We must protect border areas to prevent the WPV1 strain from slipping into the country

Polio, like COVID-19, is a highly contagious disease and given that we have not completely eradicated it, we wonder this World Polio Day if we and our children are safe from this seemingly dormant threat. COVID-19 has taught everyone that a virulent virus can travel swiftly across geographies, which is why India must guard its hard-earned immunity against polio as stringently as possible. 

India once accounted for over 60 percent of all polio cases in the world. Starting in October 1994, a concentrated effort by the government, Rotary, and its partners in the Global Polio Eradication Initiative (GPEI) achieved remarkable success in the Pulse Polio Immunization program. In March 2014, the WHO declared India 'polio-free'.

Today there is a fear that mass migrations may export the wild poliovirus type 1 (WPV1) to other nations, which according to WHO, is the only strain currently active (wild poliovirus type 2 and type 3 have been wiped out). Specifically, the type 1 wild virus continues to circulate in the neighbouring countries of Afghanistan and Pakistan. Although there has been one reported case of WPV1 in each country this year to date, the government of India remains cautious, and authorities are quick to vaccinate India-bound refugees against polio. It is still extremely important that we remain vigilant and protect border areas to prevent WPV1 from slipping into the country through proactive immunization practices and surveillance and screening techniques - tactics India has been using to try to control the spread of Covid-19.

We must also guard against potential outbreaks from another polio strain that could develop if not enough children are vaccinated. Specifically, the weakened poliovirus contained in the oral polio vaccine (OPV) can start to circulate and, over time, can change to a form that causes paralysis in under-immunized populations. This variant is called circulating vaccine-derived poliovirus (cVDPV) and type 2 is the most common strain. Thus, circulating vaccine-derived poliovirus type 2 (cVDPV2), primarily occurring in Africa and Asia, remains a key concern.

Although the risk of cVDPV2 outbreaks in India remains low thanks to strong protocols in the country that assure newborns are well-immunized, Pakistan and Afghanistan have had cases. So, the polio program must remain prepared and continue to strengthen routine immunization campaigns as it also deploys new tools-like the novel oral polio vaccine type 2 (nOPV2) that carries less risk of changing to a harmful form.

Lastly, while the infrastructure built to end polio in India has been used to help contain the coronavirus, it must be noted that routine immunizations overall have been significantly impacted. March 2020 saw child immunization for measles, mumps, and rubella (MMR) dip by around 70 percent over the previous year.

In hindsight, the effort to end polio has taught us many lessons on how to manage a public health crisis and has informed our COVID-19 response efforts. Thanks to our hard-fought battles against polio, we have learned the value of ensuring equitable access to vaccines and launching strong campaigns against vaccine hesitancy.  

Yet, India has more work to do if we are to ensure polio remains a largely neutralized threat within the country. It is important for policymakers and organizations to carry out routine immunization programs and conduct 'catch up' initiatives to cover those who may have missed out on immunizations. In a globalized era, even sporadic polio outbreaks in neighbouring countries need to be monitored and proactively managed. As long as polio circulates anywhere, all children are at risk. We must remain committed to making polio a disease of the past for everyone, everywhere.

(The writer is chairperson, Rotary International's India National Polio Plus Committee (RI-INPPC). The views expressed are personal.)