Many more than the usual number of deaths have been caused by the flu during this winter in Britain, with the death toll standing at 155 as of the end of January – around triple the number seen in the winter of the previous year. January also saw a large increase in the number of hospitalizations and visits to GPs because of symptoms associated with the flu, and much of the mainstream media in the United Kingdom has claimed it is the result of the “Aussie flu”, a strain originating in Australia that has now come to Britain.
However, the number of people who are contracting the flu has now started to plateau, according to Public Health England figures and the Royal College of GPs. (1) 1.5 million more individuals have been given a flu jab in the current season, in comparison to the flu season that ran over 2016 and 2017, adding to the hope that the spread of the infection will be more limited because of the vaccination.
The flu in Britain
Flu viruses circulate all over the world all year round, and mutation means that they are also in a state of constant evolution. This means that viruses from the same subtype can be different in minor ways, and newly mutated forms of the virus may not be able to be protected against by the initial vaccine.
Air travel is largely responsible for different types of flu making their way around the world. In any country, including the UK, multiple different strains of the flu are usually prevalent at any one time, but are usually broadly grouped into type A and type B. The latter of these forms two primary groups, while there tends to be more variation in influenza A viruses, though the most common strains are A/H1N1 (the strain that resulted in the so-called “Swine flu” epidemic of 2009) and A/H3N2 (2).
In 2017/2018 in the UK the primary influenza A subtype has been the same as it was during the season in Australia, A/H3N2, which is the most rapidly mutating subtype of flu virus, although both types of B virus and some A/H1N1 strains are also around. According to the UK flu report, the primary virus that is being detected this season in the UK is H3N2, but B flu viruses are also having a large impact, and resulting in admissions to intensive care in every age group, particularly the very young.
The Aussie flu
However it is difficult to accurately ascertain whether Australia is really where the current flu epidemic originated from, or if it is really any worse than most other strains. Detective work and detailed genetic sequencing may be able to make the connection, but such work is not being done – and the question is largely academic to begin with. Between October and December of 2017 a speedy analysis of the flu virus protein known as H3N2 haemagglutinin’s gene sequences showed that there was every bit much variance among the H3N2 strains seen in the UK this season as there was between Australian and British strains, meaning simply that there are multiple different strains at work (3). According to studies, the flu vaccine performed unsatisfactorily last season in Australia against H3N2, being just 5 to 19 percent effective against the strains of H3N3 that were in circulation at the time (4). Since the height of the media reporting of the “Aussie flu”, a report has been issued by the UK government showing that the most dominant strain of flu in the country was type B, which is different from that seen in the most recent Australian flu season.
The best defence
The best defence against multiple different strains of the flu that surge during the United Kingdom’s annual flu season, regardless of where they originated from, still remains vaccination. Pressure for more resources to improve vaccines would be far more likely to help people who become sick (and even die) from the flu. This would arguably be a rather more helpful tack for the media to take than stories about where various strains may or not have originated from.