“The initial results give us reason to believe this could be the first effective Ebola vaccine developed,” says John-Arne Røttingen, Director of the Division of Infectious Disease Control at the Norwegian Institute of Public Health and head of the study’s steering committee. Røttingen is also Professor of Health Policy at the University of Oslo and Professor of Global Health at the Harvard School of Public Health.
The vaccine study, which began at the end of March this year, was done in collaboration between the health authorities in Guinea, the World Health Organization (WHO), Doctors Without Borders, and the Norwegian Institute of Public Health. So far, approximately 4000 participants have been recruited for the study.
During the study, researchers vaccinated a “ring” of people around new Ebola cases, meaning typically the village or neighbourhood in which the infected person lives.
A randomly selected half of these “rings” were given the vaccine immediately, while the other half of rings receives the vaccine 21 days later. The number of infected cases among those vaccinated immediately was then compared to the number of cases identified in the group with delayed vaccination. This enabled researchers to measure the protective effect of the vaccine, while at the same time making sure that all participants were offered the vaccine.
“None of the participants receiving immediate vaccination have become ill so far, 10 days after the vaccine was given and expected to work,” says John-Arne Røttingen.
In the control group, however, where participants received the vaccine 21 days later, there were several Ebola cases. This could indicate that the vaccine provides complete protection against Ebola, Røttingen continues.
Because of this, an independent committee in charge of surveilling the participants’ safety and the outcomes of the study has concluded not to continue with the delayed vaccination. This means discontinuing the control-arm of the study and instead continuing the study and offer vaccines immediately to all contacts of Ebola-infected people.
“From a strictly scientific point of view we would want more solid data, but from a public health perspective as well as for ethical reasons we have decided to proceed with immediate vaccination of all rings and to publish the interim results,” Røttingen adds.
Røttingen emphasizes that the study will continue to gather more data, due to the low number of participants, and in order to follow up on everyone recruited and vaccinated.
“In this way we wish to make sure that the evaluation of the effect of the Ebola vaccine is even further strengthened,” says Røttingen. “The final results of the study with full follow up will be published at a later point.”
Guinea is one of the countries in West Africa which were most severely affected by the Ebola epidemic. As of early July 2015, more than 11 000 people have died from the disease, 2 500 of which died in Guinea.
The continuation of the study could contribute to controlling the still ongoing outbreak in Guinea, and ring vaccination could be relevant for new cases also in Sierra Leone.
The study is carried out in close collaboration with the health authorities of Guinea, the World Health Organization (WHO) and Doctors Without Borders /Epicentre. It is financed by the Norwegian Ministry of Foreign Affairs through the Norwegian Research Council, as well as by the Wellcome Trust and Canadian health authorities. In addition, Doctors Without Borders, WHO and the Norwegian Institute of Public Health have invested considerable resources.
Røttingen says the Ebola vaccine will most likely be licensed and available on the market at the earliest in 2016, once necessary approval procedures have been carried out. Recommendations on use are decided by the WHO Strategic Advisory Group of Experts (SAGE), and implementation is decided by health authorities in each country. It will most likely be used in ring vaccination in future Ebola outbreaks.