Highest viral disease fatality rate

The viral infection with the highest case fatality rate in humans is rabies, which, if not caught before symptoms appear, has a fatality rate of effectively 100 percent. There are only 14 documented cases in which a patient has recovered from symptomatic rabies, even with aggressive treatment.

Rabies can be effectively treated by post-exposure prophylaxis (PEP; the administration of a vaccine after infection) but it is not treatable after the patient has begun to show symptoms. There are some experimental protocols for post-symptom treatment – involving placing the patient into a medically induced coma – but these have only been tried a few times.

Around 30 million people receive the post-exposure vaccine every year, though the disease remains a major killer in countries where access to healthcare is limited.

Tens of thousands of people die of rabies every year (17,000 in 2015) with 95 percent of these cases occurring in Asia and Africa. Campaigns to eradicate rabies typically focus their attention on dogs, as dog bites are the cause of 99% of cases. Vaccinating animals and working to control feral populations is seen as the best approach to reducing cases in humans.