For parents of children who have received their first H1N1 shots, the frustrations may not be over.
Clinics are warning they may not have enough vaccine on hand to give booster shots exactly on schedule -- 28 days after the first dose.
Federal officials have said children 9 and younger need two doses of the H1N1 vaccine.
But this week, Park Nicollet Clinic began notifying the parents of 4,200 children that their booster-shot appointments have to be postponed because of the vaccine shortage. "We will reschedule them," said spokesman Jeremiah Whitten. But at the moment, it's not clear when.
Parents are getting a similar message at Allina clinics.
"We've been telling patients 'go ahead and make that four-week appointment,' [but] please understand that you may not have it available," said Lynn Berg, safety director for the Allina Medical Clinic.
Health experts say there is no reason to panic about delays between the first and second shots. The recommended interval "is a minimum, not a maximum," according to Dr. Anthony Fiore of the U.S. Centers for Disease Control and Prevention (CDC).
At the same time, he said, "one shot is better than none."