So many of us in primary care now work at the juncture of individual, one-on-one patient care and the care of populations and communities that we are acutely aware of the very real issues that happen along that interface. News headlines from the past few months offer an example that many of us must address each day we are in clinic.
We are seeing a resurgence of measles in the United States. As of Feb. 20, 154 people from 17 states had become infected with the virus in the most recent outbreak in this country, according to the Centers for Disease Control and Prevention (CDC).
A great deal of public discussion has taken place about the value of vaccinations, and the choices of parents who do not wish to vaccinate their children for measles and other infectious agents. The concept of “herd immunity” often comes up in these discussions, and this idea is central to the reason we vaccinate individuals in the first place.
Herd immunity refers to the proportion of individuals who are immune to a certain disease in a given population. The more individuals who are immune (the higher the herd immunity), the more protection the community receives from the disease, so that not everyone needs to be immunized, but most do in order to protect the entire community.
Typically, a population immunity (herd immunity) proportion of 80 percent (for polio) to 90 percent (for measles) must be achieved in a community to protect most individuals in that community, according to the article “Vaccination Mandates: The Public Health Imperative and Individual Rights.” In order to achieve such immunity rates, most individuals in the community must have either natural immunity (from having the disease) or be vaccinated. In this country, until recent years, we have generally accepted a social responsibility to others as part of the reason to vaccinate ourselves and our children.
In recent years, unfounded fears about vaccine safety have caused some individuals to question this social contract, and more and more parents, in particular, are choosing not to vaccinate their children. This shift has caused herd immunity in some communities to drop below the threshold needed to protect the community, and we are seeing a resurgence of preventable infectious diseases, including measles. This is a classic conflict between individual rights and social responsibility that has a negative health impact on some of the most vulnerable members of our population.
As primary care clinicians, it is our responsibility to assess the evidence available to us, including evidence of harm as well as benefit, in order to provide patients and their families with the best information available to them. At present, there is no reproducible evidence of direct harm from the measles vaccine, according to the CDC, and our responsibility is to help families understand that, and to encourage them strongly to vaccinate.
Debating the conflict between individual rights and social responsibility is a significant issue, but if there is no evidence of harm, then the conflict is nonexistent, and protection for both individuals and the community is the higher good.
Sharon Hull is division chief of the Division of Family Medicine. Emailsharon.hull@duke.edu with questions.
Editor’s note: Dr. Hull guest blogs the first Friday of every month.