Yesterday, health officials in Charlottesville, Virginia, confirmed the existence of a small measles outbreak in the area. The Charlottesville-Albemarle Health Department says that an area woman who contracted the disease in India has passed it along to at least two people, and more may have been exposed. This is the first measles outbreak in the Charlottesville area in over twenty years. More worryingly, this outbreak brings the number of cases in the US so far this year to more than 120. That's easily the highest number since 1996; in the past decade, the median number of cases each year has been only 56. Officials tie the increase to increased case numbers overseas, with almost 90 percent of the cases in the US this year having been imported. Nevertheless, though measles now primarily comes from abroad, the CDC still strongly recommends children be vaccinated at an early age. (Side note: the measles vaccine was one of the vaccines that some incorrectly claimed caused autism, a claim that much-beatified talk show host Oprah Winfrey helped promote long after the scientific community dismissed it.) But just how costly is the vaccine?
Actually, even now, the vaccine can be a savings for the United States, but only if worldwide efforts to eradicate the disease continue. Ten years ago, three doctors at the University of Rochester Medical Center looked at the cost-effectiveness of increasing measles immunization rates, calculated in dollars per quality-adjusted life year (QALY), which measures "how many extra months or years of life of a reasonable quality a person might gain as a result of treatment." They found that, as the pre-existing immunization rate rose, the cost-effectiveness of immunization declined steeply, primarily because the number of measles cases averted fell while the cost for each immunization remained flat. For example, in a measles outbreak in Milwaukee, Wisconsin in 1990, the authors determined that each additional QALY would cost $48,000 when the local pre-program immunization rate was 55%, but when the rate rose to 75%, the cost per QALY jumped to $162,000. The doctors concluded that, past a 70 to 80% immunization rate, raising the immunization rate was no longer cost-effective on a local, regional, or even national level. The only way to return to cost-effectiveness is as part of a worldwide eradication program, because of the savings once the disease disappears; thankfully, eradication's exactly what the World Health Organization has targeted.