UNC Health Care

What to Expect This Flu Season

It’s the most miserable time of the year: flu season.

Every year, millions of Americans get sick with the flu. Some become so sick they must be hospitalized; in fact, tens of thousands of flu sufferers die each year.

There are different types of the flu virus, the most important of which are types A, B and C. Although flu season happens every year and influenza A always predominates, it can be hard to predict which subtypes will be more prevalent or how widespread the flu will be; the virus is always changing.

“That’s something that makes flu unique,” says Christopher Hurt, MD, assistant professor of infectious diseases at the UNC School of Medicine. “That’s also part of why epidemics and pandemics can happen so quickly. You can get combinations from different viruses that we’ve never seen before.”

Epidemics happen when an infectious disease spreads rapidly, and a pandemic is a global disease outbreak. Flu pandemics have occurred more than once and happen when a new flu virus arises—most recently in 2009—which means humans have little to no immunity against it.

The good news is the current flu season isn’t slated for either an epidemic or a pandemic, but that doesn’t mean it’s going to be an easy one. Here’s what Dr. Hurt says we can expect for the 2017-2018 flu season and how you can stay healthy.

Impact of the Flu

When people think of deadly flu, they might think of the 2009 H1N1 infection (the “swine flu”) that caused a pandemic and killed 151,700 to 575,400 people around the world. Although H1N1 is still a threat, vaccines are now equipped to help protect against it.

On the other hand, the typical seasonal flu virus, called H3N2, is more common and tends to get more aggressive each year.

“H1N1 is still important and still causes infection, but for the folks who land in the hospital, a lot of them have H3N2,” Dr. Hurt says. “We know that seasons that are heavier in H3N2 tend to have more hospitalizations and sicker people in general. That goes a little bit against what most people think of because H1N1 was so shocking.”

In humans, the flu is caused by three types of viruses: influenza A, B and C. Influenza A is the most common form of the flu and is responsible for the seasonal breakouts experienced every year. Both H3N2 and H1N1 are variations of the influenza A virus.

Type B is less common and results in milder symptoms, though it can also cause epidemics similar to Type A. Type C is also less common and though it does cause a respiratory infection, it often does not cause flu-like symptoms.

Predictions for the 2017-2018 Flu Season

For the 2017-2018 flu season, the pattern of flu observed so far has been more severe than in years past.

Because new flu viruses originate in animals such as birds and pigs, when it comes to making flu predictions for the United States, a lot is based on what happens in the Southern Hemisphere.

“Most of the global surveillance for flu is in southern China and Southeast Asia, and that’s because there’s really nowhere else in the world that has the same density of people, birds and pigs, so new flu viruses can spring out really rapidly,” Dr. Hurt says.

Because there’s a greater likelihood that a new virus would pop up in that region, agencies such as the World Health Organization and the Centers for Disease Control and Prevention look at how the flu manifests in that area.

“There is concern this year that we could have a bad year because of the amount of H3N2 that was observed in the Southern Hemisphere, especially in Australia,” Dr. Hurt says. “They had a bad season this past year, and they had a lot of H3N2.”

However, the flu’s spread can also depend on the weather. “The atmospheric humidity and general weather have a lot to do with how efficiently the flu spreads,” Dr. Hurt says. “Flu circulates more readily if it’s cold and dry, or warm and wet. This explains why flu circulates year-round in tropical areas of the world but only in colder months in places where there are changes of seasons. Long-term weather forecasts can help determine what the flu season might look like. It turns out this year, at least for North Carolina, we’re not supposed to be especially cold or dry.”

What You Can Do to Stay Healthy

Although some might think getting sick is inevitable, it doesn’t have to be. Dr. Hurt says simple measures such as washing your hands regularly can help keep sickness at bay. Sneezing or coughing into your inner elbow—rather than your hand—can also help limit the spread of the flu virus.

But the most important step to prevent flu is getting a flu shot. In the 2015-2016 flu season alone, the CDC estimates that the flu vaccine prevented 5.1 million flu-related illnesses.

This year, only injectable flu shots are recommended, which means alternatives such as the nasal spray flu vaccine will not keep you protected. The CDC also recommends that people who are more vulnerable to the flu and serious complications get vaccinated, including older adults, people with chronic lung conditions, pregnant women and young children.

This year’s flu shot is equipped to protect against the viruses that research has deemed will be most common this flu season, which include H3N2 and H1N1. Vaccine effectiveness can vary, but it’s estimated that the flu shot can reduce the risk of catching the flu by 40 to 60 percent. And even if this year’s vaccine doesn’t turn out to be a perfect match for what is in circulation, research has shown that even poorer matches can help reduce the severity of illness if you do catch the flu, Dr. Hurt says.

While some people believe the flu shot will give you the flu, this is simply not true, because the vaccine does not contain live virus. “Manufacturers use strict quality controls to make sure the virus is killed and the vaccine purified before they are released,” Dr. Hurt says. The most common side effects of the flu shot are soreness, redness, tenderness or swelling where the vaccine was administered.

Remember, just because you got a flu shot last year doesn’t mean you should skip it this year. The vaccines are updated each year to better match circulating viruses to keep you better protected.

What to Do if You Get the Flu

If you’re experiencing moderate to severe flu symptoms, talk to your doctor as soon as possible so he or she can administer Tamiflu, an antiviral medication used to treat and prevent flu.

In years past, oseltamivir (also known as Tamiflu) was prescribed only after a person had experienced flu-like symptoms for 72 hours. But after the H1N1 pandemic in 2009, studies done on people who were hospitalized with the flu showed its overarching benefits. “Study after study after study showed that people who got oseltamivir, even if it was beyond that 72-hour mark, tended not to land in the hospital, and if they did end up being admitted, they ultimately left the hospital alive,” Dr. Hurt says.

Since then, the consensus has shifted, and the CDC recommends that providers consider starting oseltamivir in patients at higher risk of hospitalization, even if they’ve been sick for longer than 72 hours. “If you’re sick and there is flu in your community and you have an illness that is behaving like the flu, you should see a physician and ask about oseltamivir,” he says. “The weight of the evidence, especially from the pandemic year, is most of the time, for people at risk of severe illness from influenza, earlier treatment can save your life.”


Talk to your doctor about getting your flu shot this season. If you don’t have a doctor, find one near you.