Battling the Flu

Each February, an elite group of scientists from around the globe gathers at the World Health Organization’s headquarters in Geneva, Switzerland. Over the course of three days, the researchers pore over notebooks overflowing with case reports from more than 140 countries. Their job is to track the spread of a disease that kills hundreds of thousands of people worldwide every year. The group’s goal? To prevent the next big influenza outbreak.

Last fall and winter was one of the worst flu seasons in a decade. As many as 36 million people in the U.S. came down with a fever, body aches, a cough, a runny nose, or other symptoms associated with the illness. More than 80,000 of them died.

A group of top scientists from around the world meets each February. The researchers gather at the World Health Organization’s headquarters in Geneva, Switzerland. For three days, they study notebooks filled with case reports from more than 140 countries. Their job is to track the spread of a deadly disease. It kills hundreds of thousands of people worldwide every year. The group’s goal? To prevent the next big influenza outbreak.

Last fall and winter was one of the worst flu seasons in a decade. As many as 36 million people in the U.S. got the flu. They came down with a fever, body aches, a cough, a runny nose, or other flu symptoms. More than 80,000 people died.

People become sick with the flu when they get infected with the influenza virus—a nonliving particle that invades an organism’s body and reproduces inside its cells. And once the virus is inside you, it can easily spread to others with a simple cough or sneeze (see Avoiding the Flu).

Luckily, scientists can create a vaccine to provide protection against the virus. This medicine helps people avoid contracting the flu. But there’s a hitch: The flu virus is always mutating, or changing. A new vaccine is needed each year to protect against whatever strains of the disease will be most common that flu season. The scientists in Geneva must try to predict the future and figure out which strain will strike next.

“Only then can drug manufacturers start working on the vaccine,” says Dan Jernigan, one of the researchers on the Geneva task force.

People catch the flu when they get infected with the influenza virus. This nonliving particle invades a living thing’s body. Then it reproduces inside its cells. And after the virus is inside you, you can easily spread it to others. All you have to do is cough or sneeze (see Avoiding the Flu).

Luckily, scientists can make a vaccine to protect against the virus. This medicine helps people avoid catching the flu. But there’s a problem. The flu virus is always mutating, or changing. During the next flu season, different strains of the disease will be most common. So a new vaccine is needed each year to protect against them. Which strain will strike next? The scientists in Geneva must try to predict the future and figure it out. “Only then can drug manufacturers start working on the vaccine,” says Dan Jernigan. He’s a researcher on the Geneva task force.

After the World Health Organization meeting, pharmaceutical companies spend the next six months creating and distributing approximately 160 million doses of that year’s flu shot. It takes a lot of viruses to produce that many vaccine doses. Viruses need living cells to reproduce. So the most common way of making those vaccine doses involves incubating, or growing, strains of the virus in an unusual place—millions of fertilized chicken eggs (see Making a Flu Vaccine).

Once the viruses replicate, they are removed and chemically inactivated. These harmless pieces of flu virus are used to create the vaccine. Don’t worry—the inactivated flu viruses in vaccines won’t make you sick. Instead, they train your body’s disease-fighting immune system to recognize the real virus. That way, your body will be ready to fend off the flu strains you’ve been vaccinated for in the future.

After the World Health Organization meeting, pharmaceutical companies begin work on that year’s flu shot. For the next six months, they make and send out around 160 million doses. It takes a lot of viruses to produce that many vaccine doses. Viruses need living cells to reproduce. So strains of the virus are incubated, or grown, in an unusual place—millions of fertilized chicken eggs (see Making a Flu Vaccine). That’s the most common way of making the vaccine.

The viruses reproduce, and then they’re removed and chemically inactivated. These pieces of flu virus are harmless. They’re used to create the vaccine. Don’t worry. Inactivated flu viruses in vaccines won’t make you sick. Instead, they train your body’s disease-fighting immune system. When you get a flu vaccine, your immune system learns to spot the real virus. Then your body will be ready to fight off these flu strains in the future.

Unfortunately, the flu vaccine isn’t always 100 percent effective. Influenza viruses sometimes mutate slightly in ways the researchers in Geneva don’t anticipate. When this occurs, as it did in the 2017-18 flu season, the vaccines that manufacturers create don’t exactly match the virus that’s spreading. Even if you get the vaccine, your body may not fully recognize the strain. A lot of people will get sick.

“Because the virus changes so much, the efficacy of the influenza vaccines is not generally as good as those for viruses like polio and smallpox, which don’t change,” says Anthony Fauci. He’s the director of the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland. “Even so, it still always provides some protection—that’s why you should get vaccinated every year.”

Sadly, the flu vaccine isn’t 100 percent successful. Influenza viruses may mutate a little, sometimes in ways the researchers in Geneva don’t expect. Then manufacturers make vaccines, but the vaccines don’t exactly match the virus that’s spreading. You may have gotten the vaccine, but your body may not fully recognize the strain. A lot of people will get sick. That’s what happened in the 2017-18 flu season.

“Because the virus changes so much, the efficacy of the influenza vaccines is not generally as good as those for viruses like polio and smallpox, which don’t change,” says Anthony Fauci. He’s the director of the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland. “Even so, it still always provides some protection—that’s why you should get vaccinated every year.”

Sometimes, though, a flu strain included in the vaccine mutates so significantly that peoples’ bodies hardly recognize the virus at all. It’s also possible for a strain that once was seen only in animals to begin infecting people. When these new strains take us by surprise, they can cause devastating pandemics, or global outbreaks.

The worst of these outbreaks occurred 100 years ago, in 1918. A strain of influenza called H1N1 swept across the world and killed 5 out of every 100 people—about 100 million in the course of a year.

Most people who die in these pandemics, and from the flu generally, develop pneumonia. This potentially deadly inflammation of the lungs is caused by influenza. Children younger than 5 and adults older than 65 are particularly at risk.

But sometimes, a flu strain in the vaccine mutates a great deal. Then peoples’ bodies don’t recognize the virus at all. Or a strain was seen only in animals, but now it begins to infect people. When this happens, more people will probably become ill.

People with severe cases of the flu may develop pneumonia. That’s an inflammation of the lungs caused by influenza. It can be deadly. Children under 5 and adults over 65 are most at risk. When new strains take us by surprise, they can cause terrible pandemics, or global outbreaks. The worst of these outbreaks was 100 years ago, in 1918. A strain of influenza called H1N1 spread across the world. It killed about 100 million people in a year’s time. That’s 5 out of every 100 people.

Researchers hope to solve the problem of mutating influenza by creating a universal vaccine. This vaccine would provide protection against all strains of the flu—even if the virus were to mutate or a new form were to appear.

“It would be a complete game-changer,” says Florian Krammer, a virologist who studies viruses at the Icahn School of Medicine in New York. “You wouldn’t have to think about getting the flu anymore.”

The problem of mutating influenza is tricky. Researchers hope to solve it by making a universal vaccine. This vaccine would protect against all strains of the flu. It would work even when the virus mutates or a new form appears.

Most of today’s flu vaccines target a particular protein, or large biological molecule, on the surface of the flu virus, says Krammer. This protein is called hemagglutinin (HA). The HA protein helps influenza enter your cells. It’s composed of two parts: a head and a stalk. Current vaccines target the head of the HA protein, which is always changing.

A universal vaccine would target the stalk, which always remains the same. Other strategies to create a universal vaccine include developing a synthetic, or human-made, flu virus. It would be designed to prime your immune system to fight off future flu infections of any type. But creating new drugs is costly and takes time. Krammer and others estimate that we are still at least a decade away from the universal vaccine the world needs.

“It would be a complete game-changer,” says Florian Krammer. He’s a virologist who studies viruses at the Icahn School of Medicine in New York. “You wouldn’t have to think about getting the flu anymore.” Most of today’s flu vaccines target a certain protein on the surface of the flu virus, says Krammer. A protein is a large biological molecule. This one is called hemagglutinin (HA). The HA protein helps influenza enter your cells. It has two parts, a head and a stalk. Today’s vaccines target the head of the HA protein, but the head is always changing. A universal vaccine would target the stalk. The stalk always stays the same.

Researchers have other plans for a universal vaccine. One is to develop a synthetic, or human-made, flu virus. It would be made to train your immune system to fight off any type of flu infection. But making new drugs is costly and takes time. The world needs a universal vaccine, but Krammer and others think that it’s still at least a decade away.

Until a universal vaccine exists, fighting the flu remains a year-round job for people like Jernigan, who is also a director at the Centers for Disease Control and Prevention in Georgia. After the annual meeting in Geneva, Jernigan returns to the U.S. and continues to track and analyze flu cases throughout the year. When flu season comes, his office spreads the word about steps to take to avoid spreading the virus.

“The best way to keep you and the people around you flu-free is an annual flu shot,” says Jernigan. “Getting the flu vaccine is easy. It’s a simple, once-a-year thing that you can do that keeps you healthy.”

Until we have a universal vaccine, fighting the flu remains a year-round job for people like Jernigan. He’s also a director at the Centers for Disease Control and Prevention in Georgia. After the yearly meeting in Geneva, Jernigan returns to the U.S. He continues to track and study flu cases all year. When flu season comes, his office tells people how to avoid spreading the virus. “The best way to keep you and the people around you flu-free is an annual flu shot,” says Jernigan. “Getting the flu vaccine is easy. It’s a simple, once-a-year thing that you can do that keeps you healthy.”