Outbreak Outlook - National - Dec 2

Flu is rising around the country, as is RSV to a lesser degree. Covid-19 remains pretty quiet.

Dec 02, 2025

Respiratory Diseases

Influenza-like illness

Flu continues to rise but is still a bit below where it has been at this point in past years. Outpatient visits for influenza-like illness (ILI) continue to increase, now at 2.5%. (However, this is still below the national baseline marking the beginning of flu season, as measured by activity.) Test positivity is also rising rapidly, growing from 2.9% to 5% in the past week.

Most states continue to report minimal or low ILI activity, though activity is now high in Louisiana and Colorado.

For the youngest age group, children aged 0 to 4, outpatient visits for ILI have risen to 7.7%, followed by those aged 5-25 at 4.2%. Young kids are almost always the first to see new trends. Older age groups are also reporting increases, but remain quite a bit lower, <2%.

Hospitalizations are increasing, but remain very low, at 1.0 per 100,000 people.

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Regional editions

COVID-19

Wastewater activity is rising, though it remains very low nationally. Activity has increased to low levels in the Midwest and Northeast. It remains very low, but is increasing in the West, and is very low and stable in the South. However, after the holiday weekend with lots of travel across the country, I expect this to change a bit in the next week or two. Stay tuned in the weeks ahead.

RSV & Other Bugs

RSV is picking up nationally, but remains fairly low compared to this point during previous seasons. Test positivity has increased to 2.4%, up from 1.8% the week before. Emergency room visits for RSV are up to about 0.2% nationally, and are on the rise particularly in the South and Northeast—but again, these numbers are pretty low.

Other bugs: Many other causes of cold- and flu-like illnesses are spreading widely right now. Sniffles abound.

Adenovirus has increased rapidly in the past week, and is now higher than it has been in the past year.
Parainfluenza is nearing its second peak of the year.
Rhinoviruses/enteroviruses are still quite elevated, but are gently declining from their peak in September.
Human coronaviruses are low, but increasing.

Norovirus

Norovirus test positivity decreased slightly this past week, but is an overall increasing trend. Test positivity is currently at 12% nationally. Noro typically begins picking up this time of year and stays high through early spring.

Food recalls

The following foods are being recalled because they are contaminated. Please check your cupboards and throw out any of these items:

New:

Grated Pecorino Romano cheese, sold under various labels, including Boar’s Head, Locatelli, Member’s Mark, Ambriola, and Pinna at major retailers, including Wegman’s (more info)
Prairie Farms Gallon Fat Free Milk (more info)
Dried Whole Smelts Salted (Korushka) (more info)

Previously Reported:

Vampire Slayer Garlic Cheddar, sold by Face Rock Creamery exclusively at the Face Rock Flagship store in Oregon (more info)
Organic Supergreens Powder Mix and Organic Moringa Leaf Powder sold under Food to Live label (more info)
Organic Moringa Leaf Powder sold under Africa Imports label (more info)
ByHeart Infant Formula recall reported last week has expanded to include more batches due to potential botulism contamination (more info).
Peach salsa sold under the Snowfruit label (more info)
First and Last tomato sauces, distributed in Connecticut and Massachusetts (more info)
Oven Dried Fish distributed to customers of African Food on Wheels in the Bronx, NY only (more info)

In other news

Avian flu detected on dairy farm in California. For the first time in over a month, there has been a new report of highly pathogenic avian influenza in dairy cattle, this time in California. The total number of confirmed cases in cows, as reported by the USDA, has been 1,083 across 18 states. The more H5N1 spreads in cattle, the greater the risk of H5N1 better adapting to spread in mammals, including potentially humans. The season (in birds) typically peaks in late winter, so we are entering a time of increased activity.
Expanding outbreak of New World screwworm in Central America and Mexico. In the past two years, there has been an expanding outbreak of New World screwworm, spreading outward from Panama and Costa Rica. New World screwworm is a parasitic fly that lays eggs in open wounds, resulting in infestation with fly larvae/maggots. It primarily affects livestock, but can also affect humans. There have been more than 135,000 reported cases in animals, and more than 980 cases in humans since 2023. The fly has not yet been detected in the United States and prevention efforts have been increased over the past several months to prevent its incursion. There has only been one confirmed case in the U.S. in late August, associated with a returning traveler.
Outbreak of infant botulism linked formula expands. The total number of affected infants has increased to 37, with all reported cases in infants needing hospitalization. The outbreak is spread across 17 states. Fortunately, no deaths have been reported. All infant formula products have been recalled by ByHeart, whose products have been linked to the outbreak. The CDC is urging caregivers not to use any such products and wash any surfaces that may have touched the formula with hot soapy water or in a dishwasher. Infant botulism can take up to several weeks to develop.

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