This neighborhood is home to Argentina's leading hospital on infectious diseases, and also one of dozens of places in the city where people are lining up to get vaccinated against yellow fever even though the closest case is miles and miles away. Yellow fever is a nasty disease, it's a virus transmitted by mosquitoes and typically only a few people die each year of it. if someone develops symptoms, odds are the person will die within weeks and in great pain. Argentina has had only one case so far but it remains a disease feared across all of the country. in 1871 and 1872 a yellow fever outbreak struck the city and killed 10% of the population of Buenos Aires. That memory highlights why experts are concerned now: and an outbreak could happen easily in an urban area, and it's hard to control even with modern techniques. Millions of vaccines have been purchased by South American governments. The WHO say anyone traveling to Paraguay or jungle regions of Brazil should get vaccinated, but the problem is people who don't need the vaccine are getting it anyway because they're scared and that's causing a shortage.