Thought of the Day - September 1 - The XYZ Hypothesis

There is growing discussion that the belief we are still a long way from Herd Immunity are probably wrong.

The XYZ Hypothesis is the idea that:

X - A percent of the population has preexisting immunity, people who have the T cells (the residual "memory" cells that reside even after antibodies have waned) possibly developed from exposure to other common coronaviruses. Indeed this may also explain the number of people who are asymptomatic. Meaning people have T cells and so when they are exposed to SARS-CoV-2 they rapidly regenerate antibodies and eliminate the virus without any significant side effects.

Y - Some people get exposed but don't develop antibodies. They just seem to be able to reject the virus, maybe with mild symptoms.

Z - The number of people that have been infected. In most countries, the numbers seem to be an order of magnitude higher than have been diagnosed with antigen (PRC) testing. Second, even antibody testing, to see how many people have already been infected, seems to be flawed as the SARS CoV-2 related antibodies seem to decrease fairly quickly and thus also underestimate the numbers.

Finally, there is another group - the most vulnerable - that is now largely isolated, meaning they are largely really no longer part of the herd.

By totalling up XYZ and those in isolation, regions that have already experienced significant outbreaks may already have an Immunity of 80%. Such as Herd Immunity might be part of the explanation concerning the falling number of new cases, and particularly severe cases now being experienced.

For example in NYC:

Similar effects are seen in other cities such as Mumbai and Delhi.

Even if this is true, don't get your hopes up for Canada yet, excepting a few neighbourhoods in Montreal, our "flatten the curve" activities mean we still have a way to go yet.

Cheers

Cliff

Cheers

Cliff