What is significance of finding of first case of polio in US in a decade?

Recently, the first case of Polio was reported in United States, nearly after a decade. An unvaccinated young adult from New York contracted polio and has developed paralysis. He developed symptoms around June 2022, even though he did not travel outside the country. Thus, it is likely that, he got contracted to vaccine-derived strain of the polio virus, perhaps from someone who received live vaccine.

History of Polio in US:

  • In Past, Polio was one the most feared diseases in US. It caused thousands of cases of paralysis annually, many being children. Vaccination against polio was started in 1955.
  • The national vaccination campaign reduced the number of cases in US to below 100 in 1960s and to below 10 in 1970s.
  • Polio was declared eliminated from US, in 1979. It meant that, there was no routine spread of the virus.
  • However, some travellers brought polio infection in the country in 2013.

Types of polio vaccines:

There exist two types of polio vaccines. U.S. uses vaccines made of inactivated version of the virus. But some countries use weakened live virus given to children as drops in mouth. In such countries, polio has become a more recent threat. In some cases, the weakened virus can mutate and become capable of triggering new outbreaks. In US, children are still administered the inactivated vaccine against polio. Four doses are recommended by officials-

  • First to be given at age of 2 months
  • Second at 4 months
  • Third during 6 to 18 months
  • Fourth during 4 to 6 years.

Spread of Polio:

Polio usually spreads from person to person or via contaminated water. It infects the spinal cord of person, causing paralysis, permanent disability or death. It mostly affects children. The disease is endemic to Afghanistan and Pakistan. Countries in Africa, Middle East and Asia have reported some cases in recent years.




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