"[E]xcessive hygiene practices, inappropriate antibiotic use and lifestyle changes such as distancing may weaken [our microbiome] going forward in ways that promote sickness and imperil our immune systems."

"By sterilizing our bodies and spaces... we may be doing more harm than good.... [T]he microbes we encounter in daily life — on other people and in our spaces — are the data that the immune system relies on to program and regulate its operations. Deprived of these exposures, especially at the start of life, the immune system is prone to malfunction. The result can be allergies, asthma, autoimmune disorders, obesity, Type 2 diabetes and other chronic medical conditions.... Hygiene zealotry not only deprives people of interactions with helpful bacteria, but it may also be driving some essential microbes into extinction.... In the months to come, the health of our microbiomes may partly depend on the willingness of those who are vaccinated and at low risk to take off their masks and intermingle with one another, as we all used to do. 'A lot of things people do when they’re together that we didn’t use to think about — shaking hands or embracing, kissing or hugging — these sorts of sociocultural practices could play a part in the exchange of microbes,' says Tamara Giles-Vernick... a medical anthropologist...."

From "Can We Learn to Live With Germs Again?/The health of our bodies and microbiomes may depend on society’s return to lifestyles that expose us to bacteria, despite the risks" (NYT). 

There are lots of different risks, and avoiding some causes you to take others. I'd say let the people who want to go without masks — and get back to hugging and kissing — do it. Study how it works out. This idea of just being extra careful about everything until we're sure isn't even coherent, as this article shows, because taking extra care to avoid contact with germs is a failure to take care to maintain exposure to good microbes. Those of us who are vaccinated should be free to encounter the world again. 

Notice that warning: "Deprived of these exposures, especially at the start of life, the immune system is prone to malfunction." That means the lockdown is particularly risky for babies and young children (who are also the ones with the least risk from the disease). 

FROM THE EMAIL: Mike sends this apt bit from George Carlin: