On Thursday, Merck publicly urged that any adjustments to the U.S. child and adolescent immunization schedule adhere strictly to comprehensive clinical data and the recommendations of vaccine experts. The pharmaceutical company’s statement followed the recent decision by federal health officials to reclassify several vaccines, moving them out of the ‘‘universally recommended’’ category. Merck emphasized that changes should be based on rigorous analysis of efficacy, safety and population-level impact, citing the need for transparent review of post-licensure surveillance data covering more than 2 million doses administered annually.

According to a Jefferies analyst report released this week, Merck may face a revenue decline of as much as $630 million in Gardasil sales over the next twelve months following the revised recommendation limiting the human papillomavirus (HPV) vaccine to two doses for most adolescents. The report models scenario-based impacts on Merck’s pediatric vaccine unit, which generated approximately $2.2 billion in U.S. revenue in the prior year. Jefferies highlighted that reduced dosing could cut annual shot volumes by up to 40%, pressuring margins and prompting potential revisions to Merck’s 2026 guidance.