searchSearch data by region...
Pandemic Data Outlook

Preparing State Data Systems for Booster Doses and Breakthrough Cases

As concerns about breakthrough infections increase and booster doses become a reality, states must prepare their data collection systems and public dashboards to best collect and disseminate this information. These new data streams could be incredibly useful to controlling COVID-19 if states follow certain recommendations and prepare accordingly.

William Moss, Executive Director, International Vaccine Access Center, JHU
Beth Blauer, Associate Vice Provost, JHU
August 23, 2021

States have rarely been able to adequately manage their data needs throughout this pandemic. Absent a centralized federal data infrastructure, states have pursued widely diverse data collection and management systems and approaches. The result: national COVID-19 data have been fragmented, disorganized, unaligned and challenging to summarize and interpret.

We began the Pandemic Data Initiative to provide insight on the critical role data plays in the public health response to COVID, hoping that governments could improve their use of data to inform smarter COVID policies. Trusted data connects deeply to public trust and public trust in turn translates to communities, families and individuals that are guiding personal decisions to keep themselves and their neighbors safe. 19 months in from the arrival of COVID on our shores, having states provide regular and timely data is and should not be an unattainable goal.

Unfortunately, States and the federal government are still grappling with significant data challenges. As vaccines rolled out in the United States, we called for states to establish standard reporting of vaccination data. Despite this, many states continue to report vaccination data from locations other than their main COVID-19 dashboard and have different groups managing these data, resulting in disconnected and inconsistent metadata.

We now have the opportunity to prepare our systems in advance of new data streams for vaccine booster shots and cases of breakthrough infections. As data experts, we want to provide states with a roadmap to responsible data governance, but the burden remains on the CDC and federal government to establish clear guidelines and reporting mandates so we can best respond to the continuing pandemic.

Booster Shots

The landscape for booster shots of COVID-19 vaccines is constantly changing. The WHO strongly recommended that wealthy countries not pursue booster shots until more of the world has been able to get their first dose.1. While the United States is already offering a third dose to the immunocompromised,2 it has now been proposed by the Biden Administration that, starting on September 20, booster shots should be available for all fully vaccinated Americans who received their second dose at least eight months earlier, pending authorization by the FDA and a recommendation from the Advisory Committee on Immunization Practices.3 We know these data are coming, so every state needs to prepare to collect and report them.

Despite multiple countries offering booster shots, Bahrain is the only one providing data on booster shots as a separate data point independent of its two main categories: “total vaccine doses administered” and “people vaccinated.” However, these data are severely limited and only list the number of individuals receiving booster doses.4 As of August 19th, Mississippi is the only state that reports any booster shot data on its COVID-19 dashboard (shown below).5 This is a good start, and other states should be following Mississippi’s lead, but data on booster shots can and should be even more detailed.


We previously explained the importance of highly detailed vaccine data that includes metainformation on vaccine type, manufacturer, and dose number. Now that boosters are inevitable, we are expanding our call for what data states must collect. Every state needs to report the number of booster doses administered and the number of people receiving booster doses. Those numbers should be identical in the near term, but we do not know whether additional boosters will be necessary down the road. We need to prepare our data management systems for this possibility now, instead of scrambling to respond when it happens. This will result in better data for decision-making and enhance our capacity to communicate progress in vaccination coverage.

The more metadata available on booster shots, the more prepared our public health agencies and governments will be to make decisions and target vaccination efforts, and the more informed our scientists and medical researchers will be to analyze the individual and public health impact of booster doses. Time is a critical factor with booster shots, particularly knowing when the booster shot was administered and how long it had been since the patient’s previous dose. Finally, as with all vaccine data, the manufacturer of the booster shot and the dose number for that individual will be essential for tracking immunity and potential adverse effects.

Breakthrough Cases

Experts have defined a breakthrough case as anyone who is fully vaccinated (two weeks after the final dose) testing positive for SARS-CoV-2. The CDC, however, is only tracking breakthrough cases resulting in hospitalization.6 If your body is fighting an infection successfully without symptoms — because it was primed by vaccination — testing positive for SARS-CoV-2 alone should not be a concern. Vaccination does not prevent the SARS-CoV-2 virus from entering your body, but it prepares your body to fight the infection quickly. Breakthrough cases are expected, and typical with vaccines.

In lieu of national standards for defining breakthrough cases (which should be set by the CDC), every state needs to describe the vaccination status of those who test positive, are hospitalized with COVID-19, and who die of COVID-19. As of August 6, 15 states report no data on breakthrough cases, and the reporting methods of the other 35 are far from consistent and do not all contain the necessary level of detail.7 Reporting breakthrough cases with detailed metadata is necessary to track COVID-19 surges, variants, and vaccine effectiveness. Over time, as the vaccinated proportion of the population increases, logically the proportion of people with a COVID-19 positive test who have been vaccinated will also increase. The ability to compare those rates will inform public health officials as to the need for additional safety and mitigation efforts.

Data on comorbidities and symptoms would also be helpful with breakthrough cases; however, these metrics are difficult to standardize in a way that can be counted and analyzed across states. We recommend simply recording whether a patient was symptomatic or had any comorbidities associated with poor COVID-19 outcomes as simple yes/no questions on testing or hospital intake forms. The name of the manufacturer of the vaccines the patient received is another piece of highly informative data that states should include with breakthrough case data.

We know that breakthrough cases and booster doses will only increase in frequency. We have the capacity to responsibly and effectively prepare our data management systems now to best collect and disseminate data on booster shots and breakthrough cases. Our data collection throughout the COVID-19 pandemic has suffered from poor preparation and planning. Now is our chance to eliminate that bad habit and provide policy makers and the public with the best data possible to inform decision-making and control the pandemic. States owe their residents timely and accurate data collection and reporting of information on booster doses and breakthrough cases.


  1. A. Furlong, WHO calls for moratorium on booster vaccines, 04 August 2021. (Accessed 17 August 2021).

  2. L. McGinley, L.H. Sun, , FDA authorizes extra vaccine doses for immunocompromised patients to bolster protection against the coronavirus, 13 August 2021. (Accessed 17 August 2021).

  3. J. Howard, Covid-19 vaccine booster shots to be offered to Americans beginning September 20, health officials say, 18 August 2021. (Accessed 18 August 2021).

  4. Daily COVID-19 Report. (Accessed 17 August 2021).

  5. Mississippi State Department of Health COVID-19 Vaccination Reporting, Mississippi State Department of Health, 19 August 2021.

  6. COVID-19 Vaccine Breakthrough Case Investigation and Reporting. (Accessed 17 August 2021).

  7. C. Mui, 15 states are keeping COVID-19 breakthrough cases under wraps, 06 August 2021. (Accessed 16 August 2021).

Title image by Jernej Furman via Creative Commons License CC BY2.0

William Moss, Executive Director, International Vaccine Access Center, JHU

William Moss, MD, MPH, is Executive Director of the International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health.

Beth Blauer, Associate Vice Provost, JHU

Beth Blauer is the Associate Vice Provost for Public Sector Innovation and Executive Director of the Centers for Civic Impact at Johns Hopkins. Blauer and her team transform raw COVID-19 data into clear and compelling visualizations that help policymakers and the public understand the pandemic and make evidence-based decisions about health and safety.