Letter: Moral reasoning on schools' rubella vaccination

Sir: When a Roman Catholic headmaster bans rubella vaccine from his school, some observers wax indignant, saying that he should keep his peculiar morality to himself and not impose it on his pupils ('Vaccine ban blow to fight against epidemic', 27 October). But this is missing the point. Roman Catholics thrive on having odd moralities imposed on them by authority figures. If freedom of conscience is what they want, they should choose another religion.

The point is not even that, as you imply in your leading article 'No immunity from responsibility' (27 October), the boys of Ampleforth may infect pregnant women with german measles, thereby causing future babies to be born blind or mentally retarded. Viral epidemics are stopped in their tracks if a critical percentage of the population has been rendered immune.

If public health authorities can succeed in pushing the immunised population just above a critical percentage, an almost certain epidemic will be averted. It follows that, when deciding not to vaccinate, you have to weigh up consequences that stretch disproportionately far beyond the suffering of the individual, his sisters, or his pregnant acquaintances and their babies.

What is truly contemptible is that Father Jeremy Sierla, of Ampleforth, apparently grasps enough epidemiological theory to know better: We understood that general immunity to rubella in the population is very high - about 97 per cent - and that gave us the freedom to go with our conscience on this (my shocked emphasis). If I thought that pulling 420 boys out of the immunisation programme was going to cause widespread harm, then I'd be a fool and a blackguard.

You might as well say, 'I understand that a high percentage of the population pay their taxes, so this gives me the freedom not to pay mine.'

Ampleforth's and Stonyhurst's decision may not, after all, make such a negligible dent on the population at large. This is where the second level of epidemiological reasoning comes in, the level of 'viruses of the mind'.

What we do and believe is strongly influenced by what we read in the papers and hear on television. There is already a fertile ground of superstition, neurosis and ignorance where the subject of vaccination is concerned - as we saw in the great whooping cough vaccination scare of a few years ago. The papers now splash the news that a couple of headmasters have publicly banned a particular vaccine from their schools. That might be more than enough to trigger another epidemic of anti-vaccination hysteria, with public health consequences that even fools and blackguards can foresee.

Yours faithfully RICHARD DAWKINS Oxford 27 October