Press play to listen to this article
LONDON — Parents in London are scrambling for a vaccine. This time, it’s not the fear of COVID-19, but rather the return of a virus that in the past has killed and paralyzed thousands of young children.
Poliovirus has been detected in the capital’s sewage, with children in affected areas being offered a booster polio vaccine. Vaccination clinics are booked out in some areas and local councils are urging parents to get their children boosted. Across the Atlantic, the state of New York declared an emergency on September 9 due to growing community spread. “On polio, we simply cannot roll the dice … the risk of paralytic disease is real,” its health commissioner warned.
But unlike past outbreaks, the virus detected in London, New York and Jerusalem is not wild polio. Rather, the two cases of paralysis detected this year in wealthy Western countries were caused by vaccine-derived poliovirus.
Cases of vaccine-derived poliovirus aren’t new. In 2020, there were over 1,000 cases of paralysis through this route. The difference is that such cases usually occur in low-income countries, with most of those reported in 2020 found in Afghanistan, Pakistan, Chad and the Democratic Republic of the Congo.
For experts who’ve worked on polio for years, the unusual emergence of the virus in countries like the U.S., Israel and the U.K. should serve as an uncomfortable reminder to Western governments that the COVID-era adage that “no one is safe until everyone is safe,” is more than just an empty slogan.
“[It’s] a wake-up call for governments and other donors that polio is not restricted only to a few, distant, low-income countries, but a reminder that we are all in the same global fight against this virus,” said Andrew Pollard, director of the Oxford Vaccine Group and one of the prime movers behind the Oxford/AstraZeneca coronavirus vaccine.
“The final efforts in controlling wild polio and the increasing relative threat of [vaccine-derived polio] mean that a surge in funding and focus on polio is urgently needed to ensure a permanent end to the scourge of this disease,” Pollard said in comments emailed to POLITICO.
The detection of polio in wastewater in the U.K., the U.S. and Israel, as well as the two cases of paralysis — one in New York and the other in Jerusalem — is part of a complex cycle.
The presence of the virus in the sewage can be traced back to vaccination with a specific type of oral vaccine that is used in some countries and contains live polio virus “attenuated” to make it harmless. This oral vaccine can be shed into wastewater and the vaccine virus can be transmitted among people. That’s not usually a problem, in fact, it can help generate passive immunity. But if not enough people are vaccinated and if spread occurs for long enough, the virus can mutate back to a form that can cause illness and paralysis.
What complicates matters is that the vaccine currently given in countries like the U.K. and the U.S. is based on the inactivated poliovirus. This vaccine doesn’t result in virus shedding, but it also doesn’t completely stop transmission. So a person can have received the inactivated vaccine, yet still become infected and transmit the virus while themselves remaining protected against paralysis.
In a world where people are traveling between countries that administer different types of vaccines, the virus can be imported. Speaking on September 12, Hans Kluge, WHO regional director for Europe, said top U.S. virologist Anthony Fauci had told him recently that the cases in the U.S. were genetically linked to the cases in the European region. These, in turn, were linked to Afghanistan and Pakistan, where polio remains endemic. “It reminds us that a crisis anywhere quickly becomes a crisis everywhere,” he told a meeting of the WHO Regional Committee for Europe in Tel Aviv.
The global plan to eradicate polio rests on eventually scrapping the oral vaccines that can result in virus shedding. But moving over to inactivated vaccines isn’t that simple, because these vaccines cannot effectively halt outbreaks. That’s because they don’t generate significant immunity in the gut, which is important to stop person-to-person transmission.
The other reason for the reliance on oral vaccines in some countries is the ease of administration and the logistics around distribution.
“It’s not entirely surprising,” said Ondrej Mach, research and product development team lead for the WHO’s polio department, when asked about the cases in countries that don’t traditionally detect poliovirus in wastewater. “If you use this [oral] vaccine anywhere in the world, then any other country is kind of exposed to this risk.”
For Mach and his team leading the work on global poliovirus, the hope is that there is still a reasonable level of protection in the population in these countries due to the use of the inactivated vaccine. “The moment we start seeing more paralytic cases, we would have to re-evaluate the response strategy,” he said.
The outbreaks in the West generate substantial media coverage and take up a lot of Mach’s time. “But in terms of our ability to control it, I have no doubt that we will be able to successfully control these events in these areas,” Mach told POLITICO. “I have more doubt, obviously, about our ability to do something in the Democratic Republic of Congo, or Somalia, or Northern Nigeria, or Yemen.”
The global expert community is now looking toward a key funding drive in October, in which the Global Polio Eradication Initiative, an international public-private partnership, will seek $4.8 billion over five years. The initiative is managed by national governments with six partners — the World Health Organization, Rotary International, the U.S. Centers for Disease Control and Prevention, the United Nations Children’s Fund, the Bill & Melinda Gates Foundation, and Gavi, the Vaccine Alliance.
Mach is aware that competing global health priorities such as the coronavirus pandemic and the broader geopolitical situation may affect the funding effort. “I’m not sure where we will end up with our ability to raise money,” he said. “Maybe these events will help us. Maybe not.”
For David Heymann, professor of infectious disease epidemiology at the London School of Hygiene and Tropical Medicine and former representative for polio eradication at the World Health Organization, the message to donors ahead of the replenishment is that “it’s almost over.”
“We need to now get busy with Africa again and help them get rid of this,” he said. “They’ve got rid of wild poliovirus. Now they need to get rid of vaccine-derived poliovirus, and it’s possible, and what’s needed is continued resources.”
Soruce : https://www.politico.eu/article/poliovirus-eu-us-a-rude-awakening-the-return-of-polio-to-the-west/