Infectious Disease Are Not Invisible


When I discuss preventive medicine on my blog and social media, most people assume that I’m referring to the importance of healthy lifestyle behaviours such as a healthy diet, regular exercise, not smoking, etc. And frequently I am, but health behaviours don’t just refer to what we eat and drink, and how much activity we do each day. Prevention in medicine is much, much broader than that, and encompasses not just the non-communicable (i.e. non-infectious) diseases which are the leading causes of morbidity and mortality worldwide today (71% in fact, according to the WHO), but also the communicable (i.e. infectious) diseases that affect our health. Many of us often forget how lucky we are, particularly in the Western developed world, to grow up with clean and safe drinking water and good sanitary facilities, antibiotics if we need them, vaccinations to prevent potentially devastating infectious diseases like measles, smallpox and polio (just a couple of examples of many!), and more medicines available than we know what to do with. But it’s these advances in modern medicine that have saved almost countless lives worldwide, and lead to what we call the epidemiological transition – the change in patterns of morbidity and mortality from predominantly infectious to pre-dominantly non-infectious causes. This transition is well-established in developed countries, and is currently ongoing in many developing countries. You can see this from the diagrams below showing the changing patterns of the global burden of disease from the 1990s to 2017, to that predicted for 2040. Each colour represents a different type of disease, which I’ve explained below:



So above you can see that the blue is lots of different chronic diseases, while the red/orange is infectious diseases, and the green is accidental and non-accidental injuries/deaths. In 1990, chronic diseases accounted for approximately just over half of the global disease burden, while infectious diseases and other causes (accidental and non-accidental) made up the lesser half.



In 2017 (just two years ago!), you can see that the burden of disease globally due to chronic disease has increased in the interim, while that due to infectious illness has decreased.



Finally, if you look at how the global disease burden is predicted to change by 2040 (not actually that far away!), chronic, non-infectious diseases are predicted to cause the greatest burden of disease around the world. However, the red/orange hasn’t gone away. Infectious illnesses are predicted to be far less prevalent, but not eradicated, and that’s especially important in the current era of anti-vaccine groups, myths, and movements on- and off-line.

Public health (my speciality as a doctor) has four major domains or pillars – health improvement, health protection, health intelligence and health service improvement. I’ve written about all four in a comprehensive article on the @thefoodmedic website, so check that out here for further reading, but in today’s post, I want to tell you about health protection, because the prevention component of this pillar is something I’ve very passionate about, and plan to share more content on here and on my social media.


So what is health protection, and why is it important? Well, as you might have guessed, health protection in public health is centred around protecting the health of the population we serve, from threats or potential threats to health and health hazards. One example of health hazards is infectious diseases. There are MANY different infectious diseases out there, some of which you may be more familiar with than others. Some common examples we’ve probably all heard of include:

  • Influenza (‘flu’)
  • Measles
  • Mumps
  • HPV – Human Papilloma Virus
  • HIV – Human Immunodeficiency Virus
  • E. Coli
  • Salmonella
  • Norovirus
  • Chlamydia
  • Gonorrhoea
  • Herpes Simplex

There many, many more examples, and some affect certain parts of the world more than others – for example, in Ireland we don’t really see many cases of malaria, while in many developing countries this potentially life-threatening illness is well-known.

The work that goes into health protection takes up a large proportion of the day-to-day work of public health physicians – it’s a key part of our role. We monitor what are called ‘the notifications’ for different infectious diseases, we investigate the cases that are flagged, and we liaise within and between different public health regions and departments to keep up to speed on the status of infectious diseases as they affect the population in its entirety. We aim to identify cases of infectious illness, if possible find the source of the infection (for example, whether from contaminated water, food, animal contact, foreign travel, an infected person, etc), identify those who might be at risk of contracting the disease from those infected, and importantly, we also do our best to put prevention and control measures in place to reduce or eliminate the risk of onward spread of a disease.


Another big part of health protection is immunisation and vaccination, which many of you will be familiar with – for example, in Ireland, we have our childhood immunisation schedule, which aims to protect growing infants and children against a range of infectious illnesses (e.g. measles, mumps, rubella, pertussis, meningitis, etc), and we also have vaccines for a range of other population sub-groups, such as:

  • The HPV vaccine for girls and boys in first year of secondary school
  • The annual influenza vaccine for certain at risk groups (e.g. healthcare workers, those over 65 years of age, those with chronic illnesses, etc)
  • Travel vaccines for those going abroad to certain countries where tropical infectious diseases are prevalent

You can find lots more information on vaccines in Ireland on the Irish website – I find it so helpful and informative.

Health protection also encompasses protecting the population from environmental hazards – for example, working in collaboration with other regulatory bodies to ensure safe and clean drinking water, air and environments for us the live in, which is particularly relevant in the global climate change emergency we face. Health protection is of course also focused on ensuring we are prepared for potential emergencies, whether these are due to disease or some other health hazard, and we have seen international examples of this with the Ebola and Zika virus in recent years.

All in all, health protection is an absolutely essential domain of public health medicine, and definitely will be a big part of my day to day as a new public health doctor trainee. I hope this article helped inform you guys of what this aspect of public health involves and why it is so important. As always, leave a comment here or drop me a line on email, Instagram, Twitter or Facebook if you have any thoughts or feedback from reading the post – @theirishbalance on Instagram/Twitter/Facebook.

Ciara 🙂 x


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