The recent study in Hyderabad and Bengaluru has brought to light an efficient and foolproof method of collecting data about Covid-19, through waste-water based surveillance. This method could prove to be a game changer in predicting and detecting viral trends, spotting new variants, limiting antimicrobial resistance, as well assisting healthcare accessibility.
Objective of the Study
The primary objective of the study was to develop a protocol and set standard operating procedures for waste-water surveillance that could be handed over to the industry for further action. The researchers sought to map out the temporal dynamics in viral load found in drainage water, with the ultimate aim of ultimately providing a service that could aid understanding and prevention of the spread of Covid-19.
Procedure and Findings
The study, carried out in Hyderabad, spanned approximately a year, covering a population of around 2.5 lakh. The researchers observed high viral load in the drainage water, a trend which was consistent from July to November 2020. An increase detected in February 2021 hinted at the onset of the second wave in March 2021. Furthermore, the study found that the majority of the virus was being transmitted through faecal samples.
The study was later replicated in Bengaluru, sampling wastewater from 28 different Sewage Treatment Plants (STPs) across the city. As STP’s collect water throughout the day for treatment before releasing it again into the system, the samples were taken prior to treatment to maintain accuracy.
Advantages of Wastewater Surveillance
Wastewater surveillance offers several advantages in combating Covid-19 spread. Firstly, it allows for the tracking of increasing or decreasing viral loads well ahead of their waves. In comparison to RT-PCR tests on individual people’s samples, wastewater surveillance allows for the sequencing of thousands of individuals’ virus contributions, bypassing the couple of weeks it would usually take for sequence analysis of a sample.
Secondly, the method enables the early detection of new variants as well as different viruses such as Dengue, Zika or TB, thereby enabling health departments to prepare and deal with potential epidemics more effectively.
Furthermore, waste-water surveillance can monitor antimicrobial resistance genes and alert civic authorities to which antibiotics are no longer effective. Unlike other forms of Covid-19 surveillance methods, waste-water surveillance is not reliant on individuals’ access to healthcare, their decision to seek healthcare when unwell, or the general availability of Covid-19 testing services.
As such, waste-water based surveillance for Covid-19 presents itself as not only an efficient and foolproof way of gathering information about the virus, but also as a critical tool in the global fight against the pandemic.