Flu season is once again upon us, and that means it’s time to get your flu shot. Getting vaccinated is especially important for older adults. The CDC states that between 70-90% of seasonal flu–related deaths have occurred in people 65 and older. 

As we get older our immune system begins to weaken, which is why people over 65 are at a greater risk of complications from the flu. That’s why the high-dose flu vaccine — also referred to by its brand name, Fluzone High-Dose (HD) — was created. We spoke with two medical professionals to answer all your questions about the high-dose flu shot.

1. What is the high-dose flu vaccine?

“The high dose flu vaccine contains four times the dose of the antigens that normal dose flu vaccines have and is given to patients 65 years and older,” Dr. Caesar Djavaherian, co-founder of Carbon Health tells us.

2. Should all older adults get the high-dose vaccine?

“Seniors should absolutely get the higher dose flu shot to protect them from the flu,” RxSense’s Chief Pharmacy Officer, Ramzi Yacoub tells us. However, it’s important to note that only those who are 65 and older should be receiving Fluzone HD, as the FDA has only approved it for this age group.

Additionally, the CDC states that, as with all flu vaccines, Fluzone HD is not recommended for persons with a history of severe allergic reaction to the vaccine or to components other than eggs.

3. If the high-dose flu vaccine is more potent, why do I have to wait until I’m 65 to get it?

“We don’t really know the answer to this question because there have been no head-to-head studies between high dose and standard dose in the general population,” says Djavaherian.

According to Dr. Djavaherian, since most people under 65 respond well to the regular dose flu vaccine and don’t need extra medication to be protected, they may have a severe reaction to the higher dose that would make them ultimately feel worse. “It’s like taking 10 ibuprofen when all you need is three,” says Djavaherian. “It won’t be any more effective than just taking three.”

4. What does the high-dose flu vaccine do that the regular flu shot doesn’t?

“The higher dose provides a better immune response for older adults who need that increased protection against the flu,” explains Yacoub.

And according to Yacoub, the HD vaccine has been shown to be more effective in clinical trials, as well. “Results of a study published by the New England Journal of Medicine, showed that the HD vaccine was 24.2% more effective in preventing flu in adults over the age of 65,” he tells us.

5. How safe is the high-dose vaccine?

According to the CDC, the most common adverse events experienced during clinical studies involving Fluzone HD were mild and temporary, and included pain, redness at the injection site, headache, muscle aches, and malaise. Most people had minimal or no adverse events after receiving the Fluzone HD, states the organization.

“The safety profile is amazingly good,” Djavaherian confirms. “[Fluzone HD] is as safe as the standard-dose vaccine for those in the target age group. And since millions of patients per year receive these vaccines with rare negative side-effects coming from [them], I would say these are incredibly safe vaccines to give—and clearly much safer than not getting the vaccine.”