Polio

Nigerian family on a motorcycle receiving the polio vaccine. By Lisa K. Esapa.
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Polio, or poliomyelitis, is a crippling and potentially deadly infectious disease caused by a virus that spreads from person to person invading the brain and spinal cord which can lead to paralysis. 1 in 200 infections leads to irreversible paralysis. Of those paralyzed, 5% to 10% die when their breathing muscles become immobilized. Additionally, even children who seem to fully recover can develop new muscle pain, weakness, or paralysis as adults, 15 to 40 years later. This is called post-polio syndrome.

There is no cure, but there are safe and effective vaccines to prevent polio infection. Polio vaccine protects children by preparing their bodies to fight the polio virus. Almost all children (99%) who get all the recommended doses of vaccine will be protected from polio. Therefore, the strategy to eradicate polio is based on prevention by immunizing every child to stop transmission and ultimately make the world polio-free.

What is the global impact of polio?

• Since 1988, more than 18 million people can walk today who would otherwise have been paralyzed, and 1.5 million childhood deaths have been averted thanks to the polio vaccine.
• Four regions of the world are certified polio free—the Americas, Europe, South East Asia and the Western Pacific.
• In August 2019, Nigeria marked three years without wild polio, opening the door for certification of the WHO AFRO region.
• In October 2019, the certification of eradication of the type-three wild poliovirus (WPV3) signifies that the world has wiped out two (WPV2 AND WPV3) of the three wild polio strains—leaving just one more (WPV1) to go.
• In 2019, cases of wild polio have increased relative to 2018, and outbreaks of vaccine-derived polio continue to spread across parts of Africa and Asia.
• If a population is seriously under-immunized, vaccine-derived poliovirus can begin to circulate in a community. Circulating vaccine-derived polioviruses (cVDPVs) are extremely rare forms of poliovirus, which has circulated for a prolonged period of time uninterrupted and can mutate over the course of 12-18 months.

Who is at risk?

• When you look at where wild polio cases or vaccine-derived poliovirus cases are arising today, they are all in places of unrest and with varying complex scenarios or limited access – Somalia, DRC, Lake Chad region, Syria, Pakistan, and Afghanistan.
• Most people who get infected with poliovirus (about 72 out of 100) will not have any visible symptoms. Poliovirus is highly contagious, and people who don’t have symptoms can still pass the virus to others and make them sick.
• About 1 in 4 people infected with poliovirus will experience flu-like symptoms, such as sore throat, fever, tiredness, nausea, headache, and stomach pain.
• A smaller proportion of people with poliovirus infection will develop other more serious symptoms that affect the brain and spinal cord, such as paresthesia (feeling “pins and needles” in the legs), meningitis, and paralysis.
• Polio anywhere is a risk to people everywhere. All countries will be at risk of polio importation until it is eradicated globally by preventing infection through vaccination.

What is CDC doing?

• CDC and its international partners have made significant progress over the past 26 years. Through the Global Polio Eradication Initiative, CDC:
  • Works jointly with WHO and national Ministries of Health to plan and monitor polio’s spread and immunization activities in multiple countries worldwide
  • Evaluates risk and conducts assessments with GPEI partners for the Independent Monitoring Board, which meets quarterly to review performance of at-risk countries towards achieving polio eradication milestones
  • Promotes innovation and conducts research to improve immunization against polio and means to detect polio cases
  • Supports all 145 member labs in the Global Polio Laboratory Network with critical diagnostic services and genomic sequencing of polioviruses to help guide disease control efforts in many countries
  • Performs applied research for supplemental immunization activities
  • Deploys personnel and resources to support country eradication efforts
  • Trains and deploys international consultants to WHO and UNICEF through the Stop Transmission of Polio (STOP) Program

CDC is working to help stop this crippling disease forever and ensure the lessons learned and polio infrastructure continue to pay dividends to keep Americans safe and save lives around the world. For example, polio infrastructure supports health priorities beyond polio, including in these recent emergency response efforts: Ebola, cholera, measles, Marburg virus and Yellow Fever.