Measles is on the march once more, even though vaccination against the disease has cut the number of worldwide deaths from an estimated 2.6 million per year in the mid-20th century to 110,000 in 2017. But thanks to the anti-scientific, anti-vaccination movement and the ever expanding reach of social media, measles cases are now at a 20-year high in Europe and as many U.S. cases were reported in the first two months of 2019 as in the first six months of 2018.

Highly contagious, measles is not a malady to be taken lightly. One in 1,000 people who catch it die of the disease; most of the victims are children under five. Even those who survive are at high risk of falling prey to encephalitis, an often debilitating infection of the brain that can lead to seizures and mental retardation. Other serious complications of measles include blindness and pneumonia.

It’s not the first time that measles has reared its ugly head since the widespread introduction of the MMR (measles-mumps-rubella) vaccine in 1963. Although laws mandating vaccination for schoolchildren were in place in all 50 U.S. states by 1980, sporadic outbreaks of the disease have continued to occur. Before the surge in 2018-19, a record number of 667 cases of measles from 23 outbreaks were reported in the U.S. in 2014. And major epidemics are currently raging in countries such as Ukraine and the Philippines.

While some parents oppose immunization on religious or philosophical grounds, by far the most objections come from those who insist that all vaccines cause disabling side effects or other diseases – even though the available scientific data doesn’t support such claims. As discussed in a previous post, there’s absolutely no scientific evidence for the once widely held belief that MMR vaccination results in autism, for example.

Anti-vaccinationists, when accused of exposing their children to unnecessary risk by refusing immunization because of unjustified fears about vaccine safety, rationalize their stance by appealing to herd immunity. Herd immunity is the mass protection from an infectious disease that results when enough members of the community become immune to the disease through vaccination, just as sheer numbers protect a herd of animals from predators. Once a sufficiently large number of people have been vaccinated, viruses and bacteria can no longer spread in that community.

For measles, herd immunity requires up to 94% of the populace to be immunized. That the threshold is lower than 100%, however, enables anti-vaccinationists to hide their children in the herd. By not vaccinating their offspring but choosing to live among the vaccinated, anti-vaxxers avoid the one in one million risk of their children experiencing serious side effects from the vaccine, while simultaneously not exposing them to infection – at least not in their own community.  

But hiding in the herd takes advantage of others and is morally indefensible. Certain vulnerable groups can’t be vaccinated at all, including those with weakened immune systems such as children undergoing chemotherapy for cancer or the elderly on immunosuppressive therapy for rheumatic diseases. If too many people choose not to vaccinate, the percentage vaccinated will fall below the threshold, herd immunity will break down and those whose protection depends on those around them being vaccinated will suffer.

Another contentious issue is exemptions from mandatory vaccination for religious or philosophical reasons. While some American parents regard the denial of schooling to unvaccinated children as an infringement of their constitutional rights, supreme courts in several U.S. states have ruled that the right to practice religion freely doesn’t include liberty to expose the community or a child to communicable disease. And ever since it was found in 2006 that the highest incidence of diseases such as whooping cough occurred in the states most generous in granting exemptions, more and more states have abolished nonmedical exemptions altogether.

But other countries are not so vigilant. In Madagascar, for instance, less than an estimated 60% of the population has been immunized against measles – because of which an epidemic there has caused more than 900 deaths in six months, according to the WHO. Although the WHO says that the reasons for the global rise in measles cases are complex, there’s no doubt that resistance to vaccination is a major factor. It’s not helped by the extensive dissemination of anti-vaccination misinformation by Russian propagandists.

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