Day: August 21, 2022

For years, global health officials have used billions of drops of an oral vaccine in a remarkably effective campaign aimed at wiping out polio in its last remaining strongholds — typically, poor, politically unstable corners of the world.

Now, in a surprising twist in the decades-long effort to eradicate the virus, authorities in London, New York and elsewhere have discovered evidence that polio is spreading there.

The original source of the virus? The oral vaccine itself.

Scientists have long known about this extremely rare phenomenon. That is why some countries have switched to other polio vaccines. But these incidental infections from the oral formula are becoming more glaring as the world inches closer to eradication of the disease and the number of polio cases caused by the wild, or naturally circulating, virus plummets.

Since 2017, there have been 396 cases of polio caused by the wild virus, versus more than 2,600 linked to the oral vaccine, according to figures from the World Health Organization and its partners.

“We are basically replacing the wild virus with the virus in the vaccine, which is now leading to new outbreaks,” said Scott Barrett, a Columbia University professor who has studied polio eradication. “I would assume that countries like the U.K. and the U.S. will be able to stop transmission quite quickly, but we also thought that about monkeypox.”

The latest incidents represent the first time in several years that vaccine-connected polio virus has turned up in rich countries.

Earlier this year, officials in Israel detected polio in an unvaccinated 3-year-old, who suffered paralysis. Several other children, nearly all of them unvaccinated, were found to have the virus but no symptoms.

In June, British authorities reported finding evidence in sewage that the virus was spreading, though no infections in people were identified. Last week, the government said all children in London ages 1 to 9 would be offered a booster shot.

In the U.S., an unvaccinated young adult suffered paralysis in his legs after being infected with polio, New York officials revealed last month. The virus has also shown up in New York sewers, suggesting it is spreading. Officials, however, said they are not planning a booster campaign because they believe the state’s high vaccination rate should offer enough protection.

Genetic analyses showed that the viruses in the three countries were all “vaccine-derived,” meaning that they were mutated versions of a virus that originated in the oral vaccine.

The oral vaccine at issue has been used since 1988 because it is cheap, easy to administer — two drops are put directly into children’s mouths — and better at protecting entire populations where polio is spreading. It contains a weakened form of the live virus.

But it can also cause polio in about two to four children per 2 million doses. (Four doses are required to be fully immunized.) In extremely rare cases, the weakened virus can also sometimes mutate into a more dangerous form and spark outbreaks, especially in places with poor sanitation and low vaccination levels.

These outbreaks typically begin when people who are vaccinated shed live virus from the vaccine in their feces. From there, the virus can spread within the community and, over time, turn into a form that can paralyze people and start new epidemics.

Many countries that eliminated polio switched to injectable vaccines containing a killed virus decades ago to avoid such risks; the Nordic countries and the Netherlands never used the oral vaccine. The ultimate goal is to move the entire world to the shots once wild polio is eradicated, but some scientists argue that the switch should happen sooner.

“We probably could never have gotten on top of polio in the developing world without the (oral polio vaccine), but this is the price we’re now paying,” said Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. “The only way we are going to eliminate polio is to eliminate the use of the oral vaccine.”

Aidan O’Leary, director of WHO’s polio department, described the discovery of polio spreading in London and New York as “a major surprise,” saying that officials have been focused on eradicating the disease in Afghanistan and Pakistan, where health workers have been killed for immunizing children and where conflict has made access to some areas impossible.

Still, O’Leary said he is confident Israel, Britain and the U.S. will shut down their newly identified outbreaks quickly.

The oral vaccine is credited with dramatically reducing the number of children paralyzed by polio. When the global eradication effort began in 1988, there were about 350,000 cases of wild polio a year. So far this year, there have been 19 cases of wild polio, all in Afghanistan, Mozambique and Pakistan.

In 2020, the number of polio cases linked to the vaccine hit a peak of more than 1,100 spread out across dozens of countries. It has since declined to around 200 this year so far.

Last year, WHO and partners also began using a newer oral polio vaccine, which contains a live but weakened virus that scientists believe is less likely to mutate into a dangerous form, but supplies are limited.

To stop polio in Britain, Israel and the U.S., what is needed is more vaccination, experts say. That is something Columbia University’s Barrett worries could be challenging in the COVID-19 era.

“What’s different now is a reduction in trust of authorities and the political polarization in countries like the U.S. and the U.K.,” Barrett said. “The presumption that we can quickly get vaccination numbers up quickly may be more challenging now.”

Oyewale Tomori, a virologist who helped direct Nigeria’s effort to eliminate polio, said that in the past, he and colleagues balked at describing outbreaks as “vaccine-derived,” wary it would make people fearful of the vaccine.

“All we can do is explain how the vaccine works and hope that people understand that immunization is the best protection, but it’s complicated,” Tomori said. “In hindsight, maybe it would have been better not to use this vaccine, but at that time, nobody knew it would turn out like this.”
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Echoing down the corridors of eastern Ukraine’s Pokrovsk Perinatal Hospital are the loud cries of tiny Veronika.

Born nearly two months prematurely weighing 1.5 kilograms (3 pounds, 4 ounces), the infant receives oxygen through a nasal tube to help her breathe while ultraviolet lamps inside an incubator treat her jaundice.

Dr. Tetiana Myroshnychenko carefully connects the tubes that allow Veronika to feed on her mother’s stored breast milk and ease her hunger.

Before Russia’s invasion of Ukraine in late February, three hospitals in government-controlled areas of the country’s war-torn Donetsk region had facilities to care for premature babies. One was hit by a Russian airstrike and the other had to close as a result of the fighting  — leaving only the maternity hospital in the coal mining town of Pokrovsk still operating.

Myroshnychenko, the site’s only remaining neonatologist, now lives at the hospital. Her 3-year-old son divides the week between staying at the facility and with his father, a coal miner, at home.

The doctor explains why it’s now impossible to leave: Even when the air-raid sirens sound, the babies in the hospital’s above-ground incubation ward cannot be disconnected from their lifesaving machines.

“If I carry Veronika to the shelter, that would take five minutes. But for her, those five minutes could be critical,” Myroshnychenko says.

Hospital officials say the proportion of births occurring prematurely or with complications has roughly doubled this year compared to previous times, blaming stress and rapidly worsening living standards for taking a toll on the pregnant women still left in the area.

Russia and Moscow-backed separatists now occupy just over half the Donetsk region, which is similar in size to Sicily or Massachusetts. Pokrovsk is still in a Ukrainian government-controlled area 60 kilometers (40 miles) west of the front lines.

Inside the hospital’s maternity wards, talk of the war is discouraged.

“Everything that happens outside this building of course concerns us, but we don’t talk about it,” Myroshnychenko said. “Their main concern right now is the baby.”

Although fighting in the Dontesk region started back in 2014, when Russia-backed separatists began battling the government and taking over parts of the region, new mothers are only now being kept in the hospital for longer periods because there’s little opportunity for them to receive care once they have been discharged.

Among them is 23-year-old Inna Kyslychenko, from Pokrovsk. Rocking her 2-day-old daughter Yesenia, she was considering joining the region’s massive evacuation westward to safer areas in Ukraine when she leaves the hospital. Many essential services in government-held areas of Donetsk — heat, electricity, water supplies — have been damaged by Russian bombardment, leaving living conditions that are only expected to worsen as the winter grows near.

“I fear for the little lives, not only for ours, but for all the children, for all of Ukraine,” Kyslychenko said.

More than 12 million people in Ukraine have fled their homes due to the war, according to U.N. relief agencies. About half have been displaced within Ukraine and the rest have moved to other European countries.

Moving the maternity hospital out of Pokrovsk, however, is not an option.

“If the hospital was relocated, the patients would still have to remain here,” said chief physician Dr. Ivan Tsyganok, who kept working even when the town was being hit by Russian rocket fire.

“Delivering babies is not something that can be stopped or rescheduled,” he noted.

The nearest existing maternity facility is in Ukraine’s neighboring Dnipropetrovsk region, a 3 1/2 hour drive along secondary roads, a journey considered too risky for women in late-term pregnancy.

Last week, 24-year-old Andrii Dobrelia and his wife Maryna, 27, reached the hospital from a nearby village. Looking anxious, they talked little as doctors carried out a series of tests and then led Maryna to the operating room for a C-section. Tsyganok and his colleagues hurriedly changed their clothes and prepared for the procedure.

Twenty minutes later, the cries of a newborn baby boy, Timur, could be heard. After an examination, Timur was taken to meet his father in an adjoining room.

Almost afraid to breathe, Andrii Dobrelia tenderly kissed Timur’s head and whispered to him. As the newborn calmed down on his father’s chest, tears came to Andrii’s eyes.

As the war reaches the six-month mark, Tsyganok and his colleagues says they have a more hopeful reason to stay.

“These children we are bringing into the world will be the future of Ukraine,” says Tsyganok. “I think their lives will be different to ours. They will live outside war.”
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While vacationers might enjoy the Mediterranean Sea’s summer warmth, climate scientists are warning of dire consequences for its marine life as it burns up in a series of severe heat waves.

From Barcelona to Tel Aviv, scientists say they are witnessing exceptional temperature hikes ranging from 3 degrees Celsius (5.4 Fahrenheit) to 5 degrees Celsius (9 Fahrenheit) above the norm for this time of year. Water temperatures have regularly exceeded 30 C (86 F) on some days.

Extreme heat in Europe and other countries around the Mediterranean has grabbed headlines this summer, but the rising sea temperature is largely out of sight and out of mind.

Marine heat waves are caused by ocean currents building up areas of warm water. Weather systems and heat in the atmosphere can also pile on degrees to the water’s temperature. And just like their on-land counterparts, marine heat waves are longer, more frequent and more intense because of human-induced climate change.

The situation is “very worrying,” says Joaquim Garrabou, a researcher at the Institute of Marine Sciences in Barcelona. “We are pushing the system too far. We have to take action on the climate issues as soon as possible.”

Garrabou is part of a team that recently published the report on heat waves in the Mediterranean Sea between 2015 and 2019. The report says these phenomena have led to “massive mortality” of marine species.

About 50 species, including corals, sponges and seaweed, were affected along thousands of kilometers of Mediterranean coasts, according to the study, which was published in the Global Change Biology journal.

The situation in the eastern Mediterranean basin is particularly dire.

The waters off Israel, Cyprus, Lebanon and Syria are “the hottest hot spot in the Mediterranean, for sure,” said Gil Rilov, a marine biologist at Israel’s Oceanographic and Limnological Research institute, and one of the paper’s co-authors. Average sea temperatures in the summer are now consistently over 31 C (88 F).

These warming seas are driving many native species to the brink, “because every summer their optimum temperature is being exceeded,” he said.

What he and his colleagues are witnessing in terms of biodiversity loss is what is projected to happen further west in the Mediterranean toward Greece, Italy and Spain in the coming years.

Garrabou points out that seas have been serving the planet by absorbing 90% of the earth’s excess heat and 30% of carbon dioxide emitted into the atmosphere by coal, oil and gas production. This carbon-sink effect shields the planet from even harsher climate effects.

This was possible because oceans and seas were in a healthy condition, Garrabou said.

“But now we have driven the ocean to an unhealthy and dysfunctional state,” he said.

While the earth’s greenhouse gas emissions will have to be drastically reduced if sea warming is to be curtailed, ocean scientists are specifically looking for authorities to guarantee that 30% of sea areas are protected from human activities such as fishing, which would give species a chance to recover and thrive.

About 8% of the Mediterranean Sea area is currently protected.

Garrabou and Rilov said that policymakers are largely unaware of the warming Mediterranean and its impact.

“It’s our job as scientists to bring this to their attention so they can think about it,” Rilov said.

Heat waves occur when especially hot weather continues over a set number of days, with no rain or little wind. Land heat waves help cause marine heat waves and the two tend to feed each other in a vicious, warming circle.

Land heat waves have become commonplace in many countries around the Mediterranean, with dramatic side effects like wildfires, droughts, crop losses and excruciatingly high temperatures.

But marine heat waves could also have serious consequences for the countries bordering the Mediterranean and the more than 500 million people who live there if it’s not dealt with soon, scientists say. Fish stocks will be depleted and tourism will be adversely affected, as destructive storms could become more common on land.

Despite representing less than 1% of the global ocean surface area, the Mediterranean is one of the main reservoirs of marine biodiversity, containing between 4% and 18% of the world’s known marine species.

Some of the most affected species are key to maintaining the functioning and diversity of the sea’s habitats. Species like the Posidonia oceanica seagrass meadows, which can absorb vast amounts of carbon dioxide and shelters marine life, or coral reefs, which are also home to wildlife, would be at risk.

Garrabou says the mortality impacts on species were observed between the surface and 45 meters (around 150 feet) deep, where the recorded marine heat waves were exceptional. Heat waves affected more than 90% of the Mediterranean Sea’s surface.

According to the most recent scientific papers, the sea surface temperature in the Mediterranean has increased by 0.4 C (0.72 F) each decade between 1982 and 2018. On a yearly basis, it has been rising by some 0.05 C (0.09 F) over the past decade without any sign of letting up.

Even fractions of degrees can have disastrous effects on ocean health, experts say.

The affected areas have also grown since the 1980s and now covers most of the Mediterranean, the study suggests.

“The question is not about the survival of nature, because biodiversity will find way to a survive on the planet,” Garrabou said. “The question is if we keep going in this direction maybe our society, humans, will not have a place to live.”

 
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Today’s sharks have nothing on their ancient cousins. A giant shark that roamed the oceans millions of years ago could have devoured a creature the size of a killer whale in just five bites, new research suggests.

For their study published Wednesday, researchers used fossil evidence to create a 3D model of the megalodon — one of the biggest predatory fish of all time — and find clues about its life.

At around 50 feet (16 meters) from nose to tail, the megalodon was bigger than a school bus, according to the study in the journal Science Advances. That’s about two to three times the size of today’s great white shark. The megalodon’s gaping jaw allowed it to feed on other big creatures. Once it filled its massive stomach, it could roam the oceans for months at a time, the researchers suggest.

The megalodon was a strong swimmer, too: Its average cruising speed was faster than sharks today and it could have migrated across multiple oceans with ease, they calculated.

“It would be a superpredator just dominating its ecosystem,” said co-author John Hutchinson, who studies the evolution of animal movement at England’s Royal Veterinary College. “There is nothing really matching it.”

It’s been tough for scientists to get a clear picture of the megalodon, said study author Catalina Pimiento, a paleobiologist with the University of Zurich and Swansea University in Wales.

The skeleton is made of soft cartilage that doesn’t fossilize well, Pimiento said. So the scientists used what few fossils are available, including a rare collection of vertebrae that’s been at a Belgium museum since the 1860s.

Researchers also brought in a jaw’s worth of megalodon teeth, each as big as a human fist, Hutchinson said. Scans of modern great white sharks helped flesh out the rest.

Based on their digital creation, researchers calculated that the megalodon would have weighed around 70 tons, or as much as 10 elephants.

Even other high-level predators may have been lunch meat for the megalodon, which could open its jaw to almost 6 feet (2 meters) wide, Pimiento said.

Megalodons lived an estimated 23 million to 2.6 million years ago.

Since megalodon fossils are rare, these kinds of models require a “leap of imagination,” said Michael Gottfried, a paleontologist at Michigan State University who was not involved in the study. But he said the study’s findings are reasonable based on what is known about the giant shark.

 
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