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Ebola vaccines developed by Johnson & Johnson and Merck & Co produced virus-fighting antibodies and appear to be safe in children and adults, according to data from two studies conducted in West Africa.

Both companies’ vaccines produced antibodies 14 days after the first of two shots and were detectable at varying levels in both children and adults for one year, data from the studies published on Wednesday showed.

The results were published in The New England Journal of Medicine. The vaccines are designed to target the Zaire strain of the virus, not the Sudan strain of Ebola that recently caused an outbreak and at least 56 deaths in Uganda.

One regimen tested a dose of Johnson & Johnson’s vaccine, followed by a booster shot of a vaccine from Danish drugmaker Bavarian Nordic, while another tested two doses of Merck’s vaccine with eight weeks in between. A third option followed the first Merck dose with a placebo.

“I think the study shows that both the vaccines elicit good antibody responses,” said Dr H Clifford Lane, one of the researchers and a clinical director at the United States National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health (NIH).