Are W. Africans “Guinea Pigs” in Ebola Vaccine Trials?

[Above image: An Ebola isolation ward in the Congo, 2012. Courtesy: Brian Bird, Ph.D]

The World Health Organization (WHO) is under fire for its management of a study in Guinea testing a Merck Ebola vaccine. According to an article in the current edition of The Lancet medical journal, critics allege some patients are getting inadequate care.

The deadly Ebola outbreak is finally on the decline in West Africa with Liberia declared “Ebola free” earlier this month. But scientists testing Ebola vaccines made by companies such as Merck and GlaxoSmithKline are in a race.

“Instead of a scramble for Africa, you have a scramble for patients, and the fear is that sometimes the patient gets lost,” said Rebecca Freeman Grais in The Lancet. She is a coinvestigator on a Merck vaccine study in Guinea and heads research at Médecins Sans Frontières’ (MSF) Epicentre.

There are currently two studies in Guinea testing Merck’s rVSV-EBOV vaccine: one tests it in front-line workers in the Ebola response. The other is a “ring trial” led by WHO and tests the vaccine in contacts of those newly diagnosed with Ebola.

Some vaccine test subjects develop vaccine-related arthritis. Twenty to 30% may develop a low-grade post-vaccine fever. How to best handle vaccine-related illnesses in West Africa is one concern. Experts say the patients should not automatically be sent to an Ebola treatment unit where they could be at high risk of exposure to the virus.

“We don’t want folks who don’t have Ebola to be exposed in a holding center or in the Ebola treatment facility,” said Thomas Clark of the Centers for Disease Control (CDC) in The Lancet article. CDC is collaborating on an rVSV-EBOV vaccine study in Sierra Leone.

In the WHO study, village community members who get the Merck vaccine are instructed to tell the village chief if they develop a fever. The chiefs have phones and a number to call.

But that strategy is “prone to failure,” says anthropologist Frédéric Le Marcis of the Ecole Normale Supérieure de Lyon because of “mistrust towards all kinds of elites, including traditional chiefs or elders” who have been known to steal food and otherwise be corrupt.

Vaccine study teams also conduct visits to the villages where test patients get the Ebola vaccine. But critics say monitoring adverse effects this way may not always be effective because residents may be difficult to find.

Another medical anthropologist, Vinh-Kim Nguyen of Université de Montréal, told The Lancet he was concerned about patient safety after visiting an Ebola treatment unit where WHO trial participants are taken if they get sick from the vaccine. He said some patients were not receiving expected care.

In response, WHO said the death rate at the center in question was comparable to any other.

The National Institutes of Health (NIH) is expected to propose a third vaccine trial for Guinea pitting the Merck vaccine against the GlaxoSmithKline version, “cAd3-EBOZ.” WHO opposes adding the NIH GlaxoSmithKline trial in Guinea saying it could affect the integrity of the Merck trial.

Read The Lancet article


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