Flu, short for Influenza, is one of those diseases that everyone knows. Whether you have suffered from it yourself, or whether a friend or family member has, it is one of those conditions that we are aware of from very young age, similarly to the common cold or chicken-pox. However, unlike the common cold, flu has a devastating effect on people’s lives year on year. While for most of us flu will clear up on its own after a week or so, flu can cause serious complications such as pneumonia and meningitis. The World Health Organisation (WHO) estimates that flu causes 3-5 million serious infections and 500,000 deaths across the globe every year! To help combat this, WHO recommend that a free flu jab should be offered to ‘at-risk’ groups to reduce chances of flu, however there are many myths surrounding whether this annual jab actually works.
What actually is Influenza?
Influenza is caused by the influenza virus that can be found in one of three types; A, B or C. Each of these types of virus have different structures and properties. Influenza A viruses are the most common strain of virus to cause flu and are the only strain able to infect both animals (such as swine and bird flu) and humans. Influenza B viruses are the second most common form of flu and can only be found in humans. This form is thought to have originated from Asian countries but now has spread globally. Influenza C viruses are rare and usually only cause mild flu symptoms in children.
Both A and B viruses can be further divided into subtypes by their structure. A viruses are sub-classified depending on which proteins are found on the virus’ surface, specifically which form of the proteins haemagglutinin (H) and neuraminidase (N). Each of these two proteins exists in a number of forms, specifically 18 forms of haemagglutinin and 9 forms of neuraminidase. The two most common forms of A viruses are the ‘H1N1’ (i.e. the virus contains type 1 of the haemagglutinin protein and type 1 of the neuraminidase protein) and ‘H3N2’ virus subtypes. B viruses fall into one of two groups, or ‘lineages’, called Yamagata and Victoria. While the viruses fall into these broad subtypes or lineages, they are not all identical. Each group has a variety of viruses where each is said to be a different ‘strain’.
Dissecting the Flu Jab
Vaccines are one of the most beneficial discoveries in modern medicine. By using weaker versions of the disease, vaccines can trigger our body’s immune system to fight off the infection, our body can remember which viruses it has fought against, allowing a faster response in the future. A vaccine for flu, the flu jab, has been approved for human use since 1945 and usage has been on the rise ever since. There are two forms of the jab, a Trivalent Vaccine, which can protect a person against 3 strains of the influenza and a newer Quadrivalent Vaccine which can protect against 4 strains which was approved in 2012. Both forms of the vaccine protect against two A-Strains and one B-Strain with the Quadrivalent including protection against an addition B-Strain. The exact strains that are chosen for the vaccine are decided by WHO on an annual basis and patients and public alike must have the jab re-administered every year.
How effective is it?
A popular news story surrounding the flu jab is that it “doesn’t work”, however the situation is a little more complex than that. The influenza virus is known to ‘shift’ and ‘drift’ meaning that the virus can mutate at any time, or even fuse to other influenza viruses, to form a new strain. Because of this, new strains of influenza are present every year, meaning we need a new vaccine every year to combat these new strains. In order to do this, we predict which strains of the virus shall be the most prominent year on year. This is done by an influenza specific subdivision of WHO, the Global Influenza Surveillance and Response System (GISRS) Network. The network collects surveillance data, both from hospitals and laboratories, computer simulations, genetic profiling, vaccine effectiveness and other forms of data on the influenza virus every year. WHO then evaluate this evidence twice a year and select which strands are to be included in that year’s vaccine, once for the northern hemisphere in February and once for the southern hemisphere in September. Each year WHO recommends an A/H1N1 strain, an A/H3N2 strain, a B/Victoria strain and a B/Yamagata strain of the influenza virus to be included in the vaccines. These predictions need to be done around 9 months before the next flu season for the recommendations to be approved and the vaccines to be mass produced. However, if these recommendations are wrong and are not the most prominent strains of the influenza virus, the jab does not protect patients.
Protecting those in need
As with most vaccines, the flu jab is available to the general public who wish to receive the jab, however certain demographics are advised to receive the jab over others. WHO recommends that 75% of the elderly, children, pregnant women and patients with chronic conditions should all receive free flu jabs from their respective countries. WHO also recommend health care workers to receive flu jabs and here in the UK, the NHS launched a flu jab awareness campaign to increase the numbers of protected healthcare workers to help protect not only themselves, but also their patients.
However, annual uptake of the flu jab still remains remarkably low in these groups across Europe. More action still needs to be done by governments and hospitals alike to help protect those in need from the dangers of influenza.