Two clinical studies have shown the efficacy of a combination regimen of Ebola virus vaccines. The results of both the first and second trials are published in The Lancet Infectious Diseases.
In two studies in Sierra Leone – among children 1 to 17 years old and among adults over 18 years old – the EBOVAC1 consortium evaluated the combined effects of two drugs: the Ad26.ZEBOV vaccine from Johnson & Johnson and the Danish company Bavarian Nordic MVA-BN -Filo. During the first phase, 43 adults received the second vaccine 56 days after the first. In the second, 400 adults and 576 children were vaccinated with either this combination of vaccines or received a dose of meningococcal conjugate vaccine and placebo. The first stage participants were offered a booster dose of Ad26.ZEBOV.
The vaccine was found to be well tolerated and provided a humoral – antibody-linked – immune response to the Ebola virus 21 days after receiving the second drug in 98 percent of study participants. The immune response has been present in adult participants for at least two years.
In March 2021, the WHO Strategic Advisory Group of Experts on Immunization recommended the use of both a combination of Johnson & Johnson and Bavarian Nordic vaccines and a Merck product for Ebola vaccination.
