Australia Bracing for Flu Season, What it Means for the US

Australia, being in the Southern Hemisphere, faces its flu season months before we do.  Flu cases started to rise in May, peak in August, and then subside as their temperatures warm in November and December.

 

Our flu season begins conversely in late fall ends in June.

US manufacturers use Australia’s flu season as a barometer of how our flu season will go in terms of virulence and vaccination efficacy.

A recent poll by finder.com.au found half of Australian’s surveyed (sample of 2,003), will refuse to get the flu shot in fear of it not being effective or believing it will make them sick.  That projects to 9.5 million people not choosing vaccination. Generation X’ers seem to be more wary of the vaccine than Baby Boomers.

Last year’s flu season for both Australia and the US was the most severe since the 2009 H1N1 pandemic.  The most predominant strain was H3N2, which is highly virulent, mutable, and therefore shifty when it comes to trying to tie it down to make an efficacious vaccine.  Numbers of flu-related deaths were much higher and the flu shot appeared to only offer 30% protection at most.

In Australia, the Department of Health has already tallied 12,281 cases of flu (according to http://www.isg.org.au) in 2018 which is 19% higher than this time last year.

So if 1/2 of those at risk fail to get vaccinated what does that mean for the US?

Less virus, less virulence

The flu virus comes in many strains.  The virus needs a host to multiple and propagate.  If fewer people choose vaccination which provides protection against three strains (trivalent vaccine) or four strains (quadrivalent vaccine), the virus has more reservoirs thus allowing easier spread and strength.  One vaccinated, even if with a 30% effective vaccine, still has some protection and may thwart a virus from setting up shop in their body.  So less virus, less virulence.

The more infected, the higher resistance

If more of the population harbors an illness, many will attempt to treat themselves or rush to get antivirals.  Improper use of antivirals, such as Tamiflu, could spurn resistance to the drug. We don’t have many antivirals to choose from during flu season so the less we need to use one the better in terms of salvaging its efficacy.

More myths get spread

Every year I hear “I won’t get the flu shot ever again because it gave me the flu”……Does this really happen??  Can you get the flu from the flu shot?

The answer is “No”, but the topic is definitely worth dissecting.

Firstly, the flu shot is made up of an “inactivated virus”.  A nice way of saying a “killed virus”.  Although the nasal spray version of the flu shot is a watered down, weakened version of the virus, the flu shot does not have active virus in it.  So technically one cannot get the flu.  Rarely someone could have an allergic reaction to the shot and scientists are investigating the incidence of neurological conditions such as Guillain-Barré and narcolepsy. Again these are rare and would not feel like “the flu.”

But, some may insist they “came down with the flu” after receiving the flu shot.  Why?

For one thing, many are getting the flu shot too late.  Influenza starts to circulate in one’s  neck of the woods and many are exposed before the shot gets a chance to prime one’s immune system.

Secondly, the flu shot is not 100% effective.  The average efficacy of the flu shot is approx. 60% but can be better in certain populations.   Moreover the flu shot usually protects against 3 or 4 strains of the flu.  One could be exposed to a strain of the flu that was not in this year’s flu shot, hence coming down with the “flu” after receiving the flu shot.

Finally, what could be occurring is, the flu shot starts to work by inducing one’s immune system to recognize the flu and this activation of the immune system makes one feel some of the symptoms of the flu.

So for those fearful of getting the flu shot, education is needed to quell their fears and stop viral spread of not only the virus but misconceptions that could be deadly.

If Australia is headed for a severe flu season, then so will we….

 

Daliah Wachs, MD, FAAFP is a nationally syndicated radio personality on GCN Network, iHeart Radio and Board Certified Family Physician