Every year, between 5-20% of Americans become ill from influenza, also called the flu. They suffer from fatigue, chest congestion, body aches and fever.
Most people with influenza recover within about 2 weeks, but in older people and those with health problems like lung disease, congestive heart failure or diabetes, influenza can trigger serious, even fatal complications, like pneumonia.
According to the Centers for Disease Control and Prevention (CDC) between 12,000 and 79,000 Americans die from influenza-related causes every year, 90% of them being over 65 years old.
Q: When’s the best time to get a flu shot?
Before it hits your community. The CDC recommends everyone 6 months and older should get vaccinated by the end of October.
Young children age 6 months through 8 years who need 2 doses of flu vaccine should get their first one as soon as the vaccine is available, and get the second one 4 weeks later.
Q: How long does it take to be protected against the flu after getting vaccinated?
It takes about 2 weeks to for a flu shot to become fully effective.
Q: Will a flu shot last you the entire flu season?
Your best protection from the vaccine kicks in at about 2 weeks and lasts for at least 4 months, after which it decreases gradually over time.
The peak flu season in the United States runs from October through March, with most infections occurring in February. If you are young and healthy, one shot provides protection for the entire flu season, even if you are vaccinated in early September.
Q: Why do we need yearly vaccinations against influenza?
Most viruses have stayed the same over the decades we’ve had vaccines against them, but influenza keeps changing its shape, making it harder for our immune system to protect us against it. Various influenza strains infect geese, chickens, ducks, pigs and humans, and chance errors occurring while the virus is reproducing can create a slightly different copy. If that copy is better than the old one it replaces it. The CDC is currently hard at work on developing a “universal” flu vaccine which will protect against the part of the virus that doesn’t mutate, providing years of immunity instead of barely a season.
Q: Is this year’s flu vaccine any different from last year’s vaccine?
Most human influenza is caused by one of two main types, called A strain and B strain. Influenza A strains are associated with pandemics and cause more severe symptoms and deaths than B strains.
The World Health Organization (WHO) keeps track of influenza patterns across the world with centers in Tokyo, Beijing, Melbourne, London and Atlanta, meeting each February to decide on the 4 strains best suited for the next influenza vaccine, usually two B strains and two A strains. This year they chose 3 of the 4 strains in February but delayed until March to select the final A strain.
Compared to last year’s vaccine, both A strains have been updated while both B strains remain the same.
Q: Is the 4-strain (quadrivalent) flu shot any better than the 3-strain (trivalent) vaccine?
There is no clear evidence that the quadrivalent vaccine is more effective, although you get broader protection against influenza with 4 strains (two A and two B) than with 3 strains (two A and one B).
Q: My pharmacy is advertising the “high dose” flu shot. Should I get that one instead of the “regular” formula?
It’s your choice. Since older adults with weaker immune systems get only about 50% of the protection of influenza vaccines compared to younger people, the FDA approved 2 trivalent formulations designed to increase effectiveness: a “high dose” influenza vaccine containing 4 times the concentration of the standard formula, and one containing squalene oil, an additive designed to increase the immune system’s reaction.
One trial showed these enhanced formulas boosted effectiveness by 24% compared to a standard trivalent vaccine, but the CDC doesn’t recommend any particular vaccine formulation over another.
These 2 options are available only in trivalent (3 strain) formulas and compared to the standard quadrivalent (4 strain) formula they can cause more redness and tenderness at the injection site, plus headache, muscles aches and fatigue.
Q: How can I avoid being exposed to thimerosol in my influenza vaccine?
Ask first. Because of convenience, nearly all vaccines today are given as single-dose injections which don’t contain or require any preservatives like thimerosol.
Q: What about the “nose spray” flu vaccine?
The nasal influenza vaccine is approved for people age 2-49 years old. It contains live influenza virus and should be avoided in people taking immunosuppressant medications, who are pregnant, or have taken antiviral medication within the previous 48 hours.
