Preventable diseasesDeclaring Vaccine Hesitancy One of the Ten Biggest Health Threats in 2019 Is Unhelpful
The rhetoric is well-known: vaccines work, the science is settled, vaccine-hesitant parents are uninformed or misguided victims of the social media platforms where crooks spread fake science. It is taken as a given that vaccines are similarly and uniformly beneficial – aside from rare side effects – and no sane person would question that. But are vaccines similarly and uniformly beneficial? There is no doubt that vaccines can induce immunological “memory” against their target disease. And, at the population level, this reduces the risk of getting the target disease. Vaccine led to the eradication of smallpox, and we are close to eradicating two other serious infections: polio and measles. But we don’t have a lot of evidence about the overall health effects of vaccines. Everybody has been so sure that vaccines only protected against the target infection, nothing else, and so nobody studied the overall health effects. They were simply assumed to be proportionally beneficial. We do not have the evidence for all vaccines to tell vaccine-hesitant parents that it is overall beneficial for their child to receive each one of them. Rather, we have to acknowledge that there are things about vaccines that have not been investigated very well.
The World Health Organization (WHO) recently declared vaccine hesitancy one of the ten biggest threats to global health in 2019, along with air pollution and climate change. The declaration followed several measles outbreaks in Europe and the U.S., but most cases were in a country where the health system had broken down: Ukraine.
Nothing suggests that these outbreaks were caused by the few who declined a measles vaccine. A substantial proportion of cases occurred in people who had been vaccinated – so the outbreaks were mainly the result of broken healthcare systems and vaccine failure rather than vaccine hesitancy.
But the WHO declaration provides extra motivation for the health authorities in many countries that now mandate or consider mandating vaccines. The rhetoric is well-known: vaccines work, the science is settled, vaccine-hesitant parents are uninformed or misguided victims of the social media platforms where crooks spread fake science.
It is taken as a given that vaccines are similarly and uniformly beneficial – aside from rare side effects – and no sane person would question that. But are vaccines similarly and uniformly beneficial?
There is no doubt that vaccines can induce immunological “memory” against their target disease. And, at the population level, this reduces the risk of getting the target disease, at least for a period.
With smallpox, the vaccine actually led to the eradication of a devastating disease that killed around 30 percent of those infected.. We are close to eradicating two other serious infections: polio and measles.
Up to fifty years ago, polio infected almost everybody. And although only a small proportion developed clinical disease, it was still a major cause of paralysis. Measles infection, although seldom dangerous in wealthy areas, can be deadly in crowded, poor areas. These two infections are now close to extinct thanks to vaccines.
Overall Health Effects
But we don’t have a lot of evidence about the overall health effects of vaccines. Everybody has been so sure that vaccines only protected against the target infection, nothing else, and so nobody studied the overall health effects. They were simply assumed to be proportionally beneficial. For instance, if a measles vaccine is 90 percent effective and measles represents 10 percent of all deaths, then introducing the measles vaccine will reduce overall mortality by 9 percent. If the DTP vaccine protects against diphtheria, tetanus and pertussis – three potentially deadly diseases – then it will reduce overall mortality correspondingly.
