As Congo Ebola outbreak festers, FDA approves first vaccine to combat deadly virus
As an Ebola outbreak rages on in the Democratic Republic of Congo — the FDA has approved the first vaccine to protect against the deadly hemorrhagic virus, months earlier than expected. Manufactured by Merck the development of the vaccine, christened Ervebo, began during the West African outbreak that occurred between 2014 and 2016, which killed more than 11,000.
The approval for the genetically engineered attenuated live vaccine comes about five weeks after its European endorsement. Merck expects to launch the vaccine in the third quarter of 2020.
“We have not yet established a price for ERVEBO. Merck has committed to making the vaccine available to Gavi (the Vaccine Alliance)-eligible countries at the lowest possible access price,” a company spokesperson told Endpoints News.
Ervebo has been tested in roughly 16,000 individuals aged 18 and above in trials conducted in Africa, Europe, and the United States, and data show the vaccine is effective against the Zaire Ebola virus that circulated in West Africa in 2014-2016, as well as the current outbreak in DRC.
In the Guinea trial, 3,537 contacts, and contacts of contacts, of individuals with laboratory-confirmed Ebola virus disease received either “immediate” or 21-day “delayed” vaccination with Ervebo. Some 2,108 individuals were in the “immediate” vaccination arm and 1,429 were in the “delayed” vaccination group, and the results show that Ervebo was found to be 100% effective in preventing Ebola cases with symptom onset greater than 10 days after vaccination. No Ebola cases with symptom onset greater than 10 days after vaccination were observed in the immediate cluster group, compared with 10 such Ebola cases in the 21-day delayed cluster group.
Antibody responses to Ervebo were assessed in 477 individuals in Liberia, roughly 500 in Sierra Leone and about 900 individuals in Canada, Spain, and the United States — across geography, the antibody responses were similar.
Ebola is thought to have infiltrated the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals such as fruit bats, chimpanzees, gorillas, monkeys, forest antelope or porcupines. Eventually, it spread between humans through direct contact, via the blood or bodily fluids of an infected person.
The current outbreak in the Democratic Republic of Congo has shown case fatality rates of more than 65%, the WHO has estimated. Although there has been a recent spike in infections, the current infection rates are well below the 120 cases a week reported during the peak of the outbreak in late April. On Thursday, the WHO said it had recorded the first Ebola relapse in the current epidemic.
Earlier this year the WHO declared the outbreak — which so far has infected more than 3,350 people — a public health emergency of international concern. As of December 17, over a quarter of all confirmed Ebola cases in the DRC have been in children aged less than 18 years. A Merck spokesperson said the company has studies underway testing Ervebo (same formulation, same dose) in children.
The vaccine was initially engineered by scientists from the Public Health Agency of Canada’s National Microbiology Laboratory and subsequently licensed to a unit of NewLink Genetics Corp. In 2014, as the virus wreaked havoc in West Africa, Merck acquired the technology from NewLink (Battered by a series of setbacks, Newlink in October became the vehicle for a reverse merger).
In response to requests from the WHO, since May 2018, the large US drugmaker has donated 275,000 doses of the vaccine to combat the outbreak in the DRC. With the FDA approval, Merck has also qualified for a tropical disease priority review voucher (PRV) — these vouchers, used to hasten drug reviews, have been sold in the past for millions, ranging from $95 million to even $350 million.
The relatively few Ebola cases in the United States have been due to international travelers or health care workers who have contracted the virus after treating Ebola patients.
“While the risk of Ebola virus disease in the U.S. remains low, the U.S. government remains deeply committed to fighting devastating Ebola outbreaks in Africa, including the current outbreak in the Democratic Republic of the Congo,” said Anna Abram, FDA Deputy Commissioner for Policy, Legislation, and International Affairs, in a statement.