Environmental surveillance has proven to be a powerful public health surveillance tool
Dr Angela Chaudhuri, Health Lead, COVIDActionCollab in an interaction with Viveka Roychowdhury talks about wastewater surveillance program for COVID-19 initiated by the COVIDActionCollab in Karnataka and highlights its role in the management of infectious diseases
Wastewater surveillance programs have been used to detect polio, based on which countries are declared polio-free. Given its benefits, are such programs being used regularly in India?
Polio surveillance has been one of the earliest use cases for environmental surveillance. It has been carried out extensively in many parts of the world, including India. In India, wastewater surveillance was first initiated in Mumbai in 2001, followed by other cities in later years. It played a vital role in the eradication of polio in 2011. India continues wastewater surveillance at 52 wastewater treatment plants and unregulated catchment areas where sewage is drained in nine states and one Union territory.
As per the Ministry of Health & Family Welfare, Government of India environmental surveillance has been established to detect poliovirus transmission and as a surrogate indicator of the progress of any programmatic interventions strategically in Mumbai, Delhi, Patna, Kolkata, Punjab, and Gujarat.
The learnings and experience from the WBE-based polio surveillance have supported the government in taking control measures and expediting the polio eradication program in India, thus making the country polio-free in 2014.
What are the challenges to making them a regular part of disease surveillance programs in countries like India?
Despite significant progress and potential for an expanded and enhanced public health surveillance system in India, there are a number of challenges that need to be addressed in the short term including:
Lack of awareness of the relevance and effectiveness of WBE: Although environmental/wastewater surveillance has been used in polio eradication programs in India, there is still minimal knowledge and understanding of its use and effectiveness as a public health tool. However, this scenario is changing rapidly as more and more cities set up ES platforms for disease surveillance.
Lack of national and state policies on WBE: As there are not many references to environmental/wastewater surveillance in public health discourses and research over a long time, it is not a part of public policies that provide essential space for its resource allocation and use. However, recent developments in this field have indicated an interest among the public health community and policymakers in India
Lack of capacities for regular testing, sense-making platforms, and communication: There are minimal capacities for planning, implementation, and usage of insights for public health actions. Hence, communication holds the key to delivering the message interpreted from the ES data.
Risk of misinterpretation of data and panic spread in the public: A slight miscommunication on data interpretation can lead to unwanted panic in the community and can pressurise the local govt to discontinue environmental surveillance due to apprehension.
What inspired the wastewater surveillance program for COVID-19 initiated by the COVIDActionCollab in Karnataka?
The concept of wastewater-based epidemiology existed since the 1930s and 1940s, when it was first used for poliovirus detection in the US. Since then, it has been used as a disease surveillance tool to some extent in different parts of the world. However, it re-emerged as a powerful surveillance tool during the COVID pandemic.
A study posted on March 30th, 2020 on MedRxiv reported that a sample collected from Amersfoort, the Netherlands, tested positive for the virus six days before the first COVID-19 case was diagnosed in the city, indicating that wastewater surveillance can serve as an early warning system. This publication triggered the public health communities and governments in different parts of the world for testing and experiment with ES for SARS-CoV-2 virus in different settings and populations.
In the same year, COVIDActionCollab also conceptualised the process and launched a pilot study in Bangalore with various partners having relevant domain expertise. The pilot study proved to be successful and provided evidence of the detection of RNA copies of SARS-CoV-2 virus from the open drain wastewater prevalent in the city. This prompted CAC to present a proposal that was accepted by Skoll Foundation which provided the grant in April 2021. We officially launched the Precision Health platform, an initiative in Bangalore on 27th May 2021 in collaboration with different partners to set up an Early Warning System through Wastewater Surveillance.
How did the CAC collect and analyse the data?
In our Bangalore initiative, we had been testing wastewater samples collected from 46 open drain sites in the city to detect traces of SARS-CoV-2 virus. A sample collection plan was developed based on the predefined conditions (grab sampling, one sample per site per week). CAC has two local implementation partners with substantial experience in wastewater management. The collection team collects samples from open drain sites as per the sample collection plan and delivers those to the assigned laboratory for processing them for RNA extraction.
The extracted RNA samples are tested with a qPCR kit to obtain RNA concentration (RNA copies/ml) for the sample. The RNA concentration is expressed as “Viral Load” and presented in a time series trend graph for any increase or decrease.
We have been reporting three findings from this initiative:
Weekly site positivity: Percentage of samples from sites where the samples are positive out of the total samples tested in a week.
Cumulative viral load trend: A trend graph of cumulative Exponential Weighted Moving Average of viral load of all 46 sites. The trend shows whether the city-wide viral load is increasing or decreasing with time.
Variant testing: The positive samples are selected on the basis of Ct values, Viral load and the Sigmoidal curve after RT PCR tests for Genome Sequencing and lineages (variants) are determined.
How did the insights from the data collected from this project help the Karnataka government respond more proactively to the COVID-19 pandemic? (Kindly give as specific examples as possible, compare to states where such programs were not running to show the impact)
The data and insights obtained from the precision health program should not be used exclusively to derive actions. The wastewater surveillance only provides an early warning signal in case the samples are tested positive. Hence, it supports the surveillance teams in the local government in the first level screening of the city by providing supplementary information. Thereafter, other surveillance data should also be used to gather additional insights and then derive any action.
The BBMP has set up a COVID war room in which all the surveillance data is reviewed by the team of professionals and officials to understand the current scenario and thereby, plan for the actions. One official from the team, who is the nodal person for the Precision Health program, reviews the PPHS data and discusses how this data could be added with other surveillance data for better planning of action. The PPHS data provides an Early Warning to the city in case the site positivity and viral load increase in the city.
The precision health team has developed a sense-making platform to help local governments interpret the data and insights in a better way so that necessary actions can be taken.
From the graphs below:
In the implementation phase since April 2021, the team obtained three early warning signals from ES in the months of October, November, and December 2021. An Early Warning Signal was reported on 26th December 2021, and a week later the Total Positivity Rate from the individual samples also started increasing, commencing the third wave in the early January 2022.
Can you give a cost breakdown of the expenses involved and, therefore, the feasibility of scaling it up from Bangalore to the rest of India?
The implementation cost of the initiative depends on the number of sampling sites and the frequency of sample collection the city should have. As the resources are required primarily in the implementation (sample collection and testing), the highest percentage of expense goes into it. A typical annual implementation cost for ES in a city like Bangalore, with 45 sites with a sample collection frequency of weekly twice per site is given below:
| Particulars | Includes | Amount in Rs |
| Programme Costs | Supplies for sample collection and testing | 37,66,014 |
| Program Equipment and Assets | One-time cost for equipment, such as
centrifuge machine, PCR machine |
9,00,000 |
| Program Administration Cost
(Salaries) |
HR cost | 37,72,881 |
| Total | 84,38,895 | |
In addition to this, other resources such as program manager, public health professional/epidemiologist, communication professional, data analyst, and stakeholder manager can be resourced separately for a successful project.
For scaling this initiative in other cities, a unit cost for sample collection and testing can be calculated taking all relevant costs into consideration. Based on the number of sites in the city and the total samples to be collected, one can estimate the overall cost of the project. As the Bangalore initiative proved the effectiveness of the ES in case of open drains, it is practically feasible to implement in any city in India.
What is the roadmap for expanding this project, the sewage surveillance system for COVID-19, beyond Karnataka into a pan India program?
The precision health platform was launched for COVID surveillance as an entry point. As the wastewater surveillance has shown potential for early warning for other infectious diseases, the precision health team has visions of utilising the platform for other disease surveillance. In addition to this, the platform is being tested in drug level testing and study on Antimicrobial Resistance (also known as a slow pandemic).
We are also looking at setting up an alliance as a pan India program. The National Alliance for Environmental Surveillance (NAES) shall be a sector-shaper for Environmental Surveillance to prove and be acknowledged as a key public health tool by harmonising academic and private sector efforts. The alliance is envisioned to be India’s first holistic platform focused on environmental surveillance by offering a unique multi-sectoral collaboration with different resource partners sharing knowledge and learnings, further disseminating information for evidence-based decision making.
In addition to this, the team is planning to scale up the COVID surveillance in seven other cities, while continuing the Bangalore Initiative. In the scale-up initiatives, Precision Health will be supporting the planning and implementation of ES in the city by providing technical support to the city leads and providing data analytics and communication support to the city teams. The proposal for all the above plans has been submitted for further review.
How will this expansion be funded?
This Alliance shall be funded by donors whose role is viewed as a prime mover in supporting through investments, sharing social capital, overseeing governance, and achieving sustainability. They will be supporting the Precision Health team in the mobilisation of partners through their social capital.
What are the long-term benefits of such sewage surveillance systems? What are the other disease conditions that can be mapped? How is this system better than community screening/testing etc.?
The presence of the virus in wastewater is a surrogate indicator of the disease being prevalent among the community living in that area. It is not based on assumptions or modeling but on actual findings of the presence of viral remnants in wastewater. The pathogens can be shed in the feces of individuals with symptomatic or asymptomatic infection; therefore, wastewater surveillance can capture data and information on both types of infection and send powerful early warning signals up to 6 days in advance of preparation.
This platform helps in identifying areas and regions where infection can be spread in the coming days or weeks, by testing the traces of the virus from the community wastewater. Hence, it provides an early warning to the government with evidence from the sample test findings, for necessary actions and steps to prevent the spread of the infection. The program can be replicable in most resource-constrained urban settlements and serve as a strong example for cities to invest in such surveillance systems.
As a long-term impact, it is expected that the city administration will get better visibility and better decision-making tools which can support taking proactive measures in disease control and management.
As the source of samples is community sewage, most enteric pathogens can be detected through Environmental Surveillance. Some examples can be Rotavirus, HIV, hepatitis A, influenza, and Salmonella typhi. All of these pathogens cause high mortality and a high disease burden in India. As the platform uses pooled samples from the community wastewater drains, which represent a large number of households, the cost of surveillance is significantly less compared to community testing.
What has been the impact of such systems /programs in India and globally, from a public health provider perspective and for communities and individual citizens?
Environmental surveillance has proven to be a powerful public health surveillance tool. The COVID surveillance is a case in point. It has provided public health providers with an additional layer of useful information about the infection rate in the city as a whole. As it uses samples from the community wastewater, it is independent of the population’s health-seeking behavior. This provides a holistic view of population health status, covering all sections of the population, including asymptomatic and untested individuals. Governments across Europe and the USA have been very active in expanding environmental surveillance in different cities and towns.
A public health provider has benefitted the most from this platform as it helps him in better resource allocation and targeting actions to control disease spread through evidence-based decision making. Hence, it supports him in taking proactive measures in disease management.
If the insights from environmental surveillance are publicly available and are shared with the community with an appropriate communication for its interpretation, the community is likely to benefit, it can support public health providers by taking unanimous decisions on containment measures. Individuals too can make informed decisions based on the insights from Environmental Surveillance. In the case of infectious diseases, each individual plays a vital role in the disease spread containment. Hence, if prior information is available as an early warning signal, he/she can take also support disease spread control.
After the COVID-19 pandemic, are such systems being made part of India’s Smart Cities roadmap to create more resilient cities? What are COVIDActionCollab’s future plans on this front?
A group of interns working in the NIUA’s Smart Cities Initiative under the Ministry of Urban Development, while exploring new and innovative ideas for Smart Cities, identified the Precision Health platform as a potential and viable system for future Smart Cities. The Precision Health team had introductory sessions with the group on the matters of navigating and promoting the ideas in higher public health discourses. Communication is still underway.
The National Institute of Urban Affairs (NIUA), a think tank for research, training, and information dissemination in urban development and management in New Delhi, India, is also supporting and funding a pilot initiative in Surat, Gujarat. They have set up a national working group consisting of scientists who provide necessary directions in its planning and implementation.
COVIDActionCollab would like to collaborate and engage champions like NIUA in scaling the initiative in more cities in the future. Also, the team will be working on advocacy for environmental surveillance and capacity building both at the state and national levels around it.
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