TIME flu

The New Bird Flu Outbreak: Should You Worry?

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So far, bird flu cases in Europe have been identified as the H5N8 strain

Bird flu strain H5N8 has been identified on a duck farm in England and in chickens at a farm in the Netherlands. Should people be scared about a new pandemic? Experts say, no.

Where are the latest cases?

On November 17, bird flu was confirmed on a duck farm in East Yorkshire. About 6,000 ducks will be killed and a 6-mile surveillance zone is going up around the farm. The emergence comes just a day after bird flu was detected in the Netherlands at an egg farm. According to the BBC, the Dutch government has imposed a three-day ban on poultry and eggs transport. Officials are currently figuring out whether the two cases are connected. Earlier this month, bird flu also appeared in Germany.

Should I be afraid?

Not right now. First, it should be noted that there are several strains of bird flu, or avian influenza, and the recent strains have only so far emerged in birds, not humans. The Dutch and German governments determined their strains of the flu are both H5N8, a highly contagious virus that has never been found in humans. The British government has not yet said what strain of bird flu is circulating in the duck farm, but they have confirmed that it’s not H5N1, which can infect humans.

So what’s the big deal?

Farms with H5N8 outbreaks can face serious economic losses.

So it hasn’t affected humans before. Does that mean it won’t—ever?

Experts cannot completely rule out the possibility of human infection. “This particular strain has not been known to infect humans but, based on experience with H5N1, we know that H5 viruses have that capacity,” says Dr. Amesh Adalja, a senior associate of the University of Pittsburgh Medical Center Center for Health Security. “Thus far, avian influenza viruses have very limited human-to-human transmission capacity, so the general public need not panic, however poultry handlers may be at risk for infection. It will be important to understand the dynamics of this outbreak and understand the potential of H5N8 to infect humans.”

What about H5N1 makes it so much more worrying?

H5N1 is the strain that can spread to humans from birds, and it’s infected more than 600 people from 15 countries since November 2003, the Centers for Disease Control and Prevention (CDC) reports. About 60% of people who have contracted the strain have died. The majority of human cases are among people with direct or close contact with sick or dead infected poultry, and the disease does not efficiently transmit from person to person. However, if that were to change, scientists say we’d have a serious problem on our hands.

Is there a treatments or vaccine for bird flu?

Not exactly. In Nov. 2013, the FDA approved a H5N1 vaccine intended for the National Stockpile and not for commercial use. The CDC has told TIME that the vaccine is not very effective and would likely require more than one dose. Researchers are working on other vaccines for bird flu and its various strains, though none are currently approved. Right now, preventing the spread of infection is the best bet for keeping cases low.

“Avian influenza will always be a major infectious disease threat. Certain avian influenza viruses—such as H5N1 and H7N9—have very high case fatality rates and are leading contenders for wider spread amongst the human population,” says Adalja.

And while the current cases of bird flu shouldn’t freak you out, it is important for the global community to pay attention to the various strains and support vaccine and drug development.

TIME health

Bird Flu Returns: What Past Outbreaks Can Teach Us

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A man wearing a face mask walks through a duck breeding farm where a case of bird flu has been identified in Nafferton, in Yorkshire, England, on Nov. 17, 2014. Oli Scarff—AFP / Getty Images

As bird flu rears its head once again, take a look at TIME's past coverage of the virus

Usually the health status of chickens in the Netherlands isn’t world news. But reports that the Dutch government had culled tens of thousands of birds at poultry farms that were potentially infected with the avian flu virus H5N8 will worry human health officials as well.

That’s because avian flus have shown the repeated ability to jump the species barrier, infecting human beings—and killing them. The most dangerous virus has been H5N1, which has infected hundreds of human beings over the past decade, mostly in Asia, killing an estimated 60% of them. Bird flu infections in human beings are still very rare, usually occurring because of close contact with a sick birds. Right now avian flus like H5N1 haven’t shown the ability to spread from person to person. But scientists fear that an avian flu virus could eventually mutate, and become more transmissible—potentially starting a new flu pandemic. And if that new flu was as transmissible as the seasonal human flu, but as deadly as H5N1 would be, the result would make Ebola look like a slight cold.

Learn about the potential dangers of avian flu with these stories from TIME’s archives:

Feb. 9, 2004: The Revenge of the Birds

An H5N1 outbreak in Asia kills thousands of chickens — and leads millions more to be slaughtered. Though the number of humans affected is low, the outbreak raises fears about what could happen if the virus mutated.

The virus probably originates in southern China, but no one knows how it has spread so widely. Transport of infected birds to chicken farms is one theory, but it’s also possible that migratory birds such as ducks and geese are spreading it through their droppings. “Did birds in Hong Kong, which nest in Siberia and North Korea, somehow spread the virus elsewhere?” asks Robert Webster, an expert in animal influenzas at St. Jude Children’s Research Hospital in Memphis, Tenn. “That’s a frightening possibility.” If H5N1 does evolve into a flu that humans can spread, a vaccine could be developed but would take months. “Once you know this virus can spread from human to human, region to region,” says Dr. Yi Guan, a SARS and avian-flu expert at the University of Hong Kong, “it’s already too late.”

Sept. 19, 2005: A Wing and a Prayer

The H5N1 virus, previously thought present in domestic animals only, appears in migratory birds, indicating that it has to potential to spread around the world.

For some time, health experts have warned of a worldwide bird-flu pandemic that could kill millions of people and wreck the global economy. “The most serious known health threat facing the world is avian flu,” said WHO director-general Lee Jong-wook earlier this year. And the threat is growing all the time, as nature keeps dropping hints that the links in a chain of events leading to a deadly pandemic continue to be forged. This summer, H5N1 spread west—perhaps in migrating birds—to new territory, including Mongolia, Tibet, Siberia and Kazakhstan. European countries are taking precautions by tightening surveillance of flocks within their borders; in the Netherlands, officials in late August ordered farmers to move the nation’s 90 million poultry indoors to prevent any contact with itinerant fowl. Meanwhile, in Southeast Asia, where at least 58 people have died and 150 million poultry have died or been culled because of avian flu since the end of 2003, the virus is still active; a Jakarta woman died of the disease on Sept. 10. The H5N1 virus has already shown it can be deadly to people who come into direct contact with infected birds or eat uncooked poultry. But bird-to-human transmission is relatively controllable because diseased flocks can be isolated or, usually, eliminated. The sum of all fears is that H5N1 could mutate into a strain with the ability to jump easily from person to person, as ordinary flu does. That could trigger a once-in-a-century catastrophe. How many would die? Nobody knows, or can know.

June 14, 2007: Living Cheek to Beak

A trip to Indonesia reveals some reasons why it’s harder than you might expect to contain the virus in birds: understanding of the potential for pandemic is low among village farmers, and the habits of daily life are harder to break. But, because of the close relationship between humans and livestock, the stakes in such a situation are particularly high.

Indonesia’s chickens are about meat and eggs, of course. But they are also a potentially deadly symbol of changing patterns of food production and consumption. While the H5N1 strain of avian flu has occasionally jumped from birds to people for several years now, the fear is that it will mutate and begin spreading easily from person to person, threatening the lives of millions. So a pandemic is why the world cares about dead chickens in a tiny rural village. Though the rare human bird-flu cases have gotten most of the attention, “the most effective way to prevent a pandemic is to stop the virus in animals,” says Dr. Bernard Vallat, director general of the World Organization for Animal Health (OIE). In other words: save the chickens, save the world.

May 18, 2009: How to Prepare for a Pandemic

An outbreak of swine flu (H1N1) highlights the reason why epidemiologists need to spend their time thinking about animals other than human beings. Many dangerous diseases (including Ebola) originate from animals and mutate into viruses that can be spread among humans.

Why should we spend scarce medical resources swabbing the inside of pigs’ nostrils, looking for viruses? Because new pathogens–including H5N1 bird flu, SARS, even HIV–incubated in animal populations before eventually crossing over to human beings. In the ecology of influenza, pigs are particularly key. They can be infected with avian, swine and human flu viruses, making them virological blenders. While it’s still not clear exactly where the H1N1 virus originated or when it first infected humans, if we had half as clear a picture of the flu viruses circulating in pigs and other animals as we do of human flu viruses, we might have seen H1N1 coming. (When it comes to sniffing out new pathogens, says one epidemiologist, “we’re like a drunk looking for his keys.”) Faster genetic sequencing and the Internet give us the technological means to create an early-warning system. But we need to spend more on animal health and get doctors talking to their veterinarian counterparts. “For too long, the animal side of public health has been neglected,” says Dr. William Karesh, vice president of the Wildlife Conservation Society’s global-health program.

Read more about the current outbreak of bird flu here on Time.com.

TIME

This Flu Shot Is Not Like the Others

Some people may get a new flu shot that’s made with dog cells instead of chicken eggs

This year Novartis shipped its first full batch of Flucelvax, a new vaccine that was only approved by the Food and Drug Administration in 2012. The company made a limited amount of the shot last year, but there are more doses to go around this flu season. And for the first time, the doses were made at the company’s newly approved U.S. plant in Holly Springs, North Carolina.

The vaccine is made without growing the influenza virus in chicken eggs, which is the way that flu shots were made for more than four decades. Instead, Flucelvax is grown in kidney cells from dogs. The technology means that the shot can be made in less time than a traditional flu shot—enough virus can be churned out in about 65 hours to 75 hours, compared to the six months or so it takes to grow in chicken eggs. It also means that people who are allergic to eggs now have another option for getting immunized against the flu.

MORE: Pregnant Women and the Flu: Why Influenza Is More Dangerous for Expectant Moms

In studies that the FDA reviewed before approving the vaccine, the shot was 84% effective in preventing flu among adults who were vaccinated compared to those who received a placebo. People getting Flucelvax produced around the same amount of antibodies to the influenza virus as those who were immunized with a chicken egg-based flu vaccine.

Using animal cells instead of chicken eggs, say Novartis officials, allows them to have more control over the purity of the final vaccine. How well influenza grows in the chicken eggs is variable—some eggs or batches of eggs help the virus grow, while others aren’t as conducive to producing large amounts of influenza.

The cell-based technology is also a plus during a flu pandemic, since the platform can produce more doses quickly to control an outbreak as a particular influenza virus spreads among a population. The kidney cells are frozen and can be thawed quickly to begin growing virus. The company has produced doses of pandemic flu vaccine against H5N1 using the cell technology, and it’s keeping them in deep freeze as part of the U.S. government stockpile in the event of a pandemic.

The FDA has approved seven different types of flu shots—in addition to Flucelvax and the standard vaccine made from chicken eggs that protects against three strains of influenza, there is also a shot that protects against four strains of flu; for the needle-phobic, one with a microneedle injects just into the skin and doesn’t penetrate into the muscle, making it less painful; for the elderly who need more protection, there is a high-dose vaccine; for younger children there is a nasal spray; and for those allergic to eggs, there’s a shot made from bits of influenza proteins grown in insect cells. Not every doctor’s office or clinic carries every shot, so if you prefer one over the others, call your health care provider to find out if it will be available.

TIME medicine

10 Biggest Myths About the Flu

Flu shots here
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Don't get us wrong, we're all for washing your hands with soap and water. But it's not enough to stop the flu

Every flu season—which starts in October and peaks in January and February in the U.S.—as many as 20% of Americans get sick with a virus that can cause serious, even lethal complications (not to mention the general awfulness of a fever, chills, congestion, and body aches). So how come there are still so many myths and rumors about the flu? While officials aren’t predicting whether this year’s influenza will be better or worse than in years past, it’s smart to make sure you know the truth about this dreaded virus and what you can do to reduce your risk of catching it.

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You can catch the flu from the flu shot

No, you can’t. Really. This longstanding rumor just won’t die no matter how often experts debunk it. “The flu vaccine is made with dead viral particles, and since the virus is not living, it can’t infect you,” explains Holly Phillips, M.D., a New York City internist and WCBS News medical contributor. The nasal-spray version of the vaccine, called the FluMist, (which is FDA-approved for kids and adults between ages two and 49 who are healthy and not pregnant) does contain a crippled version of live flu virus. However, it still can’t make you sick, says Dr. Phillips. This misconception may stem from the fact that it takes 2 weeks for your body to form antibodies to the vaccine and fully protect you. So if you pick up a cold or the flu before or just after rolling up your sleeve, don’t blame your runny nose and sore throat on the shot.

Young, healthy people don’t need to worry about the flu

“While it’s true that influenza is most threatening to the very young, the elderly, and people with underlying illnesses, it can still cause severe symptoms in otherwise healthy people,” says Dr. Phillips. That’s why the CDC recommends that everyone get the shot, preferably early in flu season. Even if you’re not in a high-risk group, getting the shot can stop you from transmitting the virus to more vulnerable people. “The more people who get the shot, the more we cut down on the amount of influenza circulating in the population, which can protect your grandmother or child,” says Dr. Phillips. Even if you don’t regularly interact with kids or seniors, take a few minutes and get the shot—at your doctor’s office, local pharmacy, or community health center. You can’t pass on a virus you never got in the first place.

HEALTH.COM: 10 Ways You Put Yourself at Risk for the Flu (Without Realizing It)

The flu includes gastrointestinal symptoms

As miserable as symptoms of the flu are, digestive distress is rarely one of them. What’s politely called the “stomach flu” is a colloquial term that refers to a group of viruses that primarily cause vomiting and diarrhea, says Dr. Phillips. “These viruses are not influenza,” she says. That’s not to say that the flu doesn’t occasionally lead to some gastrointestinal issues; some sufferers do experience nausea and even vomiting. But if you develop these symptoms without any of the classic flu tip-offs, you’re probably dealing with an entirely different germ.

Pregnant women can’t get a flu shot

On the contrary, all pregnant women should get the jab as soon as possible. “The flu shot is very safe for pregnant women, and getting it can even protect the baby for the first few months of life, when he or she is not old enough to get the flu shot yet but is very vulnerable to illness,” says Dr. Phillips. (Babies at least six months old are eligible for the vaccine.) Antibodies that form in response to the shot will not only protect you from the flu, they will protect your baby after birth and be delivered via breast milk, according to the CDC. Pregnancy causes immune, heart, and lung changes that can increase your risk for a bad case of flu, which can affect your pregnancy. “High fevers and severe infections can lead to serious pregnancy complications and even premature labor,” says Dr. Phillips.

HEALTH.COM: 10 Diet Changes All Pregnant Women Must Make

You can stop the flu by washing your hands a lot

Don’t get us wrong, we’re all for washing your hands with soap and water. But it’s not enough to stop the flu. Influenza is spread through the air via droplets of saliva from a person who is contagious (which starts a day before symptoms show and up to seven days after). The droplets can land on you and get into your nose, mouth, and eyes. You can also pick up the flu by touching contaminated surfaces (the flu can live up to eight hours on surfaces, according to the CDC), then touching your hand to your face. So wash your hands with soap and water and avoid touching your eyes, nose, or mouth. This slashes your risk somewhat, Dr. Leavey says. It’s also important to stand at least six feet from anyone with the flu; the airborne droplets can’t travel farther than that. Disinfect common areas in your home or workplace if someone with the flu spent time there. And above all, get vaccinated.

If you get the flu, the shot didn’t work

The flu vaccine isn’t like vaccines that protect you against measles or polio, which offer 100% protection. Usually, the flu shot is only about 60 to 90% effective. That’s because multiple strains circulate every year, and it’s difficult for scientists to predict perfectly which strains will be dominant. “If you do get the flu after going for the shot, it just means that you contracted a different strain that wasn’t included in the vaccine,” says Dr. Phillips. If this happens, there is an upside: your symptoms will likely be less severe, since the shot will probably be at least somewhat effective against the strain you have, she adds. And keep in mind that to the CDC, a flu shot is a success if it prevents hospitalizations and deaths, not if you sail through the season without a sniffle.

Antibiotics can fight the flu

There’s no point in bugging your doctor—antibiotics don’t work on viruses. That said, there are Rx antiviral meds that might help. Tamiflu is the best known; this drug has been shown to cut the course of the disease by 1-2 days, if you take it within 48 hours of the first sign of flu symptoms. These are generally recommended only for those at high risk of complications. “The effects are relatively modest,” says Dr. Phillips. “Once you have the flu, you’re going to be miserable regardless. Prevention with the flu shot is a better approach.” Other meds that can offer some relief include over-the-counter fever reducers such as ibuprofen and acetaminophen, as well as congestion fighters. Best bet? Stay home, get some rest, drink lots of fluids, and wait it out (but be on your guard for serious complications).

Bell’s palsy is a side effect of the flu shot

Bell’s palsy is a condition that causes weakness or paralysis on one side of the face. It’s usually temporary, clearing up after several weeks, and it’s typically thought to be triggered by a viral infection, such as herpes simplex (the virus responsible for cold sores) or Epstein-Barr, which leads to mononucleosis. How did the flu get into the mix? Decades ago, a few isolated cases of people developing Bell’s palsy after getting a flu vaccine were reported. Yet no link was ever established showing that one caused the other, says Dr. Phillips. The overwhelming consensus is that the two have nothing to do with each other, adds Dr. Leavey.

HEALTH.COM: Unexpected Ways to Prevent the Flu

Flu shots can cause Alzheimer’s

The flu shot doesn’t cause any illness or condition, and that includes Alzheimer’s disease, says Dr. Leavey. Alzheimer’s is a type of dementia that leads to memory loss and other cognitive changes. Why some people develop Alzheimer’s is not fully understood, and that opens the door to lots of speculation—which seems to be how the rumor linking the flu jab to Alzheimer’s got its start. “The connection also has to do with the fact that senior citizens are strongly advised to get a flu shot every year, so people associate old age with flu shots, the way they associate old age with Alzheimer’s,” he says. “Or an elderly person who had a flu shot begins showing signs of memory loss months later. The two are unrelated, yet people conclude that the vaccine had something to do with it.”

This article originally appeared on Health.com.

TIME Infectious Disease

Pregnant Women and the Flu: Why Influenza Is More Dangerous for Expectant Moms

Immune responses are enhanced during pregnancy, study finds

Only 50% of pregnant women get the flu vaccine, but they’re among the most vulnerable to influenza. When mothers-to-be catch the virus, they tend to get much sicker than other healthy adults, and it increases their risk for delivering prematurely.

A new Stanford University study published in the Proceedings of the National Academy of Sciences looked at why pregnant women are so susceptible to the flu, and they found the culprit may be over-zealous cells that are key to fighting off infection.

Researchers collected immune cells from about 50 women, half of whom were pregnant and half who weren’t. They then infected the cell samples with influenza virus in a lab. In the samples from the pregnant women, two types of white blood cells, called natural killer and T cells, had enhanced immune responses, causing them to attract even more immune cells to help fight the virus.

While it might seem that such a strong response to the flu is exactly what expectant mothers would want, it can be too much of a good thing, says Dr. Catherine Blish, assistant professor of infectious diseases at Stanford School of Medicine and the study’s senior author. “Having too many immune cells in the lung can cause inflammation that makes it hard to breathe,” she says, which might help explain why pregnant women who get the flu are at greater risk for pneumonia and death. “If these findings are confirmed in bigger studies and then natural infection, they could explain why pregnant women do so poorly.”

“We normally think that these particular cells are suppressed by pregnancy to protect the fetus—it’s what we all learned in medical school,” Blish says. “And we found when we used a generalized stimulation that that was the case. But there’s something specific about flu that leads to this enhanced response.”

Getting the flu vaccine helps protect pregnant women, Blish says, and she and her team “really strongly recommend” that all women who are pregnant or considering getting pregnant get vaccinated.

Blish and her colleagues plan to study whether other viruses have the same effect and whether it’s possible to treat severe influenza by turning down this immune response. But even if these findings eventually lead to new therapies, she says, “the most important thing to remember is that influenza vaccine is really the best tool to prevent infection in the first place.”

TIME Infectious Disease

Health Experts Urge Flu Vaccination

Pregnant women and children are particularly vulnerable

“We can’t predict what this year’s flu season will be like,” said Centers for Disease Control and Prevention (CDC) Director Tom Frieden at a National Foundation for Infectious Diseases press conference Thursday. “But we can predict that the best way to protect yourself against the flu is to get a flu vaccination.”

More than 90 percent of doctors and nurses receive a flu vaccination, experts said. They stressed that pregnant women and children are particularly vulnerable and should prioritize taking the vaccine. Flu-related complications can lead to early labor in pregnant women, said Laura Riley, director of labor and delivery at Massachusetts General Hospital.

A lack of understanding of the risks of the and a belief in “scientifically unfounded views” were the most common reasons people decided against taking the vaccine, according to Children’s Hospital of Philadelphia infectious disease expert Paul A. Offit.

“The riskiest thing about vaccines is driving to the office to get them,” he said.

Last year 10 million people in the United States caught the flu, causing thousands of deaths. More than 100 children died, 90 percent of whom didn’t take a flu shot.

TIME Infectious Disease

Hand Sanitizers Don’t Lower School Absences

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A new study shows hand sanitizer doesn't keep kids in school Paul Velgos—Getty Images

Putting hand sanitizers in schools and encouraging kids to use them doesn’t lower the rate of school absences, according to new research published Tuesday in the journal PLOS Medicine.

“These findings suggest that in high-income countries, where clean water for hand washing is readily available, putting resources into extra hand hygiene by providing hand sanitizer in classrooms may not be an effective way to break the child-to-child transmission of infectious diseases,” the study authors conclude.

The team of New Zealand researchers randomly assigned 68 primary schools to either have alcohol-based hand sanitizers in the classroom or not. All of the students in the participating schools underwent a 30 minute session on hand hygiene. The kids were also told that they should use the hand sanitizer after they coughed or sneezed, as well as when they left the classroom.

Despite the high level of encouraged use of the dispensers, the researchers found that there was no difference in the rates of school absences between the schools with dispensers and the schools without. Still, the study had some limitations. During the study period, there was an flu going around in the region—which means that the population was likely hearing public health messages about flu prevention in other places, making the effectiveness of their specific intervention difficult to parse.

For now, a good bar or soap and water, for those lucky enough to use them liberally, should do the trick.

 

TIME

Nasal Flu Spray Better Than Shot For Young Kids, CDC Panel Says

Kids who use the nasal flu vaccine are half as likely to get sick as those who get the shot

Needle-phobic kids, rejoice!

U.S. health officials say the nasal spray flu vaccine is more effective than a traditional shot for children ages 2 to 8.

The Advisory Committee on Immunization Practices, a group of experts that makes recommendations to the Centers for Disease Control for which vaccines children and adults should get, voted to recommend the spray over the shot late Wednesday. The panel said studies show children who had the spray are half as likely to get the flu as those who had the shot.

So far, there is only one nasal spray flu vaccine available — AstraZeneca’s FluMist, which was approved in 2003 for people ages 2 to 49.

The spray differs from the needle-based vaccine in another important way — it’s made from a live, weakened influenza virus, while the shot drums up an immune response using killed virus. Studies have shown the spray can lead to a stronger immune response in children who have not had the flu before, but the same may not hold true for adults.

Not everyone agrees with the panel’s recommendation, however. The American Academy of Pediatrics, the nation’s largest pediatric group, does not think any one vaccine should be given preference for kids, since both are effective. One concern they cite is the fact that FluMist is typically more expensive than the flu shot, according to the Associated Press. AstraZeneca’s product costs about $23 while shots range from $8 to $22.

Other experts say that the spray isn’t for everyone. “Some kids can’t take the mist, namely those with compromised immune systems and kids with asthma, who could have a respiratory response,” Marc Siegel, an associate professor of medicine at NYU Langone Medical Center in New York City, told HealthDay. “So when in doubt, get the shot.”

The committee’s advice, which government pubic health officials usually follow, also comes too late for the upcoming flu season in the fall. Doctors have already ordered their vaccine doses, so if approved, most pediatricians won’t be able to follow the advice until next year.

Still, according to the AP, AstraZeneca may have anticipated the decision and made more of the spray for the coming flu season. The company will manufacture 18 million doses to distribute globally, up from 13 million made for the U.S. last year, Kathleen Coelingh, the company’s senior director of U.S. medical affairs told the news agency.

While not everyone agrees on the panel’s advice, public health experts do agree on the fact that every child should be immunized. If the nasal spray is not immediately available, children should get the flu shot so that they do not miss or delay an opportunity to get vaccinated.

 

TIME health

The Medieval Black Death Made You Healthier—If You Survived

Plague killed millions in Europe
The Black Death killed as much as half of Europe's population Photo by Science & Society Picture Library/SSPL/Getty Images

The plague was horrific, could hit without warning and killed tens of millions in 14th century Europe. But paradoxically, the population that survived ended up better off, with higher wages, cleaner living conditions and healthier food

Game of Thrones doesn’t tell you the half of it. Life during the medieval ages was nasty, brutish and short. That was especially true during what became known as the Black Death. The widespread outbreak of plague struck between 1347 and 1351, killing tens of millions of people, resulting in the loss of 30 to 50% of the region’s population. The disease itself was horrific. “In men and women alive,” wrote the Italian poet Giovanni Boccaccio, “at the beginning of the malady, certain swellings, either on the groin or under the armpits…waxed to the bigness of a common apple, others to the size of an egg, some more and some less, and these the vulgar named plague-boils.” And it seemed to strike indiscriminately and without warning. People could be healthy in the morning and dead by evening.

The upside, if you can call it that, is that the plaque left in its wake populations that were healthier and more robust than people who existed before the plague struck, according to a new study published today in PLOS ONE. “The Black Death was a selective killer,” says Sharon DeWitte, a biological anthropologist at the University of South Carolina and the author of the paper. “And after the Black Death ended, there was actually an improvement in the standard of living.” The plague was natural selection in action.

In a way, that’s a marker of how brutal the medieval era was. It took a serial killer of a plague to actually bring about an improvement in living conditions. If that sounds counterintuitive, think about how life might have changed after half of Europe’s population died off. Suddenly there was a dramatic drop in the number of able-bodied adults available to do work, which meant survivors could charge more for their labor. At the same time, fewer people meant a decreased demand for foods, goods and housing—and as a result, the prices for all three dropped. By the late 15th century, real wages were three times higher than they were at the beginning of the 14th century, before the plague struck. Diets improved as employers were forced to raise wages and offer extra food and clothing to attract workers. As a result, the money spent per capita on food in the wake of the Black Death actually increased. “People were able to eat more meat and high-quality bread, which in turn would have improved health,” says DeWitte.

But the clearest evidence that people were healthier after the Black Death than they were before it comes in the bodies themselves. DeWitte looked at skeletal samples taken from medieval cemeteries in London both before the plague and after it. She found that post-Black Death samples had a higher proportion of older adults, and that morality risks were generally lower in the post-Black Death population than before the epidemic. In other words, if you were strong and lucky enough to survive one of the deadliest epidemics in human history, you were probably strong enough to live to a relatively ripe old age. And since the Black Death was so widespread, that was true for the surviving population as a whole.

Earlier studies looking at historical documents like diaries, letters and wills from the time period had shown conflicting results, but that kind of data only covers the very small part of the population that was literate, male and relatively well off. The advantage of DeWitte’s grave-combing bioarchaeological research methods is that they encompass a much more representative swath of the medieval population. “This provides information about the people who are missing from historical documents, including women and children,” says DeWitte. Not everyone in medieval London left a will behind—but everyone left a corpse.

So for survivors, life after the Black Death would have been at least a little less nasty, brutish and short than life before it. But that doesn’t mean the survivors were really the lucky ones. The Black Death was a period of unremitting horror and terror, the likes of which we can’t imagine. No one knew how the disease spread, or how to treat it. Popular but gruesome methods like blood-letting or boil-lancing would have been counterproductive at best, assuming victims could find anyone to treat them. Doctors abandoned their patients for fear of infection, and priests even refused to give last rites to the dying—an appalling dereliction given medieval fears of eternal damnation. Even animals like sheep, cows and pigs fell victim to the disease. “The people who survived the Black Death would have lost everyone they knew,” says DeWitte. “They’re the people I feel sorry for.” If the Black Death really was natural selection at work, it was the cruelest form imaginable.

TIME health

Solving the Mystery Flu That Killed 50 Million People

The deadly 1918 flu pandemic
The 1918 flu pandemic killed an estimated 50 million people Photo Researchers via Getty Images

Researchers have wondered for decades why the 1918 flu disproportionately killed so many young people, but a new study in the Proceedings of the National Academy of Sciences suggests the answers are in the pattern of past flu infections

Years ago the environmental historian Alfred Crosby was at Washington State University, where he was teaching at the time, when on a whim he decided to pick up an old almanac from 1917. (This is apparently the kind of thing historians like to do in their spare time.) He looked up the U.S. life expectancy in that year—it was about 51 years. He turned to the 1919 almanac, and found about the same figure. Then Crosby picked up the almanac from 1918. The U.S. life expectancy in 1918 had fallen to 39 years. “What the hell happened?” Crosby told the New York Times writer Gina Kolata in her book Flu: The Story of the Great Influenza Pandemic of 1918. “ The life expectancy had dropped to what it had been fifty years before.”

What happened was the 1918 influenza pandemic. A virus that usually does little more than make people feel awful for a few days killed an estimated 50 million people worldwide, if not far more, with 650,000 people dying in the U.S. alone. The flu killed more people in a year than the bubonic plague killed in a century in the Middle Ages. Worst of all, this flu disproportionately took the lives of men and women in their 20s and 30s, while often sparing the very old and the very young—two population groups that are especially vulnerable to the flu in most years.

This has confounded scientists for almost a century, but a new study in the Proceedings of the National Academy of Sciences (PNAS) puts forward a fresh answer to one of the enduring mysteries of medical science. Researchers led by Michael Worobey of the University of Arizona reconstructed the origins of the 1918 pandemic, concluding that the pathogen arose when an existing human H1 flu virus acquired genetic material from a bird flu virus. That new H1N1 flu virus was able to evade immune systems, which helps explain why it infected more than a quarter of the U.S. population at the time. But it was young adults between the ages of 20 and 40 that died in the greatest number—and Worobey’s study suggests that the unusual death pattern was due as much to flus of the past as it was to the flu of 1918. “Prior immunity, or lack of it, seems to be the decisive factor,” says Worobey.

Flu viruses are constantly changing and mutating, which is why we can’t develop a lifelong vaccine for it the way we can for more stable viruses, like the ones that cause smallpox or the measles. A flu virus has two parts: hemagglutinin and neuraminidase proteins, shortened to HA and NA (and just H and N when naming a virus). It’s the HA protein that seems to drive our immune system response, as Worobey put it in a statement:

Imagine a soccer ball studded with lollipops. The candy part of the lollipop is the globular part of the HA protein, and that is by far the most potent part of the flu virus against which our immune system can make antibodies. If antibodies cover all the lollipop heads, the virus can’t even infect you.

Worobey and his colleagues looked back at the kinds of flu viruses that were in circulation in the decades preceding the 1918 pandemic by examining antibodies found in old blood samples. (Your immune system will produce customized antibodies in response to a flu infection, and those antibodies will remain in your body, which allows scientists to identify the genetic makeup of the virus that led to their creation.) It turns out people born between 1880 and 1900—the generation hit hardest by the 1918 flu—were mostly exposed during childhood to a H3N8 flu virus that began circulating during an earlier pandemic in 1889, but not to an H1 virus, which meant that generation had virtually no antibodies to fight it off.

By reconstructing the genetic origins of the 1918 flu, Worobey found that a version of that H1N1 flu virus was circulating for years before the pandemic began. Because flu strikes most commonly in childhood, those born after 1900 were more likely to have had previous exposure to an H1N1-like flu virus, which would have offered them some protection. Meanwhile those born before 1880 were more likely to have been exposed to the H1N8 flu strain that was prevalent when they were children. In both the very young and the old, having earlier exposure to an H1 flu—even one different from the strain that caused the 1918 pandemic—offered a level of protection not present in those who had never been infected by an H1 strain. That could explain the unusual mortality curve in the 1918 pandemic.

1918 flu mortality curve
The researchers found a remarkable overlap between death rates in various age groups in 1918 and childhood exposure to an H3 flu virus that was mismatched with H1N1 pandemic virus. Credit: Michael Worobey

Thankfully, no flu pandemic since 1918 has been anywhere near as deadly. The 2009 swine flu pandemic killed an estimated 284,000 people worldwide, comparable to flu deaths in a non-pandemic year. But two avian flu viruses — H5N1 and H7N9 — have for years been periodically jumping the species barrier and infecting human beings. And like the 1918 flu, H5N1 and H7N9 are unusually deadly, particularly for the young and elderly, respectively. “Lots of different age groups might be exposed to these viruses, but the virus that kills them is the one that’s mismatched to the virus they encountered as a child,” says Worobey.

The PNAS paper suggests that this might be due to past flu patterns as well, with both groups having been exposed to flu viruses in their youth that offered them little protection against the new pathogens. If either virus were to mutate to the point where it could spread easily in the human population, the results could be catastrophic.

But the PNAS paper offers hope that doctors could begin to design flu vaccination strategies that compensate for the strains that different age groups never experienced as children. Down the line, scientists may even be able to develop a universal flu vaccine that targets parts of the virus that almost never change from strain to strain. “This work is encouraging that possibility,” says Worobey. If we’re smart, the global catastrophe that was the 1918 pandemic will remain confined to the history books.

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