Skip to main content

Medicaid: COVID-19 Vaccination Data Access and Strategies Used to Improve Immunization Rates

GAO-24-106526 Published: Apr 18, 2024. Publicly Released: Apr 18, 2024.
Jump To:

Fast Facts

Medicaid needs to ensure that its beneficiaries receive COVID-19 vaccines to prevent hospitalizations and deaths. But during the public health emergency, COVID-19 vaccines were provided to the public for free, and not by state Medicaid programs. Consequently, Medicaid didn't always know which of its beneficiaries had received the vaccines.

We reviewed 6 state Medicaid programs and found that 4 of them got vaccination data on beneficiaries from their state public health departments' immunization information systems. These 4 states had policies in place prior to the pandemic that allowed their state Medicaid programs to obtain such data.

COVID-19 Vaccine Information from the Idaho Division of Public Health and Idaho Medicaid

Skip to Highlights


What GAO Found

Six selected state Medicaid programs GAO reviewed varied in their ability to obtain data on beneficiaries with COVID-19 vaccinations from state immunization information systems during the COVID-19 public health emergency from 2020-2023. During the emergency, these systems—maintained by state public health departments—were the primary source of such data. This was because providers administering COVID-19 vaccinations were required to report to them. Specifically, state policies—which govern provider reporting requirements and data sharing—in effect prior to the emergency enabled Medicaid programs in four selected states to obtain patient-level vaccination data from state immunization information systems. In contrast, state policies in effect prior to the emergency in two selected states either did not specify or did not permit such data exchange.

COVID-19 Vaccination Data Collection and Transmission to Certain State Medicaid Programs

COVID-19 Vaccination Data Collection and Transmission to Certain State Medicaid Programs

State officials and stakeholders described interoperability gaps between state immunization and Medicaid systems, the volume of vaccination data collected, and other factors as affecting the availability and quality of COVID-19 vaccination data collected by immunization information systems during the COVID-19 public health emergency. State officials described how some factors resulted from the public health emergency. They also noted solutions they implemented as the emergency progressed, such as using a temporary storage system for the increased volume of data. State and federal officials also identified state policies as continuing to be important drivers of vaccination data collection and data sharing with Medicaid programs after the public health emergency.

In the four selected states with access to patient-level data, GAO found that Medicaid programs used the data to implement two types of strategies to increase COVID-19 vaccination rates: incentives and targeted outreach. For example, one state awarded incentive payments to its 25 managed care organizations based on performance across 10 vaccination measures. Additionally, Medicaid and managed care officials in five of the six states described using data from other sources, such as Medicaid claims, to increase COVID-19 vaccination rates among high-risk and vulnerable populations. For example, Medicaid officials in these states told us Medicaid claims data helped them to identify and focus efforts on beneficiaries most at risk of adverse outcomes from COVID-19. Although states reported using various strategies to increase vaccinations, the effectiveness of their specific strategies is unclear due to the nature of the COVID-19 public health emergency. According to Medicaid officials, it is difficult to attribute changes in Medicaid beneficiaries' vaccination rates to a specific strategy, because the emergency required multiple concurrent strategies.

Why GAO Did This Study

Given the importance of COVID-19 vaccinations in preventing severe outcomes, such as hospitalizations and death, ensuring Medicaid beneficiaries receive the vaccine is important. However, state Medicaid programs did not always receive information on the vaccination status of beneficiaries directly from providers during the public health emergency. This was in part because vaccines were purchased by the federal government rather than by insurers like Medicaid.

GAO was asked to examine Medicaid programs' access to and use of data from immunization information systems to improve COVID-19 vaccination rates among beneficiaries, and factors contributing to data completeness. This report describes (1) the extent to which selected states' Medicaid programs obtained patient-level COVID-19 vaccination data, and any factors affecting data availability and quality; and (2) how that data helped inform selected states' strategies to improve COVID-19 vaccination rates, and information on the effectiveness of such strategies.

GAO reviewed relevant federal laws, interviewed federal agency officials, as well as reviewed information and interviewed officials from state public health departments and Medicaid programs in six states. The states were selected based on characteristics of their Medicaid and immunization programs, among other various factors. GAO also interviewed 10 stakeholder organizations, including those representing immunization managers and Medicaid directors.

For more information, contact Catina B. Latham at (202) 512-7114 or

Full Report

Office of Public Affairs


MedicaidVaccinationsImmunizationsInformation systemsBeneficiariesPublic healthPublic health emergenciesManaged health careHealth careMedicaid program