Ebola: The Race for a Vaccine

In West Africa, the number of cases of Ebola has exceeded 20,000 with almost 8,000 fatalities reported. It is by far the worst Ebola outbreak on record. To help put the brakes on this runaway epidemic, the National Institutes of Health and the World Health Organization are accelerating clinical trials on vaccines currently in development. And to remove more of the roadblocks, the U.S. Department of Health and Human Services has granted legal immunity to Ebola vaccine manufacturers so that concern about liability won’t stand in the way.

A Promising Vaccine

A promising new Ebola vaccine has been developed at the National Institute for Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), and is already being tested by GlaxoSmithKline. These trials are being fast-tracked with support from the World Health Organization (WHO) and NIH to speed up Ebola research and find an effective vaccine to halt the rapid spread of the disease. The accelerated trials will, hopefully, prove that the vaccine is safe and effective in generating an immune response that will provide protection from the Ebola virus.

The vaccine uses an adenovirus that is genetically engineered with Ebola virus. It has already been shown to be effective in non-human primates, but this is the first time is it being tested in humans.

The vaccine began clinical trials on 20 human volunteers in the U.S. a few months ago. A nurse received the first dose. Clinical trials have also begun on 60 subjects in the U.K. and on another 40 in Mali. Additional NIH trials may be conducted in Gambia and Mali. The Centers for Disease Control and Prevention is considering a trial in Nigeria.

A Second Vaccine

A second vaccine has also received approval to proceed to Phase 1 clinical trials and is being tested by NewLink Genetics, a small, Iowa-based biopharmaceutical company. This vaccine uses attenuated strains of vesicular stomach virus (VSV) that are genetically modified with an Ebola virus protein. It was developed in Canada and has shown promising results in non-human primates exposed to lethal doses of Ebola.

Clinical trials began last fall. However, researchers who were conducting clinical trials on the drug at the University Hospitals of Geneva called a temporary halt to the testing when some volunteers in the trial complained of joint pain in their hands and feet. Joint pain, which is a common side effect of many vaccines, affected a small number of volunteers who were receiving higher dose levels of the vaccine. Researchers expect to be able to proceed with additional testing of lower doses of the vaccine.

Roughly 40 healthy volunteers will be immunized and then followed to determine the safety of the vaccine and the magnitude and durability of any immune response, including whether these volunteers develop the same levels of antibody responses that are thought to protect monkeys in Ebola challenge studies.

Other Drugs

The vaccines being tested by GlaxoSmithKline and NewLink Genetics could be ready for large-scale efficacy trials in early 2015 and available for widespread distribution as early as this spring. In the meantime, research is continuing on several additional Ebola vaccines:

  • VesiculoVax, a prototype manufactured by Profectus Biosciences; this vaccine has already demonstrated single-dose protection against Ebola in monkeys
  • a vaccine made by Crucell that provides immunity to Ebola as well as Marburg, a related virus; testing is expected to begin in late 2015 or early 2016
  • a rabies-based vaccine that Thomas Jefferson University is working on with NIAID that uses a genetically engineered version of the rabies virus to protect against both rabies and Ebola; research is focusing on an inactivated version of this vaccine for human and veterinary use and a live vaccine that could be used in wildlife in Africa to halt the transmission of Ebola from animals to humans
  • a vaccine that uses immune-stimulating protein from the Ebola virus to boost the immune system response; a small Canadian company has just begun testing the vaccine in monkeys but, so far, results are promising

Legal Immunity for Ebola Vaccine Manufacturers

To help advance the development of an effective Ebola vaccine, the U.S. Department of Health and Human Services (HHS) has recently extended liability protection to pharmaceutical companies that are fast-tracking development of Ebola vaccines. The objective is to avoid delaying production of effective vaccines because of legitimate concerns related to liability. HHS’ offer of immunity will protect pharmaceutical companies from legal claims related to the development, testing, manufacturing, distribution, and administration of three vaccines for Ebola. These vaccines include the two being tested by GlaxoSmithKline and NewLink Genetics along with a third being developed by Johnson and Johnson. However, the declaration does not provide immunity for any claim brought in a court outside the U.S. HHS is urging other countries to enact similar protections. The U.S. has extended similar protection for many years to companies that develop childhood vaccines.

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