Welcome to this year’s flu season.
This year’s flu strain has already begun to spread across the United States, according to new data from the US Centers for Disease Control and Prevention. At least 880,000 flu cases, nearly 7,000 hospitalizations and, tragically, 360 flu-related deaths this fall, including one pediatric death. Not since 2009, at the height of the H1N1 swine flu pandemic, have there been so many flu cases this early in the season.
Despite these numbers, many people wonder if the flu is really a serious illness. What is the benefit of the vaccine, especially since some people can still get the flu despite being vaccinated? Could you get the flu from the vaccine? If you get the covid vaccine, do you still need the flu vaccine?
To address these questions and more, I spoke with CNN medical analyst Dr. Leana Wen, an emergency physician, public health expert and professor of health policy and management at the Milken Institute School of Public Health at George Washington University. He is also the author of “Lifelines: A Doctor’s Journey in the Fight for Public Health.”
CNN: Is the flu a serious illness? What symptoms do people have?
Dr. AS Leana Wen: It can certainly be serious. The CDC estimates that influenza caused 9 million to 41 million illnesses, 140,000 to 710,000 hospitalizations, and 12,000 to 52,000 deaths each year in the US between 2010 and 2020.
Flu symptoms include fever, muscle aches, headache, fatigue, cough and runny nose. Many people recover within several days, but some may still be unwell for up to 10 days to two weeks after symptoms appear. Some will develop complications, including sinus and ear infections, pneumonia and swelling of the brain. The flu can aggravate underlying medical conditions; for example, people with chronic lung and heart disease may find that their conditions worsen with the flu.
Even people who are generally healthy can become very ill from the flu. However, those most at risk of serious consequences are those over 65, young children under the age of 2, pregnant people and people with medical conditions.
CNN: What’s the benefit of the vaccine, especially since some people can get the flu even if they get the vaccine?
Wen: The flu vaccine does two things. First and foremost, it reduces the chance of serious illness, which means hospitalization or death. Second, it can also reduce the chance of getting sick from the flu.
In a sense, this is not very different from the Covid-19 vaccine. The most important reason to get the flu and coronavirus vaccine is to prevent serious illness. New data released in the CDC’s latest morbidity and mortality report show that this year’s flu shot reduces the risk of hospitalization by about 50%. A 2018 study showed that people who received the flu vaccine were 59% less likely to be admitted to the ICU due to the flu compared to those who were not vaccinated.
The effectiveness of the vaccine can vary depending on how well the vaccine matches the flu strains in circulation. The CDC cites vaccine effectiveness against “medically treatable diseases” as 23% to 61%, depending on the year and vaccine strain. So it’s true that you can get the flu shot and still get the flu. But the vaccine reduces your chance, and most importantly, the likelihood of getting very sick.
Another thing to keep in mind is that there are many other viruses that can cause flu-like symptoms. The flu vaccine helps protect against viral infections caused by the flu, but there are many other causes of viral syndromes, including adenovirus, rhinovirus, parainfluenza, and others. These other viruses also spread easily, and there is no vaccine against them. I often hear patients say that they got the flu once the same year they got the flu shot, and that’s why they don’t want to get vaccinated again. But when I ask them if they’ve actually been diagnosed with the flu or if they’ve had flu-like symptoms, they’d say the latter.
CNN: Should children and pregnant people get the flu shot too?
Wen: Absolutely. These are groups that are particularly vulnerable to serious outcomes, so it is very important to get the flu vaccine.
According to a study, the flu vaccine reduces the risk of life-threatening flu in children by 75%. Another said it cut flu-related emergency department visits in half in children.
Similar results are found in pregnant people. The flu vaccine not only protects the pregnant person, but if the vaccine is given during pregnancy, it helps protect her baby from the flu in the first months of life. This is important because the flu vaccine is not available for babies until they are 6 months or older.
CNN: Can you get the flu from the vaccine?
Wen: no The flu vaccine is an inactivated vaccine, meaning it does not contain live virus and therefore cannot cause the flu. It is also a very well-tolerated vaccine, with the most common side effect being discomfort at the injection site that disappears after a day.
CNN: If you’ve gotten the Covid-19 vaccine, do you still need the flu shot?
Wen: yes Different vaccines target different viruses. The Covid vaccine helps protect against Covid, but does not protect against the flu, and vice versa. You can get the covid vaccine (or bivalent booster) at the same time you get the flu shot, at a different injection site.
CNN: Some people wait until later in the flu season to get the flu shot. Is it a good idea?
Wen: At this time, no, because it is now clear that this flu season is starting earlier than usual. Cases are already high, and it takes about two weeks after vaccination to achieve optimal immune protection. I would encourage people who have not received the flu shot to get it now.
CNN: What should people know about flu treatments?
Wen: Most cases of the flu can be treated symptomatically, meaning patients rest, hydrate, and treat any symptoms that occur with fever-reducing medications such as acetaminophen or ibuprofen. There are also antiviral treatments. These are especially important for people who are at high risk of serious flu complications and/or who are very sick. The earlier such treatments are started, the better. An oral drug, oseltamivir (Tamiflu), can also be given to high-risk patients within 48 hours of the onset of illness.
I would encourage everyone to have a flu plan, just like they should have a Covid plan. Ask your doctor if you should take Tamiflu or another antiviral treatment beforehand. Find out how you can get tested and where to get treatment, including after hours and weekends.
CNN: How can people avoid getting the flu?
Wen: Influenza spreads mainly through droplets; if an infected person coughs or sneezes, those droplets can spread to someone else nearby. Droplets may land on a surface and infect someone after touching it and then touching their nose, mouth, or eyes.
We can help reduce the transmission of the flu by staying away from others while symptomatic. We should all cough or sneeze into our elbow or tissue, and we should wash our hands frequently, including after touching high-touch surfaces. People who are particularly vulnerable to serious outcomes should consider wearing a mask to reduce the chance of contracting viral illnesses such as the flu. And of course, get vaccinated!