Dr Katz is a Yale professor with a long and distinguished career in preventive medicine. This video begins with what should be obvious: COVID is not the only thing that can kill us. Any sensible program to mitigate spread of the disease must be calibrated to minimize total harm taking all risks into consideration.
He goes on to note that quarantine is very effective in early stages of a pandemic, but it is not a viable strategy once the disease is widespread. Lockdown measures can slow the spread of the disease, but cannot limit its eventual reach.
We've long ago passed a point where the only thing that can halt the spread of COVID is herd immunity. So if we are going to lock down, we will have to do it until everyone is vaccinated. The most optimistic time frame for a vaccine is 18 months, and past efforts to create a SARS vaccine suggest that it may not be possible at all. Are we going to lock down for months and years, waiting and hoping for a vaccine?
The alternative, Dr Katz suggests, is a phased return to normality. First the healthy young people can go out and deliberately expose themselves in small doses. Small doses of the virus stimulate the immune system before any danger it can be overwhelmed. And healthy young people are at minimal risk of dying from COVID. Once these people have some antibodies, we have begun to establish herd immunity in the population, and the next wave of people slightly more vulnerable can be exposed, again to small numbers of virus particles. Elderly and immune compromised people should continue to be sequestered until herd immunity is established by the rest of us.
At the end of the video, the interviewer asks about the political motives for this huge disruption. Dr Katz wisely steps back and says this is outside his expertise, but he reaffirms the interviewer's point: There are many more serious threats to health that the government won't lift a finger to stop: pollutants, pesticides, toxins that cause cancer. There is an epidemic of diabetes in this country that is entirely preventable, that kills more people every single year than total expected deaths from COVID, and yet our CDC does not make a serious effort to oppose it.