Flu rates back to pre-pandemic heights
By Lia Taniguchi | February 2, 2023
It’s early 2023, and across the country flu-like illness has returned with a spike not seen for three years. Practices are struggling to keep up with patient demand, and many clinicians say they’re resigned to the fact the current trends are likely to continue for months.
Indeed, many practices agree that the current season can be accurately described as a “tripledemic” of flu, COVID, and RSV. Prior to the pandemic, diagnoses of flu-like illness usually increased in late fall before peaking near the start of the new year. Two years of masking and social distancing meant relatively few were exposed to the typical viruses during the 2020-21 and 2021-22 flu seasons, but that’s not the situation for 2022-23.
Data highlight seasonal differences during and “post”-COVID
Anyone practicing medicine at the moment won’t be surprised to learn that athenahealth network data confirm the trends these physicians are seeing.
Using diagnosis codes from insurance-claims data submitted by network practices nationwide, athenahealth researchers are tracking the spread of flu and similar viruses on a weekly basis. They’re also using data from the last three flu seasons to get a sense of the seasonal trends year over year. Patients with a diagnosis of influenza-like illness (ILI) include symptomatic patients with either a specific diagnosis of flu or a fever co-presenting with a cough or sore throat.
The data show that this flu season, ILI diagnoses began to climb in late August, earlier than in previous years (20% higher than in August 2019), and that by early October accounted for 1.2% of all patient visits. It wasn’t until the end of November, when nearly 5 % of visits were for ILI, that diagnoses finally started to decline.
How long will this trend continue? “For the foreseeable future, I’m afraid,” predicts Stephen Morgan, M.D., CIO at Pediatric Associates of Greater Salem. Laughlin, for his part, anticipates it could be as late as June before his clinic is out of the woods, while Vik Mali, M.D., owner of Mali and Mali Pediatrics, ventures “all winter through March or April if one considers all of the various viruses” involved.
By contrast, over the previous two flu seasons, when the public health message from state and federal agencies still stressed the importance of masking and social distancing, ILI diagnoses hardly climbed at all. There were more flu visits as a percentage of visits overall in 2021-22 than in 2020-21, but the highest diagnosis rate during either season occurred in the final week of 2021 when 1.6% of all visits were for ILI.
The trends have been similar for pediatric patients, who received relatively few ILI diagnoses prior to fall 2022. The data show diagnoses increasing in late summer 2022 and eventually peaking (at nearly 8% of all pediatric visits) the week of Thanksgiving. (See the interactive athenahealth flu dashboard for the latest data.)
On the other hand, compared to patients of all ages, pediatric patients have consistently been more likely to receive a diagnosis of ILI. By early January 2023, for example, about 3% of all patients were diagnosed with flu while close to 5% of pediatric patients received such a diagnosis.
Current infection rates similar to those seen pre-COVID
Overall, the current flu season looks a lot like 2019-2020, the last pre-pandemic season. Among patients overall, ILI symptoms have spiked this year at a rate nearly identical to three years ago, while rates for pediatric patients have been somewhat higher than those reported prior to COVID.
While the athenahealth flu dashboard data say nothing about why children are receiving ILI diagnoses more often this season compared to 2019-20, a closer look at specific diagnoses show it could be due to cases where definitive RSV determination was not possible. Tracking actual diagnoses, rather than symptoms, may not capture all cases, but it does make over-counting less likely. When looking at these diagnoses, it is clear that this fall and winter have seen higher rates of COVID and RSV diagnoses, with flu quickly catching up as we move into 2023.
Whereas in the winter of 2020-21, flu-positive tests were so uncommon they barely register on a graph, while cases of RSV likewise were the lowest on record. Those children who weren’t exposed to flu or RSV over the last two years of COVID are now encountering all three of these diseases for the first time.
This graph presents the monthly percent of all claims with an official diagnosis of flu, COVID-19, or RSV. Unlike the other plots, it does not track symptoms, so it is less likely that it is over-counting a given disease.
Morgan, of Pediatric Associates of Greater Salem, says the shift has meant his practice is now seeing a near-constant stream of sick patients. They’re struggling with shortages of some of the medications they need to effectively treat them, and the viruses they’re battling are all over the map, including enteroviral strains that can mimic influenza and COVID, “and especially the D68 variant that creates an RSV-like illness.”
Flu-season focused practice best practices
For practice leaders like Morgan, Laughlin, and Mali, one remaining question is whether another COVID spike is on the near horizon. Should the pandemic gain steam again—athenahealth data does indicate a slight COVID uptick in early 2023—that could lead to more masking and social distancing and, presumably, fewer cases of ILI.
Meanwhile, clinicians everywhere say they’re doing everything possible to keep those patients and staff who are not yet sick from joining the ranks of those who are. They’re encouraging everyone they see to get vaccinated against flu and COVID if they aren’t already, and they’re reiterating that message through electronic communications and by hosting on-site vaccine clinics. Many continue to offer telehealth as an option to reduce the chances that symptomatic patients might spread ILI to others in the office.
Telehealth, population health campaigns, and “strong education in the office” have all been important this flu season at ESD Pediatric Group, says Jeff Drasnin, M.D. While his practice been extremely busy, he says, “we have been able to accommodate all of our patients.”