An interesting article published in Nature magazine by Heidi Ledford raises hope that one day malaria vaccine may prove to be an effective weapon against one of the world’s biggest killers of children.
In a trial of 450 children aged 5-17 months, the vaccine called R21 was up to 77% effective at preventing malaria over the course of one year which, if confirmed, results in 75% effectiveness target set by the World Health Organisation.
This vaccine is a modified form that has already been deployed in an ongoing study in 100s of 1000s of children in Malawi, Kenya and Ghana.
The vaccine there called RTS.S is about 56% effective at one year and 36% effective over four years.
RT1 was designed to be both more potent and cheaper to produce than RTS.S.
Researchers are planning to test R21 in a larger trial of 4,800 children which is due to start next week.
The Serum Institute of India has pledged to produce at least 200 million doses of the vaccine each year if it is eventually authorised for use.
It has taken many years for a vaccine that meets WHO’s efficacy to be produced. A part of the problem has been low investment in preventing a disease that affects predominantly low and middle income countries. Another issue is that the malaria parasite itself has a complex lifestyle and the ability to mutate key proteins generating fresh strains.
Malaria kills about 400,000 people a year, most of them are infants and children under the age of 5.
These vaccines target the malaria parasite in the sporozoite phase of its life cycle. This is the phase in which it enters the human body from its mosquito host.
The vaccines include a protein secreted by the parasite at that stage in the hope of stimulating an antibody response against it.
R21 has a higher concentration of these proteins.
Both vaccines have an adjuvant that the R21 is easier to make and hopefully cheaper.
This adjuvant boosts the immune response to vaccination.
The durability of the vaccines is yet not known.
The author suggests that the R21 results are encouraging and when coupled with other preventative measures such as effective mosquito control, even a vaccine with less than 75% efficacy would help to reduce deaths.
This is an exciting development in an area where no previous vaccination has existed.
The London General Practice, a leading London doctors’ clinic provides full travel advice and pre travel vaccination with all current approved vaccines in the United Kingdom.
It also offers a full COVID testing service including fit to fly, test for release, day five, day two and day eight mandatory COVID tests and a rapid antigen service and same day PCR testing.
Dr Paul Ettlinger
BM, DRCOG, FRCGP, FRIPH, DOccMed