Australia can’t be blamed for the ‘Aussie flu’
It has been widely reported that the death rate from influenza is much higher this year than usual.
The flu has been dubbed ‘‘Aussie Flu’’ in the belief it arrived from Australia where in the winter of 2017 they experienced higher than normal flu related fatalities.
The origin of Aussie flu has nothing to do with Australia since flu viruses circulate worldwide all year, constantly evolving through mutation.
Influenza tends to be seasonal in temperate parts of the world for several reasons.
The virus doesn’t decompose easily in cold temperatures remaining intact longer on doors and handrails etc; in winter there is less UV radiation to kill it; in winter people are indoors more and in close contact, which helps to transmit the virus.
Flu types and the make-up of vaccines are determined in a worldwide cooperative effort.
Throughout the year, thousands of influenza strains obtained from throat swabs are sent to five laboratories located in Beijing, Melbourne, Tokyo, London and Atlanta.
Twice a year, once for the northern hemisphere and once for the southern hemisphere, the results of the analysis are produced and manufacturers are given the offending strains to make the vaccines. Within 8 months about 400 million doses are available worldwide.
A virus is so small that only a grainy image can be seen even using a powerful electron microscope.
In humans the genetic information is contained in a complex double stranded molecule called deoxyribose nucleic acid (DNA) whereas in many viruses the genetic information is contained in a simple single stranded molecule called ribonucleic acid (RNA).
Viruses consist of the nucleic acid molecule and sometimes a few enzymes stored, not in a cell but in a capsule made of a protein, then wrapped in an envelope made of molecules called lipids.
Viruses cannot replicate on their own, instead they hijack a host cell. Influenza viruses typically hijack throat cells in humans and use the machinery of these cells to make copies of the virus which are then released to infect new host cells.
There are four types of influenza virus, A, B, C and D. A and B cause seasonal epidemics in humans, C is milder and not thought to cause epidemics and D doesn’t infect humans.
Influenza A has two subtypes, whose names are based on two proteins present on its surface, hemagglutinin (H) and neuraminidase (N). There are 18 H and 11 N subtypes.
These subtypes in turn have many different strains but it is the subtypes A(H3N2) and A(H1N1) that are found in humans.
Influenza B has two types, Victoria and Yamagata, named after the places they were first isolated, Victoria Australia and Yamagata Japan respectively.
The genetic material of the influenza A virus is contained on eight RNA gene segments.
The goal of vaccination is to combine gene segments from more than one strain which have had their dangerous sections removed.
The vaccine stimulates the body’s immune system to recognise the threat and destroy any of the real viruses it may encounter in the future.
In an interview with The Guardian newspaper, Professor Derek Smith of Cambridge University pointed out that even after the vaccine has been made, the virus may evolve and about one in three years the vaccine doesn’t work as well.
Furthermore, the optimal vaccine won’t be the same for everyone.
Your first infections and resistance as a child set the stage for your future response.
In a scientific article published last week, the US National Institute of Allergy and Infectious Diseases (NIAID) announced a strategy for trying to develop a universal flu vaccine, effective regardless of virus subtype or the mutations that occur between the time the vaccine is prepared and issued.
The young and old are the most vulnerable because their weaker immune systems mean that the virus can enter unchallenged sometimes going deeper into the lungs, leading to serious infections such as viral pneumonia or bacterial infections.