Malaria vaccine breakthrough
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The Jenner Institute at Oxford University is conducting Phase III trials of a malaria vaccine – R21/Matrix-M – in northern Tanzania. The vaccine has shown a high-level efficacy of 77 percent
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1. Transmission:
Bite by Anopheles mosquito – infected with one of four Plasmodium parasites – injects malaria sporozoites into blood

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Small blood vessels in skin
Sporozoites

R21/Matrix-M: R21 vaccine is combined with Matrix-M – adjuvant which boosts antibody response from immune system

Vaccine: Targets circumsporozoite protein (CSP) on surface of sporozoite. R21 induces attack with CSP-specific antibodies to block liver stage

2. Infection: Sporozoites travel via blood to liver where they invade hepatocytes – main cell type in liver

3. Liver stage: Infected hepatocytes rupture, each releasing around 20,000 merozoites

3 2 LIVER Merozoites
Gametocytes
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4. Merozoites: Infect red blood cells to replicate. Cells burst, releasing merozoites to infect more red cells

5. Sexual cycle: Some merozoites produce gametocytes. If mosquito bite infects human,
gametocytes eventually produce new sporozoites. Cycle begins again
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Sources: University of Oxford, CDC, Harvard University, The Lancet
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