Yes, you read that correctly: we’re in a crisis. Bloomberg recently reported that in 17 states, preschool MMR vaccination rates have fallen below 90%. Well, that’s because vaccines cause autism, right?
Of course not. Most of us have heard the story of Andrew Wakefield. Wakefield had plenty of motivation to spread false information. For instance, he once filed a patent for an alternative measles vaccine, among other conflicts of interest. Hindsight may be 20/20, but everyday we are bombarded in the media with new celebrities claiming enlightenment on the topic of vaccines. Recently, Kristin Cavallari of “Laguna Beach” and “The Hills” fame indicated that she will not vaccinate her children because “she has read too many books about autism.” And in light of the recent outbreak of measles from Disneyland, her words could not be more concerning.
In the month of January, we have had more cases of measles in the United States than we typically have in an entire year. The reason the United States is able to keep cases of measles so low is because of MMR vaccination. In an ideal world, everyone would receive vaccines so that the entire population would be immune to measles. This way, when someone brand new arrived, their infected state would not have grave implications. The reality is this: there are some groups of the population who cannot receive vaccines. Some babies are too young, some people are immunocompromised, others are allergic to certain ingredients within the vaccines, and some religions prohibit any artificial medical treatment, including vaccines. These people always have an intrinsic risk of getting measles if they are exposed, so how can we protect them?
In public health, herd immunity refers to the percentage or proportion of the population that is immune to a particular disease, typically by vaccination, providing some degree of protection even to those unvaccinated. So if you have one hundred people in a room, and three of them cannot receive vaccines, the best way to ensure these three people will not become infected is by vaccinating the remaining 97, or as many of those people as possible. This ensures that if any of the vaccinated 97 people come into contact with measles, their immune systems will not allow them to become infectious, and as such, they protect the herd, or everyone else in the room. But when fewer and fewer people receive vaccinations, even just one or two percent, the risk of an isolated measles infection spreading increases. Think about it: if 97% of people are vaccinated, and one person with measles appears in the population, their odds of finding someone unvaccinated to transmit the infection to is 3%. But if you drop to 90% vaccination, 10%, or roughly one in ten people, are at risk for contracting measles. And the thing about measles that makes it so problematic is that it is incredibly infectious and contagious. It is spread by air droplets and has a 90% transmission rate, so if someone coughs on you and you are not immune, you have a 90% chance of developing a measles infections. Measles is debilitating, and in some cases, deadly.
Most of the cases in the Disneyland outbreak are from children who were not vaccinated for a variety of reasons. There are concerns that measles will continue to spread, and if it does, that it could infect classrooms of students. This has raised concerns and talk among many politicians about whether it is reasonable to mandate vaccinations on a statewide policy. People in favor of mandatory vaccinations cite requirements for car insurance and health insurance. Opponents note that parents should have the final say in any and all healthcare decisions made for their children. But as a student of public health and of medicine, I offer this question: what about the parents of infants too young for vaccinations? What about children who are immunocompromised or have certain allergies and can never receive vaccinations? Do we not have an obligation to protect, within reason, those who are not able to protect themselves?
Do no harm: this forms the very foundation of medicine. If I am to espouse the path of least harm, vaccines protect not only those of us who receive them from complicated, potentially lethal infection, but those who are unable to receive the vaccination. As such, I feel justified in my assertion that everyone who can receive vaccines should. If we don’t begin to address dropping rates of vaccinations in preschools, we run the risk of facing more and more outbreaks of measles, and perhaps downstream, other infections, too.