Monday, March 6, 2023

Covid, Three Years On

This is an attempt to organize at a very high level what we have learned about covid in the past three years. It is much more for myself than any broader audience, and is not a completely or extensively footnoted article; if I were going to provide cites for what is now largely common knowledge it would have to be a much longer and more extensively researched piece. I have generally stuck with moderate sources and information, attempting to avoid both denial and unreasonable fear.

The disease is real and the reality is enough.

Where sources conflict, for instance studies of the risk and incidence of long covid, I have attempted to chose plausible median data. This reflects both skepticism of extremes and of over-precision; many people demand precise numbers, and on these matters precise numbers are difficult to come by.

Once I post an article, I usually leave it standing with only minor changes, but in the case of this article I will correct errors as they are reported to me.

What We Know Now

Covid is, above all, a disabling disease.

  • A mild case is similar to a cold.
  • A moderately severe case is a pneumonia, though other body systems are often infected. Moderately severe covid typically completely disables for two weeks, and there is an additional two or so weeks of recovery. (Doctors often call this “mild,” reserving “severe” for cases requiring hospitalization, but this terminology is deceptive.)
  • A severe case hospitalizes, requiring respiratory support.
  • Covid often (perhaps 1 case in 5) has disabling sequelae – long term effects. These range from unpleasant (loss of taste and smell, impotence) to totally disabling (severe chronic pain, permanent lung dysfunction) to lethal (heart attack, stroke, renal failure.) This is not a complete catalog of sequelae.1
  • Covid can reinfect.2 The risk of sequelae from a second infection is the same or worse as that than from an initial infection.
  • Over time, as more and more people are reinfected, there will be a large number of people with covid-induced disabilities. Assuming the chance of disability is a constant 1 in 5 (it probably actually increases), after three infections, the odds of a disability are nearly 1 in 2, after five infections, more than 2 in 3.

But, sometimes, it kills3

  • Unvaccinated people at a rate of perhaps 1 in 10.
  • Vaccinated people at a rate of perhaps 1 in 100.

In general, men are more vulnerable than women, elders are more vulnerable than younger people, and people with other health conditions are more vulnerable than people without. People with respiratory and circulatory conditions are especially vulnerable; covid attacks the lungs and blood vessels.

It endangers children

The idea that it does not comes from the Swedish government epidemiologist Anders Tegnell4, who suppressed data about childhood morbidity and mortality (he also set a policy of withholding care from at-risk elders, euthanizing them.) In fact, covid does sometimes disable or kill children, though covid deaths among children are rare. Children, however, can still transmit the disease to other members of their families, and there are children who have transmitted the disease to parents and become orphans.

Transmission is primarily airborne

Most people get covid from small airborne particles exhaled by infected people. The small particles hang in the air forming what is called an aerosol. This is called “aerosol transmission.” Fortunately, the virus carried by these particles rapidly become inactive.5 Outside, on a warm sunny day, 99% of the virus is inactivated in about an hour. Inside, without ventilation, filtering, or disinfection, it takes 9-½ hours. (Ventilation, filtering, and disinfection are effective control strategies, and we will discuss them later.)

If someone coughs in a person’s face, that can also transmit covid. This is called “droplet transmission.”

Transmission via objects (“fomite transmission”) is unusual, a small blessing.

Progress of covid infections

Covid infections are similar to tuberculosis infections: the spread is airborne, and the lungs become infected. Tuberculosis, though, is a bacterial, rather than viral, infection and is more dangerous - uniformly fatal once it becomes symptomatic.6

A covid infection proceeds in three stages:

  1. First, an upper respiratory tract (nose and throat) infection. If it goes no further, as can be the case in a vaccinated person, it may not even be noticed, or passed off as a cold. It is, however, infectious in this stage. Unlike colds, this stage often includes a loss or distortion of taste and smell.7
  2. Second, a lung infection. Covid, like tuberculosis and unlike flu, directly infects the lungs, causing pneumonia. Depending on the severity of infection this may heal completely, or lead to lasting disability.
  3. Third, a multi-system disease. In these cases, covid spreads beyond the lungs. It will unpredictably infect most organs, and the linings of blood vessels (vasculitis.) This stage is when most sequelae emerge.

Some researchers believe that covid is primarily a vasculitis and all symptoms derive from that.

Covid is much more dangerous than the flu

Covid’s fatality rate is roughly ten times that of influenza, and the rate of disabling sequelae is much higher.8

Reinfection is possible

Immunity wanes. Like the common cold, covid is caused by an RNA virus; the SARS-2 virus which causes covid mutates quickly, and immunity to one variant does not reliably confer immunity to others.

Responding to the Continuing Epidemic

Airborne diseases like covid are hard to control

There are three known diseases whose major mode of transmission is airborne: tuberculosis, measles, and covid. Prior to 1800 CE, tuberculosis was responsible for one death in seven.

  • Tuberculosis, a bacterial disease, was controlled through vaccination, masking, and quarantine and, eventually, antibiotics. It is, however, still endemic in parts of the world, and immune compromising viruses have caused a resurgence where it was previously controlled.
  • Measles, a viral disease, has been controlled through quarantine and the use of a sterilizing vaccine.
  • Covid is not controlled. The apparent mildness of the disease in many vaccinated people means that people are unwilling to take the strong measures that controlled tuberculosis, and what treatments there are are of limited efficacy.



If you get a sniffle, test early

Anti-virals work best when given early, so test early for covid and flu. Get a PCR (NAAT) test. Go to some place where the test can be turned around in an hour or less. If you test positive, get antivirals as soon as you can. (See treatment, below.)

If you are exposed and remain asymptomatic, test in five days

Testing too early is likely to miss an infection, so wait, but test.


With a 1 in 5 chance of disability, infection is a risky way to acquire immunity. The vaccines do have some risks, but they are treatable and the risk is lower than 1 in 100,000. On the odds, vaccination is far and away the safer choice.

Vaccines reduce your risk of infection, drastically reduce your risk of hospitalization and death, and somewhat reduce your chances of long-term sequelae.

Risk of infection
Vaccination reduces the risk of infection by perhaps 50%.10
During the early 2022 Omicron variant peak, unvaccinated people were 12 times more likely to be hospitalized with severe covid. The vaccine, after three doses, reduced the risk of ventilation (a desperate technique of respiratory support) or death by 94%.11
Long covid
Vaccination reduces the risk of long covid. Exactly how much is hard to determine but most studies have found a significant difference.12 One study of nearly 1.6 million patients found that the risk was reduced 50-85%.13

Nonetheless, vaccination alone is not enough.


Mask when indoors with strangers. (An exception can be made for uncrowded, well-ventilated indoor spaces.) Mask outdoors in close crowds. The best comfortable masks for most people are N95 respirators, however some people cannot tolerate them. If you are one of those people, try a cloth or surgical mask, and be extra-careful.

Avoid high-risk situations

This is one of the hardest things to do, and you are going to have to decide for yourself how cautious you want to be. People at high risk - over 65, immune compromised, or with multiple risk factors, should probably avoid any unmasked social activity with strangers; for them a covid infection is likely to be severely disabling, even lethal. Yes, that means no eating indoors in restaurants.

Your family has to do it, too – grandpa can be as careful as he likes, but if his grandson infects him it is all for naught.

Healthier vaccinated people can be a bit less cautious, but the virus is still out there, so be careful. Remember that the virus travels quickly in households, and mask when around vulnerable family members; yes, that means grandma in the nursing home. If the nursing home staff won’t mask, find her another nursing home.

If you can’t avoid high-risk situations, mask if you can.

If you can’t avoid high-risk situations and can’t mask, see below, “if you are infected.”

Home medical supplies

Stock up on tests
Home tests are available for no charge from a variety of sources. Have a few around at all times. When you have cold-like symptoms – coughs or sneezes –, test.
Get a pulse oximeter
This is the device that will tell you when you need to go to the hospital - you won’t necessarily feel short of breath. Make sure the one you get works for people of your skin color.
Get a CO2 monitor
Guangdong Bioall Medical Technology sells an inexpensive, fairly accurate one under the trade name “Vitalight.” This is useful for letting you know if an indoor space is well-ventilated. Even in a well-ventilated space, however, the precautions you would take outdoors are still necessary.

Precautions for gatherings

With precautions, it is possible to run fairly safe gatherings.

  1. Check the vaccination status of guests. People are ashamed of discussing this – ask, and if at all possible insist on seeing vaccination cards. Politely ask unvaccinated or symptomatic people to leave. If you can afford it, consider offering your guests rapid tests.
  2. Ventilate. Open windows. If possible, buy or make HEPA filter boxes.
  3. If serving food, do so outdoors.
  4. If not serving food, consider asking guests to mask.

If you are infected

Get antivirals early

The best treatments currently available are the antivirals Paxlovid and remdesivir, which must be given early in the course of the disease. All other antivirals have become ineffective against current variants. Paxlovid must be started within five days of the onset of symptoms; remdesivir, seven days.14

It appears (early research) that metformin, given within four days of the onset of symptoms, reduces the odds of sequelae.15

Protect the people around you

Covid moves through households like wildfire. Because of covid’s long presymptomatic period, the rest of your household has been exposed. Now is the time to break out the home tests, and follow those tests up with PCR lab tests – household members who are symptomatic, immediately, household members who are asymptomatic in five days. Chances are your entire household will benefit from antivirals.


If you can quarantine in a well-ventilated room within your home, do so. Have visitors wear N95 masks. If you can tolerate it, wear a mask yourself. Be aware, however, that when your lungs are compromised, masks may make matters worse.


This is also the time to break out the oximeter. You won’t always know if your lungs are compromised, so test regularly even if you feel fine. If you are having trouble breathing or if your Sp02 falls below 90, do not wait, go to the emergency room.

Looking Towards the Future

Research into vaccines continues

Researchers are hoping to develop a vaccine that confers “sterilizing immunity” that would entirely eliminate transmission, but such a vaccine is years in the future.

New indoor air quality standards are on the way

Because of the recirculation of indoor air, covid transmission occurs more often than outdoors. Better air filtration and disinfection reduce the transmission of covid.16

ASHRAE, the HVAC engineering association, hopes to release a national indoor air quality (IAQ) pathogen mitigation standard by July of 2023, that will eventually become part of construction codes and, finally, law, but once the codes are accepted (some jurisdictions may not adopt them), there will be a period of years when existing buildings are refitted to conform with the new standards.

  1. Nearly One in Five American Adults Who Have Had COVID-19 Still Have “Long COVID”, Long COVID or Post-COVID Conditions ↩︎

  2. What doctors wish patients knew about COVID-19 reinfection. ↩︎

  3. Our World in Data: Mortality Risk of COVID-19 ↩︎

  4. Hiltzik, LA Times: Did Sweden beat the pandemic by refusing to lock down? No, its record is disastrous ↩︎

  5. Estimated Airborne Decay of SARS-CoV-2 ↩︎

  6. Controlling Airborne Diseases: Tuberculosis and Covid ↩︎

  7. Mechanism revealed behind loss of smell with COVID-19 ↩︎

  8. COVID-19 vs. the Flu ↩︎

  9. COVID-19 Testing: What You Need to Know ↩︎

  10. Vaccine Effectiveness (VE) Estimates, March–September 2022 ↩︎

  11. COVID-19 vaccines continue to protect against hospitalization and death among adults ↩︎

  12. The effectiveness of vaccination against long COVID ↩︎

  13. The Protective Effect of Coronavirus Disease 2019 (COVID-19) Vaccination on Postacute Sequelae of COVID-19: A Multicenter Study From a Large National Health Research Network ↩︎

  14. Interim Clinical Considerations for COVID-19 Treatment in Outpatients ↩︎

  15. # Outpatient Treatment of COVID-19 and the Development of Long COVID Over 10 Months ↩︎

  16. Indoor Air and Coronavirus (COVID-19) ↩︎

1 comment:

The Blog Fodder said...

Sharing this on Facebook. An excellent summary.