The onset of June usually spells the end of Arizona's flu season, but this year is different.
Health officials in the state continue to report widespread flu, a very abnormal occurrence they attribute to the swine flu, which first infected people in April. Arizona's flu season typically begins just after Thanksgiving, peaks in February, and subsides in late May.
"I've been doing this for 20 years, and I can't ever remember seeing widespread flu in the middle of June," said Will Humble, interim director of the Arizona Department of Health Services. "It's not just in a little pocket here and there, it is across the whole state."
He said the flu is at the highest level in a scale used to monitor the virus; that occurs when at least half the regions in the state report lab-confirmed cases of the illness.
Typically, Arizona sees between 1,600 and 5,300 influenza cases a year. This year's season was on track to follow that path until the swine flu showed up on April 29.
The state reported widespread flu activity from mid-February until the first week in April, when the number of confirmed cases began dropping. But once the swine appeared, flu activity shot back up to widespread and remained as such for the past five weeks.
Arizona had 580 confirmed cases of the swine flu as of Monday, about 11 percent of the state's overall flu activity. To date, Arizona's health officials have recorded 4,877 flu cases and six flu-related deaths.
"We were just very fortunate that this new virus turned out to have similar severity to the seasonal flu," Humble said. "We were just lucky that way."
State health officials say it's too soon to know when this year's flu season will end, saying that new cases are still rolling in.
Officials already are turning their attention to next year's season, when the allocation of flu vaccines is expected to be challenging.
There are indications that federal officials may have to create two separate vaccines this fall, one for swine flu and one for seasonal flu. Depending on availability and when it's ready, there could be shortages for the swine flu vaccine.
Humble said that means state health experts would have to decide who would get the boosters first. Usually experts recommend the elderly, children, pregnant women and people with chronic health problems be given priority.
"My personal opinion, if we get into that situation, is that it should be kids," Humble said. "They are the population that amplifies the virus. "But that's a decision that will be made later this summer."