Measles surveillance: 2011
The latest issue of the CDC’s publication Morbidity and Mortality Weekly Report presents national statistics for the highly contagious respiratory-transmitted measles virus for calendar year 2011. Measles has traditionally been a disease of childhood, and an extremely effective vaccine to prevent infection was introduced in 1963 which has essentially eliminated the disease from countries with active vaccination programs. Although measles in most cases was not extremely serious, with the main signs and symptoms of the disease being high fever, systemic rash, and cough, complications were generally common. Fatality due to measles while it was endemic in the United States was around three deaths per 1000 cases, but considering the huge number of cases annually (approximately 700,000 per year), this resulted in a rather large number of deaths. In countries where measles remains endemic, the fatality rate due to poor healthcare is around 28%, and among people immunocompromised due to AIDS the fatality rate is similar.
The United States was “measles-free” during calendar year 2000, with no reported measles cases at all, however this has significantly changed for the worse during the intervening decade. As a notifiable disease, all cases of measles are reported to the Centers for Disease Control. In 2011, 222 cases of measles were reported in 31 states, marking the highest number of US cases in over 15 years. The 222 cases in 2011 resulted in 70 patients (32%) with complications serious enough to warrant hospitalization, however no US deaths due to infection were observed.
Of these cases, 200 of them (90%) were associated with importation of the disease from other countries, and in most of those cases, the patients were either unimmunized against measles or had unknown immune status. Of the patients eligible for vaccination, 76% of them had refused the MMR vaccine either for religious, philosophical, or personal objections. The sudden increase in measles outbreaks in the US demonstrates the fact that the disease remains endemic elsewhere in the world, and that surveillance and active immunization remains our best defense against further domestic outbreaks.
Editorial comments on the CDC report stress that health-care providers play an essential role in monitoring outbreaks, by recognizing the signs and symptoms of the disease in order to prevent rapid spread in local communities. Measles is highly contagious, and in regions with incomplete vaccination compliance, encouraging all eligible individuals to become vaccinated especially prior to international travel is important. The CDC recommends that all individuals over the age of 6 months who will travel outside of the US to receive the MMR vaccine.