A clinical trial of one of the leading Ebola vaccine candidates has been suspended temporarily by Swiss researchers after four patients complained of experiencing unexpected side effects, the University of Geneva Hospital said on Thursday.
The human safety trials of the vaccine, developed by the Canadian government and licensed to U.S. companies Merck and NewLink, began in Geneva on Nov. 10 with the participation of 59 volunteers, who have all been vaccinated so far, Reuters reported.
"The Geneva team has decided to allow time to understand what is happening. This precaution of momentarily suspending the trial is habitual and classic in all clinical trials," the researchers said.
"They are all fine and being monitored regularly by the medical team leading the study," the Hopitaux Universitaires de Geneve said in a statement, adding that the trial had been suspended "as a precautionary measure."
On Dec. 2, Geneva researchers had confirmed that the first person to receive the experimental vaccination shot had experienced no side effects, although a few others did show symptoms of a mild fever.
Going into the second week of the trial, four patients reported feeling mild joint pains in their hands and feet, according to the Associated Press. This first phase of the trial had been due to continue for another week.
After checking the four patients to ensure that joint pain symptoms in hands and feet were "benign and temporary," the hospital is scheduled to resume the clinical trials on Jan. 5 with up to 15 volunteers.
Currently, hospital officials have halted the treatment to gain more data and liaise with other researchers who are testing the same vaccine in the United States, Canada, Germany and Gabon.
"These centers have not observed symptoms of inflammation in their volunteers to date," the hospital said.
The delay would allow some time for researchers to figure out how widespread the problems with the vaccine are, Marie-Paule Kieny, vaccine expert at the World Health Organization, said in a news briefing.
"It's not a setback, not at all," Kieny said in Geneva.
