Every difference between a live and a killed viral vaccine falls out of one fact: the live one still replicates inside you. That single property explains every trade-off, with polio at its heart: the vaccine that beat the disease, and the rare reversion that now drives most of what remains.
Who's who
- Jonas Salk+1 more episodeDeveloper of the inactivated polio vaccine
- Albert Sabin+1 more episodeDeveloper of the live oral polio vaccine
Where it happens
- UgandaSite of a rare neurovirulent nOPV2 strain reported in 2025
Timeline
- Mid-1950sSalk's injected, inactivated polio vaccine licensed
- c. 1960Sabin's live oral polio vaccine licensed and becomes the global workhorse
- 1988Global Polio Eradication Initiative launched
- 2015Wild type 2 poliovirus declared eradicated
- 2020WHO grants nOPV2 an Emergency Use Listing
- February 2026WHO prequalifies nOPV2 from a second manufacturer
Still debated
nOPV2 reverts far less than the older Sabin type 2, but a rare dangerous recombinant reported in 2025 shows the risk is not zero. How and when to withdraw all oral polio vaccine in favor of inactivated vaccine remains an active programmatic debate.
