You could see Covid-19 as an empathy test. Who was prepared to suffer disruption and inconvenience for the sake of others, and who was not? The answer was often surprising. I can think, for instance, of five prominent environmentalists who denounced lockdowns, vaccines and even masks as intolerable intrusions on our liberties, while proposing no meaningful measures to prevent transmission of the virus. Four of them became active spreaders of disinformation.

If environmentalism means anything, it’s that our damaging gratifications should take second place to the interests of others. Yet these people immediately failed the test, placing their own convenience above the health and lives of others.

Now there are even fewer excuses, as we have become more aware of the costs of inaction. One of the justifications for selfishness was that liberating the virus would build herd immunity. But we now have plenty of evidence suggesting that exposure does not strengthen our immune system, but may weaken it. The virus attacks and depletes immune cells, ensuring that for some people, immune dysfunction persists for months after infection.

We also know that, with every new exposure, we are more likely to suffer adverse effects. A massive study in the US found that the risk of brain, nerve, heart, lung, blood, kidney, insulin and muscular disorders accumulates with every reinfection. The impacts of long Covid, according to health metrics researchers, are “as severe as the long-term effects of traumatic brain injury”. Now that we know how the virus attacks our cells, “traumatic brain injury” looks less like an analogy than a description. The outcomes can be devastating, ranging from extreme fatigue and breathlessness to brain fog, psychotic disorders, memory loss, epilepsy and dementia.

We are all playing Covid roulette. The next infection could be the one that permanently disables you. I’ve been hit three times so far, and feel lucky still to be active. But I’ve lost a little every time: stamina, lung capacity, sleep, general fitness, however diligently I’ve exercised since. In all three cases, it seems, the infection has come from school. For families with school-age children, the chamber turns more often than for those without. Yet, three years after the pandemic began, the government still does almost nothing to make schools safe.

There’s a powerful argument that just as cholera was stopped by cleaning the water, Covid will be stopped by cleaning the air. The virus thrives in badly ventilated, shared spaces – especially classrooms, where students sit together for long periods. One study found that mechanical ventilation systems in classrooms reduce the infection risk by 74%.

The importance of ventilation and filtration is not lost on our lords and masters. Parliament now has a sophisticated air filter system, incorporating electrostatic precipitators. According to the contractor that fitted them, they ensure airborne viruses and bacteria are “kept to an absolute minimum within the space”. The same goes for the government departments where ministers work. At the World Economic Forum in Davos this month, there were filtration systems in every room, in some cases protecting politicians who have denied them to their own people. It’s almost as if they believe their lives are more important than ours.

The clean air standards rich and powerful people demand for themselves should be universal, rolled out to all schools and other public buildings. Instead, while private schools have been able to invest in ventilation and filtration, state schools, many of which are close to bankruptcy, rely on government disbursements that are strictly rationed by a series of nonsensical conditions. It’s another classic false economy. The extra costs of healthcare caused by repeated waves of infection and the long – perhaps lifelong – impacts for many of those affected must greatly outweigh the investment in cleaner air.

But instead of taking simple and effective actions – proper (N95) masks in public places, filtration in shared spaces – we have steadily normalised a mass disabling agent. It’s likely, eventually, to reduce the number of quality years for almost everyone. Those who suffer the extreme version of this disablement, long Covid, are treated as an embarrassment we would prefer to forget.

You need only gently propose that we might return to wearing masks on public transport to provoke hundreds of people on social media to bray “freedom!” and denounce you as a tyrant. Against their tiniest of freedoms – keeping their faces uncovered on trains and buses – the trolls weigh freedom from disability and even death, and decide that their right to breathe germs on to other people is the indispensable liberty.

These are the people who, with their threats and conspiracy theories, may have helped drive Jacinda Ardern, the politician who arguably protected more people from the virus than any other, out of office. They are the people who, in some cases, have abused mask wearers in the street, and doctors and nurses in hospitals. If they have not yet been infected, they attribute their good fortune to “natural immunity”, rather than not getting out very much. An Old Testament ableism pervades the ideology: those who are ill deserve to be ill.

I’m not suggesting that everyone who fails to wear a mask on public transport fails the empathy test. That would now condemn almost the entire population. But, without direction from the government and the cultural shift this could provoke, even the kindest people end up behaving as if they have no regard for others.

“Move on”, “get over it”: these are the incantations of people who seek to shed responsibility for their actions. It’s what Tony Blair said after the Iraq war. It’s what Boris Johnson said after he was caught repeatedly breaking the rules. Of course we urgently want it to be over. But it isn’t. The virus is now embedded, and will continue to mutate to avoid our defences, grinding down – unless we treat each other with respect and demand universal standards of clean indoor air – our immune systems and our health, until everyone’s life is a shadow of what it might have been.

Do we really mean to sit and watch as this infection encroaches on our freedom to be well, brutal winter after brutal winter? Or do we step in where the government has failed, and normalise concern for the lives of others once more? Like all the other moral challenges we face, this is now on us.

George Monbiot