Surveillance – What’s In A Name?

Surveillance, particularly mass surveillance and issues involving privacy and data leaks, are never far from the news. However, disease surveillance and the benefits that result from it rarely generate the same kind of column inches.

Disease surveillance involves collecting data on people’s health and, in a crucial addition to the general definition of surveillance (directly translatingto watch over), the use of this information to protect and improve the health of a population. This is done through a) monitoring patterns of disease over time, b) setting health priorities through determining who is affected and where disease is occurring, c) targeting health initiatives to the appropriate people, and d) assessing how well such initiatives are working.

This activity is by no means new, with the ancient Greek physician Hippocrates reportedly the first to describe the concept. Initially, disease surveillance involved monitoring of individuals exposed to an infection and at subsequent risk of developing disease. The first documented action that can be attributed to surveillance occurred during the Black Death in the 14th century-Venetian Republic, where incoming ships were prevented from docking if plague-infected people were aboard. However, it wasn’t until the 17th century when information was first used for surveillance purposes and applied to health planning. During the plague in London, progress of the disease was followed by analysing registers of deaths to determine the number and causes of deaths.

Fast forward 400 years, and while mortality monitoring remains crucial, disease surveillance has expanded and developed considerably into routine monitoring of a range of infectious and non-infectious diseases in people presenting to different healthcare services. Examples include reports of the number of people presenting to hospitals and GPs with given symptoms (e.g. cough) and laboratory-confirmed infections (e.g. measles virus).

Disease surveillance is now focused on assessing the health of groups of people (rather than individuals) and on the use of data for action. Surveillance, in particular mass surveillance, is perceived by some to be intrusive monitoring akin to ‘Big Brother’ in George Orwell’s dystopian novel, 1984. In disease surveillance, the use of anonymous routine health records free from any identifying information such as names, addresses, and dates of birth at a population level means the privacy invasion anxieties are not a concern.

So what are the practical benefits of disease surveillance in the UK? Health data has the power to transform patient care and can help public health professionals answer key topical questions like those below:

How badly is the flu hitting us this winter?

We are currently in the middle of the flu season following concerns of high levels of influenza activity reported in the Southern Hemisphere last year. But how do we know flu is circulating here and how bad it is? Surveillance data, such as the number of people visiting a doctor with flu-like symptoms and laboratory reports of influenza, are monitored in near real-time to look at patterns to see a) if activity is increasing, b) if activity is higher or lower than seen in previous winters, c) if the symptoms are more severe and d) whether particular areas of the country or age groups are more affected.

Do global health events pose any public health concerns to the UK?

Disease surveillance is carried out globally and includes the capacity to detect newly emerging and re-emerging pathogens elsewhere such as Zika and Ebola. Surveillance informs the assessment of the risk to the population and UK-based surveillance can detect any imported cases and advise any public health response. During the 2012 Olympics (one of the largest population gatherings in British history), daily disease surveillance was carried out to provide any warning of potential threats to health such as a norovirus outbreak or bioterrorist attack. Of the reports that were received, none were assessed as being a potential threat, however, it was just as vital to provide reassurance that nothing was happening – something that could not have been done without surveillance.

Do vaccines actually work?

Yes, after clean water vaccination is the most effective public health intervention in the world for saving lives and promoting good health. Success stories, such as the near global eradication of polio and the reduction of cases of shingles in the UK following introduction of the vaccine are reliant upon surveillance data demonstrating which population group has the highest levels of disease and should be targeted, and to provide evidence showing that vaccination is or isn’t working and why.

A general perception of surveillance as intrusive snooping can make it difficult for those working in disease surveillance to communicate the benefits and purpose of their work. In fact, the field is active in protecting sensitive information, using the findings to drive health improvements, continually adapting to ensure disease surveillance provides the information that is needed, and stopping diseases from spreading. Shakespeare was right: that which we call diseasesurveillance by any other name would smell as sweet.