But sometimes the reports are real. A classic example occurred in 1976 when a new strain of swine flu was identified in Fort Dix, New Jersey. Fearful of a repeat of the 1918 epidemic, a mass vaccination campaign began, and 45 million people were immunised.
Two events led to the abandonment of the programme by the end of the year. First, there were around 50 reported cases of Guillain-Barré syndrome - a gradual paralysis that is now thought to have been former US president Franklin D Roosevelt’s condition. Eventually 500 cases were reported among vaccinated people – an increased risk of around 10 in a million for the disease – and 25 people died. The second reason for stopping the programme was that the epidemic never got out of Fort Dix – nobody else had the flu and so there seemed no upside to balance out the possible risk of Guillain-Barré syndrome. The Director of the CDC was later sacked, but he still believes the vaccination programme was the correct response.
That said, not all flu vaccines have the same risks. Following the UK swine flu outbreak in 2009, nine cases of Guillain-Barré syndrome were diagnosed within six weeks of vaccination; however, the eventual conclusion was that this would be expected by chance alone. But Finland and Sweden have reported increased rates of narcolepsy – sudden paralysis and sleepiness – in children after the swine flu vaccination, and this is still being investigated.
As the MMR saga showed, disproving an association is difficult and can take a long time, if indeed ever. Sometimes a change is made even without absolute proof of guilt. Thimerosal is a preservative used in some vaccines and contains mercury, and has long been accused of harming children. The CDC say there is “no convincing evidence of harm”, but in 1999 it was agreed that it should be “reduced or eliminated in vaccines as a precautionary measure”.
The official line that the overall benefits of vaccination outweigh any risks ignores the way in which imposed and highly visible harms, however rare, are seen very differently from potential downstream benefits, which can never be confirmed and seem ‘virtual’ in societies where the risks of infectious diseases are so low.
It is a different matter in less-developed societies: for instance, the WHO report that there are still 140,000 deaths from measles each year, one every four minutes. And, as we have seen in England, these are preventable. Vaccination has already made huge inroads: there used to be 2.6 million deaths a year from measles worldwide. Eradicating measles is seen to be a feasible goal, and the days of being dragged round to someone’s house to get infected are thankfully over. But as the numbers show, whatever the potential risks of vaccinations are, they pale in comparison to the risk in shunning what is often our best option for eradicating deadly infectious diseases.