Health officials in New York are making sure people are aware that an Australian tourist with measles visited multiple hotels and the Metropolitan Museum of Art earlier this month. Measles is incredibly contagious and is spread through the air via coughing and sneezing. According to the CDC, the virus can survive in the air for up to two hours. Symptoms usually begin 7 to 14 days after exposure and may include high fever and cough, followed by a rash. Measles may cause serious complications, like pneumonia and encephalitis, which are more likely to lead to death in young children. The vaccine’s effectiveness rate is around 90%.

In the United States and elsewhere, lower vaccine rates have been associated with the anti-vaccine movement, led by people who mistakenly believe vaccines cause autism. I have no doubt the government is out to get us, and I am all for conspiracy theories, but that’s not what is happening here. The Washington Post notes:

Despite global efforts to combat the disease, measles has remained a serious threat, mostly to children in the developing world. In 2016, there were 89,780 measles deaths worldwide, the first year the figure dipped below six figures, the World Health Organization said…

The disease has sometimes roared back in the United States in incidents tied to anti-vaxxer efforts. For instance, MMR vaccines in Somali communities in Minnesota dropped 50 percentage points from 2004 to 2014 because of activist work there, sparking the worst measles outbreak in the state in three decades.