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). www.vanguardngr.com/2015/04/malaria-end-in-sight-as-who-sets-to-approve-1st-human-vaccine/