Deciphering the Flu Vaccine


If you’re keeping up to date on flu season news, you may feel like you need a dictionary to understand all of the different vaccination options: FluMist, high-dose, quadrivalent, and egg-free vaccines are just some of the new varieties. The endless options may compound lingering questions you already have about getting vaccinated for the flu.

How the Flu Vaccine Works

Traditionally, flu vaccines have included three different viruses: two type A”s and one type B. Type A viruses can come from animals and cause pandemics (think H1N1). Type B viruses only affect humans.

When you get a flu shot, the inactive virus is being put into your system so that you will build up antibodies against it. Since the virus is inactive, you can’t get the flu from it. Flu vaccine nasal sprays use a live, weakened virus which, on rare occasion, can cause the flu. Usually, if you get the flu after your shot, you already had it or you caught in the two weeks before your antibodies kicked in.

How the Vaccine Is Designed

More than 100 national influenza centers in over 100 countries monitor the flu throughout the year. The data they collect helps them recommend which viruses should go in the next vaccines. Traditionally, the recommendations include two type A viruses and one type B virus. Now, they include a second type B virus for manufacturers of the new quadrivalent vaccines (those with four viruses instead of three). What flus are infecting us change every year, which is why you should get your shot each flu season.

Who Should Get the Flu Vaccine

People who are at particularly high risk for complications from the flu include children six months to four years old, people over 50, pregnant women, and people with certain underlying health conditions, such as asthma and diabetes. A full list of high risk groups is posted on the CDC’s website.

However, these groups aren’t the only ones who should get vaccinated. “My general advice is that it is a good idea for everybody to get the vaccine,” says Dr. Arnold S. Monto, professor of epidemiology at the University of Michigan, School of Public Health. To address common concerns, Monto says that there is plenty of vaccine to go around and that vaccines are one of the safest ways we have of preventing disease.

Also, getting vaccinated isn”t just about your protection but also that of those around you. This is particularly true for people who are around newborns since children cannot be vaccinated if they are less than six months old. “You want to cocoon the child by giving protection to those around,” says Monto.

The Newer Vaccines

Quadrivalent: Contains four viruses (two type A, two type B) instead of the usual three. May offer additional protection depending on which type of flu is spread this season.

FluMist: This is the nasal spray that uses a live virus that has been significantly weakened. FluMist this year is quadrivalent.

FluZone: This is a shot that has a significant shorter needle than traditional flu shots.

Egg-free: Many flu vaccines are made using egg products, so people with very severe egg allergies had to avoid them. Now some egg-free versions exist.

High-dose: This shot is designed for people 65 or older because they are at greater risk from the flu. It has a higher dose of virus and may cause greater side effects. However, that might be a worthwhile tradeoff for enhanced protection.

Even being good about getting your flu shot doesn’t guarantee protection. On average, the shot reduces the risk of flu by about 60 percent, so you should still wash your hands often and stay home if you’re feeling under the weather.

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