The COVID-19 pandemic highlighted the importance of reliable, real-time information on the health status of the population. In Hungary, 82% of the population is connected to centralised sewerage. Every pathogen or pollutant, which is shed into wastewater via faeces, urine or other routes, can be detected at the inlet of the wastewater treatment plant. Thus a single sample from this point represents the entire population served by the wastewater collection system. The scientific field of deriving public health information from wastewater data is termed wastewater-based epidemiology (WBE).
In Hungary, national wastewater monitoring system for SARS-CoV-2 was launched in July 2020. Sampling was carried out at least weekly from the three wastewater treatment plants serving the capital, Budapest, from its agglomeration and 18 county seats. The concentration of SARS-CoV-2 in wastewater correlated to clinical data (weekly average of new and hospitalised cases) with an offset of one and two weeks, respectively, before the omicron variant. The association was observed both on national and city level. Since the emergence of omicron variant, wastewater data provides representative real-time information about the COVID-19 cases in the population. With the decline in clinical testing, this is the only reliable source of information on outbreak trends.
Data was used during the pandemic both for public health decision making in outbreak management (e.g. capacity planning of the healthcare facilities on a county level) and for the information of the public. Weekly reports on the sewage data received wide media coverage, contributing to awareness raising in the communities, which was especially important in the rising phase of the outbreak waves.
Beyond the SARS-CoV-2, WBE is a useful tool for following many communicable diseases and other public health hazards. The current Hungarian wastewater surveillance system covers also Influenza A virus, but further expansion for environmental monitoring of poliovirus and other enteric pathogens as well as antibiotic-resistance genes is also in progress. There is also opportunity for monitoring other health-related targets like illegal drug or alcohol consumption, smoking, tumor markers or lifestyle-related markers.
Results in this area:
Weekly SARS-CoV-2 wastewater results in Hungary: https://www.nnk.gov.hu/index.php/koronavirus/szennyvizvizsgalatok
Forecasting potential of WBE in the early phase of the COVID-19 pandemic: https://doi.org/10.1016/j.scitotenv.2021.147398
SARS-CoV-2 variants is wastewater: https://doi.org/10.2166/wh.2022.179
Waster-based modelling of COVID-19 outbreaks: https://doi.org/10.1016/j.watres.2023.120098