London, Sep 15 : The two-dose vaccine against Ebola virus developed by US drug maker Johnson and Johnson is safe, well tolerated and produces a strong immune response in people over the age of one, according to two new papers published in The Lancet Infectious Diseases.

The study provides important further evidence for the potential of the regimen using the Ad26.ZEBOV and MVA-BN-Filo vaccines to be used as a protective measure against Ebola virus disease for both children and adults.

The researchers from London School of Hygiene and Tropical Medicine (LSHTM) and Sierra Leone's College of Medicine and Allied Health Sciences (COMAHS) found that the vaccine regimen was well tolerated and induced antibody responses to Zaire ebolavirus 21 days after the second dose in 98 per cent of participants, with the immune responses persisting in adults for at least two years.

During the 2014-16 outbreak of Ebola in West Africa, 28,652 cases and 11,325 deaths from Ebola were reported. Approximately 20 per cent of cases were in children under 15 years, and children younger than five years are at a higher risk of death than adults.

"This study represents important progress in the development of an Ebola virus disease vaccine regimen for children, and contributes to the public health preparedness and response for Ebola outbreaks," said Dr Muhammed Afolabi, Assistant Professor at LSHTM.

"The results show that this vaccine regimen has the potential to save many young lives," he added.

For the clinical trial, divided into two stages, the team recruited participants from September 2015 to July 2018. In stage one, which aimed to gain initial information about the vaccine regimen's safety and immunogenicity, 43 adults aged 18 years or older received the Ad26.ZEBOV vaccine followed by the MVA-BN-Filo vaccine after 56 days.

In stage two, 400 adults and 576 children and adolescents (192 in each of the three age cohorts of 1-3, 4-11 and 12-17 years of age) were vaccinated with either the Ebola vaccine regimen (Ad26.ZEBOV followed by MVA-BN-Filo) or a single dose of a meningococcal quadrivalent conjugate vaccine followed by placebo on day 57.

Adults participating in stage one of the study were offered a booster dose of A26.ZEBOV two years after the first dose which induced a strong immune response within seven days.

J&J's two-dose Ebola vax regimen safe: Study