Anti-Ebola vaccine and drugs arrive

Rona Ambrose, Canada's health minister, revealed on
Wednesday that Canada is sending about 800 to 1000
doses of an experimental vaccine known as VSV-EBOV to West
Africa to help the World Health Organisation to fight the
Ebola epidemic. The vaccines would be distributed through
the WHO in West Africa, to Sierra Leone, Nigeria, Liberia
and Guinea. The VSV-EBOV vaccine was developed at
Canada's national microbiology laboratory in Winnipeg,
Manitoba.
In addition to this, a consignment of experimental Ebola
drug arrived in Liberia by plane on Wednesday, to treat
two doctors suffering from the virus. The drug, Zmapp,
arrived in two boxes on a commercial flight from the United
States of America. This drug has shown good results when
tested on non-human primates such as monkeys and apes,
but human trials of the drugs have not yet begun.
On records, Zmapp has only been administered to three
humans. The first two are the US aid workers, Dr. Kent
Brantly and Nancy Writebol, who contracted Ebola in
Liberia, and were flown to and treated at the Emory
University Hospital in Atlanta, Georgia. These two
Americans have showed significant improvement. However,
the third person to receive Zmapp, Miguel Pajares ,a 75-
year-old Spanish priest who contracted Ebola while in
Liberia, died in a Madrid hospital on Tuesday, August 11.
The go-ahead to allow the use of Zmapp despite the fact
that it has not been tested on humans was the result of an
emergency WHO meeting which involved a panel of 12
advisers and four resource persons, consisting of mainly
doctors and professors. According to WHO, the panel
concluded that "it is ethical to offer unproven interventions
with as yet unknown efficacy and adverse effects, as a
potential treatment or prevention."
Also, Dr. Marie-PauleKieny, assistant Director-General at the
WHO, said, "If these treatments can save lives, as the
animal studies suggests, should we not use them to save
lives?"
If the usual protocol in testing vaccines and drugs on
human populations before they are certified fit for human
use is carried out, the earliest we may have to wait will be
2015. The reason for this is that the time needed to fully
release the vaccine into the market is quite lengthy due to a
thorough process guarded by strict bioethical procedures.
Stages of vaccine development and testing include
Exploratory stage – which involves basic laboratory
research that often lasts two to four years. During this
phase, federally funded academic and governmental
scientists identify natural or synthetic antigens that help
prevent or treat a disease.
The preclinical stage - which involves the use tissue culture
or cell culture systems and animal testing to assess the
safety of the candidate vaccine and its ability to provoke a
desired immune response. Animal subjects may include
mice and monkeys. These studies give researchers the idea of
the cellular responses they might expect in humans. Studies
will also suggest a safe starting dose for the next phase of
the research as well as a safe method for the administration
of the vaccine. This stage often lasts for 1-2 years.
Investigational new drug application – A sponsor, usually
a private company, submits an application to the
regulatory bodies. The sponsor describes the manufacturing
and testing processes, summarises the laboratory reports,
and describes the proposed study. Once the IND application
gas has been approved, the vaccine is subject to a three-
phase clinical studies on human subjects.
The Phase 1 trials – is the first attempt to assess the
candidate vaccine in a small group of between 20 and 30
people. The goal of phase 1 trials are to assess the safety of
the candidate vaccine and to determine the type and extent
of immune responses that the vaccine produces. A promising
phase 1 trial will progress to the next stage.
Phase 11 trials – will involve a larger group of several
hundred individuals than the phase 1. The goal of the
phase 11 trials are to study the candidate vaccine's safety,
immunogenicity, proposed doses, schedule of immunisation
and method of delivery.
Phase 111 trials – will include thousands of people. The
goal is to access the vaccine safety in a larger group of
people because certain rare side effects which may not
surface in smaller number of people, but may occur in one
out of every 10,000 people.
After a successful phase 111 trial, the vaccine developer will
submit a biologics licence application to the country's body
that is responsible for protecting the public health by
assuring the safety, efficacy and security of human and
veterinary drugs, biological products, medical devices,
nation's food supply, cosmetics, and products that emit
radiation. The regulatory body will inspect the factory
where vaccine will be produced and also approve
vaccination labelling. The final stages are manufacturing,
quality control and distribution.
The standard WHO practice in assessing new medicine
involves these series of trials in humans, to ensure the
medicines are safe for use. However, the severity of Ebola
has made WHO to by-pass these stages and give a green
light for the use of these experimental drugs on humans.
Vaccination is the best strategy to containing this deadly
infection. It would also provide a medical tool to
discourage the use of the Ebola virus as an agent of bio-
terrorism.
Have a great weekend.