This is getting to be a long haul for all of us and just when we think it might be cooling off, the media finds a way to hype it all back up again. I am just summarizing a few things of where we are, and where we may be going and what to watch for.
We still don’t know some basics about this virus and won’t until someone does some better research. Is it largely transmitted by droplets, which would imply pretty close contact with an infected person? Is there some aerosol or airborne transmission, which would mean that depending on the lifetime of the aerosols and the viability of the virus in those aerosols, infection could occur without that close sustained contact? Is there any surface transmission, from droplets or aerosols being deposited in places that a person might touch? Right now it appears to me that droplet transmission is pretty certain, aerosol transmission seems likely and surface transmission appears minimal, if it occurs at all. What is the minimum dose, or number of virus particles, needed to infect a person and how wide is that range–how variable are people in the dose it takes to infect them? How effective are basic hygiene measures, like hand-washing or mask-wearing at physically preventing transmission?
The models were very wrong partly because they assumed 100% susceptibility of the population and assumed everyone, once infected, was equally infectious to others. That is clearly erroneous. Not everyone is susceptible and pre-existing immune defenses appear to be the primary reason. But we don’t know how many people have cross-reactive T cells or antibodies or have aspects of innate immunity defenses that prevent infection. We don’t know the extent to which those defenses are dose-dependent, can they be overwhelmed by a large enough dose? We do know that viral loads likely vary by level of infection–people who are asymptomatic or have mild illness are less infectious because they often have lower viral loads.
We know that children are much less likely to be infected or if infected, to have a serious illness, and they aren’t major transmission agents. The rate of serious illness appears to scale by age, becoming quite extreme in the very old, especially if they are frail. Certain comorbidities appear to increase risk, as they would for most diseases. At all ages, there are many asymptomatic and undetected illnesses. Across the population, it is likely that only 1% of illnesses are severe enough to require hospitalization. It would be extremely helpful to have much better data around hospitalizations, including average length of stay by admission date, and how many people are admitted with a CV diagnosis and how many get one after being admitted.
Most people appear to develop a good antibody response, which does seem to vary by severity of illness. There are issues with the adequacy of the current antibody tests to detect the low levels that may exist in people who had asymptomatic or mild illnesses. But everyone also appears to develop a robust T cell response, which may be more important for protecting against re-infection by this pathogen. We need much better combined antibody/T cell prevalence testing.
I suspect, and the CDC supports this view, that we have had many more infections than reported. Because of this and because I believe there is a high level of pre-existing immune defenses, we may be further along to substantially slowing the ability of the virus to transmit than is generally accepted. In fact, some areas like NYC may be pretty safe from any significant re-emergence of infections.
I do not know the explanation for the apparent regional variation in incidence. Why is the epidemic so quiescent in places like Minnesota and Wisconsin and apparently gaining strength in others? The Northeast I understand because it was so bad there that the epidemic may have largely run its course. Is there some seasonal factor that we don’t appreciate yet? Is it really testing and contact tracing that means we are finding cases in these states that we wouldn’t find because of testing limitations in the early weeks? It would be good to figure that out, so we know if we might expect re-emergence in the current low case states.
The mitigation of spread approach has been a disaster. Period. We did not protect the obviously vulnerable populations, who would likely suffer a lot of severe illnesses and deaths no matter what was done, but some of our policies clearly actually made it worse. We locked everyone else down and shut businesses down, even though the risk was miniscule to the bulk of the general population. We lost tens of million of jobs, which will take an extraordinary amount of time to recover, and we killed small business. As usual, minorities and low-income people bore the bulk of the damage from the epidemic and the mitigation measures. States are hurting for revenue when they need it most. Our national debt and financial condition is even worse than the already bad situation it was in. I have detailed extensively the health harms done by frightening the population and discouraging receipt of health services. We will be enduring that damage for many years. We have allowed state governors to become dictators and undermined democratic processes.
My recommendations at this point would be to have a clear policy regarding acceptable limits of spread and they should be fairly relaxed. I am anxious about the assumption that there will be a great vaccine or vaccines. We can safely allow the virus to run through the bulk of the general population with minimal risk, and doing so protects everyone, but especially the most vulnerable. We have to stop freaking out every time cases get higher somewhere. And we need to reassure the population that they are at minimal risk and can resume normal activities with some basic cautionary measures. If we are going to rebuild the quality of people’s lives we have to get the economy moving more quickly and more workers back on the job. And schools should absolutely be open and doing in-person education with few limits.
So that is my two cents at this point.