29 July 2021
The Price of Immunity
Why the gamble?
By John Watson
It may be the mark of the cynic to know “the price of everything and the value of nothing” but the concept of price is fairly hard baked into the structure of today’s world. Take the struggle with Covid, for example. Time was when everyone hoped that the disease would either die out or be eliminated as a result of worldwide vaccination. That is plainly not going to happen now as opposition to vaccines puts down firm roots not only in dictatorships like North Korea but in the pottier sections of modern democratic states. In any case there are arguments that jabbing children who would not be much affected by the disease would be unfair, and, without judging whether those arguments are right or wrong, they are not going to go away soon. Total eradication of Covid is therefore unlikely.
That pushes us all to plan B, a level of immunity within the population which means that, rather than spreading, outbreaks of infection die out their own accord. Once that has been achieved, life can go forward as normal with Covid regarded as simply one more relatively minor public health risk. It is of course the strategy which the UK Government favoured at the beginning of the pandemic although then it was rapidly pushed off course by casualty levels which, without the help of vaccine, threatened to overwhelm the health service.
Well, here we are again but this time with the vaccines which, it seems, provide a partial answer. The double-jabbed are clearly much less likely to die of the disease but can still become infected although the likelihood of that infection is reduced. It seems that to create herd immunity, vaccination has to be supplemented by the resistance developed by those who have had the disease and of a few, no doubt, who have some natural genetic immunity.
Put yourself into the position of government then and the strategy must be to push up the levels of herd immunity at the lowest possible “price” in human suffering and death. Of course vaccination will form the bedrock here but if it, of itself, will not get immunity levels over the line then you need infections too and the game becomes one of how to let a high level of mild infections run through the population. What policy levers do you have to deliver this?
The first is to focus infections on those in the community who will not be much affected. Suppose, for example, a child catches the disease and suffers no significant symptoms. Provided it does not pass it on that is a good result because the herd immunity of the population has increased at effectively no cost. Suppose some elderly anti-vaxxer contracts the disease, has to go to hospital and suffers from long Covid; that is a bad result because, although herd immunity has been strengthened, the price is relatively high. Arguably, then, the more the infection runs through the young who recover from it relatively undamaged, the better it is for the strategy – herd immunity is bought at negligible cost. If one could guarantee that none of the young would be damaged at all, the right policy would be to run spreader parties. Unfortunately even the young can be badly affected so no government would dare to go this far but it does throw into perspective the drop of infection rate due to the beginning of school holidays. Yes, children feel heathier but a relatively cheap way of boosting herd immunity is lost.
The second lever is one of timing. One government adviser, when challenged on the wisdom of reopening, asked “if not now, when?” and that is exactly the right question. Restrictions cannot sensibly remain in place for ever if the disease is never going to be wholly eliminated. The question is when the cases should be allowed to surge in order to push us over the herd immunity thresholds. The UK’s decision has been to press ahead now because the effects of the disease are likely to be less in the summer months so the costs of herd immunity is relatively cheap. Wait until the autumn when the effects of respiratory illness are more drastic and much of the effect of mass vaccination is beginning to wear off and that cost would go up.
That at least must be the calculation and on the surface it looks a plausible one. Still, Covid has thrown us a number of curveballs over the last three months and things could easily go pear-shaped. The choice for the Government, then, was whether to lift restrictions and risk the blame if things went wrong or to take the politically safer course of remaining locked down. That might have meant accepting higher casualties when the relaxation eventually came but at least they would not have been caused by government action. Either way involved a gamble but as a highly vaccinated country with good medical facilities the UK was in a better position to experiment than most others. Those who describe that experiment as “criminal” or “irresponsible” are plainly not right. Whether it is successful or not remains to be seen.
