Flu cases in Arizona increased 35% in the last week of 2025, and we haven't reached the peak

Cases of flu are on the rise across the country, and in Arizona. The state Department of Health Services says there have been nearly 6,900 cases so far this flu season, but the most recent data — as of the end of December — shows a 35% increase in cases from the prior week. That’s more than 2,200 cases in a week.

The Show spoke with Dr. Michael White, executive vice president and Chief Clinical Officer at Valleywise Health about this. He said Valleywise’s clinics and ERs are seeing an increase in patients coming in with flu symptoms, and that the rate of Influenza A is continuing to rise.

Full Conversation

MARK BRODIE: I want to ask you about that because it seems as though there might be a bit of a mismatch between, as you say, the predominant strain and what was in the vaccine. Are you finding that patients are coming in even as they have been vaccinated against the flu or is it mostly patients who haven't gotten the shot?

WHITE: The majority of the patients that we see in the emergency departments that are coming in with severe illness — so those very high fevers, those difficulty breathing type cases — the preponderance of those patients have been those that have not received the annual influenza vaccine. Those folks that are coming into the clinics and some of the milder symptoms that people have that still have influenza are those that have received the vaccine.

As you noted, this variant did not and was not included in the annual vaccine that we all received this year. However, that vaccine does provide protection against some of those severe cases and likely is helping those just have mild symptoms and milder cases if they were to contract the flu.

BRODIE: Are you finding that for those patients that did not get the vaccine, are they coming in with worse symptoms? Are they sicker than the kinds of patients you maybe have seen in past years?

WHITE: Yeah, those patients that have chosen not to receive the annual influenza vaccine that catch the influenza this year, yes, those individuals are usually more ill, have more severe symptoms, fevers may be higher, worsening of the cough, worsening of sometimes the shortness of breath around that. And those are the folks that are at risk of developing some of those complications where they may ultimately need hospitalization, supplemental oxygen and things to be able to recover from that.

BRODIE: What are you seeing in terms of the ages of the patients coming in terms of kids versus adults?

WHITE; Unfortunately, it's across the continuum this year. We're seeing this in our pediatric population, our children. We're also seeing this in our adult population as well. Influenza is an equal opportunity virus, unfortunately, and can affect any of us within the population. So we're seeing it as a broad streak around this.

Now, as our children have gone back to school and we're starting to see some of that activity here post the holidays, people being together for the holidays, we're seeing it, again, across the entire family.

Katherine Davis-Young/KJZZ

BRODIE: Yeah, I'm glad you brought up the holidays because a lot of the numbers that we've seen have not incorporated the time between Christmas and New Year's and, as you referenced, kids going back to school this week. Are you expecting the numbers to continue to go up given sort of those gathering points over the last couple of weeks?

WHITE: Yes, we have not reached the peak of what we anticipate to see this year due to those gathering items that we've had over the last two weeks. So I suspect as we've seen this upward trajectory, we are going to reach the peak, and we'll probably reach the peak in the next week to 10 days as we get past the New Year's, going back to school type season as this virus travels through the community.

BRODIE: So we talked just a moment or so ago. about the vaccine and the mismatch this year. I'm wondering also, though, about the fact that the new guidance from the federal government is generally that people don't need to get the flu vaccine. Do you think that's having any kind of impact or maybe that's something we're not going to see until next year's flu season?

WHITE: I think that all of the conversations around vaccination and immunization that have been going on — within the community, with the changes that we've even seen this week in the vaccination schedule — have increased the conversation about the necessity of vaccinations and immunizations.

There has really been no change in the science. We know that vaccines help us prevent these diseases and prevent the transmission of these diseases. I think as the public awareness as these conversations have been included has raised that question.

I'm here to say that the science has not changed. All of these vaccines are proven to help people not only prevent these illnesses, but in the rare cases that they were to get one of these viruses, makes the symptoms significantly less and the chance of survival significantly higher around this.

So even these with these discussions of change, it's important for us to continue to advocate for these devices, these procedures, these immunizations that we know are effective in preventing these illnesses, or again, if you were to get it, to reduce the severity of these illnesses.

BRODIE: Do you worry, though, that given some of those conversations and given the skepticism that a lot of folks are showing toward vaccines in general and the flu vaccine specifically, that going forward the rest of this season and going forward in future years, you're just going to continue to see more patients coming in with the flu and with worse versions of the flu?

WHITE: Absolutely. Yes, that is a concern around this, which is why education here is so important and why these conversations are so important for us to say we know and we have numerous studies, preponderance of evidence that these vaccines are safe, that they prevent these illnesses, they prevent the severity of these illnesses and are important for that.

So we as the healthcare community need to continue to advocate for what we know is the best science, what we've seen over previous years about how this has helped improve and decreased our mortality from infectious diseases like the flu. Vaccines are important. We need to continue to advocate for them and we need to continue to advocate and educate people on the importance of receiving them.

BRODIE: Given, as you said just a few moments ago, that the peak seems to be coming maybe a little bit earlier than we've seen in past years, does that mean that it's going to be a longer season? Or maybe if we peak a little earlier, might we also end flu season a little earlier?

WHITE: Yeah, it's a great question. Time will tell for that. But yes, usually after we see the peak, that usually will indicate that we may see a quick reduction in the length of the flu season. So we may not see this extend into March and April as we've seen years in the past. We'll know more as we see the rate of decline after we see that peak.