12/11/2014 12:37 EST | Updated 02/10/2015 05:59 EST

Ebola vaccine trial halted in Switzerland, continues in Halifax

Despite an Ebola vaccine trial in Switzerland being halted after unexpected side effects in patients, a similar trial in Halifax is continuing as planned, say researchers.

The trial at the IWK Health Centre is the only one in Canada and one of a handful taking place across the world.

"There is no change to the Canadian study," hospital spokesperson Ben Maycock said on Thursday.

In Switzerland, four out of 59 volunteers experienced mild joint pain in their hands and feet, according to the Associated Press.

The Hôpitaux Universitaires de Genève said in a statement Thursday that the trial has been suspended "as a precautionary measure."

In Halifax, researchers haven't seen a change in side effects since administering the vaccine recently to Nova Scotia volunteers, said Maycock.

The vaccine dose in the Switzerland trial is three times higher than the highest dose used in Halifax, said the Canadian Centre for Vaccinology in a news release late Thursday afternoon.

The centre said Canadian researchers are aware of the pause in Switzerland and will stay in touch with researchers at all Ebola vaccine trial sites. They will also inform Canadian participants in the study why Swiss researchers put their study on hold.

The Halifax trial is using the same vaccine as the Swiss trial, but it is at an earlier stage in its results. 

In Switzerland, the symptoms were reported 10 to 15 days after vaccination.

In Halifax, as of the end of last week, volunteers hadn't all been administered their shots.

The goal of Halifax researchers is to vaccinate 40 volunteers. As of Dec. 5, 65 participants had been screened and 28 had been vaccinated, Maycock said.

In Halifax, preliminary data on the vaccine's safety should be available by the end of December, said IWK spokesperson Mary Appleton. 

The full observation period is six months from the vaccination date, but some information on the volunteers' immune response should be available by the end of January. Researchers in Halifax will be sharing their preliminary data with other researchers as they receive it, said Appleton.

The vaccine was developed by the Canadian government at its laboratory in Winnipeg and is licensed to two American companies. Another type of Ebola vaccine was developed in the United States and its trials began earlier this year, according to the World Health Organization.

At the end of November, the Associated Press reported that the U.S. vaccine appeared to be safe and to trigger an immune response in the first 20 volunteers to test it.

In Switzerland, officials will stop giving the vaccine next week to learn more about the data and consult with others running similar trials around the world, including in Halifax. They plan to resume it in January, according to the Associated Press.