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. Continue...
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.
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