States haven't yet been able to obtain Covid-19 shots from the Centers for Disease Control and Prevention, delaying their distribution to millions of children through federal programs, according to people familiar with the matter. The CDC hasn't initiated the process states use to place orders for the Vaccines for Children program, which covers around half of the country's youths, the people said, causing a delay in the typical fall immunization schedule for Covid.

The typical communication from CDC to begin the ordering process hasn't arrived yet, said Dr. Michelle Fiscus, chief medical officer of the Association of Immunization Managers, which represents directors of state and local public-health immunization programs.

This delay could also prevent millions of children and adults from getting Covid shots during the early fall season, when vaccination drives typically kick off. States provide the shots for youths through the Vaccines for Children program and for uninsured or underinsured adults through a different government program. Meanwhile, Covid-19 vaccines are already available for commercially insured patients at pharmacies including CVS.

"Even if there's a little delay, that's creating a disparity," said Dr. Demetre Daskalakis, who formerly led the CDC division overseeing immunization efforts.

Pfizer, one of the Covid-19 vaccine makers, said it began shipping doses on Sept. 7 without any delays on the company's end. Moderna, the other Covid vaccine maker, didn't immediately comment.

"Every day there are opportunities to vaccinate children and protect them that we're missing because those vaccines aren't yet in the field," Fiscus said.

Emily Hilliard, an HHS spokesperson, said Covid-19 doesn't follow the same seasonal pattern as flu and other respiratory viruses.

"CDC is finalizing decisions regarding COVID-19 vaccine procurement through the Vaccines for Children and Section 317 programs, and additional information will be available soon," she said.

It is difficult to predict when the right time in the year is to administer a Covid booster shot, former CDC leaders said. There were efforts previously at the CDC to sync the distribution of Covid-19 vaccines with when flu shots are released--typically around Labor Day. That was part of a public health strategy to increase accessibility, said Daskalakis, who resigned last year in part because of changes to the agency's vaccine policies.

Dr. Daniel Jernigan, former director of the CDC's center for emerging infectious diseases who quit last year alongside Daskalakis, said it doesn't make sense to delay the Covid vaccine orders because of different seasonal patterns. "If the timing is unpredictable, then make it available as soon as you can," he said.

CDC data show an increase in Covid-related hospitalization rates this summer in the U.S.

The CDC contracts with manufacturers of the U.S.-licensed vaccines each year and negotiates discounted prices for federal programs. States will then purchase vaccines through the agency to administer at no cost under the Vaccines for Children program or to a program for uninsured or underinsured adults.

States typically order Covid-19 shots within two weeks of them becoming available to order for commercially insured programs, according to a person familiar with the process.

Under the Trump administration, the CDC no longer recommends all children receive the Covid-19 vaccine, instead advising parents and doctors to discuss risks and benefits for each child. The health agency previously recommended everyone six months and older receive the shots. Earlier this year, a federal judge blocked the Trump administration from implementing its pared-down list of recommended childhood vaccines.

The administration has broadly backed away from vaccine recommendations under Health Secretary Robert F. Kennedy Jr., who has publicly discredited the Covid shot.

Vaccine hesitancy is increasing across the country, upending years of public-health work to high enough levels of vaccination to stop the spread of certain deadly infectious diseases. There are outbreaks of measles across the country, a vaccine-preventable disease. In Pennsylvania, four people have died of measles in the past month, according to the state's health department.

Demand for the Covid booster has fallen in recent years as the virus has become less of a threat than how it started out. Just under 10% of children between the ages of six months to 17 years old received last year's Covid-19 vaccine, according to CDC data.