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Vaccines can kill. No medical intervention is ever completely devoid of risk. If you selectively comb through the archive, there is plenty of historical evidence of death. In 1928, twelve children died after being given Bacillus Calmette-Guérin (BCG), the anti-tuberculosis vaccine. In 1952, just weeks after it had been licenced for use on a mass scale, the Jonas Salk’s poliomyelitis vaccine caused 164 cases of paralysis and 10 deaths. Indeed, Britain stopped the routine use of smallpox vaccine in 1971 in part because it killed more people than the disease itself. 941 people in Britain have successfully claimed from the Vaccine Damage Payments Fund since it was established in 1979. 

Vaccines are also not always effective. Again, no medical intervention works on every person every time. Thousands of children who had been immunised against diphtheria in the 1940s went on to contract the disease. Similarly, the reason the British government recommends two doses of measles-mumps-rubella vaccine (MMR) is because in an estimated 5 per cent of cases the vaccine does not ‘take’. 

This is why selective use of evidence is unhelpful. We need to see the history of vaccination in the round. Undoubtedly, improvements to sanitation, hospital care, drug therapies and living standards have contributed to the decline of infectious diseases. We cannot say for certain that vaccines are responsible – or necessary – for the eradication of smallpox, the near-eradication of polio or the vastly-reduced morbidity and mortality of diseases such as diphtheria and measles. Look, for instance, at scarlet fever. There is no immunisation against this disease, yet its mortality has declined in a very similar pattern to diphtheria. 

Context matters. 

Relative risks matter. 

For while there is no lie in the statement ‘vaccines are not 100 per cent safe, vaccines are not 100 per cent effective, vaccines are not 100 per cent necessary’, it is also meaningless. No public health practitioner with access to the evidence has ever made these claims. Nor are any of these conditions necessary for the claim ‘vaccines are safe, they are effective, they are vitally important’. 

In 1928, in Bundaberg, Australia, children did die as a result of BCG – because the GP who administered it had left the vial out of the refrigerator and injected his patients with deadly bacteria. In 1952, a faulty batch at Cutter Laboratories did cause an outbreak of polio – because the company had not followed the manufacturing guidance. More people were damaged by smallpox vaccine in the 1960s than caught the disease in England and Wales – because the disease had been all-but eliminated. While thousands of vaccinated children caught diphtheria in the 1940s, the proportion on unvaccinated children who caught the disease was four times higher – and if the unvaccinated did catch it, they were twenty times more likely to die. The use of the second dose of MMR increases the chances of it working from 95 per cent to 99.75 per cent. While other health interventions have helped, morbidity has declined significantly and more quickly in populations where effective vaccines have been introduced. And while mortality has declined significantly for scarlet fever, morbidity has not fallen anywhere near as quickly or to such a low level. 

If any single piece of evidence on the safety or effectiveness of health care interventions is to be understood, it must within the context of the evidence around it. The number of complications from vaccines is tiny when compared to the morbidity and mortality rates of those diseases before immunisation was introduced. They are quick and convenient, saving millions of dollars for states across the world compared to hospitalisations and lost work hours. The economic and medical cost of not vaccinating is undoubtedly much higher by the metrics employed by nation states. 

We make such calculations about relative risk all the time. We could eliminate road traffic accidents by banning all motor vehicles tomorrow; but the knock on effects for our way of life would be catastrophic. Similarly, alternatives to vaccination (such as the “Leicester Method” in the eighteenth century) required a much more draconian intervention into people’s lives, including strict isolation conditions and the destruction of property. 

While the scientific community is virtually unanimous on the relative risks of vaccination, there are always political and philosophical considerations. These questions and the answers they generate are also important evidence. They have been used in conjunction with the scientific and economic data for centuries. Is it right that even a single person is damaged in a scheme designed to protect the population? Why are vaccines pushed for non-lethal diseases such as chicken pox in the United States rather than improving access to child minding and affordable health care? Why do some countries require vaccination of children before they enter schools? Although no longer the case in the UK, some countries make certain vaccines compulsory. Regardless of the medical benefits, should any person be compelled to accept a medical treatment with which they fundamentally disagree?  

While anti-vaccination or pro-vaccination absolutists might have a clear answer to these questions, in reality there has always been a debate about where the lines on personal autonomy and collective safety are drawn. A proper appreciation of risk allows for proportionate responses that take into account the economic, medical and cultural needs of the community. 

Gareth Millward