Everyone is asked to get the flu shot every year to slash their risk of infection and hospitalization.
And more than 100million line up for the vaccine, particularly those 65 and older — with more than 70 percent of seniors in the US getting the shot.
While the flu shot is widely recommended, doctors are advising people to be careful about the medications they use before or after they get vaccinated because some drugs could decrease the vaccine’s efficacy.
There are more than 295 drugs that can interact with flu shots and make them less effective, ranging from some over-the-counter painkillers to treatments used to ease pain from arthritis or to fight cancer.
Around 41million people are infected with the flu in the United States every year and 710,000 people are hospitalized. More than 36,000 people die from the infection — with up to 85 percent of the deaths among those 65 years or older.
But flu vaccination coverage is falling in the US, largely thought to be the result of the mass vaccination drive and vaccine mandates during the Covid pandemic.
Latest data showed only 45 percent of adults over 18 got the shot in the 2023 to 2024 flu season, a decrease of two percent from the year before.
Coverage has not been this low since the 2017 to 2018 season, when 37.1 percent of adults came forward for a flu shot.
Health officials are calling for more people to get the flu vaccine this winter
The flu shot was around 35 percent effective against hospitalization from the virus last year, studies suggest, lower than the average of about 50 percent.
Efficacy varies because experts have to guess which flu strain is likely to be most common every season based on observations from the Southern hemisphere — which has its winter when the north has its summer — but these are not always correct.
For the people who do roll up their sleeves for the vaccine, experts recommend consulting a doctor and discussing the medications that may interfere with the shot.
Below, DailyMail.com details some of the drugs that could impact your flu vaccine’s efficacy this season:
Pain medications
The discomfort or pain around the injection site caused by a flu vaccination can lead many to reach for an over-the-counter painkiller.
These may include non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen — the active ingredient in Motrin and Advil — and naproxen — the active ingredient in Aleve.
A flu shot works by teaching the immune system to recognize and fight the influenza virus.
It normally contains an inactivated virus or a protein from the virus that is injected into the blood and triggers an immune response, causing the immune system to make antibodies — virus-fighting proteins — that stay in the body to fight off the virus.
Doctors recommend avoiding NSAIDs after a flu vaccination because these can dampen the immune response by slashing the production of antibodies.
This happens because the drugs suppress inflammation, reducing the immune response to the vaccine.
Dr David Topham, a doctor at the University of Rochester, said on his university’s website: ‘Unless your healthcare provider tells you otherwise, it’s best not to take pain relievers one or two days before the flu vaccine and for a week afterward.’
Other pain medications such as acetaminophen — brand name Tylenol — should be safe to take after the vaccination, however, because they work in the body differently.
Prednisone
One of the most commonly used drugs in the US, about 20million prescriptions for prednisone are written every year.
Pictured above are prednisone tablets. Doctors warn that certain types of these pills can make the flu vaccine less effective
A type of steroid, it is used to slash inflammation to ease symptoms from many conditions — including arthritis, asthma, inflammatory bowel disease and for organ transplant patients.
But doctors say if someone is taking more than 20 milligrams (mg) per day for two weeks or more, it can make the flu vaccine less effective.
This is because, like some over-the-counter painkillers, it can also reduce the body’s ability to form antibodies — weakening its immune response to the vaccine.
Jodie Pepin, clinical pharmacy program director at Harbor Health in Texas, told AARP: ‘High doses of steroids can weaken your immune system and potentially reduce the effectiveness of the flu vaccine.’
The CDC says online in reference to prednisone’s interaction with other vaccines, including the MMR shot: ‘Substantially immunosuppressive steroid dose is considered to be more than two weeks of daily receipt of 20mg or 2 mg/kg body weight of prednisone or equivalent.’
The usual dose strength for prednisone ranges between 5mg and 25mg for tablets.
Steroid injections
About 9million people get steroid injections per year in the US to help ease chronic, or long-term pain.
The injections are administered to areas including the hips, knees and shoulders and work by reducing inflammation at the joint, slashing sensations of pain.
Research has, however, shown these injections can affect how the body responds to a flu shot.
The above post from the NYC Health Department urged residents to get their flu vaccines
Dr William Raoofi, a doctor from the Center for Interventional Pain Medicine in Maryland, told AARP: ‘When getting an injected steroid in a joint or epidural space, you get some systemic absorption of the medication, which causes a [short-term] dampening of your immune system.
‘Then, when you are vaccinated and exposed to the weakened flu virus, your immune system is not as good at responding to it.’
A 2018 study from the Mayo Clinic on 15,000 people found those who received a steroid injection around the same time as a flu shot had a 52 percent higher risk of infection with influenza compared to those who only had the flu vaccine.
In some cases, patients seeking injections for their pain will have to be turned away if they recently received a flu shot and told to wait for up to two weeks for the body to mount a full response to the vaccine.
Chemotherapy
Chemotherapy drugs are powerful medications that fight cancer by targeting and destroying rapidly dividing cells in the body.
But they may misfire and attack the immune system, which also contains rapidly dividing cells.
Doctors warn chemotherapy drugs weaken the immune system which, in turn, can make flu vaccinations less effective.
They say patients receiving chemotherapy — which amount to about 1million people — should consult with their provider on whether to also sign up for a flu vaccine.
A previous study from the NIH suggested that people receiving chemotherapy need to get two doses of the flu vaccine every year for it to be as effective as in someone not battling the disease, who only needs to receive one annually.
Cancer patients are at higher risk of developing complications from the flu, such as pneumonia, because of their weakened immune system.
One study from 2022 found cancer patients had a 41 percent higher risk of death from pneumonia compared to those who were cancer free.
For those whose cancer had spread in their body, they were twice as likely to die from pneumonia.
Biologics
Cancer patients may also take a type of drug called a biologic.
These are medications that bind to cancer cells in the body to help the immune system find and destroy cancer.
But this can also damage the immune system, making it less able to respond to vaccines and build a strong immune response.
Doctors say patients taking biologics should consult with their provider on whether to get a flu shot.
Types of biologics include atezolizumab, or Tecentria, avelumab, or Bavencio, and pembrolizumab, or Keytruda.
