WASHINGTON—An experimental Ebola vaccine appears safe and triggered signs of immune protection in the first 20 volunteers to test it, US researchers reported on Wednesday.
The vaccine is designed to spur the immune system’s production of anti-Ebola antibodies, and people developed them within four weeks of getting the shots at the National Institutes of Health (NIH). Half of the test group received a higher-dose shot, and those people produced more antibodies, said the study published in the New England Journal of Medicine.
Some people also developed a different set of virus-fighting immune cells, named T cells, the study found. That may be important in fending off Ebola, as prior research found that monkeys protected by the vaccine also had that combination response.
Stimulating both types of immune response is “a promising factor,” said Dr. Anthony Fauci, director of NIH’s National Institute of Allergy and Infectious Diseases, whose employees led the work.
The researchers reported no serious side effects. But two people who received the higher-dose vaccine briefly spiked fevers, one above 103 degrees Fahrenheit (39 Celsius), which disappeared within a day.
In a study published in the New England Journal of Medicine on Wednesday, the researchers said all 20 volunteers, who participated in the trials, which started some two months ago, produced the immune response.
The White House has congratulated the doctors on the success, saying the news “is another important milestone” in the effort to fight Ebola.
US President Barack Obama is expected to visit the institute next week to thank the researchers.
The US leader is also due to ask the Congress to approve allocation of additional budget funds in 2015 to this aim.
Earlier this month, Fauci told Congress this first-stage testing was promising enough that the US planned much larger studies in West Africa, starting in Liberia in early January, to try to prove whether the vaccine really works.
Scientists are racing to develop ways to prevent or treat the virus that has killed more than 5,600 people in West Africa, most of them in Guinea, Liberia and Sierra Leone.
Wednesday’s publication offered scientific details about the initial testing of the vaccine candidate furthest along, one being developed by NIH and GlaxoSmithKline. Additional safety studies are underway here and abroad. A different Canadian-made vaccine also has begun small safety studies.
Many questions remain as larger studies are being designed, including the best dose and how soon protection may begin, cautioned Dr. Daniel Bausch, a Tulane University Ebola specialist, who wasn’t involved in the study. Plus, monkey research suggests a booster shot will be needed for long-term protection.
“The road is still long and there are many challenges, but we are, nevertheless, one step closer to a solution,” he wrote in an accompanying editorial.
The Ebola virus disease (EVD), previously known as the Ebola hemorrhagic fever, is a severe illness in humans, often fatal, according to the World Health Organization. The virus is passed on to people from wild animals and can be transmitted from humans to humans. The average EVD case death rate is some 50 percent.
The first outbreaks of the virus occurred in remote Central African villages, near tropical rainforests. However, major urban and rural areas have been involved in the most recent outbreak in western Africa.
Early supportive care, which includes rehydration and symptomatic treatment, improves the survival rate.
No licensed treatment has yet been proven to be able to neutralize the virus, but a number of blood, immunological and drug medications are under development.
AP and PNA/TASS
Image credits: AP/Keystone,Jean-Christophe Bott