The Chelsea Project: How an adaptive, multidisciplinary approach brought COVID-19 numbers from among the nation’s highest to among the nation’s lowest in Chelsea, MA.


The small city of Chelsea, Massachusetts had one of the highest COVID-19 transmission rates in New England in the summer of 2020. Many factors contributed to the spread of COVID-19 in Chelsea including overcrowded living conditions, a high proportion of residents working in essential jobs, and misinformation about COVID-19 and testing. 

The Center of Complex Interventions, a nonprofit organization that specializes in applied scientific research, initially started The Chelsea Project to address testing hesitancy in Chelsea. The Chelsea Project is now a collaborative effort that includes government entities in Chelsea, local nonprofits, and startups that have partnered to deploy three different interventions: city-wide wastewater analysis, targeted PCR testing, and a community-led communications strategy. The unique combination of these interventions helped increase both testing and vaccination rates in Chelsea. As of November 2021, Chelsea has one of the highest vaccination rates among cities with comparable demographics in the U.S. 

Key learnings from The Chelsea Project include: 

  • Health equity is an attainable goal. The Chelsea Project is an example of health equity in action. Improving quality of care and access to healthcare in vulnerable communities is extremely challenging because of language barriers, lack of trust and lack of resources. However, taking the time to understand these specific barriers in Chelsea and how trust networks in the community operate enabled The Chelsea Project to implement interventions that actually addressed these barriers and improved access to health resources.
  • Understanding the reality on the ground is essential for effective intervention and adoption. The Chelsea Project team carefully considered how Chelsea’s unique challenges would impact adoption of potential interventions. 
  • The ultimate impact should be long-term change. In systems with many moving parts and different actors, connecting existing entities in new ways is more likely to result in long-term change. The new partnerships and funding opportunities enabled by the Chelsea Project will ensure that this public health work will continue even if CCI and The Chelsea Project no longer operate in Chelsea. 
  • An iterative approach will produce better outcomes. The Chelsea Project went through many cycles of research, development of interventions, implementation, and synthesis. Taking the time to synthesize the outcome of each intervention we attempted to implement helped the team reevaluate the problem and develop more effective interventions. This iterative approach resulted in three different focus areas—wastewater, testing, and communication—that, when combined, were extremely effective at increasing testing and vaccination rates. 
  • Flexible funding is necessary for an iterative approach. Flexible funding allowed the Chelsea Project the time necessary to tailor interventions to current obstacles and enabled the team to adapt in real-time to unpredictable on-the-ground developments. This iterative approach would not have been possible without flexible funding. 

Despite higher vaccination rates and a decrease in COVID-19 infections, our work is not done. The next phase of the Chelsea Project focuses on providing education and tools that will empower Chelsea residents and city policy makers to prevent future outbreaks of COVID-19 and address other health issues in the city.