What Australia's bad flu season means for the United States.

Article By: Patrick Mansfield | U.S. Health Alerts
Flu Season

Influenza is categorized into two groups, the A viruses and B viruses. Although both strains can be equally severe, the A groups are typically responsible for larger outbreaks. The predominant strain circulating this year has been Influenza A (H3N2). The majority (81%) of deaths this year have been due to this particular strain. 

The early flu seasons in the Northern Hemisphere are usually mostly A strains. B strains often take over later in the season. The Flu Season in North America does't have a set date, but on average increases in Flu begin around October.

     Chart Below Shows Times Of Month Flu Is Most Prevelant.
Flu Season Chart
Chart From CDC.gov

Every year, a flu vaccine featuring a combination of A and B strains is formulated for the Northern and Southern Hemisphere by a committee of scientists. To develop the vaccine, the scientists consider what strains of viruses are making people ill, how effective last year's vaccine was, and areas the viruses are spreading. Each hemisphere's vaccine can be identical or feature different strains. The vaccine formulation for the United States this year is identical to the formula that Australia is currently using.

What Does Australia's Bad Flu Season Mean for the United States?

With almost 94,000 laboratory-confirmed flu cases, Australia's flu season is turning out to be worse than usual this year. Certain groups have been particularly susceptible: 
  • Adults over 80 years of age
  • Children between the ages of 5 and 9
There have been 52 confirmed deaths associated with influenza this year as compared to 27 at the same time the previous flu season. The number of influenza-related hospitalizations has also risen - 1,429 vs. 719 last year.

The highest concentration of cases, 60,000, is in New South Wales, Australia's most populous region. August turned out to be the worst flu month ever recorded in New South Wales. 

Many are wondering what the bad flu season in Australia means for nations in the Northern Hemisphere such as the United States and Canada. 

Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases in the United States, explains that we experience a similar flu season to "what the Southern Hemisphere got in the season immediately preceding us." This could mean that the north will most likely experience a bad flu season. He notes, however, that "with influenza, it is never 100 percent".

According to Adolfo García-Sastre, a professor, and director of the Center for Research on Influenza Pathogenesis located at the Icahn School of Medicine at Mt. Sinai, the most important factor is determining what particular strain is responsible for the outbreak and if it is similar to ones that have circulated previously. 

He indicates that a change in the strain may reflect a change in the makeup of the virus. Such changes can cause the virus to be more effective at causing infection and leading to a larger outbreak. 

Fauci also notes that it is important to consider how many individuals were sick during the last season. If the strains that are currently circulating are the same as the previous season and relatively few individuals became sick, fewer people will have immunity and may be more susceptible to getting sick now. Alternatively, if a country had more individuals sick during the prior season, more people will be naturally immune and may not get hit as bad this season.

Symptoms of Influenza

It is important to understand and recognize the symptoms of possible influenza infection: 
  • Fever
  • Chills
  • Headaches
  • Muscle aches
  • Congestion
  • Cough
  • Fatigue
  • Runny nose
  • The Importance of the Flu Shot
The CDC (Centers for Disease Control) recommends that everyone six months of age or older receive the flu vaccination. Although the shots are not 100 percent effective in preventing infection, they are the best way to protect against the virus and related complications.
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