United States measles elimination status

An independent commission of experts that reports to the director of the Pan American Health Organization determined that the US no longer qualified as having eliminated measles.

The decision was widely expected after years of falling vaccination levels and surging case counts, but it’s still a black mark on the nation’s public health policy.

The international committee that determines countries’ measles elimination status considers an infection to be endemic, or regularly occurring, if infections caused by the same strain are passed from person to person for at least a year within the same country.

To determine this, the committee members look at the genetic code of viruses sampled from patients.

Every time a virus copies itself, it makes tiny changes in its genetic code. By studying the genomes of different viruses in an outbreak, scientists can determine how closely the infections may be related and whether they are likely to have been part of the same chains of transmission.

“This is just so devastating and so sad that we are where we are today,” said Dr. Nuwan Gunawardhana, an infectious disease epidemiologist at Columbia University Irvine Medical Center in New York. “This just kind of points towards the direction of really reversing a generation of public health progress.”

But it also means people who are too young to be vaccinated against measles or who have lowered immune function because of organ transplants or cancer or other conditions are at higher risk in areas with outbreaks than they were just two years ago.