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What is a Variant?

Viruses are constantly changing and evolving as they spread throughout a population. This is a natural process which can sometimes result in the introduction of new variants.1

Whilst different from one another in many ways, one thing most viruses have in common are the ways in which they attempt to survive our efforts to kill them. As they infect and reproduce in living things, a virus’s genetic makeup can change or mutate. Though many viral mutations will have little impact on the virus’s ability to cause infection, some of these genetically mutated viruses can result in a variation whose behaviour is significantly different to the original virus - such as being more contagious or making the host even sicker.2 These are known as variants.

Mutations in viruses are one of the reasons that we see the routine roll-out of some vaccinations3 - and it is also one of the factors challenging the eradication of COVID-19.4,5


How do variants happen?

When viruses infect new people and animals, they use its cells to reproduce, multiplying that same process millions of times.6 At the same time, the virus is also trying to escape the host's immune system, which is fighting to kill it. This leads the virus to produce small changes to its genetic code in an attempt to survive.3

A helpful analogy would be to think of it like a photocopy: when you copy a document, there’s always a chance that the new version will be slightly different, for example some text gets cut off or becomes faded. The more you copy the copies, the more significant these changes become.

This is similar to the mutations seen in viruses.

Though some viruses will be unsuccessful in adapting and may die off quickly, others will have a much better success rate. And its these viruses which will lead to variants, helping the virus survive and infect more living beings so that it can continue to spread and mutate over time.2


When variants become concerning

The occurrence of variants is a natural process. Like a tree, the virus begins with the trunk, growing different limbs and branches over time. As it continues to reproduce, scientists will work hard to differentiate the branches from one another and may attempt to develop vaccines that are intended to work against them.1

However, sometimes a virus can mutate so drastically and quickly that it’s considered a whole new family of viruses.3 A real-life example of this was when the H1N1 flu virus appeared, causing the 2009 swine flu pandemic. In this case, the seasonal flu vaccine was unable to curb the spread because it was not designed to protect people from that specific variant of the flu virus.7

Today, there are similar concerns around the COVID-19 variants - as the virus that causes COVID-19 spreads, we’ve seen mutations leading to new variants which could be considered more deadly or more transmissible.1,8

That’s why researchers around the world are using epidemiological surveillance and real-world data collection to monitor the evolution of the pandemic, watching variants closely and examining how current vaccines perform to help reduce the likelihood of severe infection and hospitalisation.8


What you can do

As viruses need bodies to infect to be able to create new variants, high uptake in vaccination can help to limit any given virus’s ability to mutate. Keeping up to date with recommended vaccines is the most effective way we can all help to keep our communities protected against current and future virus variants.2,9

If we look back at history, older generations will remember the positive impact of vaccination against polio; once a devastating disease, polio is no longer the public health threat it once was thanks to global vaccination efforts.10

Vaccines are routinely available for several infectious diseases. By following the NHS’s recommended vaccination schedule, we all have the power to help protect ourselves and our loved ones against the spread of viruses and potentially curb the creation of their variants.2,4


  1. Centers for Disease Control and Prevention. Understanding Variants. Accessed Jan 2023.
  2. WHO. The effects of virus variants on COVID-19 vaccines. Accessed Jan 2023.
  3. Centers for Disease Control and Prevention. How Flu Viruses Can Change: “Drift” and “Shift”. Accessed Jan 2023.
  4. WHO. Coronavirus disease (COVID-19): Variants of SARS-COV-2. Accessed Jan 2023.
  5. Okpeku, M. (2022). Possibility of COVID-19 eradication with evolution of a new omicron variant. Infectious Diseases of Poverty. 2022; 11(1). Accessed Jan 2023.
  6. Cohen, F.S. (2016). How Viruses Invade Cells. Accessed Jan 2023.
  7. Centers for Disease Control and Prevention (2009). Effectiveness of 2008–2009 Trivalent Influenza Vaccine Against 2009 Pandemic Influenza A (H1N1). MMWR. 2009; 58(44):1241-1245. Accessed Jan 2023.
  8. WHO. Tracking SARS-COV-2 variants. Accessed Jan 2023.
  9. European Centre for Disease Prevention and Control. Why do I need a flu vaccine every year? Accessed Jan 2023.
  10. Baicus A. (2012). History of polio vaccination. World J Virol. 2012;1(4):108-114. Accessed Jan 2023.
PP-UNP-GBR-3543 / January 2023
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