• Home
  • Latest
  • Fortune 500
  • Finance
  • Tech
  • Leadership
  • Lifestyle
  • Rankings
  • Multimedia
PoliticsCDC

CDC blocks release of study on COVID vaccine effectiveness

By
Mike Stobbe
Mike Stobbe
and
The Associated Press
The Associated Press
Down Arrow Button Icon
By
Mike Stobbe
Mike Stobbe
and
The Associated Press
The Associated Press
Down Arrow Button Icon
April 23, 2026, 1:10 PM ET
cdc
A sign with the CDC logo is displayed at the entrance to the agency's headquarters in Atlanta on March 2, 2025. Miguel Martinez/Atlanta Journal-Constitution via AP, File

U.S. health officials stopped the publication of a study on whether the COVID-19 vaccine was keeping adults from becoming sick enough to have to go to the hospital.

Recommended Video

A U.S. Department of Health and Human Services spokesman on Wednesday confirmed the decision to halt publication, citing a dispute about the study’s methodology.

The research paper was to appear in Morbidity and Mortality Weekly Report, the Centers for Disease Control and Prevention’s flagship publication.

One way scientists have studied COVID-19 vaccine effectiveness is by focusing on sick people who were admitted to hospitals or visited emergency rooms. The researchers check whether patients were vaccinated and then calculate the odds of a positive COVID-19 test among vaccinated patients vs. those who were unvaccinated.

Papers using that methodology have been published — after review by experts in the field — in a number of esteemed journals, including Pediatrics and the New England Journal of Medicine.

Following the same approach, the new study concluded that the vaccine cut ER visits and hospitalizations among otherwise healthy adults by about half this past winter, according to The Washington Post, which first reported the cancellation.

HHS officials did not say exactly why that methodology was a problem in this instance but argued that prior infection, behavior and differences in who seeks care can affect results.

The wider scientific community does not have those concerns and many researchers have used the approach, said Dr. Fiona Havers, an Atlanta-based doctor who previously worked at CDC. The methodology is built to address differences related to who seeks care, and prior infection shouldn’t be much of an issue because so many Americans have been infected by the coronavirus, she added.

No study design is perfect, but HHS officials haven’t proposed an alternative “that’s realistic and ethical for getting real-time estimates of how well vaccines are working each year,” said Havers, who once led a CDC hospital network surveillance team that focused on COVID-19 and other respiratory viruses.

During President Donald Trump’s first administration, public health advocates worried that political appointees were trying to control what was being published in the MMWR.

Those concerns returned last year, when Trump returned to office and publication of the MMWR was temporarily suspended. It returned, but has remained a thinner version of its former self.

“Health care professionals rely on the MMWR for timely, objective and fact-based information about the nation’s public health,” said U.S. Sen. Dick Durbin, an Illinois Democrat who voiced concern when CDC communications were halted last year.

“Muzzling scientists and doctors on how to prevent Americans from being hospitalized can have deadly consequences. The CDC must abandon plans to place a political gag order on this critical research,” Durbin said in a statement Wednesday.

___

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.

Subscribe to Fortune Gulf Brief. Every Tuesday, this new newsletter will deliver clear-eyed, authoritative intelligence on the deals, decisions, policies, and power shifts shaping one of the world’s most consequential regions, written for the people who need to act on it. Sign up here.
About the Authors
By Mike Stobbe
See full bioRight Arrow Button Icon
By The Associated Press
See full bioRight Arrow Button Icon

Latest in Politics

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025

Most Popular

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Fortune Secondary Logo
Rankings
  • 100 Best Companies
  • Fortune 500
  • Global 500
  • Fortune 500 Europe
  • Most Powerful Women
  • World's Most Admired Companies
  • See All Rankings
  • Lists Calendar
Sections
  • Finance
  • Fortune Crypto
  • Features
  • Leadership
  • Health
  • Commentary
  • Success
  • Retail
  • Mpw
  • Tech
  • Lifestyle
  • CEO Initiative
  • Asia
  • Politics
  • Conferences
  • Europe
  • Newsletters
  • Personal Finance
  • Environment
  • Magazine
  • Education
Customer Support
  • Frequently Asked Questions
  • Customer Service Portal
  • Privacy Policy
  • Terms Of Use
  • Single Issues For Purchase
  • International Print
Commercial Services
  • Advertising
  • Fortune Brand Studio
  • Fortune Analytics
  • Fortune Conferences
  • Business Development
  • Group Subscriptions
About Us
  • About Us
  • Press Center
  • Work At Fortune
  • Terms And Conditions
  • Site Map
  • About Us
  • Press Center
  • Work At Fortune
  • Terms And Conditions
  • Site Map
  • Facebook icon
  • Twitter icon
  • LinkedIn icon
  • Instagram icon
  • Pinterest icon

Latest in Politics

starmer
PoliticsUnited Kingdom
Starmer sees open rebellion break out, challenge incoming from former Health Secretary
By Danica Kirka, Brian Melley, Pan Pylas and The Associated PressMay 14, 2026
3 hours ago
trump
AsiaWhite House
Trump tells Xi, ‘It’s an honor to be your friend.’ Xi responds by talking about Taiwan
By Will Weissert, Aamer Madhani and The Associated PressMay 14, 2026
3 hours ago
Wall Street no longer believes Kevin Warsh can do what President Trump wants
EconomyMarkets
Wall Street no longer believes Kevin Warsh can do what President Trump wants
By Jim EdwardsMay 14, 2026
6 hours ago
trump
Commentarynational debt
The deficit just grew by $955 billion in 7 months. It’s time for a constitutional fix to control the budget
By Steve H. Hanke and David M. WalkerMay 14, 2026
7 hours ago
Photo: Elevate Jet CEO Greg Raiff
EnergyOil
The airplane fuel shortage is a myth propagated by airlines who want to cancel unprofitable flights, says private jet CEO
By Jim EdwardsMay 14, 2026
8 hours ago
Sens. Tim Scott (R-S.C.) and Elizabeth Warren (D-Mass.) whisper to each other during a Senate committee meeting
CryptoCryptocurrency
The crypto industry’s Clarity Act hits a critical juncture: Where things stand going into Senate markup
By Jack KubinecMay 13, 2026
18 hours ago

Most Popular

Despite having a $165 million net worth, Scarlett Johansson says work-life balance doesn’t exist—and the first step to success is admitting that
Success
Despite having a $165 million net worth, Scarlett Johansson says work-life balance doesn’t exist—and the first step to success is admitting that
By Preston ForeMay 13, 2026
1 day ago
The Bezos family just donated $100 million to help achieve one of Mayor Zohran Mamdani’s top campaign promises
Politics
The Bezos family just donated $100 million to help achieve one of Mayor Zohran Mamdani’s top campaign promises
By Jake AngeloMay 12, 2026
2 days ago
Nearly 50,000 Lake Tahoe residents have to find a new power source after their energy source looks to redirect lines to data centers
Travel & Leisure
Nearly 50,000 Lake Tahoe residents have to find a new power source after their energy source looks to redirect lines to data centers
By Catherina GioinoMay 12, 2026
2 days ago
It’s not just Canadian tourists snubbing U.S. cities. Business leaders are cancelling more trips to America as geopolitical tensions continue
North America
It’s not just Canadian tourists snubbing U.S. cities. Business leaders are cancelling more trips to America as geopolitical tensions continue
By Sasha RogelbergMay 12, 2026
2 days ago
I spent 8 years building Google Sheets. Now I think apps are on their way out
Commentary
I spent 8 years building Google Sheets. Now I think apps are on their way out
By Zach LloydMay 13, 2026
1 day ago
Current price of oil as of May 13, 2026
Personal Finance
Current price of oil as of May 13, 2026
By Joseph HostetlerMay 13, 2026
1 day ago

© 2026 Fortune Media IP Limited. All Rights Reserved. Use of this site constitutes acceptance of our Terms of Use and Privacy Policy | CA Notice at Collection and Privacy Notice | Do Not Sell/Share My Personal Information
FORTUNE is a trademark of Fortune Media IP Limited, registered in the U.S. and other countries. FORTUNE may receive compensation for some links to products and services on this website. Offers may be subject to change without notice.