A large-scale pilot of what has been called the world's first malaria vaccine to give partial protection to children has begun in the African country of Malawi, reports the BCC.
The RTS,S vaccine trains the immune system to attack the malaria parasite, which is spread by mosquito bites.
Earlier, smaller trials showed that nearly 40 percent of the 5-to-17-month-olds who received it were protected, says the report.
Malaria cases appear to be on the rise again after a decade of success in combating the deadly disease.
"This is a landmark moment for immunisations, malaria control, and public health," Dr Kate O'Brien, Director of Immunisation and Vaccines at the World Health Organization, told the BBC.
According to the most recent annual figures, global malaria cases are no longer falling, sparking concerns about its resurgence.
Malaria kills some 435,000 people around the world each year, the majority of them children. Most of these deaths are in Africa, where more than 250,000 children die every year, according to the World Health Organization (WHO).
RTS,S has been more than three decades in the making, with scientists from drugs company GSK creating it in 1987.
Years of testing supported by a host of organisations, including the Path Malaria Vaccine Initiative, and costing an estimated $1 billion, have led to this point.
The vaccine needs to be given four times - once a month for three months and then a fourth dose 18 months later.