LONDON — The world's first viable malaria vaccine could be available by as early as October, after final trial results showed it can potentially prevent millions of cases of the deadly disease every year.
The vaccine candidate (RTS,S/AS01) is the first to reach phase 3 clinical testing and is partially effective against clinical disease in young African children up to 4 years after vaccination, according to final trial data published in The Lancet journal.
The results suggest that the vaccine could prevent a substantial number of cases of clinical malaria, especially in areas of high transmission.
The findings show that vaccine efficacy against clinical and severe malaria was better in children than in young infants, but waned over time in both groups.
However, protection was prolonged by a booster dose, increasing the average number of cases prevented in both children and young infants.
"Despite the falling efficacy over time, there is still a clear benefit from RTS,S/AS01," Brian Greenwood, corresponding author and Professor of Clinical Tropical Medicine at London School of Hygiene & Tropical Medicine in the UK said.
"An average 1,363 cases of clinical malaria were prevented over 4 years of follow-up for every 1,000 children vaccinated, and 1,774 cases in those who also received a booster shot.
"Over 3 years of follow-up, an average 558 cases were averted for every 1,000 infants vaccinated, and 983 cases in those also given a booster dose," said Greenwood.
"Given that there were an estimated 198 million malaria cases in 2013, this level of efficacy potentially translates into millions of cases of malaria in children being prevented," Greenwood added.
The RTS,S/AS01 vaccine was developed for use in sub-Saharan Africa where malaria still kills around 1,300 children every day. There is currently no licensed vaccine against malaria anywhere in the world.
The phase 3 randomised trial enrolled 15,459 young infants (aged 6 to 12 weeks at first vaccination) and children (5 to 17 months at first vaccination) from 11 sites across seven sub-Saharan African countries (Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and United Republic of Tanzania) with varying levels of malaria transmission.
In 2014, initial phase 3 results at 18 months showed vaccine efficacy of about 46 per cent against clinical malaria in children and around 27 per cent among young infants.
"The European Medicines Agency (EMA) will assess the quality, safety, and efficacy of the vaccine based on these final data. If the EMA gives a favourable opinion, WHO could recommend the use of RTS,S/AS01 as early as October this year. If licensed, RTS,S/AS01 would be the first licensed human vaccine against a parasitic disease," Greenwood added.