Polio (Poliomyelitis)

A crippling disease on the brink of global eradication. Two effective vaccines—Salk (IPV) and Sabin (OPV)—have brought the world close to elimination.

Overview

Poliomyelitis (polio) is a highly infectious viral disease that primarily affects children under 5 years of age. The virus is transmitted through contaminated water and food and multiplies in the intestine. In approximately 1 in 200 infections, the virus invades the nervous system, causing irreversible paralysis (WHO, 2024).

Global polio eradication remains a top public health priority. The WHO's Global Polio Eradication Initiative (GPEI), launched in 1988, has reduced cases by 99.9%. As of 2024, wild poliovirus remains endemic in only two countries: Afghanistan and Pakistan (CDC, 2024).

The United States has been polio-free since 1979. However, the threat of importation remains, making continued vaccination critical.

Vaccines: Salk vs Sabin

IPV (Inactivated - Salk)

  • Type: Inactivated (killed) virus
  • Introduced: 1955
  • Administration: Injection
  • Protection: Induces humoral immunity
  • Advantages: Safe for immunocompromised
  • U.S. Status: Used exclusively since 2000

OPV (Oral - Sabin)

  • Type: Live attenuated virus
  • Introduced: 1961
  • Administration: Oral drops
  • Protection: Humoral and intestinal immunity
  • Advantages: Easier administration, spreads
  • Global Use: Still used in endemic countries

CDC Recommendations (U.S.)

The U.S. uses IPV exclusively. Children receive doses at 2 months, 4 months, 6-18 months, and 4-6 years. Adults who are unvaccinated or have unknown status should receive 3 doses.

Sources & Citations

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