Polio Eradication And Endgame Strategy

Note4students

Mains Paper 2: Governance | Issues relating to development & management of Social Sector/Services relating to Health, Education, Human Resources

From the UPSC perspective, the following things are important:

Prelims level: Poliovirus and its immunisation

Mains level: Need of using IPV instead of OPV to eradicate Polio in India

Context

Eliminating Polio

1. With wild poliovirus strains reduced by 99.9% since 1988, the world is inching towards eradicating polio
2. But unfortunately, more children today are affected by the live, weakened virus contained in the oral polio vaccine (OPV) that is meant to protect them.
3. The weakened virus in the vaccine can circulate in the environment, occasionally turn neurovirulent and cause vaccine-derived poliovirus (VDPV) in unprotected children

Less awareness about VAPP

1. While circulating VDPV strains are tracked, and outbreaks and cases are recorded and shared, little is known about vaccine-associated paralytic poliomyelitis (VAPP) cases, particularly in India
2. VAPP occurs when the virus turns virulent within the body of a recently vaccinated child and causes polio
3. With high-income countries switching to the inactivated polio vaccine (IPV) that uses the dead virus to immunise children, the VAPP burden is concentrated in low-income countries which continue to use the OPV
4. In spite of the World Health Organisation asking all countries using the OPV to include a “continuous and effective system of surveillance” to monitor the frequency of VAPP in 1982, India did not comply
5. Data on VAPP became available only years after active polio surveillance was initiated in 1997
6. Even after 1997, India did not count VAPP cases

Use of OPV main culprit

1. The decision to use only the OPV was faulty
2. Vaccination (using OPV) has become the main source of polio paralysis in the world
3. Despite knowing that there is a higher burden of polio caused by oral vaccines, India continued to use the OPV
4. OPV fared poorly on two important counts: safety and efficacy
5. The primary objective of polio vaccination is to prevent the disease, which the OPV failed to fully achieve
6. The OPV was used for eradicating purposes but without fully protecting the children
7. Parents were obliged to accept the OPV and face the consequences of VAPP as well as VDVP

Resoning behind the use of OPV

1. India’s goal was to eradicate polio, and the OPV was crucial for that
2. The IPV produces humoral immunity (involving antibodies in body fluids) so the immunised child does not get paralysis, but it can’t stop the circulation of wild polioviruses
3. For instance, no polio cases were seen in Israel but wild polioviruses were detected in the environment
4. The viruses will continue to circulate in the community
5. It is easier to administer the OPV than the IPV and the cost per dose of OPV is also lower than that of the IPV
6. Another reason given for not switching over to the IPV was that global production was too low to meet India’s demand. India is the largest cohort. It needs 48 million doses per year to immunise all children

Need for IPV

1. The IPV is essential for post-wild-type poliovirus eradication, to get rid of VDPV and VAPP
2. A single dose of the IPV given before the OPV prevents VAPP cases
3. A single dose of the IPV primes the immune system and the antibodies against the polio virus, seen in more than 90% of immunised infants
4. The globally synchronised switch from trivalent to bivalent OPV in mid-2016 was accompanied by administering a single dose of the IPV prior to administering the OPV

Way forward

1. The justification that VAPP cases can be ignored as they are “sporadic and pose little or no threat to others” is ethically flawed
2. The stand that VAPP cases are epidemiologically irrelevant is ethically problematic