The Inflation Reduction Act (IRA) eliminated out-of-pocket costs for Medicare Part D–covered vaccinations beginning in January 2023. One result was a substantial increase in shingles vaccinations dispensed to Part D enrollees compared with commercially insured individuals at retail pharmacies, according to a new study.

That was significant, according to researchers from the University of Southern California Mann School of Pharmacy in Los Angeles and colleagues, because “although vaccinations prevent morbidity and mortality among Medicare beneficiaries, uptake of vaccines recommended by the Advisory Committee on Immunization Practices covered by Medicare Part D (i.e., shingles, tetanus, diphtheria, pertussis, and hepatitis A and B) is suboptimal.”

A research letter on the topic, published recently in the Journal of the American Medical Association, pointed out that unlike Americans who are commercially insured and had no cost sharing for recommended vaccinations in 2021, “Medicare beneficiaries receiving vaccines covered under Medicare Part D paid $234 million out of pocket (OOP), with a mean OOP cost of $76.94 for shingles vaccines.”

In an effort to improve affordability of vaccines for Medicare beneficiaries, the IRA eliminated cost sharing for vaccines covered by Part D beginning in January 2023. The researchers sought to evaluate the association of the zero cost-sharing policy on the use of shingles vaccinations, which account for more than 90% of Part D vaccinations.

To do that, they used monthly data on shingles vaccinations that were dispensed at retail pharmacies between January 2022 and December 2023 from IQVIA’s National Prescription Audit, which includes 92% of U.S. retail pharmacies. Most (80%) of shingles vaccinations are administered in pharmacies.

Outcomes before (January 2022-December 2022) and after (January 2023-December 2023) implementation of the policy were compared.

The results indicated that between January 2022 and December 2023, 16.3 million shingles vaccines (8.3 million to individuals with Part D and 8 million to those with commercial insurance) were dispensed at retail pharmacies. “Trends in shingles vaccines dispensed from January 2022 through December 2022, prior to the policy change, did not significantly differ between individuals with Part D vs commercial insurance (P = .37),” the authors advised.

“Following the implementation of the IRA policy, total Part D shingles vaccinations dispensed increased by 46%, from a mean of 281,283 per month in 2022 to 410,564 per month in 2023,” the authors pointed out. “Over the same period, monthly vaccinations dispensed with commercial insurance decreased by 21%, from 374,176 in 2022 to 295,231 in 2023.”

In regression analyses, the adjusted difference-in-differences estimate was 208,225 (95% CI, 187,829-228,622) total shingles vaccines dispensed per month (P <.001) and 400,720 (95% CI, 375,160-426,279) dispensed with zero cost sharing per month (P <.001), the authors indicated.

The article added that in December 2022, prior to the IRA cost-sharing policy, 337,622 of 350,395 (96%) shingles vaccines paid for with commercial insurance had no-cost sharing compared with 67,132 of 215,561 (31%) paid for with Part D insurance. By December 2023, according to the researchers’ calculations, the percentage of shingles vaccinations paid for with Part D insurance with no patient cost sharing had increased to nearly 100% (325,955 of 326,330).

“The implementation of the IRA policy eliminating OOP costs for Part D–covered vaccinations was associated with substantial increases in shingles vaccinations dispensed to Part D enrollees compared with commercially insured individuals at retail pharmacies,” the authors concluded. “A decline in prescriptions dispensed is usually observed each January due to insurance plan deductible resets and higher OOP costs. Future research should investigate the association of the IRA policy and disparities in vaccination rates.”

The study team says their results are limited because they lack individual-level data on demographic characteristics, including age. “However, changes in vaccine use among commercially insured individuals would likely be similar to Medicare beneficiaries because the shingles vaccine is only recommended for adults aged 50 years and older,” the researchers noted.

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