Influenza has puzzled scientists and healthcare professionals for many years. The unpredictability of the virus makes it an aspect of public health that is difficult to understand and, consequently, tame.

Each year aspects of the virus change, for example:

  • when the flu season commences;
  • its reach within the general population;
  • and its duration.

However the results of a recent study suggest that the size of the city where you live may have an impact on the length of flu season you have to endure.

What did the study look at?

The study, published in Science, looked at the number of instances of influenza-like illnesses from medical claims data between 2002-2008.

Smaller cities were found to experience shorter, yet more intense spikes in flu cases. Larger and more densely populated cities were found to experience flu seasons that were spread out over a longer period of time.

What do the results mean?

If you live in a highly populated location, the climatic conditions are shown to have less of an impact on the potential spread of the virus. This is because the virus does not need to rely on low humidity in order to survive in moisture droplets in the air, before it infects a new host.

Lead author, Benjamin Dalziel explains: ‘If there [are] lots of people and transportation patterns frequently bring them together, it helps the virus find new hosts even when climate conditions aren’t at their most favorable.’

This means that big cities provide conditions that allow the virus to continue to spread even when the climate is not ideal. Large numbers of commuters are placed in close proximity with one another on a regular basis providing ample opportunity for the virus to spread.

What does this mean for where I live?

Obviously the results of this particular study are not intended to prompt people to move out of the city; but it is hoped that the findings may prompt public health officials to make more preparations for influenza season.

Big cities may need to reassess what precautions they have in place to try and keep the flu virus from spreading; whereas smaller cities may need to reassess how well they are prepared for intense spikes in flu cases.

Surveillance of flu patterns in large cities could potentially be used to help predict the overall population reach.

How can I prevent flu?

The study does not go as far to indicate the ‘best’ size city in order to minimise the spread of flu. Ideally, no matter where you live you should still try and follow good hand hygiene to prevent the spread of infection.

Prevention advice remains the same regardless of where you live. You can find out more about preventing flu by reading our article on flu precautions and lifestyle tips.

One of the best ways of preventing the flu virus is with the influenza vaccination, although it is not 100% effective. The NHS provides free flu jabs to certain at-risk groups including:

  • those aged over 65;
  • women who are pregnant
  • and those living with certain underlying health conditions.

However, if you do not fall into one of these categories you can still purchase a flu vaccine at various pharmacies throughout the country. We’ve previously created a guide to the flu vaccination which should tell you most of what you need to know. If you aren’t sure whether you are eligible for the flu jab, contact your GP surgery.