NEWS HIGHLIGHTS
Theme : Health
Paper : GS - 2
New York declared a State disaster emergency after poliovirus was discovered in wastewater samples from three counties. In India, vaccine-derived poliovirus (VDPV) was detected in the environmental surveillance of sewage samples from Kolkata this year, although the Health Ministry said that such an incident can occur in any country where oral polio vaccines (OPVs) are given.
Poliomyelitis, commonly called polio, is a highly infectious viral disease that can leave patients disabled, and in some cases, even prove fatal. The virus enters the nervous system and can cause total paralysis in just a few hours.
TABLE OF CONTENT
- Context
- What is Polio disease
- Wild Polio Virus
- Types of Polio Vaccines
- Immunization in India
- Mission Indradhanush
- Global Resurgence & India
Context :
New York declared a State disaster emergency after poliovirus was discovered in wastewater samples from three counties. In India, vaccine-derived poliovirus (VDPV) was detected in the environmental surveillance of sewage samples from Kolkata this year, although the Health Ministry said that such an incident can occur in any country where oral polio vaccines (OPVs) are given.
What is Polio disease?
- Poliomyelitis, commonly called polio, is a highly infectious viral disease that can leave patients disabled, and in some cases, even prove fatal. The virus enters the nervous system and can cause total paralysis in just a few hours.
- Initial symptoms of the infection include fever, fatigue, headache, vomiting, stiffness of the neck and pain in the limbs. According to the World Health Organization (WHO), one in 200 infections leads to irreversible paralysis, usually in the legs. Among these, 5-10% die when breathing muscles are affected and immobilized.
- There is no known cure for polio. It can only be prevented by way of vaccination.
Wild Polio Virus:
- WPV has three known strains – types 1, 2, and 3 – each with a slight difference in structure. Immunity to one type does not guarantee immunity to others.
- According to the Global Polio Eradication Drive, only type 1 of wild poliovirus remains in circulation. Type 2 was declared eradicated in 2015, and type 3 WPV eradicated in 2019.
Types of Polio Vaccines :
- Currently, there are two types of vaccines available against poliomyelitis – oral poliovirus vaccine (OPV) and inactivated poliovirus vaccine (IPV).
- IPV was developed in 1955 by virologist Dr Jonas Salk. It consists of inactivated (killed) poliovirus strains of all three types. The vaccine is administered through an intramuscular or intradermal injection. It produces antibodies in the blood against all three types of the poliovirus.
- OPV uses a weakened (also called attenuated) form of poliovirus, which can either be one strain or a combination, to enable the vaccinated individual to build immunity against the virus. According to the Global Polio Eradication Initiative, the attenuated viruses are able to replicate in the intestines but are “around 10,000 times less able to enter the central nervous system than the wild virus”.
- Since OPVs are administered orally, they are more suitable for mass vaccination campaigns than IPVs that must be administered by qualified health workers. Although both modes of vaccination are safe, the live attenuated virus in OPV can cause vaccine derived polio (VDPV).
- IPV, on the other hand, induces a very low level of immunity in the intestine. It is usually given to immune-compromised persons or those with low levels of immunity. In such a case, if an IPV vaccinated person is infected with wild poliovirus, the virus can still multiply inside their intestines and be shed in the feces, risking continued circulation.
- In some seriously under-immunized communities, the excreted vaccine virus can continue to circulate for a longer time period, with a possibility of undergoing genetic changes. In rare instances, it can mutate into a form that can paralyze people. This is known as cVDPV – the form of virus that put the U.S. on the outbreak list.
Immunization in India :
- India committed itself to WHO’s goal of global polio eradication in 1988. The Government launched the National Immunization Day (NID), commonly called the Pulse Polio immunization programme in 1995, aiming to administer polio drops to all children in the 0-5 years age group. Additionally, Sub-National Immunization Days are also conducted every year in high-risk areas.
- In 2012, WHO removed India from its list of endemic countries with active poliovirus transmission. India, along with 10 other countries in the WHO South-East Asia region, was certified polio-free in 2014.
Mission Indradhanush :
- Children up to 2 years will be covered in this drive.
- It is the Universal Immunization Programme (UIP) of India which aimed to prevent mortality and morbidity in children and pregnant women against 12 vaccine-preventable diseases:
- Diphtheria, Whooping cough, tetanus, polio, tuberculosis, hepatitis B, meningitis and pneumonia, Haemophilus influenzae type B infections, Japanese encephalitis (JE), rotavirus vaccine, pneumococcal conjugate vaccine (PCV) and measles-rubella (MR).
- It is the largest immunization programme globally where it annually covers more than three crore pregnant women and 2.6 crore children
- Recently, the Ministry of Health virtually launched Intensified Mission Indradhanush (IMI) 4.0. It will ensure that Routine Immunization (RI) services reach unvaccinated and partially vaccinated children and pregnant women.
Global Resurgence & India :
- India’s proximity to polio-endemic countries Pakistan and Afghanistan, and possible gaps in vaccination in the past two years due to Covid-19 are causes for concern. However, according to WHO, there is “no evidence of VDPVs circulating in the community”.
- In 2021, India had also announced that people returning to the country from Afghanistan would be vaccinated against polio as a preventive measure.
- In a report outlining the investigation of the Kolkata sewage water sample, WHO said that India’s acute flaccid paralysis (AFP) surveillance, along with routine immunization and NIDs, meets the recommended global standards.