Flu Virus Mutation

The mutation of the influenza virus: A virus famed for its rapid mutation, the influenza virus has been one of the longest lasting viruses known to humanity.

Artistic Rendition of the Influenza Virus (CDC)

This rapid mutation of the flu virus has resulted in the imminent need for a new vaccine on an annual basis.

What is the reason behind this? And how does the mutation occur?

How does mutation take place?

Mutation can generally be defined as a genetic variance of an object/ organism across a same species. Usually, mutations are caused when there is a slight error during the replication process of a DNA/ RNA strand. This causes a slight difference between two objects/ organisms within the same group or family. When discussing viruses, we call each of these different mutated particles as 'strains'.

Why does the flu virus mutate rapidly?

The main reason behind this lies in the genetic structure of the flu virus. The influenza virus is a single-stranded RNA virus. During the replication process, DNA- unlike RNA- possesses a mechanism that functions similarly to a proofreader. This is known as '3' exonuclease activity'. Therefore, when DNA replicates, this mechanism allows it to correct the previous base.

Therefore, one potential reason behind the rapid mutation of RNA viruses (such as the flu virus) is that there is a high risk of base replication error rate, causing more mutations. Additionally, objects/ organisms with a smaller genome may replicate faster than those with larger genomes.

What are the types of mutation?

All viruses contain proteins on their surface known as 'antigens'- these antigens are the actual substances that our immune system needs to fight against in our body: this is one of the primary components of a vaccine. In a flu virus, there are two main antigens: hemagglutinin and neuraminidase. The two types of mutations involve the changes that occur with these two antigens.

The first type of mutation is an 'antigenic drift'. During this process, there are very slight, subtle changes in the antigen that result in the rise of a new influenza strain. The second type of mutation is an 'antigenic shift' in which there is a massive change: this is caused by the unification of two viral genomes.

Implications of viral mutations

Viral mutations certainly present us with major implications. One primary way is with their unsuspecting ability to cause global catastrophe. Even slight changes to viral genomes pose a threat to us since they have the ability to cause epidemics or pandemics, as people lack immunity to the new strains. Such examples include the 1918 H1N1 virus pandemic. Viral mutations, contrarily, can pave the way for further scientific advancements. Every year, virologists and scientists must predict the most likely strain of the influenza vaccine for the coming year and produce a vaccine to support the immunity of the public.

Ultimately, as the public, the most that we can do is educate ourselves about public health and the necessity for health interventions, such as vaccines- and educate others too. Ultimately, one of the worst viruses in history is human ignorance.