Effective does not mean realistic – the challenge of malaria vaccines

“This is a scientific advance rather than a practical one,” said Dr. William Schaffner, of Vanderbilt University’s Medical School to the New York Times. So goes the fate of the latest in research reports on efforts to develop a malaria vaccine.  Prof. Schaffner goes on to explain that, “Giving multiple IV doses of any vaccine is also impractical because it requires sterile conditions, trained medical personnel and follow-up. IV drips are particularly hard to administer to children.”

It seems that every possible media outlet in the planet picked up on the fact that this intravenous dose of irradiated/killed malaria parasites was 100% effective. Most though did not see this as just one more step in understanding the long string of immunological research processes needed to come up with a vaccine that can actually work under real life field conditions.

recent-dhs-reports-on-child-immunization-coverage-sm.jpgJust last year, hopes crashed on a long-tested malaria vaccine known as RTS,S that had been through clinical trials in several African countries.  Not only did the vaccine need to be administered three times, but even then achieved limited effectiveness, though severe malaria appeared to have been reduced by around 50%. Just last year unfortunate results from monitoring showed that over time the vaccine lost the effectiveness it initially achieved.

It had been hoped that if this or another successful vaccine candidate could be ready for scale up, that it could be integrated into the existing child immunization programs of malaria endemic countries. Findings from recent Demographic and Health Surveys shown here remind us that even vaccines that have been routinely delivered to children for decades still have problems achieving adequate coverage.  Two of those depicted, DPT and Polio, like the RTS,S required three doses. This is a logistical and management challenge to be sure, but also a social, cultural and behavioral one.

The vaccine search goes on with several research reports appearing monthly on new findings about human immune responses to malaria in it various forms.  We trust that one day a vaccine that is effective as the existing child immunizations will come to market. Even then, as we can see from ‘normal’ vaccine coverage rates, we will not be able to rely totally on a malaria vaccine for preventing the disease. Of course none of the existing preventive measures reaches all people, and hence our malaria elimination strategies must continue to include a combination of approaches.

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