New York, January 5, 2026, 21:32 (EST) — Market closed
- Merck shares closed up 0.9% but slipped about 0.2% in late trading.
- U.S. health officials revised child immunization guidance and shifted the HPV shot to a one-dose recommendation.
- Investors now look to Merck’s Jan. 12 JPMorgan conference appearance and Feb. 3 earnings call for clarity.
Merck & Co shares dipped in late trading on Monday after U.S. health officials rewrote the childhood and adolescent immunization schedule, including a change to a one-dose recommendation for the human papillomavirus (HPV) vaccine. Merck (MRK.N) closed up 0.93% at $107.44 and was last down 0.22% at $107.20 after the bell.
The shift matters for Merck because Gardasil 9 is the only HPV vaccine available for use in the United States, and the CDC’s guidance helps shape how physicians counsel families. Even modest changes in dosing guidance can ripple through demand and purchasing patterns.
The timing is awkward for investors. It lands a week before the J.P. Morgan Healthcare Conference and a month before Merck’s quarterly report, two moments when the company’s leadership typically faces pointed questions about outlook and execution.
The Department of Health and Human Services said the CDC will keep a “recommended for all children” list covering 11 diseases, while reclassifying other immunizations into high-risk or “shared clinical decision-making” categories. Shared decision-making means a doctor and family decide case-by-case, rather than following a blanket recommendation for every child.
HHS said the updated schedule recommends one HPV dose instead of two, citing studies and international practices, and said vaccines on prior CDC schedules will remain covered without cost-sharing through Affordable Care Act plans and federal programs.
Merck has previously pushed back on a reduced-dose shift, saying CDC recommendations should stay consistent with FDA-approved labeling until regulators license an alternate dosing regimen. The current U.S. label for Gardasil 9 uses multi-dose schedules.
“Literally children’s health and children’s lives are at stake,” said Dr. Sean O’Leary of the American Academy of Pediatrics, criticizing the process behind the changes.
During the regular session, Merck traded between $105.80 and $108.44, before settling near the middle of the range into the close. Traders often treat those intraday extremes as near-term support and resistance levels.
Merck said CEO Robert Davis and research chief Dean Li will take part in a “fireside chat” — an on-stage Q&A — at the JPMorgan conference on Jan. 12 at 7:30 p.m. EST. The company’s fourth-quarter earnings call is set for Feb. 3 at 9 a.m. ET. Merck.com
But the financial hit from the vaccine overhaul is unclear: coverage is set to continue, yet demand can still shift when universal recommendations are softened and physicians adjust their playbooks. Investors will watch for follow-up CDC implementation guidance and for Merck’s comments on Jan. 12, with the earnings call on Feb. 3 the next hard checkpoint.
