(CNN) Fauci: You get vaccinated because you want to save your life.

Chris Cuomo leads with the question (paraphrasing) “If people should now wear masks, why should people get vaccinated at all?” Fauci’s reply deserves attention.

The math behind this is given in Delta Strain; the Rough Ride Begins. Quoting,

A breakthrough infection percentage of between 5X and 10X the percentage of hospitalized patients, breakthrough of 20%-40%. compared to 5% for the viruses of the original Phase 3 study.

In consequence,

• Delta has put us in a situation closely resembling the early days. Then, a substantial fraction of transmission swere due to asymptomatic carriers.
• Now a substantial fraction may be due to asymptomatic vaccine breakthroughs.

This does not rise above suspicion — until it does; epidemiology is a weak science. In science, this is hypothesis, supported by Pfizer Booster is Needed? Breakthrough Case Infectivity; Managing Public Health Communications.

The same arguments support booster and/or face masks.

Fauci says we could have a smouldering epidemic. It’s subtle optimism, implying it is unlikely to fulminate. I can’t put a cap on it; Delta has potential to surpass the previous peaks. A sociological argument renormalizes this epidemic:

• People tend to cluster with others of similar attitudes.
• The U..S. is in a state of deep division which accentuates clustering.
• Antivaxers comprise such a group, with social interactions biased to stay within this group.
• This group of perhaps 140 million moves through a vacuum in which groups with other attitudes do not socially exist.
• This is in effect an unvaccinated nation of 140M, as was the U.S. in February 2020, except the virus is much worse.
• Fulmination is possible.

This is why I advocate for a Delta-specific booster dose.  The legally mandated CDC/FDA criteria of need may be structurally suboptimal for COVID.

I hope with Dr. Fauci for no worse than a smouldering epidemic. The above logic allows for much worse, a  Western wildfire.