Reversible Resistance: What Three National Reversals Teach Stewardship Programmes

Antimicrobial resistance is conventionally narrated as a one-way ratchet: drug pressure selects resistant variants, the variants persist, and the curve rises or at best plateaus. The upward direction is fast—mass azithromycin distribution in Niger left pneumococcal macrolide resistance at 12·3% after 24 months, versus 2·9% in placebo communities [1]. The downward direction is barely documented—a decline is credible only where surveillance survives to record it. Yet between 1992 and 2019, three national interventions produced population-level reversals, each pairing a policy change with a measured fall in selection pressure.