A story of our very own virus library, fresher’s week and that inevitable runny nose.

Words by Rob Barrie, Science And Technology Editor

New friends. Alcohol. Parties. And that cold that just won’t go away. Why do so many students fall ill during the opening weeks of university?

The human body has evolved many attributes over hundreds of thousands of years. The five senses, the heart, which functions as a pump, and the liver, which acts as a filter of toxins are all examples. But none are more impressive than our immune system – an intricate arrangement of interconnecting systems of cells, proteins and organs. Humans encounter approximately 60,000 germs – mostly viruses – on a daily basis, and our immune system is our defence against these tiny microbes. So why don’t we become ill more often? Well, it turns out our immune system is actually rather resilient. Indeed, scientists estimate that only 1-2% of germs are dangerous because of the metaphorical fortress we are all born with. 

The immune system operates on two primary levels: physical and chemical. The physical is a barrier we usually take for granted, and it is the biggest organ of our body – skin. For a microbe to enter our body, it cannot simply diffuse through our fingertips. It must enter through openings – the mouth, nose, eyes or even the sexual organs. 

If the physical barrier fails, then reinforcements arrive courtesy of a chemical system. Viruses survive by invading host cells, and so each virus microbe that enters our body will target a cell as a new ‘home’. If one of our healthy cells is attacked by a virus, it secretes signals – an SOS call effectively – to white blood cells. White blood cells identify compromised cells and travel over to those affected and kill the viral inhabitant. If someone sneezes on you, the chances are that a few million of these microbes enter at once – and so this white blood cell defence happens simultaneously across millions of infected cells. 

For the tough viruses that survive even this, a back-up system activates – the adaptive immune response. This system effectively employs a ‘virus library’ that has noted down every illness you’ve had. If you encounter the same common virus that made you ill three months ago, your white blood cells recognise it immediately and recruit the same weapons – antibodies – that expelled the same virus three months ago. This response is the basis for immunity. Everyone’s metaphorical library is of course different depending on different viral exposures, and this forms the variability of immunity in the population. There are of course caveats. Firstly, some viruses are known for mutating regularly – HIV for example – and if it changes its appearance enough, our white blood cells can’t recognise it. Secondly, our memory stores have different duration. Just as books in a library become forgotten if never loaned out, our antibodies gradually become lost if a virus is not encountered for a period of time.

So, if all these barriers, reinforcements and even backups are so efficient, why do we become so ill in fresher’s week?

Let us first tackle the infamous name. Students might ask: ‘how can I catch the flu if I’ve had the vaccine?’ or ‘I had the flu recently so I should be immune’. And they’re absolutely correct. In fact, ‘Fresher’s Flu’ is not the flu at all. It isn’t even a single virus. ‘Fresher’s Flu’ is the collective name for a plethora of thousands of viruses being spread around by university students. Flu is the umbrella term given to all of them because most give symptoms – you guessed it – similar to the flu. Now the slightly lazily named term has been debunked, let’s tackle why many students fall ill.

Is the first line of defence, our physical barrier, operating at maximum efficiency? Not particularly. Large amounts of people in small spaces, such as parties, clubs and even lecture halls, mean our airways are quite regularly in the ‘splash zone’ of coughing and sneezing. Increased rates of sexual activity too are also a factor. Mixing of saliva introduces a considerable ‘viral load’ (virus concentration) if one of the participants is infectious. Incidentally, the rate of sexually transmitted infections increases during freshers too. As these are caused by both viruses and bacteria, and also because the symptoms are not flu-like in nature, these are not included under ‘Fresher’s Flu’!

So, let us assume one of the many types of viruses has bypassed our physical defence and has now entered our body, and consequently our cells are now being targeted. Cells under viral fire secrete their SOS signal – but the white blood cells are nowhere to be seen. Where are they?

It turns out that we meet so many new people during the first weeks of university (many of whom are infectious) that our immune system is overwhelmed by the quantity – and, practically speaking, there aren’t enough white blood cells in our body to go around. As a result, the call for assistance by many of the invaded cells goes unheeded.

Our second barrier now lies in crumbles as the viral armies march on through our body. But fear not, we have our adaptive immune system – our brilliant library of viruses. But here another problem arises, and it’s not just us meeting a lot of new people in freshers. The diversity of those we meet is a hugely significant factor, too. Individuals from different regions of this country, indeed from different countries all together, bring their own unique cocktail of viruses if they’re ill when joining university. And so, when our white blood cells go to our ‘virus library’ and look amongst the shelves to find any historical records of said virus, they are disappointed when no book exists, because a lot of the viruses encountered during freshers are novel. The common cold in England has a different viral genetic makeup to the common cold in Spain. Indeed, even the common cold that’s in fashion in Brighton will differ slightly to the one currently infecting students in London. The consequence is that our white blood cells have no previous knowledge to act upon. The result? Our immune system is completely overwhelmed. Cells are invaded by the virus and we become ill. 

Past the point of no return, our body initiates its protocol for getting rid of these foreign particles. Fevers are high temperatures to kill viruses above their survival range and runny noses try to literally flush out microbes. The virus itself does not cause these – it is our body’s response to a virus that’s already taken a hold. 

Another reason why our immune system becomes overwhelmed during freshers is the increased consumption of alcohol, poor diet and lack of sleep. The immune system is, in essence, a reflection of our general well-being, and if we are not at our optimum neither will be our defence system. Even depression has been shown to reduce the efficiency of the immune system.

Though being ill is never fun, ‘Fresher’s Flu’ is particularly advantageous from an evolutionary and biological perspective. The body, in a very short space of time, is exposed to a plethora of viruses – locally sourced and from land afar, too. Indeed, some may never be encountered again, but our ‘virus library’ expands at a great rate during the opening stages of university. New experiences create longer book shelves of viral knowledge and result in future interactions being less problematic.

So, if you become ill this week and miss that important house party, don’t blame your immune system too much – it’s doing its best. After all, it’s already protected you from a few thousand germs today alone!

[Most viruses during freshers are not dangerous, but if illness persists, a visit to the campus surgery is recommended.]

Image: Max Pixel

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