What is Japanese flu?
As we learned in my previous blog, How to protect yourself from Australian flu, there are many different strains and variations of the flu virus. ‘Japanese flu’ is a stain of the influenza B virus, which you may hear referred to as the Yamagata strain. Its full name is B/Yamagata/16/88, but we’ll stick to Yamagata for now!
Why has Japanese flu hit the headlines?
Week by week Public heath England (PHE) have been updating us on the current flu stats. Along with the numbers of people affected by flu, they report on the types and variations of the viruses that are currently circulating. In their latest update they outlined that since the middle of September, 63 out of 67 of the influenza B samples that they tested were the Yamagata strain. But what does this mean?
Alarm bells might start to ring because this particular stain of the virus isn’t covered by the most common type of flu vaccine given to adults this winter.
To understand what this means we need to know a little bit more about how vaccines work …
How vaccines work
In general, vaccines contain a small amount of the virus(es) that we want it to protect against. The virus is usually dead or deactivated, which means that when it enters your body it doesn’t cause you harm. Instead, it’s recognised by your immune system (the part of your body that fights infection) so that if your body comes across it again, it’s able to protect itself.
In the UK, the most common type of flu vaccine given to adults contains three deactivated (or ‘disarmed’) strains of the influenza virus – two influenza A strains and one B strain. This is known as a trivalent vaccine. The problem is the particular B strain used doesn’t help to protect against the Yamagata strain.
But don’t be fooled, the flu vaccine is – and was – still worth having. This is because it offers protection against the other types of influenza included in the vaccine.
Are there other types of vaccine available?
Although the trivalent vaccine is the most common, there’s another type called the quadrivalent vaccine. It’s known as a quadrivalent vaccine because it contains an additional fourth strain of the influenza virus.
The additional strain is a type of influenza B, which PHE have shown has the potential to offer protection against the Yamagata or ‘Japanese flu’ strain. You can ask to have the quadrivalent vaccine, but it’s important to know that it’s not available everywhere.
In the UK, most children are given the quadrivalent vaccine as a nasal spray. It isn’t offered to adults because it’s thought that it isn’t as effective for them as the standard vaccine. But the good news is protecting children with this vaccine can help us all. Children are ‘super spreaders’, meaning they spread the infection fast, so by protecting them we can also help protect our wider community.
How to protect yourself from Japanese flu
It’s important to remember that flu caused by influenza B is often less severe and there’s usually only small outbreaks. However, if you have a chronic (long-term) condition or are high risk, then call your GP for advice if you get the flu – you may need special antiviral medication.
Whether it’s ‘Aussie’ or ‘Japanese flu’, the key messages around controlling the spread of infection are the same. You can protect yourself and others from flu by:
- regularly washing your hands
- using (and binning) a tissue when you cough or sneeze
- avoiding unnecessary contact with people – especially those vulnerable to flu, including children and older people
As the saying goes: ‘prevention is the best cure’, so familiarlise yourself with the above and help us stop the spread of flu this winter.