Apples to Viruses

Some who won’t accept the vaccines or wear masks say they are simply asserting their rights over their own body. Morally, it’s more like choosing not to have routine safety maintenance done on your car. Refusing to wear a mask is less a matter of exercising a personal liberty than comparable to driving at 60 mph in a 40 mph zone. The point is that though it may be up to you what risks you run for yourself, it is not purely up to you what risks you impose on others. That has to be a matter of the social contract. We can no more accept personal choice about infectious-disease control than we can over speeding limits.
Jonathan Wolff, "The COVID-Risk Social Contract Is Under Negotiation"

For nearly the past two years, there has been a steady stream of articles that tackle the ethics of the choices that people make concerning the SARS-CoV-2 pandemic. What trips most of them up is difficulty with the rather unique circumstances in play. Consider the analogy that Professor Wolff makes; that not masking is like driving 60 mph on a road where the speed limit is 40 mph. But if I happen to be driving down a road at 20 miles per hour over the speed limit, it's unlikely that I know neither my car's rate of speed (since cars have speedometers) or the speed limit (since it needs to be posted somewhere visible to drivers). It's also unlikely that any people who live along the road on which I'm driving are unfamiliar with automobiles. And unless I'm being particularly reckless, they're also likely acquainted with people driving down the road faster than the local speed limit allows.

Both of these factors create a distinction with SARS-CoV-2 in the fact that what has driven many of the public non-pharmaceutical interventions is the idea that it's not really possible to know whether or not one is infected. A lack of symptoms is not considered a good enough indicator of heath to be trustworthy. By the same token, if of less concern, is that SARS-CoV-2 has no universal and unique symptoms, so it's possible that someone could be showing symptoms that are similar but turn out to have a different pathogen. Likewise, many of the people who are still susceptible to the disease, and likely to become unwell enough to require hospital care, are in that position because their immune systems are relatively (or even completely) naïve to the disease.

This makes the comparison a very superficial one. And while one might reasonably expect that there are statistics on how many injuries and fatalities are caused by drivers who were in accidents while driving 60 mph in a 40 mph zone, there aren't really statistics on the risk of transmitting the virus due to being in proximity to others without taking certain precautions, because the level of surveillance that would required to determine that just isn't there.

As an aside, it's one of the things that I wonder about when people speak of the reproduction numbers of diseases more broadly.

The original strain of SARS-CoV-2 has an R0 of 2·5, while the delta variant (B.1.617.2) has an R0 of just under 7. Martin Hibberd, professor of emerging infectious diseases at London School of Hygiene & Tropical Medicine (London, UK), reckons omicron's R0 could be as high as 10.
Talha Khan Burki, "Omicron variant and booster COVID-19 vaccines"

It's one thing to understand that a single infected person may pass an infection on to 10 other people in a naïve population of a given size, but it's another thing to understand that it's 10 out of an actual number. In other words, how large is the presumed population of people that someone would need to come into contact with over the time that they're infectious such that those 10 infections materialize?

It's all well and good to tell people that some or another action on their part carries risks to third parties. But with no real way of quantifying that risk, how are people intended to weigh the risks against their personal tolerance? Or understand how to weight against the risk tolerance of those around them?

In this pandemic we’ve been making it up as we go: new public-health measures, new vaccines, new medicines. Lagging a bit behind is the new ethics for this new world, by which I mean a revised moral social contract dealing with risk for infectious disease.

Complicating the revisions to the social contract is the fact that "we" have also been making up the risk numbers as we go. This is, I suspect, what tends to push people towards absolutes; the idea that someone will definitely die if a person spends enough time in public unmasked and unvaccinated is definitely wrong, but it likely feels more solid than some nebulous probability that no-one seems to be able to actually articulate. And it's hard for contracts in general, let alone social contracts, to work when clauses are undefined. There shouldn't be an expectation that people will rush to sign on the dotted line when there's a whole section marked "to be figured out later."