A pause in the immunisation programme at the beginning of Covid pandemic has led to the finding of fresh polio cases in countries like the US, UK and Mozambique this year, according to Dr Ananda Sankar Bandyopadhyaya, a scientist associated with the Bill & Melinda Gates Foundation.

The finding of the poliovirus was also a reminder that if it exists anywhere in the world, it remains a threat everywhere, said Bandyopadhyay, Deputy Director of Technology, Research and Analytics at the Foundation’s Polio Team.

The virus of polio was found in wastewater in a part of London and New York some months back. A case of wild poliovirus was detected in Mozambique in May and another in Malawi in February this year.

“Any polio detection is a result of low immunisation rates. When the Covid-19 pandemic first hit in 2020, polio campaigns were briefly paused for four months to protect communities and health workers from the coronavirus spread. This led to some increased spread of the poliovirus in countries," Bandyopadhyay told PTI in an exclusive interview here.

It was clear that the Covid pandemic has had a negative impact on immunisation rates globally, said the epidemiologist who graduated with a gold medal from Calcutta National Medical College and Hospital in Kolkata in 2005. However, there were other challenges like misinformation, vaccine hesitancy, and issues like reaching every community with the polio vaccine, he said.

Bandyopadhyay coordinates global research aimed at achieving and sustaining polio eradication besides developing novel polio vaccines, generation of data to generate polio immunisation policies, and advancement of improved detection and surveillance tools.

"The recent polio detections in the US and UK — and wild poliovirus outbreak in Malawi and Mozambique confirmed earlier this year — are an urgent reminder that if polio exists anywhere in the world, it remains a threat everywhere,” Bandyopadhyay said.

Poliovirus’ history

Wild poliovirus was last reported in the USA and UK in 1979 and 1982 respectively, while in the case of Malawi and Mozambique, the years were 1992 and 1992, according to the website of Global Polio Eradication Initiative (GPEI), a WHO agency.

“Polio-free countries are not polio-risk free until global eradication is achieved,” said the epidemiologist who completed his graduation from Calcutta National Medical College and Hospital in Kolkata in 2005.

To a question, Bandyopadhyay said the health authorities in the US and the UK are responding appropriately, launching urgent vaccination campaigns to protect those at risk and intensifying disease surveillance systems to better track virus spread.

"The key will be to unite in our effort to stop polio in countries where outbreaks have been persisting in addition to strengthening public health response in countries with importation events," he said.

India's success

Bandyopadhyay hailed India's success against polio as one of the greatest achievements in global health, as, he said, many people had felt that the country would be the last one to stop the disease because it is one of the most challenging geographies.

Bandyopadhyay, who worked as a Surveillance Medical Officer with National Polio Surveillance Project, WHO, and contributed to India’s polio elimination effort and measles surveillance initiatives, said that the Indian government should continue maintaining high immunisation rates against polio.

"The strong commitment of the government, supported by meticulous planning and seamless coordination across all levels of the government, communities, health workers and partners showed what is possible in public health when everyone is united and working together,” he said.

India, along with 10 other countries in South East Asia, was declared polio-free by the World Health Organisation (WHO) in 2014. "As with every country around the world, it is important that India maintain high immunisation rates against polio and other vaccine-preventable diseases,” Bandyopadhyay said.

In July this year, the virus was found in an unvaccinated adult man in Rockland County in New York as well as in several wastewater samples near his residence there. Poliovirus was also detected in sewage in north and east London between February and May 2022.

In May, the virus was found in Mozambique when a child contracted the disease. It is the second imported case of wild poliovirus in southern Africa this year, after one in Malawi in mid-February.

The ‘gold standard’

To a question, Bandyopadhyay described the oral polio vaccine (OPV) as the "gold standard" to inoculate people against the disease and said it is responsible for bringing down polio cases by 99 per cent since 1988 across the world.

“To understand what is possible when we work together, it is important that we look at the incredible signs of progress made. Two of the three wild polio strains were eradicated, 20 million cases of polio paralysis were averted and there is a 99 per cent fall in cases. Now is the time to redouble efforts and finish off that last one per cent,” the expert in the Foundation said.

Bill & Melinda Gates Foundation, a nonprofit organisation fighting poverty, disease, and inequity around the world, was founded by Microsoft co-founder Bill Gates and his former wife Melinda French Gates.