Two Ebola vaccines show immune response lasting for at least a year, says study

Two shots that protect against Ebola virus yielded immune responses lasting for at least a year, according to a study suggesting they might keep the virus at bay for the long-term.

Researchers studied the vaccines, one from Merck & Co. and a two-dose regimen from Johnson & Johnson and Bavarian Nordic A/S, in 1400 adults and 1401 children enrolled from April to December 2018, according to a report from the Partnership for Research on Ebola Vaccinations research consortium.

People responded to the shots within two weeks of receiving them, and the highest rate of response was achieved by the Merck vaccine plus a booster, according to the study published Wednesday in the New England Journal of Medicine.

Ebola has been a thorn in the side of health officials as it continues to emerge unpredictably in African countries. The World Health Organization is working with Uganda to fight a vaccine-resistant Ebola strain called Sudan that’s caused more than 140 confirmed cases and 55 deaths there. While the shots studied in this trial haven’t shown an ability to prevent the Sudan strain, they may provide a foundation for developing vaccines that do, according to Cliff Lane, a National Institute of Allergy and Infectious Diseases deputy director who helped write the study.

Merck’s Ervebo vaccine for Ebola is already licensed in the US, and the J&J-Bavarian regimen has pre-qualification from the WHO. The trial only assessed immune responses that indicate the potential for protection, but it was unable to compare rates of infection in immunized and non-immunized people. There were no safety concerns found in the trial, according to the report.