Tuesday, August 15, 2017

Australia's Flu Epidemic Worsens

Credit NSW Flu Surveillance Report 06082017


As official surveillance data lags 2 to 3 weeks behind current events, it isn't possible to say exactly how bad this year's flu season in Australia currently is, but based on early numbers and recent headlines, they appear to be on track for their worst epidemic in years.

We began to see evidence of a particularly rough flu season in late June - when Hong Kong and Taiwan were also in the throws of flu epidemics - with Australian media reporting a spike in flu cases in New South Wales (see Flu season in New South Wales tracked to be worst on record). 
This was followed in mid-July with reports from NSW: Sydney Hospitals `Slammed' By Flu-Like Cases. On August 10th, we saw reports of strong flu activity in Queensland (see Flu Queensland: State Government enacts hospital management plan.
Overnight the Australian media has been sounding the alarm, with headlines such as: 
Australia hit by worst flu outbreak on record in 2017

Australia in grip of worst flu season yet, with experts saying vaccinate now
'It's been hell': Australia in grips of worst flu season in at least 15 years

    As the chart on the top of this blog illustrates, this year's influenza epidemic began earlier than any in the past five years, and appears on track to exceed the numbers posted during any of those five years.

    According the the most recent summary from the NSW Influenza Surveillance System:
    • Seasonal influenza activity continues to rise above its predicted peak. Influenza activity is expected to remain high for at least the next few weeks.
    • Influenza A strains are predominating, particularly the A(H3N2) strain.
    While the recent severe flu in Hong Kong, Taiwan, Guangdong province, and Australia can't tell us with any certainty what kind of flu season the Northern Hemisphere will see this fall, the United States has come off two relatively mild flu seasons in a row (see FluView Chart below).


    At some point, this welcomed lull will end While we are always concerned over the emergence of a novel pandemic strain, seasonal flu is fully capable of killing tens of thousands.  
    Flu seasons dominated by H3N2 - as we've seen this summer - are often more severe than H1N1 seasons.
     While far from perfect, there is considerable evidence that the flu vaccine can reduce both morbidity and mortality from influenza infection (see CID Journal: Flu Vaccine Reduces Severe Outcomes in Hospitalized Patients).

    When combined with good flu hygiene (washing hands, covering coughs, & staying home if sick) – you can greatly improve your odds of staying healthy this winter. Which is why I'll be rolling up my sleeve next month, and hope my readers will do the same.

    For more on the recent evolution of the H3N2 viruses around the world, you may wish to revisit:

    The Enigmatic, Problematic H3N2 Influenza Virus

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