Based on data from Australia's flu season, the United States appears poised to have a difficult flu season of its own. Writing for USA Today, Michael Daignault, an ED doctor in Los Angeles, debunks three common myths many believe about the flu.

What the Northern Hemisphere can learn from this year's Australasian flu season

Myth 1: You can get the flu from the flu vaccine

The viruses used in the annual flu vaccine are inactivated, meaning "you cannot get the flu from dead virus. Period," Daignault writes.

Some people may get the flu soon after receiving their vaccine, but Daignault writes that this is likely a simple coincidence and notes that flu vaccines don't provide immediate protection. Daignault advises that, if you're planning on traveling or attending a large event, you receive your flu shot one to two weeks beforehand to ensure your immune system has enough time to mount a protective response.

There are also viruses that can cause a "flu-like illness" that isn't actually the flu, Daignault writes. According to data from CDC, there's been an upward trend of "influenza-like illness" reported this fall, especially among those ages 0-4.

Myth 2: The flu shot doesn't work

It's important to remember that, much like Covid-19 vaccines, flu vaccines are intended to reduce your risk of getting the flu and to prevent severe illness, hospitalization, and death, Daignault writes.

Research from CDC has found that flu vaccines reduce a person's risk of illness by 40% to 60% on average, and a study published in Vaccine in 2021 found that people vaccinated against the flu had a 31% lower risk of death from the virus than those who were unvaccinated. Other research from CDC also found that flu vaccines prevented an estimated 105,000 flu-related hospitalizations during the 2019-2020 winter.

Daignault notes that news from Australia has found that between 92.4% and 94.3% of all Influenza A samples were antigenically similar to the strains chosen for this year's flu vaccine, which "bodes well for the effectiveness of this year's vaccine."

Myth 3: Taking over-the-counter pain medications after your flu shot will reduce its effectiveness

One study from 2009 warned that NSAIDs like ibuprofen should be avoided after vaccination as they block the cox-2 enzyme involved in pain. That enzyme is needed to produce memory B cells, which develop antibodies to protect against the flu, meaning taking NSAIDs could reduce the immune system's response to the vaccine, the researchers suggested.

However, Daignault notes that memory B cells take months post-vaccine to develop the ability to form antibodies against strains of the flu virus, meaning it's unlikely that taking over-the-counter pain medications is likely to cause a long-term effect.

Also, a meta-analysis published in the journal Evidence-Based Practice in 2020 looked at 13 studies and found that taking ibuprofen and acetaminophen before getting vaccinated didn't limit the efficacy of the shot in children.

Daignault writes that his recommendation is to "try to soldier thru the post-vaccination discomfort." Typically, discomfort only lasts 24-48 hours, and if you're concerned about the potential for medications to reduce the effectiveness of your vaccine, Daignault recommends using ice packs or taking an Epsom salt bath. If you feel must take some medicine, Daignault writes that you should choose acetaminophen over ibuprofen. (Daignault, USA Today, 10/13)