Outbreak Outlook, Jan 15

An interim update on flu and Covid-19

The holiday season and the federal holiday declared for President Carter's funeral last week have thrown the data off a bit. During holidays, two things typically happen:

1. Slower and less complete data flows from healthcare systems

2. People change their normal patterns about when they visit doctors or emergency rooms

Because of this, I'm keeping this week's update brief and skipping the regional breakdowns. I expect everything will return to normal in time for Monday’s update.

Influenza-like illness

Influenza-like illness made a welcome (if not entirely believable) retreat during the week ending January 4th.

The percentage of outpatient visits that were for fever and cough or sore throat dropped to 6.1%, down from 6.7% the week prior. I'm not ready to say we have passed peak because of the aforementioned data issues. Still, it's a good sign, and I'm hopeful that we will see declines again in this week’s data.

Interestingly, this season's pattern closely tracks the 2019-2020 flu season. That year saw additional peaks later in the season, partly due to the emerging Covid-19 pandemic. However, there's no reason to expect similar additional peaks this year.

Outpatient ILI declined slightly in children ages 0-4 to 15.6%. The 5-24 age group saw more substantial declines, down two points to 7.9%. These age groups have also seen a big improvement in severe illness (e.g., visits to the emergency department) which is a good sign — but again, we’ll have to see if these improvements stick around.

The older age groups have not seen any relief yet, with outpatient and hospitalization indicators still rising. Adults usually run a few weeks behind children in terms of ILI trends, so I expect them to turn the corner soon.

The majority of the country is still experiencing high or very high levels of ILI. In fact, all four regions of the country are swathed in orange and even purple, the highest activity category. Careful out there!

Source: CDC

Covid-19

I’m seeing really mixed indicators when it comes to Covid-19. For example, emergency department visits and test positivity are down, but wastewater concentration is still rising in all four areas of the country. For now, I think it’s best to assume that there is still plenty of SARS-CoV-2 circulating. I’ll check in with more details next week.

---