WASHINGTON (Reuters) - There is no sign the Ebola virus is mutating in an accelerated way that could make it more virulent or thwart vaccines or drugs under development despite some earlier fears to the contrary, researchers said on Thursday.
Earlier analyses had suggested to some experts that the virus might have been mutating at twice the rate observed in previous outbreaks, raising fears it could become even deadlier.
But a study backed by the U.S. National Institutes of Health and published in the journal Science found the virus was changing at about the same rate as in prior outbreaks.
“The data really shows that the virus isn’t changing any more than would be expected. So, for example, it doesn’t appear to be becoming more virulent or more transmissible,” said virologist David Safronetz of the NIH’s National Institute of Allergy and Infectious Diseases (NIAID), one of the researchers.
“I would say it’s definitely reassuring,” Safronetz added.
The biggest Ebola outbreak to date, centered in three West African countries, has killed more than 10,000 people but is showing signs of waning.
The researchers analyzed genetic information on the virus from samples taken over nine months last year from patients in Guinea in March, patients in Sierra Leone last June and patients last November in Mali who were infected in Guinea.
The routine genetic changes observed indicate the viral mutations are not likely to affect diagnostic testing or the effectiveness of experimental Ebola vaccines or drugs, the researchers said.
There are no approved vaccines or medicines for Ebola. There had been concern that a rapidly mutating virus could present a tricky moving target that could complicate efforts to develop ways to prevent and treat the virus.
“This does not appear to be a moving target,” said Dr. Anthony Fauci, NIAID’s director.
Ebola is transmitted only through direct contact with the blood or body fluids of an infected person. Fauci said the findings also allay concerns raised by some last year that a rapidly changing virus could change how Ebola is transmitted, becoming airborne or respiratory.
Also in the journal Science, researchers led by Yoshihiro Kawaoka of the University of Wisconsin and the University of Tokyo described promising results in monkeys from an experimental vaccine, one of several in the works.
They called it a safe, inactivated whole-virus vaccine that primes the recipient’s immune system with the full complement of Ebola viral proteins and genes.
Reporting by Will Dunham