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CoVPN and Socialisssima use Facebook Ads to spur recruitment for COVID-19 vaccine trials among underrepresented groups.

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The COVID-19 Prevention Network (CoVPN) and Socialisssima used Facebook ads to accelerate recruitment of underrepresented Black and Latinx populations for COVID-19 vaccine clinical trials. Through its multi-media approach, CoVPN promoted open conversations within the Black and Latinx communities about COVID-19, health, and clinical trial participation -- leading over 65,000 people to click the “Volunteer Now” button that directed them to the CoVPN website,, to register.

“We needed to pivot our campaign in relation to news about COVID-19 and respond to other perspectives about vaccines with speed. Facebook enabled us to be nimble. We were able to listen to the concerns of our organic community and respond to it in real time- Facebook gave us that ability.”

–Sally Bock, Senior Director of Marketing, COVID-19 Prevention Network


Diversity in clinical trials is essential because differences between people based on age, sex, health conditions, and other factors such as where people live, their lifestyle and the impacts of systemic racism can influence their health and how well vaccines work for them. Unfortunately, Black, Latinx and other racial and ethnic minorities are often underrepresented in study populations.

The COVID-19 Prevention Network (CoVPN) was formed by the National Institute of Allergy and Infectious Diseases (NIAID) at the U.S. National Institutes of Health to respond to the global pandemic. When the rapid development of vaccines during the COVID-19 pandemic created an urgent need for a large number of clinical trial volunteers, CoVPN partnered with Socialisssima, a socially-minded marketing company, to encourage Black and Latinx populations over 45 years old to sign up for the CoVPN clinical trial registry through Facebook. CoVPN reported they were tasked with recruiting more 40,000 volunteers in just 8 weeks, compared to the years-long timeline of a typical trial.

CoVPN and Socialisssima used Facebook Audience Insights, a tool that helps build an audience for ads based on user demographics, to direct ads to users in 1,200 zip codes that reflected the most highly impacted populations in their study areas. Within those zip codes, CoVPN targeted content towards users who were a part of general health interest groups and nurse and doctor associations, based on the assumption that people in those groups might be more interested in volunteering for vaccine clinical trials.

The team ran 16 ad campaigns with 49 distinct ads that featured a variety of content: infographics, quotes from a well-known public health leader and testimonial videos in both English and Spanish. Most ads linked to the CoVPN website, and the number of people who clicked on the registry volunteer button were used to track the ads’ effectiveness.

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With the CoVPN ad campaign, over 65,000 people clicked the “Volunteer Now” button after seeing the ads on Facebook and Instagram (also known as 65,000 ad “conversions”) within eight weeks. The average cost per conversion was $8.80 - significantly less than some trials spend on recruitment per volunteer.

“When we were advertising from paid communication on Facebook, we saw the composition of people in the registry shift to greater percentages from our target groups. We knew we could dial up advertising on Facebook to grow the registry data.”

— Sally Bock, Senior Director of Marketing, COVID-19 Prevention Network

The highest performing ads varied in language, content style and message, demonstrating that multiple approaches to engaging users can be a successful strategy. People can resonate with different types of ads depending on their motivations for volunteering, like protecting their community or protecting themselves and their loved ones. If people were receptive to certain ad content about the clinical trial process, the team would follow up with ads directing them to the registry. CoVPN saw an incrementally better conversion rate through this process, underscoring the importance of re-engagement in an ad strategy.

CoVPN reinforced messaging across multiple platforms to better connect with potential volunteers and boost conversions. For example, some of the ads directed people to COVID in Black, a Facebook Live series created by CoVPN that addresses health inequities from systemic racism, mistrust of clinical trials, and the impacts of COVID-19 on Black communities. Additional Facebook Live talks with vaccine experts encouraged long-form conversation to complement short videos and static ads. CoVPN also collaborated with partners like UNIVISION and Urban One to amplify messages across Facebook, radio and TV broadcasts, and reiterate the content in their ads.

“The more people that saw the content shared it and could influence a larger population by creating an open conversation. We saw that people who went to the Youtube content then went to the [registry] website after that, even though the ad didn’t direct them there. This shows that there are so many levels of things we needed to say, and promoting that open conversation can be really successful.”

— Norberto Zylberberg, Founder, Socialisssima

Using Facebook also provided CoVPN with real-time insights that enabled them to quickly respond to relevant events throughout the ad campaigns. In response to comments on the ads and news about COVID-19, CoVPN and Socialisssima adapted ad content to better address current attitudes within the community and dispel myths. For example, when studies were paused due to serious adverse events in a trial participants, Socialisssima created static and video content explaining how study pauses are a planned safety measure to protect the wellbeing of all participants.


CoVPN and Socialisssima prioritized setting up a responsive and open dialogue to help drive people towards volunteering. They partnered with influential people, news outlets, and organizations, while also re-engaging with people who showed interest in the ads. Taking time to respond to comments was crucial for answering questions, dispelling fears and myths and presented opportunities to identify common questions or misconceptions that helped inform ad content. This strategy empowered their audience with information and reinforced factual messages across platforms to help viewers make informed decisions about joining the clinical trial registry.

*Case study results will vary, as they depend on a variety of factors. These results may not be achieved by all.