Jan 8 (Reuters) - Merck on Thursday said any changes to the U.S. child and adolescent immunization schedule should rest on ​comprehensive data and guidance from vaccine experts, after federal health ‌officials shifted several shots out of the "universally recommended" category.

The Department of Health and Human ‌Services and the Centers for Disease Control and Prevention this week moved vaccines for rotavirus, influenza, meningococcal disease and hepatitis A to a "shared clinical decision-making" category, telling parents to consult healthcare providers.

Public health specialists warned ⁠the rollback could drive ‌preventable hospitalizations and deaths by lowering uptake for routine childhood immunizations.

"Clear, evidence-based recommendations remain essential to support informed ‍decisions and ensure that children and adolescents receive reliable protection against preventable diseases," Merck said, adding that declining vaccination rates can have serious consequences amid recent ​U.S. outbreaks.

The company said it "stands firmly behind an immunization framework ‌grounded in rigorous science, strong regulatory processes and ongoing safety monitoring," and said it would work with public health partners on policies that protect children and adolescents.

President Donald Trump last month urged the United States to "align with other developed nations" by reducing the number of shots ⁠for children.

Merck said international comparisons require ​context, including differences in disease burden, healthcare ​infrastructure and population needs.

Bernstein analysts said Merck could take the biggest hit from the schedule changes, estimating a potential $2 ‍billion impact on ⁠annual revenue because of exposure to its rotavirus vaccine RotaTeq and the human papillomavirus vaccine Gardasil.

The updated schedule also calls for ⁠a single dose of the HPV vaccine for U.S. children, rather than the two-dose ‌series typically used for most adolescents.

(Reporting by Puyaan Singh ‌in Bengaluru; Editing by Tasim Zahid)