December 13, 2023 – Figuring out the effectiveness of COVID-19 vaccines as the pandemic raged—often with inadequate data—was one of the major challenges Rochelle Walensky faced as director of the Centers for Disease Control and Prevention (CDC).
Walensky offered details about lessons she learned during her CDC tenure at the 175th Cutter Lecture on Preventive Medicine at Harvard T.H. Chan School of Public Health. She is currently a senior academic fellow at the Petrie-Flom Center for Health Law Policy, Biotechnology, and Bioethics at Harvard Law School, a senior fellow in the Women and Public Policy Program at Harvard Kennedy School, and an executive fellow at Harvard Business School.
Organized by the Department of Epidemiology, the December 8 event was part of the Cutter Lectures, which have been held since 1912 thanks to a bequest from John Clarence Cutter, a doctor and graduate of Harvard Medical School.
Integrating health data
Walensky, who served as CDC director from 2021-2023, began her term during the COVID-19 pandemic, around the same time that the first mass vaccination campaigns were being rolled out across the country. The key question at the time was whether the vaccines were effective—a question that could not be readily answered using health data in the U.S.
“‘Does the vaccine work?’ is a very complicated question,” Walensky said. “It’s one that our public health system and our health care system would have incredible power to examine, if in fact they talked to one another. And that’s a real challenge in our public health system.”
She explained that public health departments keep track of vaccination data, while health care systems have data about hospitalizations and urgent care use. Because of challenges in combining the data, U.S. public health officials ended up having to use more complete data available from the U.K. and Israel in order to determine vaccine effectiveness.
Walensky said that data challenges will continue to affect vaccine strategies moving forward, as questions remain about the effectiveness of booster shots, as well as vaccine effectiveness in subpopulations, including different age groups and people who are immunocompromised. She emphasized the need for data integration to improve public health response.
Real-time data
In addition to health data being siloed, the lack of real-time data also hampers the ability to make key policy decisions, Walensky said. As an example, she shared details about the monkeypox outbreak that occurred in 2022. In May, monkeypox cases were first identified in New York. Public health officials had to respond quickly, developing a national vaccination strategy that took into account the limited number of doses available.
However, the CDC lacked important case and vaccination data from local and state governments. It was not until a public health emergency was declared in August of that year that the CDC gained the authority to require data reporting—after the number of monkeypox cases in the U.S. had already peaked.
“We have a responsibility to be nimble, but we have no authority to actually be able to see the data in real-time,” Walensky said. She highlighted the CDC’s efforts to modernize data collection, including expanding the use of standardized electronic health records in health facilities across the U.S. She further called for improving the security of public health data, and for updating laws so that the CDC can gain timely access to the data it needs in order to shape policies and offer advice to the public.
‘Would I do it all again?’
Walensky shared other recommendations to improve the nation’s public health capabilities, including building a national surveillance system to detect infectious diseases, bolstering the public health workforce, and communicating information clearly to multiple audiences—government officials, health providers, and the general public.
She also reflected on the ups and downs of being a highly visible government official in the public spotlight.
“There were way many more harder times than there were fun ones,” she said, noting that she received death threats and online harassment. “But I got to work with an incredible group of people,” she continued. “Would I do it all again? Absolutely.”
– Jay Lau
Photo: Jenna Schad