Measles has been around a long time. A Persian doctor is credited with writing one of the first accounts of measles in the 9th century. One of the most notable features of the measles virus is its contagiousness. Spread by airborne respiratory droplets, measles virus is, in fact, now considered the most contagious of all infectious agents.
In 1963 when the measles vaccine developed by John Enders and colleagues became available, it was heralded as a major medical breakthrough. In the decade before the vaccine’s availability, nearly all children in the United States got measles by the time they were 15 years of age (I was among them). It is estimated that back then every year in the U.S. the measles virus infected 3 to 4 million children, killed 400 to 500 people, precipitated 48,000 hospitalizations, and caused 1,000 cases of encephalitis (inflammation of the brain). And worldwide an estimated 2.6 million people died each year of measles.
Subsequently, the measles virus was combined with mumps and German measles viruses giving us the MMR vaccine. While the vaccine dramatically reduced the number of deaths, measles remained a serious disease, especially in the developing world. And measles outbreaks continued to pop up in the U.S. and Europe among unvaccinated people. In recent years, matters have taken a dramatic turn for the worse. The reason for this alarming situation is a newly recognized ‘disease’—vaccine hesitancy.
On January 20, 2019, the World Health Organization released a list of “Ten Threats to Global Health in 2019.” For the first time ever vaccine hesitancy appeared on the list, ahead of dengue virus, the cause of 390 million infections a year, and HIV.
Here’s how the WHO defines vaccine hesitancy—the reluctance or refusal to vaccinate despite availability of vaccines. The prime example is measles, which has seen a 30% increase in cases globally, despite a highly effective vaccine. And in the U.S., where measles was declared eliminated in 2000, we are in the midst of an outbreak that threatens to erase this public health status. As of August 22, 2019, a total of 1,203 measles cases had been reported in 30 states, the greatest number of cases since 1992. More than 75% of the cases were linked to an outbreak in New York, a large majority of whom weren’t vaccinated.
The current New York epidemic of measles started in early October 2018 when a fourteen-year-old boy from Israel (Patient Zero) attended religious services at a synagogue in the Rockland County village of New Square, an enclave of roughly 8,500 Hasidic Jews, many of whom weren’t vaccinated against measles. To help stop the rapidly spreading outbreak, New York eliminated religious exemptions for required vaccines, like MMR. As of this writing, it was announced that the measles outbreak in New York City was over.
Protection of a community against measles is dependent on what is called “herd immunity” (also known as “community immunity”). Experts suggest that at least 95% of people in any given community need to be immune to measles for protection of those who aren’t immune. As the measles vaccine is a live attenuated virus, people with an immune deficiency shouldn’t be vaccinated. Thus, they are dependent for protection by a high rate of vaccination of those around them.
So why is this giant step backwards happening? Why aren’t people getting the measles vaccine? In recent years, public health officials have come to recognize that the disease they’re fighting isn’t so much measles as it is vaccine hesitancy. On August 28, the WHO Director-General declared that misinformation about vaccines is as contagious and dangerous as the infectious agents that vaccines are aimed to prevent. And the vector of the spread of misinformation isn’t mosquitoes, as in the case of malaria and Zika virus, but rather it’s social media platforms.
The basis of vaccine hesitancy is complex and in some ways impossible, at least for me, to understand. Misinformation about the dangers of vaccines plays a major role. In the case of measles, unfounded fear about autism, promulgated most notoriously by Andrew Wakefield—a British researcher whose fraudulent report in The Lancet in 1998 of a link between the MMR vaccine and autism energized a cascade of fearmongering celebrities who continue to oppose vaccination.
But the opposition of so-called “anti-vaxers” isn’t explained by mere stupidity. In a September 2, 2019 article in The New Yorker by Nick Paumgarten (“The Message of Measles”), he cites Howard Zucker, New York State’s Commissioner of Health, “What surprises me is the really educated people who are passionately against vaccinations. I see this as part of a larger war against science-based reality. We need to study vaccine hesitancy as a disease.”
“Vaccines are the tugboats of preventive health.” William Foege
Without any doubt in my mind, vaccines are the most important of all medical breakthroughs, ever. The best example of their impact is smallpox, a disease that historically killed more people than all wars combined. The smallpox vaccine was introduced in the late 18th century by William Jenner (the Father of Vaccinology), and concerns about its safety haunted its use right up to when the last case of smallpox was diagnosed in Somalia in 1977. This accomplishment was the result of a heroic effort led by the WHO. (Among several notable giants in the field of medical epidemiology, William Foege stands out.)
To this day smallpox remains the only infection in humans that has been eradicated. (A devastating infection in cattle called rinderpest that is caused by a paramyxovirus similar to measles virus was likewise declared eradicated in 2011 by a similarly rigorous vaccine campaign.)
Eradication is defined in various ways but generally means the permanent reduction of the worldwide incidence of an infection to zero obviating the necessity of further control measures. Elimination of an infection means a reduction in incidence to zero in a geographical area with continued measures necessary to prevent reestablishment of transmission. Examples include measles and poliomyelitis.
The recognition of vaccine hesitancy as a disease raises the question of whether it can be eliminated, if not eradicated. It seems that the ultimate eradication of measles is now dependent upon improved understanding of vaccine hesitancy and on developing better methods to eliminate misinformation about vaccines from social media platforms.
