Today, 17 countries use the WHO’s Early Warning, And Response System (EWARS), developed jointly by the Institute of Medicine at Sahlgrenska Academy, Umeå University and the University of Freiburg, Germany. EWARS is a framework that encompasses surveillance, early detection, and organizes response and recommendations to public health agencies and other organisations to deal with infectious disease outbreaks that are sensitive to climate change.
“WHO’s choice to issue a Policy Brief is gratifying. This way, more countries will gain knowledge of EWARS as a tool that can support their public health disease control activities and scope for sharing their own experiences,” says Laith Hussain-Alkhateeb, Senior University Lecturer and researcher in charge at the University of Gothenburg.
Early Disease Prediction
To combat vector-borne (insect-borne) and water-borne infectious diseases like dengue, malaria and cholera, promptly predicting outbreaks and with adequate and time response to curb them is essential. For many of these diseases, effective vaccines are lacking and outbreaks often occur in poor areas where the health care system is already over-stretched and weakened.
“If the authorities can be warned in time and space of disease outbreaks – for example, to receive early signal of a dengue outbreak eight to ten weeks in advance, vector control and response agencies have time to prepare. They can then warn the population, prepare health care services, and start preventive measures of various types, such as insect control,” Hussain-Alkhateeb says.
Such action requires access to data, advanced statistical analyses, and presentation of results in a readily comprehensible way. Efforts have been made to combine all this in EWARS.
“There are plenty of tools exist as early warning, but studies describing how well they work in practice are often lacking. I think there are several success factors in this WHO-EWARS tool: we’ve cooperated on the design of EWARS, engaged key players regionally, tried out the system with local teams in the field and worked extensively on its actual implementation. EWARS should be easy to work with, even if among unskilled users and statisticians, and there should be clear connections with local protocols for managing outbreaks.”
Impact of climate change
Development of EWARS as a statistical tool for predicting outbreaks of climate-sensitive infectious diseases started ten years ago. The tool has continued to advance and widespread in method and applications and included agencies such as WHO and the World Meteorological Organization (WMO) as well as partners countries from PAHO and SEARO regions.
Meteorological data on variables like precipitation, humidity and temperature are key alarm indicators since they affect the mosquito life cycle. Epidemiological data, such as numbers of disease cases and their distribution in the population are also important.
“One challenge has been defining what an ‘outbreak’ is. For example, Ebola outbreak can be defined with just two cases in a defined area. However, for other vector-borne diseases like dengue, one often compares with the moving average in the country for a certain period. To predict and prevent outbreaks early on, access to reliable and timely local data and a tool that can predict and facilitate the probability of various response scenarios is needed,” Hussain-Alkhateeb says.
Researchers from Umeå University have also studied how big data could be used in this process. For example, data from social media and Google searches were assessed to show promising usefulness in predicting outbreaks of disease. This EWARS tool is well amenable for employing this kind of data is available.
“The results are promising, but more research is needed. Data availability in various countries is also a problem. Vector-borne diseases are found mainly in poorer countries, and you can’t be certain of being able to access data on a weekly basis,” he says.
Increasing interest in Europe
According to Laith Hussain-Alkhateeb, there is growing interest in this type of system in Europe as well. The COVID-19 pandemic has demonstrated the importance of good surveillance of infectious diseases, as well as revealing the state of global public health today.
“Climate change also means that, in the future, diseases like dengue and others may both have large outbreaks and spread to new areas. We’ve already begun to see cases of chikungunya in Southern Europe,” he says.
Chikungunya fever, a viral disease that can cause long-term joint problems, occurs largely in tropical countries. It is one of the five diseases that have been monitored in EWARS to date. Another is Zika virus, which made headlines during the Latin American outbreak in 2015–2016. Then, a link was discovered with the fetal disorder microcephaly, which causes children to be born with abnormally small heads.
“So far, Europe has been spared from many vector-borne diseases, but increasingly as the climate becomes warmer, the mosquitoes that carry them are expanding their ranges. Several start-up initiatives are under way at both the EU and WHO levels to supplement the surveillance,” Laith says.
Starting a regional centre
The next step in the research will be to investigate how well EWARS reduces outbreaks of disease — few multinational studies are underway to explore this tool during 2022-2023. Laith Hussain-Alkhateeb’s goal is to start a new centre for climate change and infectious diseases studies in Gothenburg, and to build local synergies and engage more researchers in the work.
“I hold discussions with the WHO and partners in the European Institutes to evaluate the system, set a long-term agenda and secure resources for further research. The timing hasn’t been optimal in terms of COVID, but recently we held two seminars with some 40 participants from seven countries, so EWARS is beginning to move,” he says.
TEXT AND PHOTO: KARIN ALLANDER
