Late last year, researchers reported a discovery from a 5,000-year-old mass grave in Sweden: DNA from the bacterium that causes plague. The people in that grave were probably felled by an epidemic that spread via trade routes from southeastern Europe and contributed to sharp population declines across the continent (SN: 1/19/19, p. 12), a precursor to the Black Death that wiped out up to half of Europe’s population in the 14th century.
Infectious microbes come and they conquer: It’s a story repeated again and again throughout human history. And we humans are often unwitting agents of our doom, spreading pathogens as we travel. That was true for Old World ills like smallpox and measles that traveled with Christopher Columbus and his crew to the Caribbean island of Hispaniola and devastated the indigenous Taino people. It was also true for the Spanish flu of 1918–1919 that killed about 50 million people worldwide and was spread by troop movements in World War I.
And we see it again with this year’s surge in measles outbreaks. Cases worldwide are increasing rapidly, according to the World Health Organization. The United States had seen 880 cases as of May 17, the greatest number since the disease was declared eliminated in this country in 2000.
In this issue’s special report, we explore why growing numbers of Americans hesitate to get their children vaccinated. The reasons may surprise you. Just saying that vaccines are safe often doesn’t allay people’s fears. With that understanding, doctors are trying new ways of connecting with people who refuse or put off getting vaccines for their families.
We also look far beyond our borders to see the challenges that other countries face in their efforts to eradicate measles. Because it spreads so easily, the virus is a tough foe, as our data visualization explains. And we’re still learning about how measles attacks; our article explains how it wipes out the immune system’s memory, leaving people more susceptible to other diseases for months or years. It’s a foe that no one should take lightly.