Sometimes it seems as if our greatest danger is not from Covid-19 itself but from the raging convictions attached to the slimmest of evidence.

From At work, school and seeing friends: How to lower your coronavirus risk by Linda Geddes. Six or seven months into the global pandemic and the only thing that we know about Covid-19 with any certainty is how little we know. It is still an epistemic issue muddied by emotionalism, ideologies, and partisan politics.

New Scientist lists the few things we are beginning to get some empirical clarity on, though, with so many contradictory and poorly designed studies, we have to still be very guarded in our confidence. Indeed, the main take-away from the article is that we have some ideas which almost certainly have merit but the effect sizes for some of the recommended actions can be small and our confidence in the validity of the recommended actions is still tentative.

The article is good because it offers the pros and cons and the positive evidence as well as the credible counter-evidence. It is notable how frequent are the conditional and limiting words such as "can" (fifteen times), "may" (fourteen times), "some" (ten times), "could" (seven), suggests (seven times), "seems" (seven times), "likely" (seven times), "however" (six times), "although" (five times), "might" (four times), "should" (four times), "tends" (three times), "unclear" (twice), "perhaps". Our knowledge is still almost entirely tentative and the effect sizes of any action modest. Some of the items suggested and investigated:

Infections rates rise with prolonged exposure in confined spaces.

They found that the risk of the infection being passed on at home or by repeated contact with the same person was approximately 10 times greater than the risk of passing it on in a hospital and 100 times greater than doing so on public transport (medRxiv, doi.org/dwgj).

SARS-CoV-2 spread tends to be higher in communal areas where there are higher numbers of people passing through, or in areas where there is more physical engagement with the surroundings, for example door handles, desks and computer keyboards

The risk also seems to be higher when people are more physically active.

The moist, warm atmosphere coupled with turbulent air flow generated by intense physical exercise can cause more dense transmission of isolated droplets

A recent study revealed that handwashing six to 10 times a day is associated with a 36 per cent reduction in the risk of becoming infected with the coronavirus (Wellcome Open Research, doi.org/dwgk).

People who travel on buses or trams during the winter flu season may be approximately six times more likely to develop a respiratory infection than those who don’t use public transport.

The evidence suggests there may be a small benefit to wearing some kind of face covering, as these seem to lower the extent to which sick people spread the virus.

The chance of catching the coronavirus in a closed environment is more than 18 times greater than in an open-air environment.

Good ventilation means changing the air within the space regularly, not just cooling and recirculating the same air.

Evidence suggests that infection in the home, and between family members, is a significant source of viral transmission.

You look at the tentativeness and conditionality of the science and the modesty of some of the effect sizes and then contrast it with the vociferous confidence and deep conviction of some proclamations.

"Follow the science" and "Listen to the evidence" are good suggestions tempered by the need to take into account moral considerations, pragmatism, and recognition of the diversity of values and goals. But the blaring headlines, and NextDoor eruptions and social media storms are all belied by the weakness of our knowledge.

NextDoor nervous nellies complain and berate people not wearing masks while out walking in a neighborhood even though the science suggests that there is indeed little to be concerned about. Sometimes it seems as if our greatest danger is not from Covid-19 itself but from the raging convictions attached to the slimmest of evidence.

What can we do to shield ourselves from a new virus of uncertain consequence?

Stay physically fit

Maintain personal hygiene

Maintain the cleanliness of your personal environment

Respect personal space

Choose your friends carefully

Avoid prolonged exposure in closed spaces with many people

Pretty mom and apple pie and true whether there is a pandemic or not.

All the pandemic is doing is reaffirming folk wisdom and traditions which are always under assault and criticism from those addicted to novelty or daring progressivism or remaking the future. It is reaffirming a Burkean and Chesterfieldian small c conservatism. It increasingly appears that Covid-19 is slightly worse than a bad flu season, that it is by far the most threatening to those who are already the most beleaguered in their health, and that tried and tested cultural norms are the best remedy.

Correspondingly, it appears that while well-intended and justifiable to some degree based on our ignorance in the early stages, the actions causing the greatest damage to our nation and globally are from government policies which were ill-founded, under-researched, damaging in themselves and with multiple, material unintended consequences. Once again it seems to be an example where the wisdom of the crowd in a free culture with free communication would have yielded a far better outcome than all the coercive policies implemented on recommendations from experts with a weak science foundation.

At least that is how it appears now. But we still don't know enough to be certain.