Ebola vaccine proven to be 100 percent effective

Kaye Garcia Monday, December 26, 2016

A new Ebola vaccine was proven to be 100 percent effective against the lethal disease, based on final trials in Guinea and Sierra Leone.

According to a study published in The Lancet, no cases of Ebola were identified in Guinean trial participants who were vaccinated with rVSV-ZEBOV immediately after exposure to a person afflicted with Ebola. This suggests that the new vaccine provides 100 percent protection against the illness.

A health worker enters a tent in an Ebola virus treatment center in Conakry, Guinea, November 17, 2015. | Reuters/Saliou Samb

The Lancet research involved 11,841 participants from Guinea in 2015. About 5,837 subjects were administered with the vaccine immediately after getting into contact with an Ebola patient, and none of them contracted the disease 10 or more days later. Meanwhile, 23 Ebola cases were reported out of the thousands of others who did not receive the vaccine immediately after exposure.

The new vaccine is not without limitations. Two of the subjects who received it had serious reactions, but most reported mild side effects such as headaches, muscle aches, and fatigue.

The vaccine also offers protection only against strains under the Zaire group. It does not cover other strains of Ebola, including the deadly Marburg virus.

It was over a decade ago when Canada's Public Health Agency and the United States Army developed rsVSV-ZEBOV, which is now licensed to Merck, Sharp & Dohme.

The World Health Organization, the Guinean Health Ministry, and the Institute of Public Health of Norway led the Ebola trial, in collaboration with other institutions.

The vaccine has yet to receive approval from any regulatory authority, but Merck has committed an emergency stockpile of 300,000 doses that may be used in case another outbreak happens, according to The New York Times.

Ebola has been around since 1976, when the virus was discovered in the former Zaire. However, a sense of urgency to formulate an effective vaccine came about only after the 2014 outbreak, which resulted in 11,000 deaths in Africa.

"While these compelling results come too late for those who lost their lives during West Africa's Ebola epidemic, they show that when the next outbreak hits, we will not be defenseless," said study lead author Marie-Paule Kieny, who is also World Health Organization's assistant director-general for health systems and innovation, as quoted by The New York Times.