Time for your flu vaccine: Do you need a higher dose?

The pros and cons of the high-dose vaccine, and tips to protect yourself from infection this season.

The flu is far more than a fever and sniffles that sideline you for a few days. In older adults, it can lead to serious complications like bronchitis and pneumonia, and it can worsen existing medical conditions such as heart disease, asthma, and diabetes. In fact, most flu-related hospitalizations and nearly all deaths from the disease occur in people 65 and older.

"The strength of the immune response tends to decrease with age. So as people get older, they are more likely to become significantly ill from diseases like the flu," explains Dr. Elisa Choi, an internal medicine and infectious disease specialist at Harvard Vanguard Medical Center. The best way to protect yourself against the flu is by getting vaccinated, but because of the natural decline in your immune system, you may produce fewer flu-fighting antibodies in response to the vaccine than you once did, and be less protected as a result.

Which vaccine is right for you?

Since 2009, a higher-dose flu vaccine called Fluzone High-Dose has been available for adults 65 and over. Like the regular-dose flu vaccine, it contains the three flu strains experts believe will be most prevalent in the upcoming flu season. But it also contains four times the usual amount of immune-stimulating antigens against the virus.

Is it worth getting the high-dose vaccine if you're over 65? "I think it's an area of much debate and discussion," Dr. Choi says. While some studies have found the high-dose vaccine stimulates a higher immune system response in the lab, it's not yet clear whether that translates into better protection against the flu in the real world.

The high-dose vaccine also comes with some downsides worth considering: more pain, redness, and swelling at the injection site, as well as bodywide side effects like muscle pain, headache, and fever. Most of these effects are mild and short-lived.

There are currently no official recommendations advising seniors to switch to the high-dose flu vaccine. Dr. Choi recommends weighing the pros and cons with your doctor to help you decide.

Even if you don't get the high-dose vaccine, make sure that you get vaccinated—and do it as early in the flu season as possible. Flu outbreaks can start in October, and it takes two weeks after you get the shot for your body to produce antibodies against the virus. Some people hold off on vaccination out of concern that the protection wanes over time, but Dr. Choi says the shot should protect you for the entire flu season.

Other ways to protect yourself

Keep in mind that the flu vaccine isn't necessarily 100% effective. It is possible to come down with the flu, even after you've been vaccinated. Yet it's still worth getting the shot. "Even if you get the flu despite having received a flu shot," says Dr. Choi, "the vaccine can lessen the severity of symptoms and help you avoid serious complications from the flu."

Should you ask your doctor to prescribe anti-influenza drugs—oseltamivir (Tamiflu) and zanamivir (Relenza)—in advance, in case you do catch the flu? Not necessarily, according to Dr. Choi. The flu shares many symptoms in common with other upper respiratory infections, and you might mistakenly treat a bacterial illness with an antiviral drug.

Plus, a research review published in April 2014 in The Cochrane Collaboration raises concerns about these drugs' effectiveness at preventing flu complications, and highlights potential side effects such as nausea, vomiting, and headaches.

"The safest course of action, particularly during the height of flu season, is to call the physician as soon as your symptoms appear," says Dr. Choi.