (herd) immunity and the continuation of all other existing efforts to disrupt virus transmission (masking/distancing/restricting).

Look back to Post #958 to see a reasonably current list of states by estimated proportion of population that has already been infected.  Although this is a little old, and ignores vaccinations, it gives you a rough cut.

Prior to the onset of vaccinations, just three states exceeded that level.

I hear that North Dakota is nice in the summer.

European policy regarding masks seems to remain months ahead of the U.S. 

In prior posts, I documented that Germany has been distributing FFP2 (N95-equivalent) masks to high-risk populations since 12/15/2020.  The obvious analogy for U.S. heath care policy would be for the Biden administration to offer N95s to the elderly via Medicare. 

And both the country of Austria and the state of Bavaria are requiring high-filtration masks in public places. Continue reading Post 980: The French ban the worst masks.

September 9, 2020

 

 

 

January 24, 2021.

 

 

Above:  Fraction of the population wearing masks when in public.  Source:  Carnegie Mellon University Delphi Group COVIDCast.

By this time, most U.S. residents seem to have gotten the memo about wearing masks.  And my reading of recent news coverage is that America now seems ready to up its game on masks.  And it’s about time.

If you’ll go to Google News and search for N95, you’ll now see a spectrum of articles on a) why you should wear an N95, b) where to get an N95, c) alternatives to an N95.   As well as articles telling you to wear two masks, if you can’t get an N95.  Or articles giving reasonably useful generic ratings of which masks are better than others.  Or introducing you to other high-filtration standards, such as the Korean KF94.

Among which is an op-ed in today’s Washington Post with the straightforward title:

Everyone should be wearing N95 masks now

The Washington Post op-ed itself is pretty good.  The comments below it are just pitiful.  Either that was a target of the Russian trolls, or Americans have a long was to go in terms of getting educated about masks.  I don’t think I’ve seen misinformation and disinformation so heavily concentrated in one place before.

In this post, I’m going to offer three bits of perspective on how far we’ve come on this issue of wearing N95 masks, and then summarize any new practical advice that I can glean from today’s  crop of articles.

In short:  We’ve gone from “you don’t need one, and you shouldn’t wear one”, and no federal leadership on the issue, to “you need one to avoid aerosols, you should find one wherever you can”.  And still no clear Federal leadership on the issue.  And still a hard time figuring out how to buy a true N95 mask.

This is an area where the Biden administration could make a real difference in ordinary citizen’s lives.  Reading those Washington Post comments, I’d say that pretty much everybody recognizes how hard it is for a citizen to buy an N95 mask and have confidence that it is the real article.   It’s not like that’s some secret.

So, anything from cleaning up the marketplace so that we could know what we are buying, to some sort of government-run certification program so we could know what we are buying, to outright provision of certified N95 masks.  Starting, as I’ve suggested earlier, with provision of N95s to the elderly via the Medicare program.

 

Continue reading Post #977: “Wear an N95” goes mainstream

Today, a headline on CNBC states:

CDC director says federal government does not know how much Covid vaccine the U.S. has

I’m shocked, shocked to hear that. 

Well, actually, I’m not.  I called this one back in June 2020 (Post #732). Which I will now quote.

We can also expect that vaccine distribution will be done with the current administration’s hallmark lack of transparency.  The usual talking-out-of-both-sides-of-their-mouths.  The usual contradictory statements by various officials.  The usual lack of not merely accountability, but basic accounting.  I’d say, based on prior behavior, that something as obvious as a simple list of which states got how many doses will not be made public.  At the time when it really matters — this fall — I’d say the odds are excellent that we (the US people) won’t even know where the vaccine is.

Continue reading Post #975: Nobody knows how much COVID vaccine the U.S. has?

Source:  Calculated from NY Times Github COVID data repository, data reported through 1/24/2021.

Just another boring post.  Thank goodness.

• The COVID-19 new case rates continue to fall.
• They are falling in more-or-less every state.
• It’s not slowing down yet.  The case counts continue to fall at a constant percentage rate.  (It looks like it’s slowing down, above, because the thick blue line is starting to bend a bit.  But a graph like that doesn’t show the growth rate.  I’ll graph it on a log scale, below, to show the constant growth rate.)
• It’s falling in more-or-less every state with more-or-less the exact same growth rate.  That’s a point that deserves further discussion.
• Finally, Virginia’s curve now shows the predicted “speed bump” (Post #964).  The rate has begin to drop abruptly as the seven-day moving average passes the “lump” of cases reported circa 1/17/2021.

Continue reading Post #974: Today’s trend update, and maybe one more lesson from the French

Source:  Calculated from NY Times Github COVID repository data.  Data reported through 1/23/2021.

U.S. new case counts are down to where they were before Thanksgiving.  And they are falling in all 50 states and DC.  That’s the only solid takeaway from this posting. The rest is just an explanation of why that’s so annoying. Continue reading Post #972: The rain falls on the just and the unjust.