Dec. 11, 2025, 1:23 PM ESTBy Aria BendixA Centers for Disease Control and Prevention study released Thursday finds that Covid vaccines continue to protect healthy children from severe illness — a conclusion top federal health officials have questioned in recent months. From late August 2024 to early September 2025, the vaccines reduced the risk of Covid-related emergency room and urgent care visits by 76% among children ages 9 months to 4 years, and by 56% among children ages 5-17, according to the study.The findings, published in the CDC’s Morbidity and Mortality Weekly Report (MMWR), are based on an analysis of roughly 98,000 emergency room and urgent care visits. Children included in the study had various levels of immunity from prior Covid vaccines and infections, so the study solely looked at added protection from 2024-2025 Covid vaccines, the authors wrote.The study appears to counter claims by Health Secretary Robert F. Kennedy Jr. about the vaccines’ effectiveness and address doubts raised by other federal health officials about whether children benefit from continuing to receive Covid shots.It comes amid widespread concern from public health experts that the CDC has lost scientific credibility, as well as claims from former high-ranking staffers that the agency’s political leaders have interfered with scientific research.Dr. Debra Houry, who resigned as the CDC’s former chief medical officer in August, said the study’s release is reassuring. “It is good to see that data and science are still coming out of the MMWR. I hope this publication will continue to be a voice for the agency scientists despite the recent cuts to the CDC Office of Science,” Houry said via text message.FDA commissioner on hepatitis B vaccine guidance03:13The Office of Science produces the MMWR, the agency’s flagship scientific publication. Among other CDC departments, it was caught up in a sweeping round of layoffs during the government shutdown in October. The layoffs were later rescinded and temporarily blocked by a federal judge. The CDC has undergone three rounds of layoffs since President Donald Trump took office in January.The agency’s Covid vaccine policy has also shifted under the leadership of Kennedy, an anti-vaccine activist who oversees all federal health agencies including the CDC.Kennedy claimed at a Senate Finance Committee hearing in September that the vaccine industry could not produce a study showing Covid shots were effective in healthy kids. He added that “there’s no clinical data” to support Covid vaccine recommendations for healthy people. The CDC’s research has consistently found that Covid vaccines and booster shots protect against severe illness in both adults and children.Kennedy announced in May that the CDC would stop recommending Covid vaccines for healthy children and pregnant women, bypassing the typical regulatory process. Then in September, a group of vaccine advisors appointed by Kennedy similarly voted not to universally recommend Covid shots, instead suggesting that people talk to their doctor about the benefits of getting vaccinated. Two Food and Drug Administration officials, commissioner Marty Makary and vaccine chief Vinay Prasad, said the benefits of Covid boosters were “uncertain” in a New England Journal of Medicine editorial published in May. In a memo last month to agency staff, Prasad claimed that Covid shots have killed at least 10 children and that “we do not have reliable data” on the vaccines’ benefits in healthy kids. Twelve former FDA commissioners denounced the claims, writing in the New England Journal of Medicine that “substantial evidence shows that vaccination can reduce the risk of severe disease and hospitalization in many children and adolescents.”Aria BendixAria Bendix is the breaking health reporter for NBC News Digital.