What We Don’t Know About SARS-CoV-2 and COVID-19

SARS-CoV-2 is a new virus in the human ecosystem. Humans didn’t pay much attention to it when it was only in bats. It’s of great interest to humans now. Because it’s new to our bodies and societies, we know nothing about it. We are picking up empirical observations quickly, but it’s hard to put them together in real time, motivated by sickness and death.

Research is proceeding, particularly for testing methods for both the virus and human immunity to it, for a vaccine, and for treatments. Many questions are still open. We will hear bits and pieces from the research, but the bigger questions won’t be answered for some time.

Here are the open questions I can easily think of. Answers to any of them would help us manage the pandemic.

Please don’t send me the latest preprints on these topics. I know they’re out there. Every day brings a new one that someone thinks is THE ANSWER to all this. None of them is by itself. Some have been out-and-out wrong. The best are small pieces in a much bigger puzzle. Science, is never fully certain. As we learn on the fly, it’s more uncertain than usual. We have to live with that.

What is the course of the disease? It is extremely variable, with relatively mild cases approximating a bad flu, running through a disabling illness that involves severe muscle pains and difficulty in breathing, to hospitalization and intubation to provide oxygen. What variables determine that course? Are there long-lasting effects?

There seems to be an incubation period in which people are asymptomatic but can spread the virus. How long is that period? How much virus do they shed? By what means? Is the virus detectable in them?

We know almost nothing about immunity to the virus. Are all recovered people immune? How immune are they? How long does immunity last? Do recovered people shed virus? Are some people immune without ever having had the virus? There are also technical questions about what part of the immune system might be most effective in fighting the virus.

A number of reports of varying quality suggest that some cases of COVID-19 show no symptoms but result in immunity. Do those people shed the virus? For how long? Or do they have some previous condition that gives them immunity without being infected? When did infections begin in the United States?

Children seem to catch the virus at much lower rates than adults do. Are they asymptomatic carriers? Under what conditions?

Death rates are often reported as the deaths for which SARS-CoV-2 infection has been verified by test. But deaths at home and in hospital, without tests, may be due to COVID-19. Additionally, people are probably dying of other conditions but don’t go to the doctor or hospital because they are afraid of being infected. We don’t know, and probably won’t know for some time, how many deaths are occurring as a result of the pandemic.

Kevin Drum: We have no idea which interventions work against COVID-19.

Is the virus less virulent in hotter weather? So far the evidence appears to be negative; countries near the equator are affected as much as cooler countries. But it’s not definitive.

We are buying time with social distancing. Scientists are collecting data and doing experiments to find answers to these questions and more. Any answers will help.

Cross-posted to Balloon Juice

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