History of Polio in Timeline

Polio, or poliomyelitis, is an infectious disease caused by the poliovirus. While many cases are asymptomatic, symptoms can range from mild, such as sore throat and fever, to severe, including headache, neck stiffness, and paresthesia. Paralysis, which can be permanent and potentially fatal, is a less common but serious outcome. Post-polio syndrome, characterized by muscle weakness, can also emerge years after the initial infection.

1900: Paralytic polio epidemics appear in Europe and the United States

Around 1900, small localized paralytic polio epidemics began to appear in Europe and the United States.

1909: Polio virus identified

In 1909, the poliovirus, which causes poliomyelitis, was first identified by Austrian immunologist Karl Landsteiner.

1911: First recorded use of the term "polio"

In 1911, the abbreviated version of poliomyelitis, "polio," was first recorded for use in the Indianapolis Star newspaper.

1950: Peak age incidence of paralytic poliomyelitis shifts

By 1950, the peak age incidence of paralytic poliomyelitis in the United States had shifted from infants to children aged five to nine years, when the risk of paralysis is greater.

1950: Gamma globulin purified for polio treatment

In 1950, William Hammon at the University of Pittsburgh purified the gamma globulin component of the blood plasma of polio survivors, proposing its use to halt poliovirus infection.

1952: Development of the inactivated polio vaccine (IPV)

In 1952, Jonas Salk at the University of Pittsburgh developed the inactivated polio vaccine (IPV).

1952: Polio epidemic in the United States and establishment of respiratory centers

In the United States, the 1952 polio epidemic became the worst outbreak in the nation's history and respiratory centers, precursors to modern intensive care units (ICU), were first established at the Blegdam Hospital of Copenhagen.

April 1955: Announcement of the Salk vaccine

On April 12, 1955, Jonas Salk announced the development of his inactivated polio vaccine to the world.

1957: Human trials of Sabin's vaccine began

In 1957, human trials of Albert Sabin's oral polio vaccine began.

1957: Polio Hall of Fame dedicated

In 1957, the Polio Hall of Fame was dedicated at the Roosevelt Warm Springs Institute for Rehabilitation in Warm Springs, Georgia, US, honoring fifteen scientists and two laymen who made important contributions to the knowledge and treatment of poliomyelitis.

1958: Sabin's vaccine selected by US National Institutes of Health

In 1958, Albert Sabin's oral polio vaccine was selected by the US National Institutes of Health over other live attenuated vaccines.

1961: Use of oral polio vaccine since 1961

Since 1961, the oral polio vaccine has been in use.

1962: Licensed oral polio vaccine

In 1962, the Sabin oral polio vaccine was licensed and rapidly became the only oral polio vaccine used worldwide.

1977: Number of people paralyzed by polio in the United States

In 1977, there were 254,000 persons living in the United States who had been paralyzed by polio.

1980: Smallpox declared eradicated

In 1980, smallpox was declared eradicated, marking a major achievement in global health.

1988: Efforts to eradicate polio started

In 1988, global efforts to completely eradicate poliomyelitis started.

1988: Global polio cases estimated at 350,000

In 1988, global incidence of wild polio was estimated to be 350,000 cases.

1988: Global Polio Eradication Initiative (GPEI) begins

In 1988, the Global Polio Eradication Initiative (GPEI) began, led by the World Health Organization, UNICEF, and The Rotary Foundation, aiming to eradicate polio worldwide.

1988: Estimated 350,000 polio cases

In 1988, there were an estimated 350,000 cases of polio.

1991: Last known case in the Americas

In 1991, the last known case of polio in the Americas was a boy in Peru.

1994: The Americas declared polio-free

In 1994, the Americas were declared polio-free.

1999: First outbreak in Syria

The polio outbreak in 2013 was the first outbreak in Syria since 1999.

2000: Elimination declared in Western Pacific countries

In 2000, polio was declared to have been officially eliminated in 37 Western Pacific countries, including China and Australia.

2001: Polio cases down to 483

In 2001, polio cases had been reduced to a low of 483 cases.

2001: Polio survivors with paralysis living in Germany, Japan, France, Australia, Canada and the United Kingdom

In 2001, there were approximately 40,000 polio survivors with varying degrees of paralysis living in Germany, 30,000 in Japan, 24,000 in France, 16,000 in Australia, 12,000 in Canada and 12,000 in the United Kingdom.

2002: Europe declared polio-free

In 2002, Europe was declared polio-free.

2003: Fatwa issued against polio vaccine

In 2003, a fatwa was issued in northern Nigeria declaring that the polio vaccine was designed to render children sterile.

2008: Organizations added to the Polio Hall of Fame

In 2008, four organizations (Rotary International, the World Health Organization, the U.S. Centers for Disease Control and UNICEF) were added to the Polio Hall of Fame.

2010: Wild poliovirus discovered in 13 countries

In 2010, wild poliovirus was discovered through importation in 13 different countries, including Chad, the Democratic Republic of Congo, and Nepal.

September 2011: Outbreak confirmed in China

In September 2011, an outbreak of polio was confirmed in China, involving a strain common in Pakistan, despite eradication ten years earlier.

2011: 80 cases of polio reported from 35 districts

In 2011, 80 cases of polio were reported from 35 districts in Afghanistan.

2011: Development of an improved oral vaccine began

In 2011, development began for an improved oral vaccine (Novel oral polio vaccine type 2 - nOPV2).

2011: Rinderpest declared eradicated

In 2011, rinderpest was declared eradicated.

2011: CIA ran fake vaccination clinic

In 2011, the CIA ran a fake hepatitis vaccination clinic in Abbottabad, Pakistan, in an attempt to locate Osama bin Laden, which destroyed trust in vaccination programs.

April 2012: WHO declares polio eradication a programmatic emergency

In April 2012, the World Health Assembly declared that the failure to completely eradicate polio would be a programmatic emergency for global public health.

2012: Return of polio in Syria

Polio likely returned to Syria in 2012 due to difficulties in executing immunization programs during the civil war.

November 2013: Confirmed cases among children in Syria

Between October and November 2013, 15 cases of polio were confirmed among children in Syria in Deir Ezzor.

2013: Attacks and deaths among vaccination workers

In 2013, attacks and deaths occurred among vaccination workers.

2013: Attack on health workers administering polio vaccine

In 2013, nine health workers administering the polio vaccine were targeted and killed by gunmen on motorcycles in Kano, Nigeria.

March 2014: Eradication of poliomyelitis in the South-East Asia Region

On March 27, 2014, the WHO announced the eradication of poliomyelitis in the South-East Asia Region, encompassing eleven countries.

2014: Cases dropped in Pakistan

From 2014 to 2018 cases dropped in Pakistan by 97 percent.

2014: Vaccinators killed

In 2014, 66 vaccinators were killed.

September 2015: Nigeria removed from polio-endemic list

In September 2015, Nigeria was removed from the polio-endemic list after more than a year without any cases.

2015: Polio remains naturally spreading in Pakistan and Afghanistan

By 2015, polio was believed to remain naturally spreading in only two countries: Pakistan and Afghanistan.

2015: WPV2 certified as eradicated

In 2015, wild poliovirus type 2 (WPV2) was certified as eradicated.

2016: Nigeria restored to polio-endemic list

In 2016, Nigeria was restored to the polio-endemic list when two cases of polio were detected.

2017: Cases caused by vaccine-derived poliovirus outnumber wild poliovirus cases

In 2017, for the first time, cases caused by vaccine-derived poliovirus (cVDPV) outnumbered wild poliovirus cases due to wild polio cases hitting record lows.

2018: Taliban banned house-to-house polio vaccination

Between 2018 and 2021, the Taliban banned house-to-house polio vaccination in Afghanistan.

2018: Cases dropped in Pakistan

From 2014 to 2018 cases dropped in Pakistan by 97 percent.

2018: Global Polio Eradication Initiative (GPEI) coordinates efforts

Since 2018, the Global Polio Eradication Initiative (GPEI) has coordinated efforts both to eliminate polio and to research means of improving surveillance and prevention.

September 2019: Polio outbreak declared in the Philippines

In September 2019, the Department of Health of the Philippines declared a polio outbreak in the country after a single case in a 3-year-old girl.

December 2019: Acute poliomyelitis confirmed in Malaysia

In December 2019, acute poliomyelitis was confirmed in an infant in Sabah state, Borneo, Malaysia.

2019: WPV3 certified as eradicated

In 2019, wild poliovirus type 3 (WPV3) was certified as eradicated.

January 2020: Further polio cases reported in Malaysia

In January 2020, a further three polio cases were reported in Malaysia, with the last case reported in January 2020. These outbreaks were found to be linked instances of vaccine-derived poliomyelitis.

August 2020: Africa declared free of wild polio

In August 2020, Africa was declared free of wild polio, though cases of circulating vaccine-derived poliovirus type 2 continued to appear in several countries.

2021: GPEI Funding

As of 2021, the GPEI had raised 18 billion dollars in funding, with annual contributions around 800 million to 1 billion dollars.

2021: Taliban banned house-to-house polio vaccination

Between 2018 and 2021, the Taliban banned house-to-house polio vaccination in Afghanistan.

2021: Polio types 2 and 3 fully eradicated

In 2021, Polio Types 2 and 3 were fully eradicated from every country; however, type 1 cases still remain in Pakistan and Afghanistan.

2021: Improved oral vaccine granted emergency licensing

In 2021, an improved oral vaccine (Novel oral polio vaccine type 2 - nOPV2) was granted emergency licensing.

2021: Four cases of polio reported from 2 districts

In 2021, only four cases of polio were reported from 2 districts in Afghanistan.

February 2022: Wild polio case detected in Malawi

In February 2022, a single case of wild polio was detected in Malawi, originating from a strain imported from Pakistan.

May 2022: Wild polio case detected in Mozambique

In May 2022, a case of wild polio was detected in Mozambique, of a strain imported from Pakistan, which did not affect the African region's wild poliovirus-free certification status.

July 2022: Polio case reported in New York

In July 2022, the US state of New York reported a polio case for the first time in almost a decade in the country; this was attributed to a vaccine-derived strain of the virus.

2022: Routine immunization coverage of eligible children exceeded 99% in Gaza.

In 2022, prior to the Israel-Hamas conflict, routine immunization coverage of eligible children exceeded 99% in Gaza.

2022: 30 confirmed polio cases

In 2022, there were only 30 confirmed cases of wild polio, confined to just three countries.

October 2023: Pakistan and Afghanistan remain endemic for wild poliovirus

As of October 2023, Pakistan and Afghanistan are the only countries that remain endemic for wild poliovirus (WPV).

December 2023: Improved oral polio vaccine granted full licensure

In December 2023, an improved oral polio vaccine with greater genetic stability (nOPV2) was developed and granted full licensure and prequalification by the World Health Organization.

December 2023: Full licensure for improved oral polio vaccine

In December 2023, the Novel oral polio vaccine type 2 (nOPV2) received full licensure.

April 2024: Countries considered polio-free, but not confirmed

As of April 2024, the following countries were considered polio-free, but not confirmed: Somalia, Djibouti, Sudan, Egypt, Libya, Tunisia, Morocco, Palestine, Lebanon, Syria, Jordan, Saudi Arabia, Bahrain, Qatar, Oman, Yemen, the UAE, Iraq, Kuwait, and Iran.

2024: Several children show symptoms consistent with polio

In 2024, the Gaza Health Ministry reported that several children have shown symptoms consistent with polio, with laboratory tests confirming that a 10-month-old child is infected with the virus.