NEW YORK - An experimental Ebola vaccine similar to one being developed by GlaxoSmithKline is effective for at least five weeks in lab monkeys but requires boosting with an additional vaccine to extend its protection to 10 months, according to a study published on Sunday.
The findings offer an early hint of which, if any, of the Ebola vaccines in development will prove effective, and in what form. Johnson & Johnson and NewLink Genetics are also among the firms accelerating their efforts to provide Ebola vaccines and treatments as the worst known outbreak of the virus ravages West Africa, killing more than 2,000 people.
The results of the new study suggest, for instance, that a GSK vaccine now being tested on healthy volunteers will protect against Ebola infection in the short term, but may have to be augmented for long-term protection.
The study, published in Nature Medicine, is the first to report that a vaccine regimen produced "durable immunity" against Ebola, protecting four out of four monkeys for 10 months.
The vaccine uses a chimp adenovirus, closely related to a human version that causes upper respiratory tract infections, into which scientists spliced an Ebola gene.
The adenovirus infects cells in a vaccinated animal, causing them to take up the gene and produce Ebola proteins. That primes the immune system to attack the proteins of Ebola viruses when an infection occurs.