Global Polio Eradication Efforts
link to page 1 
November 4, 2016
Global Polio Eradication Efforts
Poliomyelitis (polio), formerly a widespread global health
20% of these funds, with U.S. funding exceeding $200
challenge, is now endemic in only a handful of countries.
million annually since FY2014. GPEI estimates that it
Efforts to fully eradicate polio by a target date of 2018 are
would cost roughly $3.2 billion from 2016 through 2019 to
challenged by a variety of factors, including regional
eliminate polio and, based on global funding trends, has
instability. Congress supports polio eradication efforts
projected a funding gap of roughly $580 million. WHO
through USAID and CDC global health appropriations and
contends that if funding goals are met and efforts are
through the World Health Organization (WHO).
maintained, polio could be eradicated by 2018. On the other
hand, WHO warns that failure to eradicate polio in
Background
countries where the disease persists could lead to a
Polio is an infectious disease that affects the nervous
resurgence of nearly 200,000 new cases per year within 10
system and can cause irreversible paralysis within hours.
years. WHO estimates that eradicating polio could save
There are three natural or “wild” types of polio virus
$40-$50 billion over the next 20 years, primarily in low-
(WPV, numbered 1 through 3). There is no cure for polio,
income countries.
but it can be prevented through immunization. About one in
200 cases results in paralysis. Among those who are
Ongoing Transmission of Wild Polio:
paralyzed, between 5% and 10% may die after their
Pakistan, Afghanistan, and Nigeria
breathing muscles become immobilized if mechanical
While the international community has made significant
ventilation is not available. Polio is spread primarily
gains in reducing the global spread of polio, efforts to
through ingestion of contaminated water or food, or after
eradicate the disease have been stymied by a variety of
placing one’s hands in one’s own mouth after touching
factors, including religious objections, misinformation, and
items contaminated with the virus. The disease primarily
intermittent conflict. These obstacles have been largely
affects children aged younger than five years.
overcome in recent years but remain problematic in
Pakistan and Afghanistan. Instability has also contributed to
In 1998, the World Health Assembly adopted a resolution
the resurgence of polio in Nigeria (Figure 1).
to eradicate polio worldwide and launched the Global Polio
Eradication Initiative (GPEI) to advance that effort. GPEI is
Figure 1. Global Polio Cases: 2015 and 2016
led by national governments, the U.S. Centers for Disease
Control and Prevention (CDC), Rotary International, WHO,
and the United Nations Children’s Fund. When GPEI was
launched, there were an estimated 350,000 cases in 125
countries. In 2014, the disease was endemic (meaning that
it is habitually present and domestically transmitted) in only
two countries (Afghanistan and Pakistan) and a total of 359
cases were reported. By 2015, only 51 wild poliovirus cases
were detected and the Global Commission for the
Certification of Poliomyelitis Eradication determined that
wild poliovirus type 2 had been eradicated worldwide. In
August 2016, two polio cases were identified in Nigeria,
two years after the last wild polio case was detected. As of
October 28, 2016, only 11 wild poliovirus cases have been
identified worldwide.
Global health experts are optimistic that polio eradication is
imminent. The CDC indicated that no type 3 wild
Source: Adapted by CRS from Global Polio Eradication Initiative
poliovirus infections have been detected globally since
webpage on polio cases at http://polioeradication.org, accessed on
November 2012, suggesting that transmission of the strain
October 28, 2016.
has likely been interrupted in the remaining two endemic
countries. Type 1 wild poliovirus is believed to be the only
Acronyms: wild poliovirus (WPV); circulating vaccine-derived
strain currently in circulation.
poliovirus (cVDPV)
International Financing
Polio in Pakistan
Between 1985 and April 1, 2016, governments,
In 2014, 91% (304) of the world’s 332 wild polio cases
nongovernmental organizations (NGOs), and public and
occurred in Pakistan. Significant gaps in vaccination
private donors have donated more than $13 billion in
coverage persist across the country, particularly in
support of GPEI. The United States has provided roughly
Peshawar, Karachi, and in the Federally Administered
Tribal Areas (FATA). These areas have ongoing polio
https://crsreports.congress.gov
Global Polio Eradication Efforts
transmission, and infected people from these regions have
including Guinea (4 cases), Laos (6 cases), Madagascar (10
spread the disease to other parts of the country and the
cases), Burma (2 cases), Nigeria (1 case), and Ukraine (2
world. Insecurity in the regions and the targeting of health
cases).
teams and facilities by Islamic militants, who believe health
workers may be spies or carry other misconceptions, have
Other Vulnerable Countries
hindered polio eradication efforts in the regions.
WHO has classified seven countries as vulnerable to polio
outbreaks due to inadequate vaccine coverage, gaps in
Polio in Afghanistan
disease surveillance systems, and proximity to countries
The unstable security situation in Afghanistan and attacks
where the virus persists.
on vaccination teams in the country have complicated
vaccination efforts in Afghanistan, especially in the
Cameroon: Historical patterns of transmission through
provinces of Kunar, Nangarhar, Kandahar, Helmand,
Central Africa and gaps in subnational disease
Uruzgan, and Farah. Most of the 28 wild polio Afghan
surveillance increase the risk of polio outbreak.
cases were imported from Pakistan. The WHO has
recommended that the two countries improve coordination
Equatorial Guinea: Historical patterns of transmission
of vaccination efforts. In early January 2016, health
through Central Africa and gaps in subnational disease
officials from Afghanistan and Pakistan met to discuss
surveillance increase the risk of polio outbreak.
ways to synchronize vaccination campaigns and improve
control of cross-border traffic.
Ethiopia: Location in the “wild polio virus importation
belt”—a group of countries from west Africa to central
Polio in Nigeria
Africa and the Horn of Africa that periodically
After being free of polio for more than two years, the
experience polio importation.
Government of Nigeria reported on August 11, 2016, that
two children had been paralyzed by the disease in the
Iraq: Three cases of WPV in the Middle East, including
northeastern state of Borno. Shortly after receiving
two in Iraq, were reported in 2014.
confirmation of the two cases, the Government of Nigeria
declared the outbreak a national public health emergency.
Somalia: Vulnerable due to its location in the “wild
According to GPEI, the new cases are closely linked to a
polio virus importation belt.”
strain of wild poliovirus last identified in Borno state in
2011. Borno is one of Nigeria’s most unstable areas and is
South Sudan: Vulnerable due to its location in the “wild
home to Boko Haram, designated by the State Department
polio virus importation belt.”
as a foreign terrorist organization in November 2013 and
well-known for having kidnapped 276 schoolgirls from the
Syria: Ongoing conflict has made parts of the country
town of Chibok in April 2014.
inaccessible to vaccination teams. WHO has sought
access to besieged areas to vaccinate approximately 2.3
Nigeria is collaborating with WHO and other partners to
million children.
stem the virus’s transmission. Throughout the Lake Chad
Remaining Issues
region (western Chad, northern Cameroon, southern Niger,
parts of the Central African Republic, and northeastern
Congressional support for fighting the global spread of
Nigeria), large-scale, cross-border immunization campaigns
polio appears to be strong, as annual appropriations have
are underway and plans to strengthen surveillance systems
grown since the start of the Obama Administration and
in the region are being carried out. According to GPEI,
have exceeded $200 million since FY2014. Despite funding
some 600,000 children aged less than five years in the Lake
increases, health experts are troubled by the reemergence of
Chad region have neither been immunized nor receive
polio in Nigeria and its implications for sub-Saharan Africa.
regular health care. This region is considered the last polio
Prolonged instability in the country and in some
reservoir in Africa.
neighboring states risks further spread of the disease,
threatens to derail polio control efforts on the continent, and
Countries with Vaccine-Derived Polio
may raise the cost of eradicating the disease.
There are two types of polio vaccines, one oral (OPV) and
the other injectable (IPV). OPV uses a weakened version of
As polio elimination proceeds, GPEI is adding IPV to its
the live virus, while the injectable version uses killed virus.
vaccination plans to reduce the risk of transmitting vaccine-
Until recently, health workers preferred to use OPV in
derived polio and plans to phase out the use of OPV
developing countries. It is cheaper, easier to administer, and
entirely. Research efforts are underway to develop a new
provides broader population immunity. The live oral
oral vaccine containing engineered strains of the polio virus
vaccine virus, however, can mutate and has caused paralytic
less likely to mutate and cause further outbreaks. However,
illness just like the natural or “wild” strains. Ongoing
significant cost is involved in bringing a new vaccine to
efforts to eradicate polio are being stymied by outbreaks of
market, and it is unclear if a new type of vaccine will be
vaccine-derived polio cases, known as persistent circulating
introduced.
vaccine-derived poliovirus (cVDPV). CDC and other GPEI
Tiaji Salaam-Blyther, Specialist in Global Health
partners hope that recent efforts to manufacture polio
Edward Y. Gracia, Analyst in Latin American Studies
vaccines without the type 2 strain may help to reduce
cVDPV outbreaks and eliminate them. According to GPEI,
IF10497
small cVDPV outbreaks occurred in six countries in 2015,
https://crsreports.congress.gov
Global Polio Eradication Efforts
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF10497 · VERSION 2 · NEW
November 4, 2016
Global Polio Eradication Efforts
Poliomyelitis (polio), formerly a widespread global health
20% of these funds, with U.S. funding exceeding $200
challenge, is now endemic in only a handful of countries.
million annually since FY2014. GPEI estimates that it
Efforts to fully eradicate polio by a target date of 2018 are
would cost roughly $3.2 billion from 2016 through 2019 to
challenged by a variety of factors, including regional
eliminate polio and, based on global funding trends, has
instability. Congress supports polio eradication efforts
projected a funding gap of roughly $580 million. WHO
through USAID and CDC global health appropriations and
contends that if funding goals are met and efforts are
through the World Health Organization (WHO).
maintained, polio could be eradicated by 2018. On the other
hand, WHO warns that failure to eradicate polio in
Background
countries where the disease persists could lead to a
Polio is an infectious disease that affects the nervous
resurgence of nearly 200,000 new cases per year within 10
system and can cause irreversible paralysis within hours.
years. WHO estimates that eradicating polio could save
There are three natural or “wild” types of polio virus
$40-$50 billion over the next 20 years, primarily in low-
(WPV, numbered 1 through 3). There is no cure for polio,
income countries.
but it can be prevented through immunization. About one in
200 cases results in paralysis. Among those who are
Ongoing Transmission of Wild Polio:
paralyzed, between 5% and 10% may die after their
Pakistan, Afghanistan, and Nigeria
breathing muscles become immobilized if mechanical
While the international community has made significant
ventilation is not available. Polio is spread primarily
gains in reducing the global spread of polio, efforts to
through ingestion of contaminated water or food, or after
eradicate the disease have been stymied by a variety of
placing one’s hands in one’s own mouth after touching
factors, including religious objections, misinformation, and
items contaminated with the virus. The disease primarily
intermittent conflict. These obstacles have been largely
affects children aged younger than five years.
overcome in recent years but remain problematic in
Pakistan and Afghanistan. Instability has also contributed to
In 1998, the World Health Assembly adopted a resolution
the resurgence of polio in Nigeria (Figure 1).
to eradicate polio worldwide and launched the Global Polio
Eradication Initiative (GPEI) to advance that effort. GPEI is
Figure 1. Global Polio Cases: 2015 and 2016
led by national governments, the U.S. Centers for Disease
Control and Prevention (CDC), Rotary International, WHO,
and the United Nations Children’s Fund. When GPEI was
launched, there were an estimated 350,000 cases in 125
countries. In 2014, the disease was endemic (meaning that
it is habitually present and domestically transmitted) in only
two countries (Afghanistan and Pakistan) and a total of 359
cases were reported. By 2015, only 51 wild poliovirus cases
were detected and the Global Commission for the
Certification of Poliomyelitis Eradication determined that
wild poliovirus type 2 had been eradicated worldwide. In
August 2016, two polio cases were identified in Nigeria,
two years after the last wild polio case was detected. As of
October 28, 2016, only 11 wild poliovirus cases have been
identified worldwide.
Global health experts are optimistic that polio eradication is
imminent. The CDC indicated that no type 3 wild
Source: Adapted by CRS from Global Polio Eradication Initiative
poliovirus infections have been detected globally since
webpage on polio cases at http://polioeradication.org, accessed on
November 2012, suggesting that transmission of the strain
October 28, 2016.
has likely been interrupted in the remaining two endemic
countries. Type 1 wild poliovirus is believed to be the only
Acronyms: wild poliovirus (WPV); circulating vaccine-derived
strain currently in circulation.
poliovirus (cVDPV)
International Financing
Polio in Pakistan
Between 1985 and April 1, 2016, governments,
In 2014, 91% (304) of the world’s 332 wild polio cases
nongovernmental organizations (NGOs), and public and
occurred in Pakistan. Significant gaps in vaccination
private donors have donated more than $13 billion in
coverage persist across the country, particularly in
support of GPEI. The United States has provided roughly
Peshawar, Karachi, and in the Federally Administered
Tribal Areas (FATA). These areas have ongoing polio
https://crsreports.congress.gov
Global Polio Eradication Efforts
transmission, and infected people from these regions have
including Guinea (4 cases), Laos (6 cases), Madagascar (10
spread the disease to other parts of the country and the
cases), Burma (2 cases), Nigeria (1 case), and Ukraine (2
world. Insecurity in the regions and the targeting of health
cases).
teams and facilities by Islamic militants, who believe health
workers may be spies or carry other misconceptions, have
Other Vulnerable Countries
hindered polio eradication efforts in the regions.
WHO has classified seven countries as vulnerable to polio
outbreaks due to inadequate vaccine coverage, gaps in
Polio in Afghanistan
disease surveillance systems, and proximity to countries
The unstable security situation in Afghanistan and attacks
where the virus persists.
on vaccination teams in the country have complicated
vaccination efforts in Afghanistan, especially in the
Cameroon: Historical patterns of transmission through
provinces of Kunar, Nangarhar, Kandahar, Helmand,
Central Africa and gaps in subnational disease
Uruzgan, and Farah. Most of the 28 wild polio Afghan
surveillance increase the risk of polio outbreak.
cases were imported from Pakistan. The WHO has
recommended that the two countries improve coordination
Equatorial Guinea: Historical patterns of transmission
of vaccination efforts. In early January 2016, health
through Central Africa and gaps in subnational disease
officials from Afghanistan and Pakistan met to discuss
surveillance increase the risk of polio outbreak.
ways to synchronize vaccination campaigns and improve
control of cross-border traffic.
Ethiopia: Location in the “wild polio virus importation
belt”—a group of countries from west Africa to central
Polio in Nigeria
Africa and the Horn of Africa that periodically
After being free of polio for more than two years, the
experience polio importation.
Government of Nigeria reported on August 11, 2016, that
two children had been paralyzed by the disease in the
Iraq: Three cases of WPV in the Middle East, including
northeastern state of Borno. Shortly after receiving
two in Iraq, were reported in 2014.
confirmation of the two cases, the Government of Nigeria
declared the outbreak a national public health emergency.
Somalia: Vulnerable due to its location in the “wild
According to GPEI, the new cases are closely linked to a
polio virus importation belt.”
strain of wild poliovirus last identified in Borno state in
2011. Borno is one of Nigeria’s most unstable areas and is
South Sudan: Vulnerable due to its location in the “wild
home to Boko Haram, designated by the State Department
polio virus importation belt.”
as a foreign terrorist organization in November 2013 and
well-known for having kidnapped 276 schoolgirls from the
Syria: Ongoing conflict has made parts of the country
town of Chibok in April 2014.
inaccessible to vaccination teams. WHO has sought
access to besieged areas to vaccinate approximately 2.3
Nigeria is collaborating with WHO and other partners to
million children.
stem the virus’s transmission. Throughout the Lake Chad
Remaining Issues
region (western Chad, northern Cameroon, southern Niger,
parts of the Central African Republic, and northeastern
Congressional support for fighting the global spread of
Nigeria), large-scale, cross-border immunization campaigns
polio appears to be strong, as annual appropriations have
are underway and plans to strengthen surveillance systems
grown since the start of the Obama Administration and
in the region are being carried out. According to GPEI,
have exceeded $200 million since FY2014. Despite funding
some 600,000 children aged less than five years in the Lake
increases, health experts are troubled by the reemergence of
Chad region have neither been immunized nor receive
polio in Nigeria and its implications for sub-Saharan Africa.
regular health care. This region is considered the last polio
Prolonged instability in the country and in some
reservoir in Africa.
neighboring states risks further spread of the disease,
threatens to derail polio control efforts on the continent, and
Countries with Vaccine-Derived Polio
may raise the cost of eradicating the disease.
There are two types of polio vaccines, one oral (OPV) and
the other injectable (IPV). OPV uses a weakened version of
As polio elimination proceeds, GPEI is adding IPV to its
the live virus, while the injectable version uses killed virus.
vaccination plans to reduce the risk of transmitting vaccine-
Until recently, health workers preferred to use OPV in
derived polio and plans to phase out the use of OPV
developing countries. It is cheaper, easier to administer, and
entirely. Research efforts are underway to develop a new
provides broader population immunity. The live oral
oral vaccine containing engineered strains of the polio virus
vaccine virus, however, can mutate and has caused paralytic
less likely to mutate and cause further outbreaks. However,
illness just like the natural or “wild” strains. Ongoing
significant cost is involved in bringing a new vaccine to
efforts to eradicate polio are being stymied by outbreaks of
market, and it is unclear if a new type of vaccine will be
vaccine-derived polio cases, known as persistent circulating
introduced.
vaccine-derived poliovirus (cVDPV). CDC and other GPEI
Tiaji Salaam-Blyther, Specialist in Global Health
partners hope that recent efforts to manufacture polio
Edward Y. Gracia, Analyst in Latin American Studies
vaccines without the type 2 strain may help to reduce
cVDPV outbreaks and eliminate them. According to GPEI,
IF10497
small cVDPV outbreaks occurred in six countries in 2015,
https://crsreports.congress.gov
Global Polio Eradication Efforts
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF10497 · VERSION 2 · NEW