‘Never give up’: Why the world’s fight against polio is not over

aEight-year-old Anita Gay was buried deep down her neck in a mud tomb during a solar eclipse, while her mother was pressured to recite verses from the Hindu scriptures — ostensibly to treat Gaye from polio, which she contracted at the age of two. “I still feel guilty — for what my mother had to put up with because of me,” says Ghai, now 67 and dean of Ambedkar University in Delhi.

Gaye thought these nightmares were over when the World Health Organization declared in March 2014 that India – home to half of the world’s cases of polio in 2009 – was free of the disease. However, eight years later, a disturbing series of events began to unfold around the world. Pakistan saw a string of new cases, ending a 15-month period without a single new case of polio. The wild virus from Pakistan has led to infections in Mozambique and Malawi, which were previously free of the disease.

In June, the World Health Organization reported cases of vaccine-derived polio — where a weakened virus in the vaccine itself spreads through the environment and infects people — in Eritrea, Ghana, Togo, Ivory Coast, Israel, Yemen, Nigeria and the Democratic Republic of the Congo. Congo. And in July, a patient in a New York City suburb was diagnosed with vaccine-induced polio. Over the past six weeks, traces of this type of virus have been found in sewage samples in Kolkata and London.

Health workers carry a box of polio vaccines at a railway station in Kolkata, India. Photo: Biel Adhikari/EPA

These seemingly unrelated cases highlight a common threat: Globally, polio vaccination levels in 2021 fell to their lowest levels in 15 years, according to WHO data, with immunization initiatives disrupted during Covid. India and Indonesia, two of the world’s most populous countries, have experienced a particularly sharp decline in vaccine coverage.

Experts say this makes the latest number of cases a canary in a coal mine — warning that the crippling disease that has been eradicated in much of the world could return, especially in densely populated areas, unless countries redouble their efforts in vaccinations and surveillance.

“It was very scary,” says virologist T Jacob John, one of the founders of the polio vaccination program in India, of the impact of the virus in Kolkata’s sewers. “A few more cases like that and we could have looked at the outbreak.”

This is not just a hypothetical scenario: In 2018, Papua New Guinea suffered an outbreak of vaccine-derived polio infection, 18 years after the country was declared free of the disease.

So far, there is no evidence that the recent cases represent any unchecked spread of the virus, at least in the United States, Britain and India, experts say. In Kolkata, investigators have surveyed all neighborhoods close to where traces of the virus have been found, to make sure no one has contracted polio.

The ability of health authorities to detect cases – and the effects of sanitation – indicates the strength of these countries’ surveillance systems. “It’s reassuring to me,” says Raman Bhatia, a veteran Indian campaigner for a polio vaccination campaign associated with Rotary International, a US non-profit organization that is a pillar of global polio immunization efforts.

But like vaccination levels, regular checks for polio-related cases have also declined over the past two years. In Indonesia, researchers found that such monitoring was severely disrupted during the pandemic.

That’s bad news, says Lutfi Azizatunisa, a public health researcher at the University of Yogyakarta Jadja Mada, and lead author of the Indonesian study. She says the country has pockets of low immunization coverage. “When surveillance is disrupted, we will never know or we may miss the polio virus circulating in the environment or community.”

Overall, the global burden of polio caused by the wild virus has decreased by 99% since 1988, when the disease was endemic in more than 125 countries and infected 350,000 people annually. Today, the number of these two countries has dwindled to just two: Pakistan and Afghanistan.

The increase in polio cases caused by vaccines has reopened the debate among some experts about the benefits of the two main types of immunization commonly used against the disease.

The first, known as IPV, uses an inactivated virus and is injected. The other, taken orally, is known as OPV and carries a weakened but active virus that, after spreading in a population, can mutate and sometimes lead to outbreaks.

“Countries using an exclusive inactivated polio vaccine are not at risk of producing new circulating, vaccine-derived polioviruses,” says Walter Orenstein, former director of the US National Immunization Program. For this reason, Western countries depend almost entirely on IPVs. But they also can mistakenly import vaccine-derived polio from countries where OPV is used, he says.

A child was vaccinated against polio and diphtheria in Banda Aceh, Indonesia.
A child was vaccinated against polio and diphtheria in Banda Aceh, Indonesia. According to the World Health Organization, annually global immunization and vaccination programs prevent between two and three million deaths. Photo: Hotli Simanjuntak / EPA

Drops are easier to use than injections because they don’t require qualified medical professionals, says Jay Finger, director of the polio team at the Bill & Melinda Gates Foundation. OPV is also more effective than IPV at reducing oral and fecal transmission of poliovirus, according to Stephen Wassack, associate chief of science for the division of global immunization at the U.S. Centers for Disease Control and Prevention (CDC). “The oral OPV vaccine makes sense in those developing countries where sanitation is a challenge,” he says.

John not convinced: In a letter published in the Lancet medical journal in July, he questioned the evidence behind the idea that the virus is mostly spread through the mouth or feces in poor countries.

What is clear is that just like the wild virus, vaccine-derived polio seeks out victims among the unvaccinated. Those who have received all of their doses are often immune to the virus derived from the vaccine, if they encounter it in air or water.

“The main risk factor for any polio virus – whether wild-type or vaccine-derived – is low immunization coverage,” says Zubair Wadud, an epidemiologist at the World Health Organization in Geneva. “If the population is fully vaccinated, they will be protected from any form of the polio virus.”

The threat escalates if vaccination levels drop below 80%, says John Ross, associate professor of medicine at Harvard Medical School. This, he adds, opens an opportunity for “the spread of the vaccine-derived polio virus, increasing the risk of it returning to a virulent form.”

Indonesia, which uses a combination of the OPV and IPV vaccine, may be particularly at risk, Azizatonisa notes. The country’s polio vaccination rates have fallen to 68% in 2021, according to the World Health Organization and UNICEF. India is also mostly dependent on the oral polio vaccine, although vaccination rates have not fallen below 80%.

A health worker walks down a narrow street filled with wastewater carrying a medical kit.
A health worker walks down a narrow street filled with sewage as she approaches a house to receive a polio vaccination, Lahore, Pakistan, 2020. Photo: KM Chaudary/AP

Disinformation and conspiracy theories have reached new heights amid the pandemic, which has also affected rates, Waslake says. “Today, this is a challenge we must face in raising vaccination levels again.”

Rich countries should not leave their poorer neighbors to deal with the decline in vaccination numbers on their own, but countries and donor agencies should increase their support for the Global Polio Eradication Initiative, a public-private alliance including the Gates Foundation, the CDC and the World Health Organization. and UNICEF, Rotary International, and Gavi, the Vaccine Alliance, says Wenger.

For health veterans like Orenstein, this is a wake-up call. “We are still in danger,” he says. For patients like Ghai, the consequences of slipping in the face of a debilitating illness are more personal.

“My parents taught me to never give up,” says the Delhi-based professor. “I didn’t let polio defeat me. Neither should the world.”

Subscribe to get a different perspective with the Global Dispatch newsletter – a roundup of our top stories from around the world, recommended readings, and insights from our team on key development and human rights issues, delivered to your inbox every two weeks:

#give #worlds #fight #polio

Leave a Comment

Your email address will not be published.