Monday, April 27, 2020

Updates, and "New Normals"

Here's an update of the graph shown on April 10th, with an end date of April 26th:
Graph: Author
The growth of new "test-positive" cases of coronavirus infections has continued its trend downward to reamain consistently less than 5%. In the next graph, check out the purple line, which represents the number of new cases day by day.
Graph: Author
Note that it has been flattening out since about April 2nd. The anticipated "peak" for Pennsylvania was at that time April 15th. On that date I checked and the peak was moved to the 18th. Whatever the case, the trendline from April 10th to date is flat to slightly negative, and that means we're coming out the other side. Of course, these changes are sensitive to how much we're testing, which has gone up and down daily, but averaged about 5,200 new tests reported per day.

New Normals?
In a press conference, Dr. Deborah Birx announced that social distancing would continue through the summer. A journalist on NPR speculated that things like telehealth would become the norm, even beyond the epidemic. These bits, and more this morning just teed me off and I switched of the radio!

There were protests in a number of state capitals last week, including in Harrisburg. A minority of people want some of the restrictions to end, and for more businesses to be allowed to open as long as precautions to limit disease spread are put in place in their workplaces. Georgia has started to allow a number of social-contact businesses (eg, barbershops) to open. Most Americans, according to polls, say it's too soon to do so, and many in those opening areas plan to keep their distance from others anyway. No one ever promised that social distancing and lockdowns would stop the virus; the intent was to "flatten the curve" so as to avoid overwhelming hospitals with very sick patients.

Sweden is an experiment that studies a different approach. The BBC reports that the Swedish government has not locked the country down, rather allowed people to continue to mix, with recommendations for keeping distance, and Swedes have mostly gone along with this. The policy is broadly popular, as is the government's epidemiologist, Dr. Anders Tegnell. Sweden is in the top 20 for deaths, and most of those are very old folks in nursing homes, but the death rate is a concern to the government. It has been suggested that Sweden is seeking to improve herd immunity through this policy.

So how is this going? Here are the deaths in four countries in Europe, compared to Sweden:
Graphic: BBC
What's interesting to me is that all of these graphs appear similar, that Norway and Denmark have fewer weekly average deaths, but Britain has more--and Prime Minister Boris Johnson took a lot of heat for this, and coincidentally got COVID-19 himself!

Herd immunity is something we've all heard a lot about, and a number of folks I know have publicly mused about it. What can we expect? We don't know yet, but if the virus--SARS-CoV-2 is similar enough to its brother, SARS-CoV-1 in 2002, then immunity after exposure probably lasts about 1-3 years. So maybe it'll be more like the flu than chicken pox, which confers life long immunity. A vaccine is likely to come into the equation in the next 12-24 months.

So what's the deal with Sweden, and why are so many countries so different from them? I suggest that both the protests here in Harrisburg and elsewhere, and many people's expressed desire to continue some social distancing despite an imminent opening up of society, are two touch points for understanding what is going on.

Swedish scientists knew there was no stopping the virus, and they also knew that no matter what was done, people would die, although most of those deaths would be among people who were quite frail, and who would die of something soon in any case (flu, a bad cold, bacterial pneumonia, urinary tract infection, etc.). It's a risk-based management strategy, and to some probably seems cruel, but in fact it simply reflects the reality of the situation. It does not ignore that younger people and health care workers would also die, but it frames all of this in a context of building herd immunity. It depends on the natural tendency of individuals to avoid danger; many Swedes are exercising a complex personal calculus that includes their own risk tolerance, and they practice social distancing voluntarily for this reason. Sweden's death rate is high, but their herd immunity after this passes may exceed 50% of its population.

Interestingly, the Swedish government has allowed schools to remain open. Special needs students still get in-person services. People are out exercising, "It’s good for their physical and mental health," says Johan Carlson, head of Sweden's Public Health Agency. Their hospital beds are not full to capacity. They have not run out of ventilators. There's evidence that Sweden's economy has not been hit as hard. Shops can still do business--less business--but keeping the doors open. In short, Sweden's approach may be more sustainable and lead to less disease and death--of all kinds and all sources--than may be the case where strict lockdowns have been instituted. Time and study will tell.

From this I think it's reasonable to conclude that we could open up the country more quickly, and rely on individual risk estimation, continued, aggressive testing, contact tracing and selective quarantine to allow people to begin to transition to a real "new normal. What's that look like?

Who knows? It irritates me when journalists, policy makers, and talking heads breathlessly speculate extremes (as I mentioned above). But I think a few things are likely:

  • Some people, but by all means not all people, will decide to keep employing some distancing behaviors indefinitely. But evidence from other epidemics (Spanish flu, Ebola) don't point to people en masse giving up on handshakes, hugs, and sharing a tasty dessert. People haven't changed that much in 10,000 years.
  • Telehealth will become more common, and be better paid for, but it will not become the "new normal" since talking to a patient on the phone or via Skype is only a "second best" way to really evaluate health and disease. I speak from experience. Just because a health system decides it's more efficient to "see" patients on Zoom, doesn't mean it's a good idea. Look for a generation of lawsuits to emerge over cases that should have been seen in-person.
  • Funding for public health, disease surveillance, and stockpiles of medical gear, and calls for changes in health care system design, are likely to be demanded by the public as a means of forestalling a similar crisis in the future. We got caught with our pants down once. I doubt people want that again.
  • Tolerance for "lockdown" in the US will begin to fade very quickly in the next month, but even then individual behavior is likely to moderate what society looks and feels like to people. When, and if, we see another outbreak of this new virus in the fall or later, the response to it will be different, less intense, more modulated to local conditions, and reframed to a risk model that looks more like Sweden's. 
  • Public health scientists have become heroes of a sort, but I think that fame has led to a kind of desire to keep the power that heroism confers--maybe for the "best" of motives, but still one-sided. I don't wish to indict anyone in particular. I just understand how people are. That power will fade, because it will be moderated by other considerations: you can't keep an economy on hold forever, and at some point people will begin, on their own, to engage in the same complex decision-making that Sweden already has, and that we've seen in other parts of the world, like Africa.
I really think that the suddenness, the surprise at the numbers of deaths, and the realization that we had really neglected disease surveillance, led to what we're seeing now--and its economic fallout. So I know everyone's hungry for predictions of the future, but I would caution: be patient. Understand that we're figuring this out together, and as such we do have a voice in the conversation, and we're not just to be herded into our pens. I was neither in favor of the protests, nor was I critical of them. It's just another part of the conversation that needs to happen.

Otherwise we'll spend the next 20 years isolated in our closets, waiting for inevitable death.

Friday, April 10, 2020

How are we doing today?

According to modeling at National Public Radio yesterday (the site is here, just scroll down and click on the blue "SHOW ALL (ORDERED BY PEAK DATE))", Pennsylvania is due to peak April 15th. This accords strongly with my own data from the PA-HEALTH case website:

Graph: Author

This shows that our daily new case rate has dropped below 10% (yay). I just came from the grocery store, where most customers and about half the staff were wearing masks. Wearing masks does work to prevent the spread of influenza-like illnesses. According to the CDC "Most experts think that flu viruses spread mainly by droplets made when people with flu cough, sneeze or talk. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Less often, a person might get flu by touching a surface or object that has flu virus on it and then touching their own mouth, nose, or possibly their eyes." This reach extends about 6 feet. (Hence, all the yellow tape marks 6 feet apart on the store's floor!)

However, with the novel coronavirus, this is less clear. The World Health Organization still lists this virus as being spread by droplets and contact. They are aware of some studies that suggest it can be breathed out, even while talking, but also note that this research is still in progress and is not conclusive, and they stress that personal protective equipment is in short supply, so masking by ordinary folks might not be a good use of that PPE.

Of course, the directive from the Governor's Office that all people should mask reflects the thinking that "Well what if is does turn out to be airborne? Why not be careful?" Urging people to "make their own" masks--sewing them, or wearing scarves or bandannas--addresses the PPE issue. The idea is not to be protected from inhaling COVID-19, rather to avoid breathing it out.

My graph above displays a consistent decline in new cases since the outbreak began and some precautions were started, and a continued decline since social distancing and stay-at-home orders were rolled out. It's possible that that masking directive will lead to an even sharper decline, but it's also possible it won't.

There are several reasons for this:

  1. It's possible that most transmission is not airborne, even if some is. Statistically, it could be difficult to impossible to see this come through the numbers.
  2. It is likely that little things, like picking up things at stores, which can involve contact with stuff that settled out of the air, is a cause of transmission, but again, statistically that would be hard to see in the numbers.
  3. It may be that there isn't any airborne expression of virus, except when someone coughs or gets a COVID-19 test (which involves sticking a swab up the nose--really far!), or gets a respiratory procedure like intubation. This would mean airborne transmission mainly happens in hospitals, but not the community.

When I was out just a while ago I saw many creative masks! It's a fun way to do something that may or may not help, so why not? On the other hand, I found it hard to feel critical toward the people I saw not wearing masks. Masks can be hot. They fog people's glasses. And they aren't 100% effective in controlling the expression of very tiny aerosol particles. They are fairly ineffective at keeping those very tiny particles out.

I also think there's something else going on. I think masking creeps some people out. It visually reinforces our fear of one another. I did see a lot of fear in people's eyes in that store--both among the people wearing masks (afraid of the virus), and those not wearing masks, afraid of what we are becoming--perhaps a society of individuals, separated permanently from one another, driven by a fear of our instinctive social, "touchy" nature.

So looking ahead, I will be watching for this. Are we to become a society of germaphobes, living in fear of one another, forever bathing in sanitizer? Looking back over the last 20 years and the proliferation of germicidal hand soaps, wipes, and a commercial emphasis in TV ads on being absolutely clean, I have every reason to believe that the trauma of coronavirus on our collective mind will lead to exactly that.

Interestingly, as I have discussed elsewhere in this blog, there's good reason to suspect that this obsession with "sterile-clean" home environments has been partially responsible for the explosion of auto-immune diseases like rheumatoid arthritis, ulcerative colitis, and other conditions.

What will happen? Too soon to tell...but when we begin to know, you can be sure I'll be talking about it!

Do what you need to do to be comfortably safe!

Tuesday, April 7, 2020

(Another) COVID19 Update

We're not out of the woods yet.

On the other hand, there is hope. I have been compiling data from the Pennsylvania Department of Health from the first day of regular reporting, March 4th. It was the first of two days which would report no cases. The clouds were still just coming over the horizon then. Today, we had the second highest daily increase in deaths, 240, or 32.5%.

Rest their souls.

It may be darkest before the dawn, and that's what I wanted to share tonight. This is the main graph, which shows the number of total (cumulative) number of cases to date (red), cumulative deaths (orange), and the daily death rate (pink).

Figure credit: Author

The average death rate is 1.10, although today it really spiked a bit. I don't expect that to continue, but it is hard to be certain. What is encouraging is the declining upward curvature of cases. There is an interesting correlation with the graph below, which is the rate of change of new cases--or, day by day, is the number of new cases higher or lower, and how does this compare to the previous day's number?

Figure: Author

For example, March 20th and the 26th weren't so great, with pretty big spikes in new cases. Look at the trendline--the black line--from the beginning of full reports with coronavirus testing, the overall trend is for slower growth.

The first closure order was March 16th, but it was advisory, and limited in scope, and this may account for why, from March 18th to the 23rd it kind of bounced around 27%, then spiked on the 26th. The hard order for the urban counties was on that date, and then the line really starts sinking. Interesting the highest numbers are in urban parts of the state (at 155 cases and 1 death, Dauphin County doesn't quite qualify).

The message: "Social distancing" is working--although I still prefer the far sunnier "healthy distancing."

The learning: I wonder what this would look like if we had tested more aggressively? This we will only be able to speculate about using modeling after the whole thing is over.

Finally, what's this mean for all of us? It means that we're not out of the woods yet!--but there is a light over the hill. Stay strong and let's hope that we get over it soon. (And if any of you feel guilty about making an extra grocery trip just to get out of the house, take heart: we're all just human).