From State Averages to Street-Level Action: What Vaccine Track Reveals About Adult Immunization

A syringe with the needle point to the vaccine vial on the white background

(Adobe Stock 225352256 by phichak)

Adult vaccination in the US has long lagged behind pediatric coverage—and state averages often hide the real story. To understand where progress is happening (and where it’s slipping), Infection Control Today® (ICT®) spoke with Kate Hashey, MA, MPH, GSK’s head of prevention and adult immunization, about Vaccine Track, a data platform GSK and IQVIA launched in 2022. The latest update drills down to 387 metro areas, offering month-by-month trends that public health teams can actually act on.

The link is here to see it in action.

Maintaining vaccination rates and encouraging patients to get vaccinated are important for keeping patients healthy. Brenna Doran, PhD, an infection prevention consultant in California, told ICT, “As controversial as it is, requiring vaccinations, is the single most effective tool, and while I respect an individual's right to choose, as a society, we also need to focus on the rights of the greater population. The reality is, is there are people and children who are unable to be vaccinated due to their own medical challenges, and so it really is our [as infection preventionists] responsibility to ensure that we're keeping everybody safe.”

ICT: What motivated GSK and IQVIA to launch Vaccine Track, and how does it fill the existing gaps in adult vaccination data?

Kate Hashey, MA, MPH: GSK and IQVIA created Vaccine Track in 2022, providing the first and only comprehensive data tool for understanding adult vaccination trends in the US. Its purpose has always been to empower public health partners and providers with transparent data that informs immunization outreach and promotes healthier communities.

The update, which provides metro-level data, can help guide local immunization strategies for expanding access and helping people make informed decisions about their health.

ICT: Vaccine Track now covers 387 metro areas. What are some of the most surprising local insights you’ve seen so far, and why do they matter?

KH: Between Q1 2024 and Q1 2025, Boise City, Idaho, had the greatest percent increase in adult vaccination of any metro area (excluding flu and RSV), while Midland, Michigan, had the greatest decrease.

Looking at the 10 metro areas with the greatest increase and the 10 with the greatest decrease, we saw that Michigan, Texas, and Montana all had metro areas that fell into both categories, indicating that state-level data doesn’t tell the whole story when it comes to adult vaccination trends.

Communities experiencing declines may benefit from improved healthcare access strategies or targeted education and outreach. Conversely, areas showing significant increases may offer best-practice insights for replication in other communities.

ICT: The Q1 2025 data show that while most metro areas improved, one in five saw declines. What factors might explain those drops in adult vaccination rates?

KH: Half of the 10 metro areas with the greatest adult vaccination decreases were in Ohio, North Dakota, and Minnesota, suggesting state-level factors could potentially be at play in these cases. Digging deeper into demographic, policy, and health care delivery differences across metro areas could potentially help to uncover the specific drivers behind adult vaccination trends. We aim to explore this approach more when we release the Q2 2025 insights later this year.

ICT: How can public health officials, providers, and even policymakers use these metro-level insights to design targeted interventions that actually boost adult vaccination uptake?

KH: The local data uncovered many areas where more work needs to be done to improve access, awareness, and trust. Local variations underscore the need for tailored public health interventions. Communities experiencing declining vaccination rates may benefit from focused policy changes, improved healthcare access strategies, or targeted education and outreach, while areas with rising rates could provide useful [lessons] that can be applied elsewhere.

Looking ahead, monitoring vaccination trends at the local level provides critical insights for public health stakeholders aiming to enhance adult vaccination coverage in communities. Continued attention to these localized data points can inform strategies and policies designed to improve community health outcomes nationwide.

ICT: Adult vaccination often lags behind pediatric rates. Based on Vaccine Track’s decade of data, what long-term trends stand out, and what strategies show the most promise for improvement?

KH: Adult vaccination rates in the US have consistently lagged childhood rates, falling short of national targets. That’s why we built Vaccine Track—to shine a light on adult immunization trends and provide an opportunity for the public health community to work together to close gaps.

One thing we noticed in the long-term data was that while adult vaccinations before, during, and after the pandemic (excluding influenza and respiratory syncytial virus) reflect significant fluctuations, the trendline shows a general upward trajectory since 2015. Increases in adult vaccination between 2017-2019 and 2021-2023 may be partially attributed to preferential ACIP recommendations issued during these time periods. A separate analysis of flu vaccination trends, not performed by GSK and IQVIA, showed that preferential recommendation could increase uptake.

When drilling down to specific vaccines, we found that adult hepatitis B vaccination rates have been rising since early 2022. This trend could be attributed in part to an ACIP recommendation for universal hepatitis B vaccination in adults aged 19 to 59 years. Previously, ACIP only recommended hepatitis B vaccination for adults at high risk for infection, those in settings where a high proportion have risk factors for infection, and adults specifically requesting vaccination.

We also noticed that hepatitis A vaccinations dropped during the pandemic years and then plateaued. According to the CDC, hepatitis A outbreaks began spreading across the US in 2016 and peaked in 2019. Vaccination is a key component of state health department outbreak response strategies, and CDC supports state response capabilities through services such as vaccine distribution, education, and outreach.

As states declared the end of their respective outbreaks, their priorities likely shifted to address other pressing public health issues. Further, declaring the end of an outbreak may have resulted in reduced public perception of hepatitis A as an immediate threat.

The goal of Vaccine Track is to provide detailed and comprehensive adult vaccination trends to guide targeted, informed action.

ICT: Looking ahead, how will quarterly updates from Vaccine Track help the healthcare community respond to emerging challenges, like seasonal surges or vaccine hesitancy in specific regions?

KH: The goal of Vaccine Track is to provide detailed and comprehensive geographic and month-by-month adult vaccination trends each quarter to guide targeted, informed action. Quarterly data updates aim to help guide public health partners on where to focus their attention in response to emerging fluctuations and geographic disparities so that all Americans have the opportunity to access vaccines and make informed decisions about their health.