WASHINGTON – Barely two weeks into the flu-shot season, the promise of a record supply of vaccine already is being tarnished by shipment delays that are causing sporadic shortages and forcing some doctors to postpone clinics or serve only high-risk patients.

About 26 million doses were distributed across the country in September, and federal officials expected that three times that many would be on their way by the end of this month. Yet having vaccine in the pipeline doesn’t mean getting it to thousands of destinations on time.

Immunizations at grocery and drug store chains are proceeding with few apparent difficulties, but physicians who can’t meet demand are questioning the stability and fairness of the distribution.

“It is a real mess,” Virginia pediatrician Gary Bergman said last week after being notified that his offices would receive only 600 of 7,000 doses scheduled by Nov. 1 and “no commitment thereafter.”

Julie Gerberding, director of the federal Centers for Disease Control and Prevention, acknowledged the kinks in the system in an address several days ago to the American Academy of Pediatrics. It’s not that some customers were given preferential treatment in deliveries, she indicated; manufacturers and distributors said they would try to ensure that all orders were at least partially filled early on.

Given the CDC’s limited ability to direct distribution, the agency is warning that many orders will not be fully filled until late November and that “significant effort” should be made to continue immunizations into January.

In 2004, contamination fears at one manufacturing plant cut the nation’s expected supply in half, causing acute shortages and anxiety. In 2005, distribution problems initially forced providers to target higher-risk individuals for the vaccine. In the end, only 81 million people were immunized and a glut of vaccine developed. Several million doses were thrown away.

The good news of this influenza season, as Gerberding noted, is that five companies are producing as many as 115 million vaccine doses.

Because flu cases usually peak in February, even doses administered as late as December provide protection.

According to the federal Centers for Disease Control and Prevention:

* Children 6 months to 59 months old.

* Pregnant women.

* People 50 and older.

* Anyone with certain chronic medical conditions.

* Residents of long-term-care facilities.

* Household contacts of the above groups.

* Household contacts and outside caregivers of infants younger than 6 months.

* Health-care workers.