Polio Contagiousness: Transmission, Risk & Prevention

Poliovirus spreads person-to-person via:

• Fecal-oral route: Contaminated water, food, hands (primary).
• Oral-oral route: Saliva, respiratory droplets.

Contagious Period

• Most infectious 7–10 days before/after symptom onset.
• Virus shed in feces for up to 6 weeks (sometimes longer).

Key Facts

• Enters via mouth → replicates in throat/gut → can invade CNS → paralysis.
• Asymptomatic carriers can transmit.
• Vaccinated individuals (IPV) are protected from disease but can still carry/shed virus (gut immunity incomplete).
• OPV (oral) provides intestinal immunity but rare risk of vaccine-derived polio.

Prevention

• Universal vaccination (IPV in most countries).
• Sanitation, clean water, hand hygiene.
• Outbreak response: supplemental immunization.

Global eradication efforts continue; polio remains endemic only in Afghanistan and Pakistan (as of 2024).