⚠ Vaccine Policy Is Being RewrittenModerate threat

Merck & Co. (MRK) — threat to the moat

The CDC changed three schedules affecting Merck's vaccines in six months, and the buyer of many of those doses is the same government.

Merck's vaccine demand depends on recommendations, and American recommendations changed repeatedly in 2025 and 2026. The CDC moved young children from the combined MMRV shot to a standalone varicella shot in October 20251, ended the universal birth-dose recommendation for hepatitis B in December 20252, and announced a single-dose adolescent HPV schedule in January 20263, which has since been stayed4.

CDC schedule changes affecting Merck vaccinesOct 2025standalone varicellaunder age 4Dec 2025hepatitis B birth doseno longer universalJan 2026single HPV dosefor adolescents2026HPV announcementstayedMerck Form 10-K FY2025 and Form 10-Q Q2 2026
Policy moved faster than the plants.

Some safeguards remain. American health insurers said their plans would continue to cover immunisations recommended as of 1 September 2025, with no cost-sharing through the end of 20265. But that commitment has an end date, and the Vaccines for Children programme follows the committee's votes6.

Merck's pediatric and adolescent vaccines are sold in large part to that federal programme7. When the buyer changes the schedule, the moat does not help.

The Keytruda-scale policy risk is in drugs; the vaccine risk is in schedules. Merck says it anticipates that any negative effect of the HPV recommendations or reduced dosing schedules on Gardasil sales will not be material8, and gives the same judgement for ProQuad9. The company is saying that each change is small; the risk is that they keep coming.

The signal is the insurers' coverage commitment after 2026. If it lapses while the stayed recommendations return, American vaccine volumes will fall on policy alone.

References
  1. ReportedThe CDC moved young children from the combined MMRV shot to a standalone varicella shot in October 2025, ended the universal birth-dose recommendation for hepatitis B in December 2025, and announced a single-dose adolescent HPV schedule in January 2026, which has since been stayed.
    Merck & Co. Form 10-K for fiscal 2025 - Item 1A risk factors, patents and exclusivity, government pricing, vaccine policy and legal proceedings. — FY2025 · publ. 24 February 2026 · source ↗
  2. ReportedThe CDC moved young children from the combined MMRV shot to a standalone varicella shot in October 2025, ended the universal birth-dose recommendation for hepatitis B in December 2025, and announced a single-dose adolescent HPV schedule in January 2026, which has since been stayed.
    Merck & Co. Form 10-K for fiscal 2025 - Item 1A risk factors, patents and exclusivity, government pricing, vaccine policy and legal proceedings. — FY2025 · publ. 24 February 2026 · source ↗
  3. ReportedThe CDC moved young children from the combined MMRV shot to a standalone varicella shot in October 2025, ended the universal birth-dose recommendation for hepatitis B in December 2025, and announced a single-dose adolescent HPV schedule in January 2026, which has since been stayed.
    Merck & Co. Form 10-K for fiscal 2025 - Item 1A risk factors, patents and exclusivity, government pricing, vaccine policy and legal proceedings. — FY2025 · publ. 24 February 2026 · source ↗
  4. ReportedThe CDC moved young children from the combined MMRV shot to a standalone varicella shot in October 2025, ended the universal birth-dose recommendation for hepatitis B in December 2025, and announced a single-dose adolescent HPV schedule in January 2026, which has since been stayed.
    Merck & Co. Form 10-Q for the quarter ended 30 June 2026 - segment profits on the recast basis, the Cidara and Terns acquisitions, the Halozyme litigation, China shipments, loss of exclusivity events and the balance sheet. — Q2 2026 · publ. 7 August 2026 · source ↗
  5. ReportedAmerican health insurers said their plans would continue to cover immunisations recommended as of 1 September 2025, with no cost-sharing through the end of 2026.
    Merck & Co. Form 10-K for fiscal 2025 - Item 1A risk factors, patents and exclusivity, government pricing, vaccine policy and legal proceedings. — FY2025 · publ. 24 February 2026 · source ↗
  6. ReportedBut that commitment has an end date, and the Vaccines for Children programme follows the committee's votes.
    Merck & Co. Form 10-K for fiscal 2025 - vaccines and China: Gardasil, the childhood and pneumococcal vaccines, and sales in China. — FY2025 · publ. 24 February 2026 · source ↗
  7. ReportedMerck's pediatric and adolescent vaccines are sold in large part to that federal programme.
    Merck & Co. Form 10-K for fiscal 2025 - vaccines and China: Gardasil, the childhood and pneumococcal vaccines, and sales in China. — FY2025 · publ. 24 February 2026 · source ↗
  8. ReportedMerck says it anticipates that any negative effect of the HPV recommendations or reduced dosing schedules on Gardasil sales will not be material, and gives the same judgement for ProQuad.
    Merck & Co. Form 10-K for fiscal 2025 - Item 1A risk factors, patents and exclusivity, government pricing, vaccine policy and legal proceedings. — FY2025 · publ. 24 February 2026 · source ↗
  9. ReportedMerck says it anticipates that any negative effect of the HPV recommendations or reduced dosing schedules on Gardasil sales will not be material, and gives the same judgement for ProQuad.
    Merck & Co. Form 10-K for fiscal 2025 - Item 1A risk factors, patents and exclusivity, government pricing, vaccine policy and legal proceedings. — FY2025 · publ. 24 February 2026 · source ↗
Sources
Generated September 25, 2026