Thursday, 27 November 2014

Ebola vaccine promising in first human trials: National Institutes of Health

The news comes amid the worst ever outbreak of
the hemorrhagic fever, which has killed nearly
5,700 people, mostly in West Africa.
Pharmaceutical companies and health agencies
are scrambling to fast-track experimental drugs
and vaccines that could help.
In the first phase of testing, all 20 healthy adults
injected with a higher or lower dose of the
vaccine developed antibodies needed to fight
Ebola, said the National Institutes of Health
(NIH), which conducted the study.
Results were published Wednesday in the New
England Journal of Medicine.
"The unprecedented scale of the current Ebola
outbreak in West Africa has intensified efforts to
develop safe and effective vaccines," said
Anthony Fauci, head of the National Institute of
Allergy and Infectious Diseases, which is
developing the vaccine alongside
GlaxoSmithKline.
The vaccines under development "may play a role
in bringing this epidemic to an end and
undoubtedly will be critically important in
preventing future large outbreaks," he noted.
"Based on these positive results from the first
human trial of this candidate vaccine, we are
continuing our accelerated plan for larger trials to
determine if the vaccine is efficacious in
preventing Ebola infection," he added.
But the NIAID/GSK vaccine is still a long way
from being ready for use in the field.
The NIAID is "in active discussions with Liberian
officials and other partners about next-stage
vaccine testing in West Africa" for efficacy and
safety, the NIH said, but no announcement on
larger-scale trials was expected before early next
year.
There is no licensed treatment or vaccine against
the Ebola virus, which is transmitted through
bodily fluids and has been fatal in an estimated
70 percent of cases in the current outbreak.The
volunteers were injected starting in September,
and each showed a positive result for Ebola
antibodies in blood tests within four weeks.
The 10 volunteers in the higher-dose group
developed higher antibody levels, the NIH said.
In addition, two of the lower-dose group and
seven of the higher-dose group developed a kind
of immune cell called CD8 T cells, which are an
important part of the body`s response against
disease.
"We know from previous studies in non-human
primates that CD8 T cells played a crucial role in
protecting animals" who got the vaccine and then
were exposed to Ebola, said researcher Julie
Ledgerwood, the trial`s principal investigator.
None of the volunteers experienced serious side
effects within the study period, though two had a
brief, mild fever within the 24 hours after the
injection.
The vaccine uses a modified chimpanzee cold
virus to deliver segments of genetic material from
the Ebola virus.
The genetic material cannot spread in the body
like the virus does, but can still prompt the
antibody response.
The version tested at NIH contains material from
two species of Ebola -- the Zaire species,
responsible for the outbreak in West Africa, and
another called Sudan Ebola.
"This work is encouraging and another significant
contribution to efforts to tackle the Ebola crisis,"
said Dr Jeremy Farrar, Director of the Wellcome
Trust.
The White House also congratulated the vaccine
researchers.
"We congratulate Drs Francis Collins and Tony
Fauci and their teams at the National Institutes of
Health on the first published results from Phase 1
clinical trials of a promising Ebola vaccine
candidate," a White House statement said, adding
that President Barack Obama would visit the NIH
next week.
A second version of the vaccine, aimed at
blocking just Zaire Ebola, also began human
testing in October, at the University of Maryland.
Another experimental vaccine that has shown
promising results in primates is the Canadian
VSV-EBOV, licensed by US firm NewLink Genetics.
It is also in early stages of human testing.
The World Health Organization said Thursday that
the global death toll from the Ebola virus had
increased to 5,689 out of a total of 15,935 cases
of infection, almost entirely in western Africa.
The new numbers increased the death toll by 230
people and a 584 case increase from reports last
week.
The WHO believes that the number of deaths is
likely far higher, given the difficulty in collecting
comprehensive figures and Ebola`s high fatality
rate.
The first case discovered in the current outbreak
was in Guinea in December 2013.

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