Dr. Jeanne Marrazzo, former director of the National Institute of Allergy and Infectious Diseases, testifying before the Senate last year.

Children learning to garden with their mothers during a “Kids Farm Day” event earlier this month in Aberlin Springs, an “agri-community” in southwest Ohio.

At least half of the eight new members of a C.D.C. panel, who are meeting for the first time on Wednesday, have expressed some skepticism about vaccines.

“The consortia for H.I.V./AIDS vaccine development and immunology was reviewed by N.I.H. leadership, which does not support it moving forward,” said a senior official at the National Institutes of Health who was not authorized to speak on the matter and asked not to be identified.

A dose of the pediatric Covid vaccine in Charlotte, N.C., in 2021. The shots will remain available to children who have a conversation with their doctor, a practice the agency calls “shared decision-making.”

“I think it’s objective to say to you that things will be better in the next 20 years.”

Deborah Sebi, right, a nurse at a mobile clinic in Teshie, a fishing village in Ghana, prepared an immunization for Rebecca Bamembaye’s 3-month-old, Doris.