BACKGROUND:
Absence of insurance benefits coverage for adult vaccines in employer-sponsored health plans may contribute to undervaccination among nonelderly adults. Benefits coverage rates for specific vaccines are unknown.

OBJECTIVE:
To formulate national estimates of the proportion of private and public employees whose health plans include benefits coverage for influenza, pneumococcal, hepatitis B, MMR, and varicella vaccines ("5 vaccines").

METHOD:
This cross-sectional study (Oct 2002 to Sept 2003) involved a national random sample of all US private employers stratified by size (# employees), and a similarly stratified national random sample of all US state and local government employers. We investigated whether plans included coverage for 5 vaccines and also analyzed each plan's risk type (self-insured or fully insured), premiums, deductibles, copays, and preventive care caps.

RESULT:
PRIVATE EMPLOYER PLANS: 596 of 892 eligible employers responded (67%). 130 employers offered no plans; 466 employers provided information on 732 plans. Vaccine benefits differed for self-insured plans (MMR and varicella coverage in <40% of plans) vs fully insured plans (>75%; p<.05). Higher enrollment in plans with better coverage mitigated these plan differences, however, so that 71% of plan enrollees overall (95% CI: 58%, 84%) had coverage for all 5 vaccines, 8% (3%, 12%) had coverage for none, and the remainder had a mix of vaccine benefits. 69% (51%, 86%) of self-insured plan enrollees had coverage for all 5 vaccines, compared to 76% (64%, 88%) of fully insured plan enrollees. Private plans with 5-vaccine coverage versus plans with coverage for none did not differ in employee premiums, deductibles, or copays. 25% of enrollees faced preventive care caps, which were higher ($440) for 5-vaccine plans than for 0-vaccine plans ($208; p<.05). PUBLIC EMPLOYER PLANS: 349 of 487 eligible public employers participated (72%) and provided information on 990 plans. 71% (58%, 84%) of plan enrollees had coverage for all 5 vaccines, versus 14% (3%, 25%) with coverage for none. Vaccine benefits differed only regarding annual preventive care caps faced by about 30% of enrollees: $385 for 5 vaccine plans vs $138 for 0-vaccine plans (p<.005).

CONCLUSION:
Employer-sponsored health plans provide benefits for 5 adult vaccines for about 70% of enrollees. This degree of underinsurance may contribute to rates of undervaccination among nonelderly adults.

LEARNING OBJECTIVES:
1) Estimates of vaccine underinsurance for adults in employer-sponsored plans