Polio Transmission: How the Poliovirus Spreads & Prevention

Poliovirus (an enterovirus) spreads via the fecal‑oral route and, less commonly, respiratory droplets.

Transmission Pathways

• Ingestion of contaminated food/water (poor sanitation).
• Contact with infected feces (diaper changing, inadequate handwashing).
• Oral‑oral spread via saliva (kissing, shared utensils).

The virus replicates in the oropharynx and gut, shedding in feces for weeks. Most infections are asymptomatic; <1% progress to paralytic poliomyelitis.

Prevention

Vaccination is the cornerstone:

• IPV (Inactivated Polio Vaccine): Injectable; used in most countries; induces humoral immunity.
• OPV (Oral Polio Vaccine): Live attenuated; induces gut mucosal immunity; used in eradication campaigns; rare risk of vaccine‑derived poliovirus.

Global eradication efforts (GPEI) have reduced cases by >99% since 1988. Continued vaccination, surveillance, and outbreak response are essential to achieve a polio‑free world.