How Many Lives Could a Fall COVID-19 Booster Campaign Save in the United States?

COVID-19 vaccination has substantially reduced hospitalizations and deaths in the United States, despite the emergence of more-transmissible, immune-evasive variants. Nearly everyone in the U.S. is now eligible for vaccination, although second boosters are only currently available for people age 50 and older, or age 12 and older if immunocompromised.

Despite the success of the vaccines, vaccination has not reached all who could benefit. As of July 25, 67 percent of the total U.S. population was fully vaccinated, but with fewer than half of those having received one additional (booster) dose, and less than one-third of people age 50 and older having received a second booster dose. Vaccine effectiveness against infection has waned, but protection against severe illness continues to be strong. Adults age 60 and older are about four times more likely to suffer from severe illness if they have not received a recent booster. Yet in recent months, the pace of all vaccination (including boosters) has steadily declined, with only about 233,000 doses administered daily. The effort to fully cover the U.S. population with booster doses is being threatened by congressional inaction regarding additional funding.

In this analysis, we examined the impact of an early fall vaccination campaign that expands booster eligibility, in the face of another surge in cases, on reducing hospitalizations, deaths, and COVID-19-attributable health care costs. We conducted this analysis using a previously developed simulation model of COVID-19 transmission dynamics to estimate the impact of increasing vaccination rates under different scenarios by the end of October 2022. (See “How We Conducted This Study” for further details.)

We examined three scenarios. For the baseline, we assumed that from the start of August, vaccination will continue at the same daily rate as the average of the first two weeks of July 2022 (i.e., about 70 vaccine doses per 100,000 population per day) until the end of March 2023. In the other two scenarios, we simulated an early fall vaccination campaign (August 1 to October 31) during which individuals age 5 and older receive a first or second booster dose, if eligible. Following the current recommendations from the Centers for Disease Control and Prevention (CDC), we considered people to be eligible for their first booster if they received the final dose of their primary series at least five months earlier. In the model, we expanded the recommended eligibility criteria for a second booster to include anyone who received their first booster at least five months earlier.

For the implementation of the early fall vaccination campaign, we considered two scenarios that differed in the level of coverage achieved.

• In the first scenario, we mimic influenza vaccination coverage: age-specific booster coverage among the eligible population would be the same as vaccination coverage achieved for influenza in 2020–2021 (see Table 1 for details).
• Under a second and more ambitious scenario, we assume 80 percent of individuals age 5 and older who are eligible to receive their first or second booster dose are vaccinated.

We then determined the estimated impact of these potential campaigns by comparing the projected number of infections, hospitalizations, deaths, and direct medical costs from August 1, 2022, through March 31, 2023, to the baseline scenario in which vaccination activity remains constant.

We estimate that an early fall booster vaccination campaign that reaches coverage similar to 2020–2021 influenza vaccination would prevent nearly 102,000 deaths, more than 1 million hospitalizations, and generate savings of $63 billion associated with direct medical costs by the end of March 2023, compared to the baseline. An even more successful campaign, which results in 80 percent of the eligible U.S. population receiving booster doses, would prevent approximately 160,000 deaths, more than 1.7 million hospitalizations, and avert $109 billion in direct medical costs over the course of the next eight months, compared with a scenario in which there is an unchanged daily vaccination rate.

If vaccination continued at its current pace through the end of March 2023, a potential fall surge in COVID-19 infections could result in a peak of around 1,500 deaths per day in December 2022 (Exhibit 1). Under both of the vaccination campaign scenarios modeled, we found an aggressive early fall booster vaccination campaign could prevent COVID-19 deaths from exceeding 1,000 deaths per day.

An early fall vaccination campaign could avert between $63 billion and $109 billion in medical costs, depending on level of booster coverage achieved, with the majority of savings resulting from averted hospitalizations, particularly in the ICU (Exhibit 2). Vaccine doses and administration costs would rise between $3.2 billion and $7.4 billion compared with the baseline scenario where vaccination rates remain at the current pace. At booster coverage mirroring the 2020–2021 influenza campaign, this translates to $1,241 in savings per dose. In moving from the lower coverage target to the higher, savings of $706 per dose would be realized.

Need for Ongoing Vaccination Funding

As population immunity wanes and new SARS-CoV-2 variants capable of evading vaccine protection emerge, an uptick in hospitalizations and deaths seems increasingly likely. Congress has failed to authorize additional funding for COVID-19 vaccines and treatments, hindering access at a crucial time. The Biden administration has not yet expanded eligibility for a second booster for all Americans who have received their first booster, but has considered doing so. A fall vaccination campaign that expands eligibility for boosters and moves aggressively to reach people could avert a surge of hospitalizations and deaths peaks in December. Our results indicate that a such an increase in late 2022 could lead to more than 2.7 million hospitalizations and more than 260,000 deaths by the end of March 2023 if vaccination continues at its current rate.

A campaign that mirrors seasonal influenza vaccination would save both lives and costs. If the COVID-19 vaccination campaign coincides with seasonal flu shots, public health officials could use existing outreach and delivery mechanisms to achieve vaccination targets, reducing costs even further than we estimate here. A fraction of the cost savings generated could be earmarked for public health outreach dedicated to vaccination.

Our analysis was conducted with current knowledge of vaccine effectiveness against the Omicron subvariants. Although we considered waning vaccine-induced and naturally acquired immunity, our estimates assume that currently available vaccines will continue to roll out and that the virus evolution does not lead to the emergence of significantly different variants. If Omicron-specific vaccines with improved effectiveness are administered, our results may underestimate vaccine impact. The Food and Drug Administration may soon review data for new vaccines that more closely match circulating variants. With more efficacious vaccines, a fall campaign would suppress COVID-19 infections, hospitalizations, and deaths even further.

While current vaccines still provide considerable protection against severe illness and death, they are less effective in preventing infections from the subvariants of Omicron such as BA.4 and BA.5. Increasingly rapid spread of these subvariants among the U.S. population, along with relaxing mandates, could lead to a wave that arrives earlier and is much larger in magnitude than what we have predicted in our analysis. As such, it will be important to ramp up booster vaccination as early as possible.

The continued absence of new federal funding for COVID-19 vaccination will limit efforts to increase booster vaccination coverage and could lead to thousands of avoidable hospitalizations and deaths.