Home Health News Vaccination strategy in long-running Ebola outbreak comes under fire – STAT

Vaccination strategy in long-running Ebola outbreak comes under fire – STAT

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The World Health Organization’s vaccination strategy in the long-running Ebola outbreak in the Democratic Republic of the Congo is coming under fire, with Doctors Without Borders accusing the agency of rationing vaccines and calling for an independent committee to ensure “more transparent management” of the situation.

The broadside, issued Monday, follows a prolonged effort by Doctors Without Borders to campaign for wider use of an as-yet unlicensed vaccine, developed by Merck. More than 226,000 doses of the vaccine have been administered in DRC’s North Kivu and Ituri provinces since August 2018, but Doctors Without Borders, one of the nonprofit groups playing a leading role in the response to the crisis, has argued that those doses are being distributed based on overly narrow criteria.

“We think that upping the pace of vaccination is necessary and feasible. At least 2,000-2,500 people could be vaccinated each day, instead of 500-1,000 as is currently the case,” said Dr. Isabelle Defourny, director of operations for group, known by the acronym of its name in French, MSF.

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The dispute comes as Congolese authorities announced late Friday that they will allow use of a second unlicensed Ebola vaccine, made by Johnson & Johnson (JNJ), the latest chapter in a separate long-running controversy. The decision reverses a decision by the country’s former health minister, who before being ousted had argued introducing the vaccine would create confusion and undermine public trust, already low in the region.

Strident debate about how to use vaccine in this outbreak has raged for months with disagreements swirling about both the strategy behind use of the Merck vaccine — the only Ebola vaccine for which there are Phase III efficacy data — and about how and where to deploy the J&J product, for which there aren’t yet human efficacy data.

The Merck vaccine is used in what is called a ring vaccination approach. When a case is confirmed, trained response staff work to determine who the person has had contact with, and to enumerate the contacts of the contacts. They are offered vaccine.

The idea is to protect people around known cases and to block the virus’ ability to spread further. But contact tracing, always difficult work, is especially so in this part of DRC, which has been a conflict zone for decades. Last spring the WHO agreed, on the advice of a vaccine advisory group, to also pursue targeted geographic vaccination — offering vaccine to all comers — in communities where, for security reasons, the opportunity to vaccinate would likely be brief.

MSF has been pushing for more such use, arguing that many of the new cases seen are among known contacts of cases that were not vaccinated. The group’s statement did not make note of the fact that in many cases, known contacts of cases refuse to cooperate with the Ebola response workers and some will not agree to be vaccinated.

Still, the organization’s frustration with the limitations of the ring vaccination approach was clear.

“It’s like giving firefighters a bucket of water to put out a fire, but only allowing them to use one cup of water a day,” said Dr Natalie Roberts, MSF’s emergency coordinator. “Every day we see known contacts of confirmed Ebola patients who have not received their dose despite being eligible for vaccination.”

By now, between 450,000 and 600,000 people in the region should have been vaccinated, MSF argued, using the estimate that the rings of contacts around every case — there have been nearly 3,200 so far — should generally number between 150 and 200 people.

But Dr. Socé Fall, WHO’s assistant director-general for emergencies response, said the MSF critique doesn’t take into consideration the social nature of Ebola transmission. Cases cluster within families and social networks, meaning there is a lot of overlap when contact lists are drawn up.

Moving to a more mass vaccination approach would burn through precious vaccine supplies and use up a lot of human resources, he said. He added that it would mean vaccinating people who are not in the virus’ path.

The current approach “is the most effective way to stop the transmission, because Ebola is a very social diseases,” Fall said.

Earlier this year there were concerns about whether supplies of the Merck vaccine might run out, but that picture seems brighter these days. The WHO said Monday that there are currently 390,000 doses available — substantially more than has been used in the first 14 months of this outbreak — and another 650,000 will be produced over the next six to 18 months.

There are roughly 2 million courses of the J&J vaccine, which must be given in two doses spaced 56 days apart. The first priming dose of the vaccine is expected to generate some protection. (By contrast, the Merck vaccine is given in one dose and protects in about 10 days.)

Multiple Phase 1 and Phase II studies of the J&J vaccine have been conducted. But the only time to determine whether an Ebola vaccine is actually protective is during an outbreak. As a result, there has been keen interest to see if the vaccine works and whether it can help to end this difficult epidemic.

Talks about getting it into the field have been underway for months, spurred by a consortium comprising MSF, CEPI (the Coalition for Epidemic Preparedness Innovations), the London School of Hygiene and Tropical Medicine, the Wellcome Trust, and others. Johnson & Johnson is on board.

The company “stands ready to help the DRC by donating the necessary doses of Janssen’s investigational vaccine regimen. We are committed to combating Ebola – and will always join forces with partners across the international community in the quest to save lives,” it said in a statement.

But there has been deep concern about how to use the vaccine — in particular, how close to the outbreak zone it could be deployed. Using two vaccines with different dosing regimens will create significant communications challenges. If they aren’t handled correctly, confidence in both vaccines could suffer, people involved in the response have warned.

There have been rumors in the outbreak zone of the pending arrival of a second vaccine. Community surveys conducted in the region have noted some respondents believe they can wait for that vaccine, rumored in some areas to be the better option.

“It is useless. Beni people all still get Ebola and they are having to make a second vaccine that will work,” one respondent said in one such report obtained by STAT.

Merely getting people to return at the right time for the second dose of the J&J vaccine will be a substantial challenge in a region where people are constantly on the move and may not have official identification. At one point, the researchers writing the trial protocol for the J&J vaccine proposed using iris scanning machines — though that idea was deemed to be unworkable given the prevailing lack of trust in authorities rife among the people of this part of DRC.

The technology may, though, be used to identify traders who move daily between Rwanda and DRC, said Dr. Jeremy Farrar, director of the Wellcome Trust. These traders, who number in the thousands, make up a group that both the Congolese and Rwandan governments are eager to vaccinated given their cross-border travel. In its statement Friday, the Congolese health ministry said these would be the first people offered the J&J vaccine.

Farrar and others have been pressing for months to use the vaccine close to the outbreak zone; one idea is create a wall of immunity to prevent the virus from taking root in Goma, the capital of North Kivu and home to 2 million people. It is located south of the outbreak zone.

Twice in recent months infected people have made their way to Goma; in the second event, several family members of the infected person contracted the virus. But the Merck vaccine was deployed rapidly and the transmission chain was stopped.

“We have the ability to protect populations on the edge of the epidemic zone,” said Farrar. “Places like Goma remain at great risk.”

But others have argued the J&J vaccine shouldn’t be used near where the Merck vaccine is being used. “I think it’s important, really, to have a very clear communications around this vaccine — and not to have it close to the outbreak area,” WHO’s Fall said.

Friday’s statement from the Congolese health ministry talked mentioned using the J&J vaccine to create a “corridor of immunity” to South Kivu — a province to the south of Goma, which has also has seen a cluster of cases recently. The statement did not say where that corridor would begin.

It is unclear how soon the trial of the J&J vaccine will start. There has been some suggestion it could begin by mid-October, but Farrar said that might be optimistic. He added: “I thought this would happen in June and we’re now in September and it hasn’t happened yet. So I’m not the best predictor of time scales.”

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