By Sola Ogundipe & Gabriel Olawale
THE end to malaria infection is in sight as the first malaria vaccine candidate to reach phase-3 of clinical testing, and found to partially protect children against the disease up to four years after vaccination, is set to be available by October this year, scientists have reported.
Giving the hint about this development yesterday, Brian Greenwood, corresponding author and Professor of Clinical Tropical Medicine at London School of Hygiene & Tropical Medicine in the UK, explained that results of the tests suggested that the vaccine candidate known as RTS, S/AS01 could prevent a substantial number of cases of clinical malaria, especially in areas of high transmission.
Greenwood noted that the European Medicines Agency, EMA, will “assess the quality, safety, and efficacy of the vaccine based on these final data. There is currently no licensed vaccine against malaria anywhere in the world.”
If the EMA gives a favourable opinion, the World Health Organisation 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.
The findings, published in the journal, The Lancet, revealed 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.
Further, Greenwood argued that despite the falling efficacy over time, there is still a clear benefit from RTS,S/AS01.
“An average of 1,363 cases of clinical malaria were prevented over four years of follow-up for every 1,000 children vaccinated, and 1,774 cases in those who also received a booster shot. Over three 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.
“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,” he said.
The RTS,S/AS01 vaccine was developed for use in sub-Saharan Africa where malaria still kills around 1,300 children every day. The phase-3 randomised trial enrolled 15,459 young infants (aged six to 12 weeks at first vaccination) and children (five 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.
In this study, members of the RTS, S/AS01 Clinical Trials Partnership followed up the infants and children for a further 20 to 30 months, respectively, and assessed the impact of a fourth booster dose.
Participants were each vaccinated three times with RTS,S/AS01 with or without a booster dose 18 months later, or given four doses of a comparator vaccine (control group).
Comments expressed here do not reflect the opinions of Vanguard newspapers or any employee thereof.