Covid-19: Vaccines (Feb 15)

From 2008 until 2013, I went back to Cornell part-time to finish up a BA in Molecular Biology. It’s an interesting field that didn’t even exist during my first shot of college. Mol Bio kinda squoze into the gap between Biochemistry and Genetics, with big help from the Human Genome Project.

Molecular biology is the reason you can get vaccinated for Covid-19 now. Previously, it took a minimum of 4 years to develop and test a vaccine. What sped things up is mastery over the big molecules of life: DNA, RNA and proteins.

Derek Lowe is a molecular biologist who blogs for Science magazine. He’s an expert on diseases and vaccines, but he writes for mere mortals. If you want to make intelligent decisions about Covid-19 vaccines, here are links to some of his recent posts. They are way better than anything you’ll ever see on Twitter or Facebook.

B Cells, Infection & Vaccination
Pfizer/Moderna Vaccines
J&J and Novamax Vaccines
Oxford/AstraZeneca Vaccine
Vaccine Production Myths
Why Lower Efficacy Isn’t That Bad (Vox)

I’ll try to summarize vaccine results so far, in very over-simplified form.

The first Covid-19 vaccines approved in the US were RNA vaccines from Pfizer and Moderna. Both require two jabs, with about 94% efficacy at preventing infection. They use mRNA that includes the code for Spike protein. It’s stuffed into a tiny sphere of fats, cholesterol and probably some proteins. Composition and size similar to a Coronavirus, or like LDL “bad cholesterol” plus RNA. When injected, the nanoparticles are absorbed by muscle, lymph and liver cells. Inside them, the mRNA hooks up with a ribosome, which uses its sequence to build Spike proteins. Some Spikes leave the cell, float around, and trigger the immune system. Later, a real Coronavirus comes along, but immune cells recognize its spiky bits and send in the killers. Protected!

The Oxford/AstraZeneca, Johnson & Johnson/Janssen and Sputnik vaccines use a different approach. Instead of nanoparticles, they deliver via a modified Adenovirus (a mild virus that causes sore throats, pink eye etc). The DNA code for Spike is spliced into its genome. After injection, the virus infects some human cells. Its DNA sneaks into their nucleus and is transcribed into mRNA. That exits the nucleus, then follows the same path as the RNA vaccines: ribosome to Spike to export to immune response.

Of the 3 DNA vaccines, Sputnik (2 jabs) has excellent results, but probably won’t be available in the US. J&J (1 jab) is mediocre at preventing infection, though it’s OK at blocking serious disease and death. Oxford (2 jabs) is somewhere in between. The lower efficacy may be because some people are already immune to Adenovirus: so they kill it prematurely. Sputnik uses two different virus forms (one from chimps). That may explain its better performance. J&J and AstraZeneca are testing variations that may also be more effective.

Novamax takes a third approach. It cuts to the chase, and injects Covid-19 Spike protein directly. The Spikes are manufactured by moth (!) cells. How cool is that? To produce the vaccine, the DNA sequence for Spike is spliced into a virus genome. That infects the moth cells, which then produce Spike via the same path as the DNA vaccines. The protein is purified, then attached to a fatty nanoparticle. To the immune system, it looks a lot like a Coronavirus. Trials in the UK showed 89% efficacy (2 jabs). US Phase 3 trials started in December.

The DNA and protein vaccines have a big advantage: both molecules are more stable than RNA. They only need fridge temperatures for distribution instead of freezers (Moderna) or dry ice (Pfizer).

As an old dude, I’m eligible to be vaccinated now. The original plan was to wait for J&J vaccine data before deciding. That quickly became moot, since there’s a huge backlog. It will be a while until I can get any vaccine regardless. By health and habits I’m low-risk, so it won’t be too bad to live the pandemic lifestyle for a few more months.

New York vaccinated nursing homes and health care staff first. Now the priority is essential workers and teachers. That approach is already having an impact. There were 20+ daily cases in the local hospital for the month after Christmas, but it’s down to 3 or fewer. Surrounding counties are also doing much better.

At the moment I probably would pick Novamax, if its US trials are similar to the UK results. I probably already have Adenovirus immunity, and it makes sense to save mRNA vaccines for the next pandemic. However, the decision is barely more than a guess. There may not even be a choice of vaccines.

The big picture for humans: the success of all these vaccines is extremely good news. They’re fast, and will be even faster to release in the future. Minor DNA/RNA/protein tweaks to keep up with mutations will only take days, and won’t need such a long approval process. All three of the methods will help fight other diseases. And that’s not even counting newer techniques like CRISPR that are gradually being developed.

Looking back ten years from now, Covid-19 may seem like a wonderful disaster that launched huge medical advances.

Dennis Kolva
Programming Director
TurtleSoft.com

Covid-19 in New York #6 (Jan 12)

In July, the local Internet provider asked me to do some in-home wiring for a few of their clients. Most of the folks were good about masking and social distancing, but one couple wasn’t. They didn’t wear masks, and got physically close to me even after I asked them not to. I left early, and decided not to go back there. Someone else finished the work.

Soon after that, the couple tested positive for Covid-19. Not surprising, considering their behavior. The second installer had to quarantine. Luckily, I was outside the exposure time window. Phew.

Lately, it feels like there are more bullets to dodge. Cases have turned up in Home Depot, Walmart, most supermarkets, the Post Office, public transport. Since March I’ve kept a spreadsheet of public places where I’ve been, and when. There have been a few near misses, but nothing close enough to need a quarantine. Yet.

New York just entered phase 1B of their vaccination program. As an over-65 I’m qualified to get a vaccine as of today. Theoretically, I’d prefer to wait a bit. For one thing, the Moderna and Pfizer vaccines are well-tested and probably fine, but they are a new technology. I’d rather let other people be the guinea pigs, just in case there are long-term, subtle effects.

Also, they were the quickest to release. It’s possible there will be a future, more dangerous pandemic. If so, it would suck if my immune system had learned how to zap their mRNA carriers. Waiting a couple of months for Johnson & Johnson or AstraZeneca is kinda like saving the big guns for when they are really needed.

A traditional killed-virus vaccine would be best of all, since that approach is extremely well-tested. However those take years to develop. That’s a long time to be living in a bubble. Plus, any vaccines that haven’t started trials yet will have a hard time finding test subjects who weren’t vaccinated or infected. They may never get out the door.

Meanwhile, active cases have spiked locally, similar to the rest of the US. Covid-19 got into one of the local nursing homes right after Thanksgiving, and the number of county deaths jumped quickly from 1 to 17. That seems to be how the disease works in other places, also.

Since Christmas, the number hospitalized here has varied from 20 to 32. That’s much worse than the Spring ’20 surge, which maxed at 16 and was only over 5 for a few days. Here’s the chart to date:

Thick blue is active cases divided by 10. Red is the number in hospital, which lags by a few weeks. There was a spike of active cases in early March, but tests were scarce then so it’s not in this chart.

Most surrounding counties are having a worse time than here. Cattaraugus only updates their website once or twice a week now, ever since new cases jumped from a few a day to a few dozen. They used to be much more chatty. Chautauqua (next door to them) has 111 hospital beds, and 131 patients. Steuben has 774 active cases, 2,214 residents in quarantine (2% of their population), and only 15 contact tracers. They’ve had 153 Covid deaths so far in a population about the same as here.

The Rt tracker website is a good predictor for future disease impact. As of today 15 states are below 1.0 and reducing their active cases. 36 are above it, and still getting worse. Now that the holidays are over, there’s more hope it will improve.

One (tiny) good impact of Covid-19 is that many people put up extra Christmas lights this year. Walking around at night has become very entertaining. Winter is a bit less bleak.

Now we just need to survive Jan 20.

Dennis Kolva
Programming Director
TurtleSoft.com

Covid-19 in Charts (Dec 26)

This chart shows new confirmed Covid-19 cases in each part of the US. A couple months ago things got bad in the Dakotas and surrounding states. Then it improved there, but got worse everywhere else. There was a sudden reverse last week. New cases declined in every region. It may be good news, but more likely it’s because health departments ended the week early.

This one shows weekly restaurant seatings from OpenTable, comparing this year to 2019. After the April/May shutdown, it rose gradually to about 60% of last year. Now it has declined back to about 35%. There’s a big spread between states: New York is at 12%, California 6%. Texas and Florida are still near 60%. I don’t know why everyone decided to eat out during Labor Day week.

Last July I divided the largest countries into 5 groups, and made charts for their cumulative confirmed Covid counts. Here are updated global CCCCCCs. All numbers are cases per 100,000 people.

First are the countries that were doing it right back then. Almost all of them are still doing it right. They have very few cases, and economies that are close to normal. The only exception is Tunisia. It’s starting to catch up with Europe.

Next are countries that were just starting to increase in July. Most of them halted the growth, but Jordan, Morocco and Greece are acting like Europe. Some of the poorer countries may have low counts from lack of testing, rather than lack of disease.

The third group is countries in Europe, plus Canada. They had serious early outbreaks, but contained the disease over the summer. Sadly, things got much worse once the weather cooled. Canada and Germany aren’t too bad, but the rest are doing almost as badly as the US.

The fourth group is countries that were just starting to have serious problems in July. They are a mixed bag now. Some are doing OK, but the ones in Europe and South America have growth rates similar to their neighbors.

The last group I called the “basket cases”, with outbreaks that were bad and getting worse. Those in the Southern Hemisphere slowed down as their summer hit. Those with disease-friendly politics became even more baskety. Portugal started zooming recently, similar to the rest of Europe.

The countries with the most per-capita Covid cases now are #1. Czechia, #2. Belgium, and #3. USA.

About 45% of the world population is in places where Covid-19 is no big deal: China, all of East Asia and Southeast Asia, Australia, New Zealand. A few island nations and isolated countries. When a disease is contained, it’s possible to keep it that way. Though it’s much harder when neighboring countries don’t have it under control.

About 5.5% of people in the US have been infected so far. Keep in mind that it takes roughly 80% to reach ‘herd immunity’. Take the pain of the past 10 months and multiply it by 15 to get there naturally. It’s why we need vaccines.

Dennis Kolva
Programming Director
TurtleSoft.com

The Economy (Dec 2)

TurtleSoft was born near the end of the Reagan presidency. Those were the days of “trickle-down” economics, with a top income tax rate of 28%. It had fallen steadily from 91% in 1963, to 70% during the 1970s, then to 50% and down during the Reagan years.

I read an article back then predicting that the new tax policy would shrink the US middle class. They expected good fortune for Walmart (more poor people) and for Tiffany’s and Neiman-Marcus (richer rich people), but problems for Sears (bye-bye middle class).

At the time it seemed like a bold prediction. But 30+ years later, the writer turned out to be spot on. Sears is almost dead. Walmart is thriving. Aside from Amazon, their biggest competition these days is the dollar stores, which cater to even poorer people. Tiffany’s and Neiman-Marcus are in trouble right now, but that’s mostly because the Internet and Covid-19 zapped walk-in retail. Or maybe it’s because the moderately rich are also shrinking. The ultra-rich can buy islands and politicians (thank you Citizens United vs FEC). They don’t need to show off with jewelry or designer clothes.

The divide keeps growing, with fewer in the middle.

Covid-19 is definitely impacting the economy very unequally. It’s accelerating a trend that was already moving at decent speed. This is a very bad time to own a restaurant, or any type of walk-in retail. It’s difficult for most service professionals. AirBnBs. Much of the gig economy. Even hospitals and medical workers are worse off: higher expenses, layoffs, and less profitable work.

Construction seems to be a mixed bag. One of my neighbors is a contractor who has kept busy since May. However, the biggest construction project in town finished last month after many delays, and it is still completely empty. Nobody wants to rent offices or apartments in a building with shared hallways. The second-biggest project shut down in April, and it is still just a partly-finished foundation and elevator towers. That’s got to be hard on owner cash flow.

I’m no economist. But as a small business owner and a developer of accounting software, I do know how to track money. As the pandemic slithers into its scariest phase, I think the US is at a crossroads.

The conservative viewpoint is that the deficit is huge, and it’s time to cut back. Based on past history, that usually leads to austerity, layoffs, bankruptcies, deflation. Money stops flowing, so it becomes more valuable. Recessions are a good chance for people with money to pick up assets cheap.

The liberal viewpoint is that people are hurting and need financial help. The US can borrow at close to 0% interest. The economy needs stimulating. Stimulus makes things better in the short run, but the debt eventually needs to be paid to those who provided the money. Mostly rich people & foreign governments.

Hopefully there is some middle ground, to keep things stable until vaccines are widely available. Then life can get back to something close to normal. If the money goes into things that create wealth in the long run, then it’s an even better investment.

Unfortunately, this year a lot of money is shifting from places suffering from pandemic (US, Europe, India, Africa) to countries that contained the disease (China and East Asia). It’s too late to do anything about that. Wealth is also shifting upwards to rich people, since they are relatively less affected.

Meanwhile, I’m keeping busy, trying to stay middle class. Goldenseal Pro is inching along. I think progress will speed up soon.

Dennis Kolva
Programming Director
TurtleSoft.com

Covid-19 Update (Nov 22)

Our staff is back to working on Goldenseal Pro, though no major progress to report yet.

Meanwhile, here’s a chart for new weekly Covid-19 infections in each region in the US:

The numbers are from Johns Hopkins University. I multiplied counts for the first few weeks by 5x, because testing was so sparse back then. There’s still lack of testing now, but not nearly as bad.

50 million people are predicted to travel for Thanksgiving, so the curves probably will get steeper.

Covid-19 is now worse than the first surge 7 months ago, but the US reaction is very different. Here’s a chart of restaurant activity from OpenTable. It covers the entire pandemic from Feb 18 until yesterday.

Between March 10 and March 20, every state dropped rapidly from normal to 0% or close. Starting in May, seatings inched back to 50% or 60% of usual in most places (Rhode Island went crazy with restaurant dining, while Hawaii and DC mostly stayed closed). Attendance has dropped off a little in the past month, but many people are still eating out like it’s 2019. Presumably they are doing other things that spread virus, also.

I don’t know what to say. It’s like watching two trains on the same track, headed towards each other. The Coronavirus train is much, much bigger.

Dennis Kolva
Programming Director
TurtleSoft.com

Covid-19 in New York #5: Early Signs (Nov 13)

Here in Ithaca, we just set a record for active Covid-19 cases and people in hospital. Nationally, the US is also setting records. Things are getting worse in every state except Mississippi.

Globally, much of Europe is shutting down. Meanwhile, the US is chugging along about like normal. OpenTable shows restaurant seating declines in a few states, but most are about the same as a few months ago.

Back in March, I posted a link that talked about how fast Covid-19 will hit. It’s worth revisiting, since conditions probably will be like that again, and soon. Except, this time it’s starting from higher ground. Most of the US is headed towards conditions that are similar to New York City last March.

My parents are in a nursing home in Cattaraugus County NY. It’s rural, just south of Buffalo NY. I check their Health Department website weekly, to get an idea of how things are going there. It’s the only nearby county with a write-up on every case: gender, symptoms, how they caught it, why they were tested.

The odds of catching Covid-19 are growing rapidly. It may outstrip the number of test kits (already happening in the Dakotas). So, I decided to put all the Cattaraugus data into Excel (633 cases), then do math on them. The results may be useful for anyone trying to figure whether they have Covid-19 or not.

60% of Cattaraugus cases are female, 40% male. 20% are health care workers or employees in hospitals or group homes. 47% reported close contact with a Covid-19 carrier. They may not have known it at the time. 8% caught it while traveling elsewhere. 92% were local transmission.

34% had no symptoms when tested (they may have developed some later).

On average, the other 66% reported 3.21 symptoms each. The most common were fever (43%), coughs (43%), congestion (36%), body aches (33%), and headaches (31%). 21% had loss of taste and/or smell. That’s the only one that is different from a bad cold or the flu.

14% had shortness of breath: the most scary sign, since most deaths are caused by respiratory failure.

Victims also reported the usual stuff: fatigue, sore throat, chills, runny nose, nausea, diarrhea, sinusitis, weakness, dizziness, chest pains, stomach pains, vomiting. Sneezing was rare: only 3 mentioned it.

UPDATE NOV 22: Cattaraugus had 52 positive tests on Nov 17. Then 30+ most days after that. Not surprisingly, they stopped listing details for every case and just give a summary now. I revised the percentages slightly, with a few days more data.

If you want one more way to track the pandemic, Carnegie-Mellon now has a website with Covid-19 maps. It uses Google and FaceBook data to track doctor visits, mask usage and other indicators.

Back in March, people changed their behavior very quickly. It happened in just a week or two, even before Governors shut down states. I’m curious to see if it happens again.

Dennis Kolva
Programming Director
TurtleSoft.com

Health Departments & Politics (Oct 21)

I’ve been more than a bit obsessed with Covid-19 since it started. For a while it was almost a full-time gig. These days it’s calmed down to just a few hours a week: reading science papers, and spot-checking a few websites.

Among them are sites for Health Departments in some nearby counties. They vary. All have current numbers, but some break it down by towns; some give a brief description of each case; some have lists of places where infected people visited. Right after the Sturgis rally, Cattaraugus County (4 to the west) even mentioned that two cases were in people just returned from South Dakota. That’s a long motorcycle ride.

The sites are entertaining, in a geeky sort of way. I keep adding more counties, and now visit 15 of their sites. Reading between the lines, they paint a picture of what the pandemic must be like for staff in local Health Departments.

Pre-Covid, their biggest job was inspecting restaurants and other food services. Keep perishables below 45° or above 145°F, don’t put meat above salads in the fridge, control rodents and the like. They also administered WIC, and tried to keep people from catching STDs or growing too obese. Flu shots. Toxic algae blooms. Ticks and Lyme disease. Mosquitoes and West Nile. Opioids. Tobacco. Rabies.

Most of these departments are pretty small. They already had a lot on their plate. This year they’ve been in crisis mode for seven months already, and the battle has just started.

Contact tracing and quarantines are an important part of controlling a communicable disease like Covid-19. That’s mostly what they do now. I’m sure it is not an easy job. You’ve got to ask people where they’ve been, and who they were close to. Then persuade them to stay home for a couple weeks. Plenty of people resent authority or think it’s all a hoax. Even the best will be tempted to sneak out for a bit. You’ve got to deal with all that, and probably don’t have much enforcement power.

Normally I avoid talking about politics. As a business owner, I’m significantly less liberal than most folks here in Ithaca. As an Ithacan, I’m more liberal than most people using our software. It’s not worth arguing about.

Thing is, right now the US probably is headed into a major emergency. A once in a century situation. It’s right in the middle of an election for President, all of the House and 1/3 of Senators. Plus local races.

Both political parties got together in March, and signed the CARES act to support people and organizations affected by the pandemic. Since then, it’s been gridlock and antagonism.

All those local Health Departments will make the difference between a moderately bad Fall/Winter season for Covid-19, and a runaway disaster (or lock-downs and economic damage). To keep everyone safe, they need more staff to trace contacts. More tests. More resources to support folks in quarantine so they don’t wander off and infect others. Problem is, the states and counties that pay them are facing bigger expenses, and reduced revenues. They can’t print money to make up the difference. They need help.

And of course, many individual people are in the same boat. Life got a lot more complicated and generally worse in March. It’s not turning any corners, anytime soon. It will take extremely competent leadership to manage the next phase of the pandemic, and recover from the economic damage. States and counties can only do so much. Covid-19 is exactly the kind of problem that needs full attention at the Federal level. It’s not happening now.

You might say this country needs to come together to fight a common enemy: the coronavirus that causes Covid-19. And maybe come together for other stuff also. Life was already headed downhill for many people, even before March 2020.

I miss the days when there were liberal Republicans and conservative Democrats. When politicians compromised and solved problems (at least some of the time). Voting in a politician is a lot like hiring an employee or subcontractor. In the end, competence and integrity are what counts.

Dennis Kolva
Programming Director
TurtleSoft.com

Covid-19: Contact Tracing (Oct 12)

Our county had its first death from Covid-19 today. The number of active cases has gradually increased as well. Surprisingly, Cornell is not to blame. They’ve only reported 5 new cases in students and staff during the past week. The rest of the county had 30.

This is not just a local problem. Some parts of Upstate NY have even bigger increases. There currently are 226 active cases in Steuben County (2 to the west of here). 870 people are in quarantine (almost 1% of their population). It’s much worse now than in March/April. So far 60 people have died in Steuben, with 15 in the past week. Their population is similar to here.

New York State is actually doing better than most places in the US. Looking ahead, it makes me very concerned.

It’s possible to divide epidemics and pandemics into three levels of severity.

The best option is full containment. It’s what happened with SARS, MERS and Ebola (twice) in this century. There’s a local outbreak, but medical help rushes in to help the infected. Contact tracers find and quarantine everyone exposed to them. There’s public education, to help folks reduce their risk of infection. Eventually the disease stops spreading. Eventually it disappears.

With Covid-19, some countries have reached containment. China is the biggest example, but most of Eastern Asia is fully contained or close. However, until the disease is completely contained in the rest of the world, they all risk new outbreaks.

The next best option is just plain old containment. It still involves contact tracing and quarantines, to reduce the spread. Still public education to help slow things down. But for whatever reason, the growth rate stays about the same. People keep getting sick, but not at crisis levels. That’s where most of Europe is right now. Ditto for much of the US, especially New England. New York was there all summer, but it’s starting to lose it. Europe is starting to lose it too.

The worst option is out of control pandemic. Contact tracing doesn’t work then, because too many people are infected at once. You can’t keep track of everyone, nor quarantine them all. The disease pretty much runs its course exponentially. Eventually there is herd immunity, but it ain’t pretty getting there.

Influenza did that in 1918 to 1920. Plenty of other diseases did that in prior history. This year it happened for a few weeks in one Chinese province, then in Italy, Spain and New York City. Hospitals are overwhelmed. Almost everything becomes unsafe. Things can get very bad, even when a disease isn’t real deadly. It’s worse when every place is in trouble at the same time.

Steuben may be close to the edge now. They have 15 contact tracers, which means each of them is running daily checks on 18 sick people, plus 40 more who were exposed and in isolation. Things were fine there until Sept 23, then it went off a cliff.

Covid-19 has dominated lives for more than seven months. I think all of us are growing very, very fatigued. The problem is that Spring and Summer 2020 were just Covid 1.0. Best guess is that this pandemic will follow the 1918/9 curve. If so, we’re right at the leading edge of the second and bigger wave.

One big thing we have in 2020 that wasn’t common in 1918 is vaccines, plus the science to develop them rapidly. Vaccines are challenging. The immune system in general is not easy to understand. Luckily, Derek Lowe’s latest write-up on vaccine development sums up current progress. He is a writer for Science magazine, and all his posts about Covid-19 are great. UPDATE: the Chairman of Pfizer also just posted info about their vaccine development.

The short answer is that creating a safe & effective vaccine is a slow process. One probably won’t be ready in time to help with that middle bump (if it happens). But it may reduce the 3rd and 4th ones.

Dennis Kolva
Programming Director
TurtleSoft.com

Covid-19: Droplets (Sep 25)

A couple weeks ago, Cornell University had over 80 active infections, and it was looking pretty dire. Then, the students got scared, and more careful. Last week there were 29 new cases. This week only 5. Someone was hospitalized for a few days last week, but it’s down to zero again. Still no local deaths.

Cornell has already run about 90,000 PCR tests since classes started. Students are tested twice weekly, and staff once. It’s probably not cheap. But, there’s a lot to be said for testing everyone: it nips outbreaks in the bud, and also acts as a reminder that the situation is serious. Having same-day turnaround also helps.

Meanwhile, I’m still doing research for a Coronavirus risk estimator. The consensus now seems to be that most infections happen through the air, so I’ve read a few dozen research publications about droplets and aerosols. The best is a 1934 paper by W. F. Wells. Here are a couple of its charts:

The first shows what happens to droplets that leave a person from talking, coughing or sneezing. Anything smaller than about 140 microns (.14 mm) evaporates, and turns into a floating aerosol. Anything bigger falls to the ground within a few seconds. What that means for Covid-19 is that there are three basic risks:

  1. if you are close enough to someone, you may inhale one of those bigger droplets while it’s still falling. That’s what the 6-foot rule is all about, and the advice to cough into your elbow.
  2. After the big droplets land, you can touch that surface, then transfer virus into your eyes, nose or mouth. It’s the reason for washing hands, and not touching your face.
  3. If you breathe air, you may inhale those small dried-up droplets, which gradually mix into the entire room volume. This is where HVAC comes in. The risk for any space depends on the number of infected people inside and what they are doing, minus air changes and filtration. It’s also why masks are so effective: they block droplets both coming and going.

The second chart from the Wells paper explains why respiratory diseases are more common in winter. People are indoors more, which is half the problem. Even worse, the air is heated and dry, so more droplets evaporate, float around, and end up in noses and lungs.

When working with droplets and aerosols, it’s easiest to do everything in microns (symbol µm, aka micrometers). A micron is one thousandth of a millimeter. It’s about the size of the biggest tobacco smoke particles, a medium-sized bacteria, or the smallest pollen grains. PM2.5 pollution is 2.5 microns and smaller (the most dangerous size because it gets into your lungs easily). N95 masks filter 95% at 1/3 micron size. They hit 99% for both smaller and larger particles. 3M says that’s because the bigger particles are heavy, and ram into a fiber. Smaller ones are extremely light, so the fibers suck them in by electrostatic attraction. 1/3 micron is the sour spot in between. A coronavirus is about 1/10 of a micron.

A few researchers have measured the amount of Coronavirus in mucus and saliva: results range from 12 million to 36 billion virions per cc. It’s simple math to translate that to the amount of virus in droplets of different sizes. As it turns out, a one-micron exhaled particle only has a 2% chance of containing a virus, even at the maximum rate. The bigger droplets that dry up and then float are worse. The maximum size that evaporates in humid air (97 microns) will contain somewhere between 3 and 17,000 virions. The maximum in dry air (172 microns) has 16 to 96,000.

As those droplets lose water, they shrink down to roughly 10 microns diameter (about average pollen size). They become a tiny glob of mucus proteins and passengers, light enough to float for hours, easy to inhale. By the math, those are probably the most dangerous.

Dennis Kolva
Programming Director
TurtleSoft.com

Covid-19 in New York #4 (Sept 5)

There are two colleges here in Ithaca. Both planned to have classes on campus. Ithaca College (the smaller one) changed their mind a few weeks ago. They will be online-only for the Fall semester. Cornell went ahead with their reopening plans, and classes started on Wednesday. The Vet School laboratories are testing all undergraduates twice a week, which sounds great in theory.

Three weeks ago, there were 7 active cases of Covid-19 in the county. A week ago there were 19. Yesterday, there were 70. Most cases happened because students had parties without masks or social distancing. Who could possibly have suspected that might happen? /s

Maybe everyone will get scared, and change their behavior. More likely, there will be enough cases to trigger an automatic shut-down, per NYS regulations. We’ll see.

Meanwhile in the rest of the US, the State Rt tracker shows wavy curves for every single state. Today the majority of states are positive. Sometimes the majority are negative. It seems to vary on a few-week cycle. Back in April I compared state responses to skidding on icy roads. Because of the feedback delay, it’s easy to lose control and end up in a ditch.

Luckily, that isn’t happening with Covid-19. Most states seem to be converging on a Rt value close to 1. That’s probably the ideal growth rate, as long as the case count is low: the best balance between health and economic activity. I guess it also applies to ice and snow: most drivers in the North eventually figure out how to slow down the feedback cycle and stay on the road.

Globally, infections are also at a steady state, with about a million new infections every 4 days. Much of Europe is starting to see early stages of exponential growth, again. It’s going to be a long haul.

I’m still working on an Excel spreadsheet that calculates Covid-19 risk. There are many studies with useful info, but nothing that translates directly into hourly risk. It will require some assumptions and guesswork to get it calculating accurately.

Covid-19 risk is mostly a matter of HVAC. The amount of virus you inhale is equal to the number of people nearby, times the % that are infected, then divided by the volume of air and the number of air changes per hour.

At least a dozen case studies have been published: cruise ships, a Seattle choir practice, a Maine wedding, church events. I have been using Google maps and other sources to estimate building sizes. Air changes is totally a guess.

The biggest uncertainty was expressed best by Dr. Gregory House: “everybody lies”. Folks don’t want to miss work, or they really need a pack of cigs, so they get into public space even though they are shedding virus into the air. Odds are good that they don’t wear a mask. They avoid testing and don’t get into the official data, so the math is more difficult. Everyone’s lives are more difficult.

Dennis Kolva
Programming Director
TurtleSoft.com