Public health surveillance

Dr Brian McCloskey CBE is the Director of Global Health Security at Public Health England and a Senior Consulting Fellow at the Chatham House Centre for Global Health Security. In this HEART Talks he introduces the HEART Reading Pack he co-authored on public health surveillance.

He explains that public health surveillance is a means to quantify the burden of disease in a community or country. It can be used to measure how the amount of disease is changing over time to understand what is relatively normal, and what is abnormal when something different has happened. It allows us to look at changes over time which helps in evaluating interventions and identify whether targeting is needed. It is also needed to identify unexpected public health events such as Ebola, Zika, and yellow fever to alert people and take actions early.

There are two main systems available. Firstly, health facility-based surveillance uses data already collected by health workers to monitor the normal. Taking this data out is an easy way of doing public health surveillance. Secondly, event-based surveillance which collects information on events as they happen to find the abnormal. There are some global systems for examples Global Public Health Information Network (GPHIN) and ProMED. These are computer-based systems which scan social media and online news looking for anything that might be relevant to public health.

International Health Regulations (IHRs) form the framework for disease surveillance around the world, they establish a framework for response, and put in legal requirements for the capacities that people need in their public health system. One of the challenges that came out with Ebola is that money spent on health systems strengthening hasn’t been focussed on public health systems, disease surveillance systems and human resource capacity. The 2005 IHR is a legally binding agreement for 194 member states of the World Health Organization (WHO). It builds on previous IHR’s and was updated because of changing threats. There was a move away from a focus on specific diseases to an ‘all hazards’ approach. It was agreed in coordination with travel and trade organisations. It sets out ‘core capacities’ for member states to deliver IHRs.

All member states must have a National Focal Point for IHRs. There are agreed protocols for risk assessment and reporting to the WHO. There are a number of criteria used to assess whether the WHO declare a Public Health Emergency of International Concern (PHEIC) when binding travel and trade restrictions can be made. All member states were meant to be compliant by 2012 but very few are. There have been four PHEIC since 2005: 1) pandemic flu in 2009; 2) polio became of international concern in 2009 when the decline started to reverse; 3) Ebola in 2014; and 4) Zika in 2015.  There have been in the region of 50,000 events reported to the WHO since 2005. The concern is something important maybe missed between the large number of items reported and the small number declared as PHIEC.

After Ebola IHRs are being revised. What IHRs were set out to do was right, the problem was they weren’t being implemented properly in enough countries. They also weren’t being properly assessed and evaluated. This has prompted a move away from voluntary self-assessment to independent evaluation. A number of countries have challenged the idea of external assessment. Another issue is that assessment is linked to the global security agenda which is seen to be US-led. Formal agreement has yet to be reached on regular assessment on how well countries are reaching IHRs. This assessment is required for targeting countries who need support. This would be in everyone’s best interest.

Improving public health surveillance has many benefits, is an urgent priority, and should be part of health systems strengthening. It is important for the country to get this capacity right. South Korea, for example, lost 0.9% of their GDP in the six months following the outbreak of the Middle East Respiratory Virus (MERS). The health systems strengthening can also benefit, non-communicable disease burdens using the same infrastructure. And also be beneficial maternal and child health. Monitoring trends and identifying what is changing and why can help to target interventions.

Future priorities are:

  • Invest in IHR core capacities
  • Encourage and support independent external evaluation
  • Develop the workforce and the systems
  • Look at IT improvements
  • Look for partners, ie in: agriculture and farming, industry/private sector, and communities.

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