The World Health Organization says 5% of people exposed to Ebola will take longer than 21 days to develop symptoms.
95% of confirmed
cases have an incubation period in the range of 1 to 21 days; 98% have an incubation period that falls within the 1 to 42 day interval. WHO Report
- Link to News Story
EVD can reinfect/reemerge in survivors after treatment and negative tests Paul Farmer, MD, PhD, from Partners in Health, Boston, Massachusetts, said "In Monrovia, a couple of children under 5 who had negative [polymerase chain reactions (PCRs) after treatment] then returned some weeks later with positive PCR. These are children who had a normal course of illness...and had a clinical recovery, and both of these children became ill in a day or two," Dr Sprecher continued. "They came back and were found to be febrile and [PCR-]positive again. Both children had some neurologic signs. The feeling amongst the virologists is...the virus gets into some parts of the body with immunologic protection, like the central nervous system. The immune response clears the virus from the periphery, the patient has a clinical recovery, while the viral infection progresses in the [central nervous system] and eventually returns and reemerges as a renewed positivity. At least one of the children became negative again." Link to Story
The CDC definition of direct contact includes being in close proximity (within 3 feet) of an infected person for an extended period of time without PPE (personal protective equipment). Link to story