ICON plc

Dinah Knotts

Disease surveillance can play an important role in detecting an emerging infectious disease (EID)early, enabling vaccine development to commence as soon as possible. Furthermore, vaccine trials depend on knowing where an EID is prevalent, so that it can be tested in a relevant population. Because infectious diseases can move quickly, disease surveillance is also a key element to vaccine efficacy trials. As a result, understanding current approaches to disease surveillance early alert systems is a helpful tool for advancing EID vaccine development.

Early alert systems

Early alert systems allow those developing vaccines to select appropriate trial sites and initiate clinical trials in those locations more swiftly. Some early warning strategies involve the use of environmental observations — implementing the knowledge that certain conditions, such as extremely rainy weather, are associated with outbreaks of a specific disease — or monitoring animals in high-risk locations for diseases.

However, when a disease is very new or uncommon, these measures may have limited effectiveness, since, in these cases, there might not be enough information available to fully utilise them. For such circumstances, monitoring populations for infection is the principal alternative. 

One particularly helpful approach is to conduct testing on sick workers in high-risk professions — for example, those in virology or agriculture, who are more likely to be in contact with a new or emerging pathogen than the general population. This allows for the detection of an EID as it enters a community. Organisations, such as the African Center of Excellence for Genetics and Infectious Disease, are dedicated to using genomics in such a context to create an early warning system for viral threats.

Wastewater Surveillance

A major pitfall of the measures outlined above is that, oftentimes, disease surveillance depends on individuals seeing a physician when they get sick. However, factors such as inaccessibility, expense and lack of trust in healthcare systems mean that this is not always a reliable expectation. The question remains: How do we detect the presence of an EID in a population as early as possible?

A fairly new technology — wastewater surveillance — may offer a compelling answer. It was first widely implemented in the detection of SARS-CoV-2, but now shows great promise with other diseases. Because many pathogens are shed from the body in stool and other waste, analysing wastewater can provide numerous helpful insights regarding the presence of an EID in a community. This method does not depend on individually testing everyone who is ill to get an accurate picture of the prevalence of a particular EID. Additionally, it can detect the presence of a pathogen before patients develop symptoms, or if they are asymptomatic carriers of disease. Such advance knowledge provides researchers ample time to mobilise vaccine trials, while an area is still being impacted by an EID, so that as much relevant data can be gathered as possible.

Bringing it together

Ultimately, the information gathered by disease surveillance has no impact if it is not put in the hands of those that can use it. For this reason, early alert systems rely on smart data reporting to aggregate epidemiological data in a central location, so that it may be acted upon by governments, health systems and, of course, researchers interested in vaccine development. This takes significant infrastructural effort, from the local level to regional and national arenas, including providing clinicians with the tools to test for EIDs and report them quickly and efficiently.

However, when such supports are in place, vaccine development and efficacy trials stand to benefit.