D&D and the rising pandemic

[Dannyalcatraz]

As I recall, MMR vaccination rates for the USA have dropped to @85%, which is why we’ve had several measles outbreaks in the past few years.

From the CDC:

The Centers for Disease Control and Prevention (CDC) analyzed data from two telephone surveys, the National Immunization Survey-Flu (NIS-Flu) and the Behavioral Risk Factor Surveillance System (BRFSS), to estimate flu vaccination coverage for the U.S. population during the 2018–19 flu season. Vaccination coverage with ≥1 dose of flu vaccine was 62.6% among children 6 months through 17 years, an increase of 4.7 percentage points from the 2017–18 flu season and 3.6 percentage points higher than coverage in the 2016–17 season. Flu vaccination coverage among adults ≥18 years was 45.3%, an increase of 8.2 percentage points from the 2017–18 flu season and 2.0 percentage points higher than the 2016–17 season.

I’m thinking we’re going to have to do better with Covid-19- and the rest, too- if we want to avoid repeated major disruptions.

...which reminds me:

Amid the coronavirus outbreak, China is now also fighting deadly bird flu in chickens

In a province near the coronavirus epicenter, China has reported an animal outbreak of the deadly H5N1 bird flu in chickens.

www.businessinsider.com

AFAIK, it’s still just confined to avians at the moment, but it should be noted and monitored.

 

[Umbran]

Working from a different direction:

• How long (if ever) until the virus is eradicated outside of laboratories?
• What proportion of people would need to have resistance to the virus to prevent a new outbreak

Well, a rough, back-of-the envelope approximation is to note that, each time the susceptible population is halved, you might expect R0 to also be rouhgly halved, effectively. Outbreaks are usually limited if R0 is below 1. So, if R0 of covid-19 is, say, 3.5... if half the population is immune, that drops to 1.75. If there quarters are immune, effective R0 drops to 0.875.

Mind you, R0 is only a guideline and average - you can have an outbreak with lots of folks sick and dying with an R0 less than one thorough super-spreader events, or if demographics make it such that specific communities have immunity, and others do not.

We can hope for a treatment or a vaccine, but the likely alternative is that social distancing will need to continue until most folks have been exposed to the virus

This needs repetition: We currently do not have evidence that exposure gives any lasting immunity to this disease! There are many in the coronavirus family that do not produce lasting immunity though exposure. So, we cannot expect it here - hope is not a strategy.

 

[NotAYakk]

As I recall, MMR vaccination rates for the USA have dropped to @85%, which is why we’ve had several measles outbreaks in the past few years.

Measles is more contagious than Covid-19.

It is "airborn" with an R0 of around 15.

Covid-19 is droplets, with an R0 of around 3.

 

[tomBitonti]

Well, a rough, back-of-the envelope approximation is to note that, each time the susceptible population is halved, you might expect R0 to also be rouhgly halved, effectively. Outbreaks are usually limited if R0 is below 1. So, if R0 of covid-19 is, say, 3.5... if half the population is immune, that drops to 1.75. If there quarters are immune, effective R0 drops to 0.875.

Mind you, R0 is only a guideline and average - you can have an outbreak with lots of folks sick and dying with an R0 less than one thorough super-spreader events, or if demographics make it such that specific communities have immunity, and others do not.

This needs repetition: We currently do not have evidence that exposure gives any lasting immunity to this disease! There are many in the coronavirus family that do not produce lasting immunity though exposure. So, we cannot expect it here - hope is not a strategy.

I set the proportion of the population relative to the R0 value: 1/2 for R0 being 2, 2/3 for R0 being 3.

I'm aware that there is no evidence of lasting immunity. If there is no lasting immunity, then what? If there is neither lasting immunity, nor an effective treatment, nor a vaccine? How many times could a person contract the virus before they succumb to it? Is the end state here an eventual reduction to only persons inherently resistant to the virus?

Be safe, be well,
Tom Bitonti

 

[abirdcall]

Well, you can pick and choose population dense spots and compare them to less dense spots. I mean, you could also compare the US as a whole to one badly struck city in Italy, and get the opposite conclusion. You can pick a single house in Iceland where one person lived and sadly died, giving you a figure of a million deaths per million population, declaring that the world epicentre.

A fairer comparison might be New York City vs. London or another equally similarly size/dense city.

In the long run, each situation is unique in terms of population density, geography, mobility, degree of social distancing, age of population, and how far into the pandemic it is. We don't really have the tools to compare them here.

That's my point exactly.

We can all play numberwang if we want to.

 

[Umbran]

I'm aware that there is no evidence of lasting immunity. If there is no lasting immunity, then what?
If there is neither lasting immunity, nor an effective treatment, nor a vaccine?

I don't think anyone really knows the answer to that question.

We should remember that R0 is not intrinsic to the virus - it is a combination of its intrinsic properties and our behaviors - that's what social distancing is all about, effectively reducing R0.

So, if there's no lasting immunity, no effective treatment, no vaccine... then if I must speculate - we go to massive testing and contact tracing to isolate outbreaks and limit their ability to spread?

 

[FrogReaver]

Well, you can pick and choose population dense spots and compare them to less dense spots. I mean, you could also compare the US as a whole to one badly struck city in Italy, and get the opposite conclusion. You can pick a single house in Iceland where one person lived and sadly died, giving you a figure of a million deaths per million population, declaring that the world epicentre.

A fairer comparison might be New York City vs. London or another equally similarly size/dense city.

In the long run, each situation is unique in terms of population density, geography, mobility, degree of social distancing, age of population, and how far into the pandemic it is. We don't really have the tools to compare them here.

agree. IMO the US and the 5 big European countries make one of the fairest comparison for now. It’s not perfect but you pointed out the issue with most comparisons very well.

 

[FrogReaver]

That's my point exactly.

We can all play numberwang if we want to.

what makes you think US vs Europe was a bad comparison?

 

[tomBitonti]

I don't think anyone really knows the answer to that question.

We should remember that R0 is not intrinsic to the virus - it is a combination of its intrinsic properties and our behaviors - that's what social distancing is all about, effectively reducing R0.

So, if there's no lasting immunity, no effective treatment, no vaccine... then if I must speculate - we go to massive testing and contact tracing to isolate outbreaks and limit their ability to spread?

Which, in the US, leads to (1) the brick wall of invasive contact monitoring, plus (2) social distancing for years, plus (3) massive increases in testing. The difficulty with testing being asymptomatic spreaders.

(I‘m trying to build a rigorous analytic framework for understanding the likely consequences of the virus.)

Be safe, be well,
Tom Bitonti

 

[Umbran]

Which, in the US, leads to (1) the brick wall of invasive contact monitoring, plus (2) social distancing for years, plus (3) massive increases in testing. The difficulty with testing being asymptomatic spreaders.

There's a lot of contact tracing that can be done with just people that isn't particularly invasive. You can imagine we might need teams of volunteers that can be trained, and then called up when necessary. Heck, just put it in National Guard training, and we have thousands of people who can do contract tracing.

Years of social distancing? Probably not. I'd expect instead a shorter period of more harsh "shelter at home" measures, with significant narrowing of what is "essential workers". Coupled with ramped up testing (which is a supply issue, not a technology issue) and contact tracing and you can avoid years of distancing, and replace it with far more targeted quarantines.

(I‘m trying to build a rigorous analytic framework for understanding the likely consequences of the virus.)

With respect - "rigorous analytic framework" is an epidemiologist's job. Unless you're going back to school to get a new degree, real rigor will be denied you.

Edit to add: a nice piece on contact tracing - How Contact Tracing Works And How It Can Help Reopen The Country