Intentionally infecting people for study isn't something that really fits with our medical ethics, at least as I understand them.

It can be controversial, but is done: https://en.wikipedia.org/wiki/Human_challenge_study

It’s common practice for diseases where healthy people are unlikely to have severe issues, even if they may be deadly for some segment of the population.

https://youtu.be/1v8u3ua6BPk?si=lzAQcZlmnBc1xvj1

IIRC it can be done when there is little risk of serious adverse effects, or there is a known treatment that works well and mitigates risk of adverse effects.

Imperial College London conducted a COVID-19 human challenge clinical trial. The risk to healthy subjects without comorbid conditions is extremely low.

https://www.imperial.ac.uk/infectious-disease/research/human...

Yeah, the medical "ethics" field is full of really weird and damaging decisions.

Someone needs to do the work exposing what the hell is going on there.

As others noted, it does happen and is called a human challenge trial. In fact, here's one for malaria that's currently accepting signups.

https://www.medschool.umaryland.edu/CVD/trials/MAM01/

There have been a half dozen challenge studies[1] of influenza in the last 50 years. They're interesting in that there are threshold effects and a dose response relationship. None of the small numbers of test subjects get sick or seroconverted at low doses. Medium doses produce seroconversion without illness. Higher doses produce illness.

Before covid I found a Thai study on the effect of masking nurses in healthcare clinics. Masks reduced infections with some respiratory viruses and not others.

Can't be stated strongly enough is you cannot use the behavior of one virus as a proxy for the behavior of an unrelated one.

[1] Lack of rigorous studies of respiratory infections in the last 70 years caught public health policy makers completely flat footed. Because they were working off out of date textbook knowledge that was low quality.

I think this is roughly what we've known for a few years—probably just more precise. I've definitely heard that early stage is when you shed the most.

People have been talking about this for at least two years. It's been a common topic in right-of-center circles, along with the (in)effectiveness of most masks.