Flu season gains momentum

Flu activity is increasing nationwide. Covid-19 activity remains low and mostly stable.

Dec 07, 20

Respiratory Diseases

Influenza-like illness

Flu activity is low but increasing nationally. Visits to the doctor for fever and cough or throat (known as outpatient influenza-like illness (ILI)) is at 2.9%, which is right on the cusp of the 3.1% threshold for the start of flu season. Given that data is reported on a one-week lag, we may have already crossed into flu season by the time you’re reading this.

To give you a sense of where we are relative to peak season, last year outpatient ILI topped out at 7.8% and ED visits hit 8.4% nationally. Peak week generally hits around the New Year, though it can be earlier or later by up a month or more.

Test positivity is also continuing to rise, now at 7.1%, up from 4.6% the week before. Of the flu samples with subtyping performed, the vast majority of samples (>80%) are H3N2, and half of those are subtype K. As I’ve been reporting for several weeks now, this pattern suggests we may have a bigger-than-usual flu season.

Hospitalizations for flu are low but increasing, now at 1.2 hospitalizations per 100,000 people. Visits to the emergency department for influenza are also rising with alacrity in all regions.

At the state level, outpatient ILI is now high in several states: Colorado, New York, and Louisiana, and has moved into the moderate category in Idaho and New Jersey. It remains low or minimal in all other states. For more state-level information, please see the regional editions available to paid subscribers.

Rates have increased particularly sharply for children. The proportion of outpatient visits for ILI for children aged 0-4 years is now 9.3% of all outpatient visits. For those aged 5-24, it is 5.2%. Rates are between 1.2-2.2% for all older age groups.

COVID-19

Covid-19 held steady at low levels this past week nationally. However, at the regional level, I am seeing different trajectories, with wastewater concentrations rates rising in the Midwest, decreasing slightly in the Northeast, and still very low and stable in the South and West.

Emergency department visits for Covid-19 are at 0.4%. This is quite low, but there are signs of increases, particularly in the Midwest and Northeast. Hospitalizations are low and stable at 1.0 hospitalization per 100,000 people.

RSV & Other Bugs

RSV: RSV remains low but spread is increasing in most states. A few states are a little worse off, including Florida and Louisiana, but even there, rates are still relatively low. RSV test positivity is currently at 2.6% nationally, still well below where it peaked last season, at 11%. ED visits are inching upward, at 0.3% nationally for all age groups, and are up to 2.5% for the 0-4 age group. Hospitalizations remain very low, at 0.6 hospitalizations per 100,000 people, though this rate is higher in parts of the South and Southeast.
Other bugs: Time to stock up on tissue boxes and your preferred over-the-counter meds. There are an assortment of infections circulating right now that cause cold- and flu-like illness.
- Adenovirus remains very high, but it decreased slightly this past week.
- Parainfluenza has been holding steady at high rates for the past few weeks.
- Rhinoviruses/enteroviruses are moderately active; they continue to decline from their peak in late September.
- Human coronaviruses are low, but are slowly starting to increase, as is human metapneumovirus.

Norovirus

Norovirus is quite active. Test positivity nationally was at 11.6% this past week, roughly on par with the week before. This is the time of year when norovirus is expected to just keep rising. To avoid infection, wash your hands frequently with soap and water (hand sanitizer is not particularly effective at killing norovirus) and avoid touching your face.

Food recalls

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

New:

Wegmans Deluxe Mixed Nuts Unsalted (more info)

Previously Reported:

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)
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 due to potential botulism contamination (more info)

In other news

Universal newborn vaccination for Hepatitis B recommendation rescinded. ACIP, the external committee that advises the CDC director on use of vaccines, has ended the recommendation that newborns receive the hepatitis B vaccine. The committee’s previous members were fired and replaced with an entirely new slate, most of whom are allies of HHS Secretary Robert F Kennedy Jr. The American Academy of Pediatrics (among other professional groups) decried the move. ACIP has only made a recommendation; the vaccine remains available to families.
Early signs that flu will be hard on children this year. In the UK, children are having particularly high rates of infection and severe illness with influenza this year, with higher-than-usual rates of hospitalizations. So far, I don’t see clear indications of this in the US — while a greater proportion of children are seeking medical care for flu than older age groups, this is on par with any other year. As of right now, however, the youngest age group is not being hit harder than in other years. I will be watching to see if we start to have a similar trend to the UK.
Gift idea: If you are looking for a holiday gift for a health- or narrative nonfiction- enthusiast in your life, consider my book, Crisis Averted. It is currently steeply discounted on Amazon ($10 for hardcover), though most other booksellers carry it as well. It’s a story-driven look at the secret life of public health. The WSJ called it an “ambitious and…successful attempt to reset our relationship with the field of public health. With a judicious blend of candor, hopefulness and pragmatism, she calls out its mistakes, reminds us of its historic accomplishments and emphasizes the need for the discipline to adjust its strategies if its full promise is to be realized.” I hope you check it out!