The pathogen shapes the tool: toxoids that neutralize a bacterial weapon, conjugate vaccines that finally protect infants, and the hard case of malaria, plus the century-old humility of the tuberculosis vaccine. The episode shows how vaccination works against bacteria and parasites.
Timeline
- c. 1924Tetanus toxoid developed by chemically inactivating the toxin
- c. 1990First Hib conjugate vaccines licensed for infants
- 2000First pneumococcal conjugate vaccine introduced for U.S. infants
- October 2021WHO recommends RTS,S, the first malaria vaccine and first against a human parasite
- October 2023WHO recommends the R21/Matrix-M malaria vaccine
Still debated
Malaria efficacy figures come from separate trials with different schedules and settings and should not be ranked against each other, and real-world durability is still being learned. Pneumococcal serotype replacement drives ever-higher-valency vaccines, and whether future approaches can beat the parasite's defenses is open.