Flying snow and frigid temperatures didn't just snarl traffic on Wednesday. They snarled the distribution of H1N1 vaccine as well.

As a result, healthy adults -- the last group on the vaccine priority list -- won't be officially eligible for their shots until next week at the earliest.

The vaccine can't be shipped when temperatures are near zero because freezing renders it useless. So the Minnesota Department of Health was unable to ship supplies this week to 629 clinics that ordered vaccine for adult patients with chronic health conditions.

"We're very eager to open things up," said Kris Ehresmann, the department's director of immunizations. "But we can't ship the vaccine because it's too cold."

Some clinics may be giving shots to healthy adults now because they had more vaccine than they needed for priority patients and they can't send it back to the Health Department, she said.

So far 1.4 million doses have been administered or ordered for 810 clinics and public health agencies -- enough for a little more than one-fourth of the state's population.

The vaccine will be given to anyone who wants it once the number of doses distributed for high-risk groups reaches about 2 million, Ehresmann said.

Meanwhile, the pandemic continued to wind down for the fifth week. Only 13 Minnesotans were hospitalized with confirmed or suspected H1N1 cases, the department reported Wednesday. That's down from a peak of 266 in mid-October. Just one school reported an outbreak of flu-like illness.

There were four deaths from confirmed or suspected H1N1 last week, bringing the state's total to 49 since last April. There was also one death related to a different type of influenza, but the patient, an infant, had other serious health conditions, Ehresmann said.

Josephine Marcotty • 612-673-7394