Researchers say now is the time to develop an effective vaccine against Middle East respiratory syndrome (MERS), and survivors of the disease could play a major role in that process.

The initial stigma of MERS, much like SARS, has made it difficult to study the survivors whose blood carries valuable information about virus-fighting strategies. But in a downturn, more survivors have agreed to donate blood samples—21 of whom contributed to a paper published on Friday in Science Immunology.

That might not seem like a lot, but only 2,040 MERS cases have ever been diagnosed and reported, in part because the starting symptoms—coughing, fever, trouble breathing—are so general.

MERS was just identified in 2012, so that’s not a lot of time to develop a new vaccine,” says Natalie Thornburg, a virologist at the Centers for Disease Control and Prevention. But they’re working on it. Most efforts target the protein the MERS virus uses to sneak into cells—it’s called spike.