From living rooms to emergency rooms, flu season is hitting the United States hard.

It mirrors what has already happened during winter elsewhere around the globe, and there are no signs of it letting up anytime soon. For those of who managed to survive the holiday season upright, this is no time to let your guard down.

That’s why we asked Stanford Medicine’s Yvonne Maldonado, MD, the Taube Professor in Global Health and Infectious Diseases and a professor of pediatrics, to shed light on what everyone should know right now.

(For starters: This isn’t technically a “super flu” – which Maldonado calls a made-up term – and it’s not a bug anyone should want to get.)

Here are the key takeaways, broken down by Maldonado.

The numbers paint a stark picture

So far this flu season has led to the highest number of cases in more than 30 years, at 11 million infections recorded by the Centers for Disease Control, with 120,000 hospitalizations and 5,000 deaths, including two children. Forty-five states have experienced high to very high levels of flu activity.

Why it’s worse isn’t clear

No two seasons are identical in terms of predominant flu strain and numbers of cases. However, we know that each year there will be global influenza circulation in the winter leading to infections, hospitalization, and deaths, especially among older individuals and sometimes very young children. This year the early rate of rise of flu cases and hospitalizations stands out compared with recent years, with more cases occurring earlier this year than in recent years.

The ‘subclade K’ is to blame

The current dominant flu strain is a variant of the influenza A H3N2 virus dubbed the “subclade K” strain. While this is not a “super flu,” it has mutated to more likely evade immunity from the current vaccine. The vaccine still provides some degree of protection; however, it appears that this new strain is leading to a higher-than-normal level of flu activity this year.

It’s not too late for a flu shot

We’re still in the middle of the flu season, which generally begins in December and ends in March, so there is plenty of time to get a flu shot and be protected. The CDC recommends that everyone six months of age and older get an annual flu vaccine, with rare exceptions. The vaccine prevents millions of illnesses and flu-related medical visits every year. We know that most people hospitalized for flu are unvaccinated. For the 2019-20 flu season, vaccines prevented about 7 million flu illnesses, 3 million medical visits, 100,000 hospitalizations and 7,000 deaths.

Speak to your pharmacist or health care provider about the risks and benefits of a flu shot. Though there is a risk of side effects from the vaccine, the risks of severe infection, hospitalization, and death for those not vaccinated – especially those in high-risk groups – are far greater.

Some are more at risk than others

Every age group is at risk for contracting the flu and being hospitalized. However, seniors 65 years and older and children less than 2; those with underlying conditions such as asthma and chronic lung, heart, kidney, and liver disease; and those with immunocompromising conditions are at highest risk of severe outcomes. Pregnant women and people living in nursing homes and long-term care facilities are also at higher risk of complications.

The symptoms remain typical

As the CDC states: Flu can cause mild to severe illness, and at times can lead to death. Flu symptoms usually come on suddenly. People who have flu often feel some or all of these signs and symptoms:

• Fever or feeling feverish/chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Tiredness
  

Some people may have vomiting and diarrhea, though this is more common in children than adults.

It’s important to note that not everyone with flu will have a fever. If you suspect you have the flu you should contact your health care provider, especially if you are in one of the high-risk categories for severe disease or complications, as antiviral therapies can help if they are given early on.