Measles in Europe, Recently at Record Low, Jumps to Highest Level Since ’90s

LONDON — Cases of measles, which appeared headed toward elimination in Europe, have soared this year, reaching their highest level in two decades across the continent as vaccination rates fall short, the World Health Organization reported on Monday.

Until the 1990s, there were hundreds of thousands of measles cases in Europe every year, but aggressive vaccination programs pushed that steadily downward, to a record low of 5,273 in 2016. Last year, the figure jumped to 23,927, and in just the first half of 2018 there were more than 41,000 cases, 37 of them fatal.

The increase in Europe has come even as measles continues to decline worldwide.

Public health officials say that at least 95 percent of a population must have immunity to control the spread of measles, which experts call the world’s most contagious human disease. But in Europe, only about 90 percent of children receive the recommended two-dose vaccine in early childhood as recommended, the WHO said, and last year, only Russia and a handful of small countries reached the 95 percent mark in young children. The rate in the United States was 94 percent.

Several European countries, including relative wealthy ones like France, Belgium and Austria, were at 85 percent or less. And in many countries, vaccination rates for young children have actually declined somewhat in recent years.

The cause is a combination of complacency, lack of information, opposition to vaccination, distrust of government, and economic and political instability, said Dr. Mark Muscat, a technical officer in the WHO’s immunization program in Europe. There, as in the United States, some people cling to the discredited theory that vaccines can cause autism.

“It’s not just one reason,” Muscat said. “People are not aware of the potential dangers of this disease, and there are parents who do not see the need to vaccinate their children.”

More than half of this year’s European cases, about 23,000 through June, were recorded in Ukraine, while Italy and Greece have also been unusually hard-hit, with more than 2,000 cases each. In Ukraine, the vaccination rate plunged beginning in 2008, as that country endured political and economic crises, a war against Russian-backed forces and medicine shortages. The rate has rebounded, but there is now a large population of older children who were not immunized.

“You need 95 percent coverage not just at the national level, but in each community, to keep it from spreading,” Muscat said. He said it was not clear whether the flow into Europe, in recent years, of millions of migrants from the Middle East and Africa, where vaccination rates are lower, had contributed to the increase.

The death rate from measles, which is spread by airborne droplets exhaled by an infected person, is relatively low — a fraction of 1 percent of cases in developed countries, but higher elsewhere — though it can do lasting harm to some survivors. The populations most at risk are people with compromised immune systems who have never had the disease and infants, whose immune systems are not fully developed and who do not receive the first dose of vaccine in the first year after birth.

Epidemiologists measure how communicable a disease is by estimating how many people would catch it, on average, from a single infected person in a population without any immunity. For influenza, the figure is 2-3. For measles, it is 12-18.

“If somebody with measles just walks through an airport, that one person could easily give measles to some others who breathe the same air,” Muscat said.

Anyone who has had measles, as many older adults have, has lifelong immunity. Vaccines — available since the 1960s, and far more commonly used in recent decades — confer long-lasting immunity, but it is not yet clear whether it is permanent.