- The World Polio Day was recently observed on October 24, to highlight the global efforts to eradicate polio from the world and to encourage countries to continue the fight against the disease.
- The day was established by Rotary International over a decade ago to commemorate the birth of Jonas Salk, who led the first team to develop the vaccine against the disease.
- The theme for World Polio Day 2020 is Stories of Progress: Past and Present.
In Focus: Polio
- Polio or poliomyelitis is a highly infectious viral disease that is transmitted from person to person mainly through the fecal-oral route.
- As the virus lives in the faeces of an infected person, people infected with the disease can spread it to others.
- People can also be infected if they drink water or eat food contaminated with infected faeces.
- The poliovirus enters the body through the mouth or the respiratory system and multiplies in the throat and intestines.
- From these areas, the virus travels to other organs of the body and affects the central nervous system, which can cause paralysis.
- Polio can be fatal if the muscles used for breathing are paralyzed or if there is an infection of the brain.
- The infection mostly affects children under the age of 5 years but can affect unvaccinated adults too.
Variants of the polio virus:
- There are three variants of the poliovirus, viz. Type 1, Type 2 and Type 3.
- Poliovirus infection can provide lifelong immunity against the disease. However, infection with one type does not protect an individual against infection with the other two types.
- For a country to be declared polio-free, the wild transmission of all three kinds has to be stopped.
- For eradication, cases of both wild and vaccine-derived polio infection have to be reduced to zero.
- The polio infection can be easily prevented by a vaccine. The development of effective vaccines to prevent polio was one of the major medical achievements of the 20th century.
- Two different kinds of vaccines are available:
- Inactivated (killed) polio vaccine (IPV)
- Live attenuated (weakened) oral polio vaccine (OPV)
- About: Oral polio vaccine (OPV)
- OPV was first introduced in 1961 and consists of a mixture of the three live attenuated polioviruses (types 1, 2 and 3).
- The ease of oral administration and the very low cost of the vaccine, have made it the most used vaccine in the global eradication programme.
- Although OPV is a safe vaccine, on rare occasions adverse events may occur. Vaccine-associated paralytic poliomyelitis (VAPP) (paralysis due to polio) is the most important of these rare adverse events.
- According to the WHO, if the oral vaccine-virus is excreted and allowed to circulate in an un-immunised or under-immunised population for at least 12 months, it can mutate (change) to cause infections.
- About: Inactivated polio vaccine (IPV)
- IPV was first introduced in 1955 and is produced from wild poliovirus strains of each type that have been inactivated (killed).
- As an injectable vaccine, it can be administered alone or in combination with other vaccines (e.g., diphtheria, tetanus, pertussis, hepatitis B, and haemophilus influenza).
- It provides immunity to all three types of poliovirus, resulting in protection against paralytic poliomyelitis.
- IPV has been used successfully in the polio eradication programs in a few countries, notably in Scandinavia and the Netherlands, but until recently most countries have used the oral polio vaccine.
- India became the first country globally to introduce fractional doses of IPV in childhood immunization programme in early 2016.
Global efforts to eradicate polio
- In 1988, the World Health Assembly adopted a resolution for the worldwide eradication of polio. It marked the launch of the Global Polio Eradication Initiative (GPEI).
- GPEI is a public-private partnership led by national governments and the World Health Organization (WHO), Rotary International and the United Nations Children’s Fund (UNICEF). Its goal is to eradicate polio worldwide.
GPEI’s pillars of eradication
- Routine immunization:
- High infant immunization coverage with four doses of oral polio vaccine (OPV) in the first year of life in developing and endemic countries (where disease is prevalent), and routine immunization with OPV and/or IPV elsewhere.
- Supplementary immunization:
- Organization of “National immunization days” to provide supplementary doses of oral polio vaccine to all children less than five years of age.
- Active surveillance for wild poliovirus through reporting and laboratory testing of all cases of paralysis among children less than fifteen years of age.
Status of polio across the world
- As per the WHO, since 1980, the cases of wild poliovirus have decreased by over 99.9 per cent as a result of vaccination efforts made around the world.
- Afghanistan and Pakistan are the last two countries where the wild poliovirus is still prevalent.
- In Pakistan, the number of reported wild poliovirus cases has increased in 2020. On the other hand, in August, 2020, the African Region was certified as wild poliovirus free.
- In 2019, polio outbreaks were recorded in the Philippines, Malaysia, Ghana, Myanmar, China, Cameroon, Indonesia and Iran, which were mostly vaccine-derived.
- As per some reports, as of October 7, 2020, there were more than 440 cases of poliovirus around the world, as compared with 378 and 71 cases globally in 2018 and 2019 respectively.
Status of polio in India
- India was declared polio-free in January 2014, after three years of zero cases. The last case due to wild poliovirus in the country was detected in
- This was achieved through the successful pulse polio campaign in India, in which all children were given polio drops.