Walgreens' role in detecting COVID-19 variants

In the last two weeks, have you been in close contact with someone who has COVID-19? Are you experiencing a fever? Do you have any chronic health conditions?

It’s likely these questions are familiar to you by now. These, along with basic demographic-related questions, are what Walgreens asks when customers sign up for a COVID-19 test to help determine the likelihood that they have it. This information, once submitted to the Centers for Disease Control and Prevention, also helps the CDC make informed decisions about managing the pandemic.

So how exactly do Walgreens, the laboratories that process these tests and the CDC work together? Walgreens Stories spoke with Michael Taitel, who holds a doctorate in health psychology and master’s degree in clinical psychology and is senior director of health analytics, research and reporting at Walgreens, and Josh Schrecker, pharmacist at Aegis Sciences Corporation, to better understand how their collaborative efforts have resulted in eye-opening information about COVID-19’s spread, trends and emerging variants.

From COVID-19 nasal swabs, a wealth of data

Taitel and his team lead Walgreens’ healthcare-related research efforts on all types of vaccinations. It should come as no surprise that their work over the past year and a half has largely focused on COVID-19 vaccinations and analyzing trends based on the test samples Walgreens collects through its pharmacies. Importantly, he and his team have tracked infection and vaccination rates among different races and communities, which helped tremendously in Walgreens vaccine equity efforts.

As COVID-19 spread throughout the country, and it became clear that Walgreens pharmacies would be major destinations for testing, it dawned on Taitel: A tremendous amount of valuable data would be amassed from the thousands of people getting a nasal swab PCR test. The PCR test, or polymerase chain reaction test, is considered the gold standard for detecting an active COVID-19 infection. Because the samples must be sent for processing at laboratories like Aegis Sciences Corporation, it only made sense to combine efforts and use the data to survey the pandemic’s trends on a national scale with an even more robust team of doctors and scientists.

“When working with Aegis, we realized that the combination of the lab result data with the information collected through Walgreens digital scheduler—age, health conditions and now vaccination status—provided a wealth of information that would allow us to understand vaccine effectiveness and waning, and track where COVID-19 rates were rising,” says Taitel. “The PCR tests Aegis processes account for roughly half of our tests, and when they are positive, Aegis conducts full genome sequencing that identifies specific COVID variants.”

Seeing viral trends emerge in real time

One of the pharmacists who works closely with the lab team that completes next-generation sequencing is Schrecker, who explains how the process identifies different variants.

“We assign a test sample with a numeric identifier that sticks with it throughout the testing process,” says Schrecker. “So when a COVID-19 test result comes back positive, it retains that identifier, and we go back in and pull it for next-generation sequencing—the test that is performed to determine whether or not an individual was infected with a particular variant. We retain high-level information like the patient’s age and location for surveillance purposes to understand where the specific variants are starting to propagate.”

Aegis began completing next-generation sequencing on positive test samples from Walgreens in March 2021, and has since identified more than 350 strains of the COVID-19 virus. When Taitel and Schrecker’s teams noticed more and more occurrences of one strain in particular, it was in line with rumblings across the scientific community.


B.1.617.2, more commonly known as the Delta variant, was becoming a more prevalent strain not only in unvaccinated individuals, but also the vaccinated.

“If we identify 10 cases of a new variant in week one, but in week three, there's 1,000 identified cases, that’s something that obviously piques our interest because that would potentially demonstrate that the virus has mutated over time and has the ability to quickly spread,” says Schrecker.

At first, Taitel points out, the majority of positive cases of COVID-19 were among the unvaccinated, and this remains true. But as the original SARS-CoV-2 virus and early variants, Alpha and Beta, waned, the Delta variant emerged—and cases subsequently increased among the vaccinated as well. Its rapid spread could be tied to its high transmissibility, one that far outweighed that of Alpha and Beta.

“Delta is like an army,” says Taitel. “It takes over and dominates, and then it mutates. And that’s a cause for concern because as it mutates it can cause additional illness or be harmful to children.”


The findings of the team have since been published in a whitepaper titled National Surveillance of COVID-19 Infections: Variants, Vaccination Status, and Viral Spread. It highlights the findings that arose from the analysis of 28,620 positive PCR tests between May and July 2021, when Delta was at its height in the U.S. The data was approved by an Institutional Review Board, a Food and Drug Administration-appointed group that reviews research to assure the protection of the rights and welfare of human subjects.

Reporting and collaborating with the CDC

Every day, the test results Aegis produces are sent to the CDC. Every week, Walgreens and Aegis meet to comb through data and spot trends. So what does the team do when a new variant, especially variants of concern like the Omicron variant, gain traction?

“It’s surveillance from both sides,” says Schrecker. “We, along with many other laboratories, speak with the CDC every week. They ask, ‘What trends are you seeing? Are there certain regions of the country where you’re seeing variation or differences in terms of what’s being identified through the sequencing of positive results?’ It’s a constant evaluation and a flow of data across all parties so we have a real-time look at what’s occurring in the country.”

Aegis processes between 180,000-300,000 PCR tests every week, leading to one of the largest end-to-end databases of COVID samples in the country. By collaborating with Walgreens, the data has allowed the CDC to better understand which variants are spreading and where. When the CDC has collected enough data from laboratories across the country, and can analyze findings like a rapid growth in breakthrough cases in vaccinated individuals, this gives the health protection agency the science-backed research it needs to make informed decisions about protective measures it should recommend to the public or guidance about additional or booster vaccine doses. Taitel is proud to play a part in that.

“Walgreens and Aegis want to help the public and our patients collectively, and we do that by working closely together,” says Taitel. “Great partnerships stay focused on the patient. The world just learned of the Omicron variant last week, and Aegis responded quickly. Together, we are on alert to notify the CDC of any occurrence and to study emerging disease patterns. The emergence of new variants of concern highlight the importance of surveillance and the necessity to vaccinate the population within the U.S. and throughout the world.”

Schrecker, who trained at Walgreens while earning his pharmacy degree, agrees.

“It’s been astounding to see the pivot Walgreens has made to respond to something like this, in order to provide adequate testing, services and surveillance,” says Schrecker. “We’ve worked hard to make this partnership successful, and it’s all for the greater good.”