⚠ One Dose Where There Were TwoLow threat

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

A single-dose HPV schedule, announced and then stayed, would cut the adolescent doses on which American Gardasil sales rest.

The largest American risk to Gardasil is not a competitor but a recommendation. Among the changes in the CDC's January 2026 announcement was a reduction of the recommended HPV doses for adolescents to a single dose1. Gardasil 9 is indicated for a two-dose regimen in adolescents aged 9 to 142.

Recommended adolescent HPV doses, US2 dosesFDA label, ages 9-141 doseCDC January 2026 announcementMerck Form 10-K FY2025 and Form 10-Q Q2 2026
Half the doses per adolescent.

The announcement has since been stayed, as Merck's second-quarter filing notes3, and many countries outside the United States have implemented a reduced dosing schedule4. Merck says it anticipates that any negative effect of these recommendations or reduced schedules on Gardasil sales "will not be material"5. That is the company's judgement; the direction of policy still matters, because fewer doses per child means less revenue per child unless more children are vaccinated.

American Gardasil sales were $2,641 million in 20256. A move from two doses to one would, other things equal, remove a large part of the adolescent volume.

The stay leaves the question open rather than answered. The January 2026 announcement is now described in Merck's filings as stayed7, and Gardasil sales rose 4% in the second quarter, on higher demand in Asia Pacific and Europe and favourable timing of European tenders8. The American effect of a single-dose schedule has not yet been tested in the sales figures.

The signal is the final status of the stayed recommendation. If a single-dose schedule is reinstated and American sales fall in the following year, the vaccine's last reliable market will have shrunk by policy.

References
  1. ReportedAmong the changes in the CDC's January 2026 announcement was a reduction of the recommended HPV doses for adolescents to a single dose.
    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. ReportedGardasil 9 is indicated for a two-dose regimen in adolescents aged 9 to 14.
    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 ↗
  3. ReportedThe announcement has since been stayed, as Merck's second-quarter filing notes, and many countries outside the United States have implemented a reduced dosing schedule.
    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 ↗
  4. ReportedThe announcement has since been stayed, as Merck's second-quarter filing notes, and many countries outside the United States have implemented a reduced dosing schedule.
    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 ↗
  5. ReportedMerck says it anticipates that any negative effect of these recommendations or reduced schedules on Gardasil sales "will not be material".
    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. ReportedAmerican Gardasil sales were $2,641 million in 2025.
    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. ReportedThe January 2026 announcement is now described in Merck's filings as stayed, and Gardasil sales rose 4% in the second quarter, on higher demand in Asia Pacific and Europe and favourable timing of European tenders.
    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 ↗
  8. ReportedThe January 2026 announcement is now described in Merck's filings as stayed, and Gardasil sales rose 4% in the second quarter, on higher demand in Asia Pacific and Europe and favourable timing of European tenders.
    Merck second-quarter 2026 results release, Form 8-K exhibit 99.1 - vaccine and Animal Health sales. — Q2 2026 · publ. 4 August 2026 · source ↗
Sources
Generated September 25, 2026