I continue my visit to Kenya, now in Nairobi, and have now seen and been bitten by mosquitos. Unpleasant, but not a disease threat. With a planned visit the Turkana the article in Malaria World reporting ‘Prevention Trial Cuts Malaria Cases in Children by 70 Percent’ by a team from Duke University led by Duke Global Health Institute professor Wendy Prudhomme O’Meara caught my attention. However, it was only a preliminary report. I asked Dr O’Meara for a research paper to review the details of the methods and analysis. She promptly and politely responded that publication was delayed by current funding crisis related to the future of USAID.
So instead my attention was drawn to the subject of vaccines, which I have addressed before, (here, here, here, here and here), but not to any particular article. But rather to the number of articles (six). The first is a press release from WHO, ‘Child health improves in Cameroon one year after malaria vaccine introduction’. A 20% reduction in cases from 2023 to 2024 is reported but there is no clear linkage to the vaccine. And of course correlation does not imply causation.
The second (and first research paper) ‘Acceptability of the R21/Matrix-M malaria vaccine alongside existing malaria interventions in the trial context’ by Diawara et al examine the acceptability of the R21/Matrix-M vaccine in Mali. They found it generally acceptable but article adds nothing on safety of effectiveness.
The third ‘Malaria vaccine introduction in Africa: progress and challenges’ by Impouma et al. This Lancet article discusses the roll-out of malaria vaccines RTS,S/AS01 and R21/Matrix-M in the first year of malaria vaccine implementation, examining achievements, challenges, and strategic opportunities. A discussion article adding little new.
The fourth ‘Genetically attenuated parasites show promise as a next-generation malaria vaccine’ by Hafalla et al discussed genetically modified parasite use in vaccine. I covered this topic recently here. It is early stage of experimentation.
The fifth ‘Malaria: Factors affecting disease severity, immune evasion mechanisms, and reversal of immune inhibition to enhance vaccine efficacy’ by Su et al is a review of the challenges developing malaria vaccines.
The sixth ‘The R21/Matrix-M malaria vaccine: questions remain’ by Aaby et al has the most interesting finding. In a letter to the Lancet they report that supplementary material of Dattoo study previously discussed reports 18 deaths—15 in the experimental group and three in the control group and state it is not significant. The statistics reported suggest otherwise (relative risk 2·50, 95% CI 0·72–8·62; Fisher exact test, p=0·21). They also state that it is important to know the correct number of deaths in both the vaccine and the control group and by sex.
And note – the control group was not even a true control, but recipients of a rabies vaccine.