Those of us who haven't had our children vaccinated aren't cranky obsessives or zealous Jehovah's Witnesses. On the contrary, we're mostly pretty well-informed, as you have to be if you refuse the orthodoxy of vaccination. We do so for two main reasons, neither of them specifically to do with autism, which most people would agree is dreadful but only affects a small number of children.

The first, and most shocking one, is that vaccination simply can't sustain the claims made for it. In the US immunisation rates are as high as 98% is some areas, and yet there are still regular measles epidemics. The Centres for Disease Control in Atlanta found that 80% of measles cases in 1985 occurred in children who had been vaccinated, while a 1987 outbreak affected a secondary school more than 99% of whose pupils had had live measles vaccine. In Italy there were just 10 deaths from measles between 1989-91, even though they had only 40% coverage from the vaccine. In the following two years coverage from the vaccine grew, as did deaths from measles (to 28). So much for "herd immunity".

Second, we believe that in the case of infectious diseases, Pasteur's germ theory has been oversold. Pasteur, Robert Koch and others focused on the bacteria that caused infections, which medicine then tried to zap. Most anti-vaccinators argue that the host, ie the body, is as important as the infecting germ. Starting from a quite different paradigm, they prefer to nourish the body's own immune system, which vaccination (they maintain) impairs.

Opponents of immunisation feel vindicated by epidemiology, for measles isn't a disease that strikes randomly unless routed by vaccination. On the contrary, it turns out to be depressingly class-conscious and poverty-aware. Those most debilitated by it are the least well fed - there's a tragic synergy between malnutrition and infectious diseases. According to a 1973 World Health Organisation report, "ordinary measles or diarrhoea - harmless and short-lived diseases among well fed children - are usually serious and often fatal to the chronically malnourished.

"Before vaccines existed, practically every child in all countries caught measles, but 300 times more deaths occurred in the poorer countries than in the richer ones. The reason was not that the virus was more virulent, nor that there were fewer medical services; but that in poorly nourished communities the microbes attack a host which, because of chronic malnutrition, is less able to resist". Given that there's no vaccination against poverty, governments prefer the quicker fix of vaccination. Vaccine producers like it too: there's gold in them thar jabs.

This isn't a sphere where conscientious objections are tolerated, either among doctors or patients. Each GP gets a "target payment" (did someone say "bribe"?) of £2,730 for vaccinating 90% of two-year-olds on their list. Some practices are now considering dropping unvaccinated families from their lists. When my first child was newborn, my GP asked why I was risking her life by refusing to have her vaccinated. I changed practices soon after. Journalists, too, are expected to toe the public health line and are labelled irresponsible (as I will be) if they don't, even though accusations of "inaccuracy" often mask genuine disagreements.

Alternative health practitioners argue that measles and other infectious illnesses, far from damaging children, actually improve their overall health. But a child suffering from the disease needs proper, labour-intensive care. Nursing used to be an essential part of the job-description of motherhood: our mothers (for it was mostly them) knew how to nurse an infected child - drawn curtains, cold drinks, and wet flannels. We now think of nursing almost entirely in professionalised terms, as something we pay others to do.

Above all nursing is slow, but life is fast. What child, today, can afford to miss a week of the national curriculum, and what mother can take a week off work? I don't usually admit it in public lest a passing doctor burst a blood-vessel, but I want my children to contract measles. Yet whenever I hear of someone from whom they could catch it, it's never the right time - an exam or deadline is always looming.

One consequence of the mass vaccination of children is to turn measles into an adult (or adolescent) disease, when it's far more dangerous. And now the government is considering the introduction of a chickenpox vaccine - thus does the vaccination cocktail grow. We're familiar with the concept of informed consent. On vaccination, increasing numbers of people are turning towards the concept of informed refusal.