Looking after people with late-stage Ebola at home puts people at greatest risk of catching it themselves – according to research from the University of East Anglia.
A new paper on risk factors for transmitting the deadly virus recommends better provision of health care facilities to ensure that people with the disease don't have to be cared for at home.
The study also finds that changing funeral traditions during outbreaks – particularly to allow cremation – could help stop the spread of future outbreaks.
But the research team say that transmission in the general community is not a high risk. And that even living in the same house as someone with the virus will not put others at great risk, provided they avoid direct contact.
The research is the first systematic review into the risk factors associated with Ebola.
Researchers studied 31 reports of the disease across 10 primarily African countries dating back to 1967. Most of the data came from interviews with survivors, their close contacts, or from clinical notes.
The team investigated variables including age group, intensity of contact, and the stage of the disease.
Lead researcher Prof Paul Hunter, from UEA's Norwich Medical School, said: "This research strengthens the evidence base for dealing with this deadly disease. Importantly, we provide a more nuanced understanding of the risks – and particularly the risks associated with indirect contact.
"Our research shows that Ebola is not very infectious in the general community, and that it does require close contact with a known case.
"We found no evidence of risk associated with casual community contact with individuals who are not yet showing symptoms.
"Even living in the same house is not that risky providing you avoid direct contact.
"Many forms of contact such as conversation, sharing a meal, sharing a bed, and direct or indirect touching, are unlikely to result in disease transmission during incubation or early illness.
"We found that infection risk is highest among those caring for a sick person at home in the later stages of infection, or preparing the recently deceased for burial.
"Urgent diagnosis and hospitalisation really is the key to stopping the spread of this disease at least until a vaccine is widely available.
"Our work also shows that vaccination strategies in future outbreaks only need to be targeted at relatively close contacts of cases and health care workers."
'Risk Factors for community Transmission of Filovirus infections (Ebola and Marburg): A Systematic Review and Meta-analysis' is published in the International Journal of Epidemiology.
The research was funded by National Institute for Health Research (NIHR) Health Protection Research Unit (HPRU) in Emergency Preparedness and Response, in partnership with Public Health England (PHE).