The Ebola epidemic is killing up to 70 percent of those who get sick, but the thousands who have survived have blood teeming with antibodies that protect them against infection again, NBC News reported. Ebola survivor Dr. Kent Brantly has donated serum to three other patients and even though no one knows if it’s helped, in theory, Brantly’s antibodies should have kick-started their immune responses. Because there’s no specific cure for Ebola, people are asking why not make blood available. Researchers in Texas say there may be an unexpected source: people with silent Ebola immunity. In some outbreaks, up to half of people at high risk of infection who were watched never got sick, but they had antibodies against Ebola in their blood.