Not a ‘super flu’ but plenty bad: Stanford Medicine expert’s tips for staying safe this flu season

Highest number of flu cases in decades

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 — both in California.

Forty-five states have experienced high to very high levels of flu activity.

What is the 'super flu' and what makes it worse than other variants? 

This year the early rise of flu cases and hospitalizations stands out compared with recent years, with more cases occurring earlier this year than in recent years. The current dominant flu strain is a variant of the influenza A H3N2 virus dubbed the “subclade K” strain. This subclade K strain is being referred to as the 'super flu,' a new flu strain (variant of influenza A H3N2) that is currently spreading rapidly in the U.S.

This flu is associated with more severe symptoms and more severe cases than typical flu, leading to serious illness and increased hospitalizations. While this is not a “super flu” in the sense of being a completely new virus, 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..

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.  

What are the flu symptoms this year and how long do they typically last?

Flu symptoms tend to be consistent year to year, but their severity varies. People who have flu often feel some or all of these signs and symptoms come on suddenly:

• 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. As the CDC states: Flu can cause mild to severe illness, and at times can lead to death.

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.

Is the flu shot still effective and should I get it?

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 2019-2020 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 populations 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.