Outbreak Outlook - National - Nov 24
Happy Thanksgiving!
Respiratory Diseases
Influenza-like illness
Influenza-like illness increased again this week to 2.7% of visits to the doctor for fever and cough or sore throat, up from 2.5% the week prior. As a reminder, the national baseline is 3%, so we are inching closer (which is normal this time of year). I expect we'll cross that benchmark in one to three weeks.
With the Thanksgiving holiday approaching, remember that flu data is reported with a slight delay. The data reported here reflects the week ending November 16th; flu activity is likely higher right now than it was last week. Keep this in mind if you’re using these updates to plan for the holiday weekend.
Children ages 0 to 4 are beleaguered as ever, with 8.8% of visits to the doctor for fever and cough or sore throat, up from 8.1% last week. It’s worth noting that not only are young children experiencing higher levels of ILI, but they are seeing much bigger change week-over-week, so they are plunging into flu season. ILI activity in the 5 to 24 year old age group rose as well, now at 4.4%. Older age groups are all at or below 2%.
New this week, three jurisdictions are now in the moderate category: Georgia, Louisiana, and the District of Columbia. Not far behind are a number of states in the Southern region at the top end of the “low” category. I expect in the week or two ahead we will see an expansion of states reporting medium and even high levels of activity. But for now, a majority of jurisdictions remain in the low category.
COVID-19
Covid-19 activity remains reassuringly quiet in most of the country. Wastewater activity stayed roughly steady this past week at a low level. All four regions have low or minimal activity, with the highest activity in the Midwest and lowest in the Northeast.
Severe illness continues to be low as well. The rate of visits to the emergency department (ED) remained stable at the minimal rate of 0.5% nationally this past week. Every state reported minimal visits to the ED with the exception of New Mexico, which increased to a low rate of 1.6%. Hospitalizations are at their lowest rate in the past year - 1.0 hospitalizations per 100,000.
RSV & Other Bugs
RSV: As with ILI, we are moving into RSV season and activity is picking up a little more. The South has the most widespread elevated activity of RSV, with several areas reporting moderate to very high wastewater levels and the highest regional concentration of elevated hospitalization rates. The Northeast has some areas showing very high wastewater levels and elevated hospitalizations, primarily along the coastal areas. The West has isolated pockets of high activity amid generally lower levels, with some areas showing marked increases from the previous week. The Midwest remains stable with minimal activity levels and very low hospitalization rates throughout the region.
Other bugs: The spread of many viruses that cause cold- and flu-like illness continues.
Parainfluenza viruses are fairly elevated, and at 5.9% test positivity are roughly three-quarters of the way to hitting their highest rate in the past year.
Rhinoviruses/enteroviruses continue to remain quite elevated, at 27% test positivity. Test positivity has been hovering between ~25-30% since September.
Adenoviruses have increased to 3.7% test positivity, which is fairly elevated. In the past five years, test positivity has tended to peak between 4-5% (with the exception of 2023, when it got up to 8%).
Human coronaviruses continued the same slow and steady week-over-week increase they’ve been on for the past two months. Test positivity is elevated but not particularly high (it is currently about half of its peak rate of the past year).
Stomach Bugs
Norovirus remains quite high, but test positivity dipped slightly this past week, from 12.6% to 11.3% nationally. However, I do not anticipate this to be the start of a longer dip: this is the time of year we tend to see sustained higher levels of transmission and it is not unusual to see norovirus test positivity zig-zag a bit while maintaining a high overall rate. Test positivity is highest in the West, followed closely by the South and then the Midwest; the Northeast continues to have test positivity rates far below the rest of the country.
As we near Thanksgiving, when many people find themselves cooking for large numbers of people, remember that norovirus continues to be highly transmissible for up to several days after your symptoms end. Preparing food or drinks for others - or putting your hands into a communal bowl of chips or a vegetable or cheese platter - is a remarkably efficient way to spread the disease to others. If you’ve been sick recently, try to refrain from preparing food or drinks for others for at least 48-72 hours after your symptoms cease. Similarly, if you feel tempted by those communal plates of food, no need to avoid the chips, but use a clean (& non-communal) utensil to put some onto a separate plate that only you eat from. Your Thanksgiving guests/hosts will thank you!
Food recalls
The following foods are being recalled because they are contaminated. Please check your cupboards and throw out any of these items:
New:
Super brand dried cinnamon powder (more info)
Bagged carrots, full size and baby, sold at multiple retailers. This was previously reported, but it expanded to carrots sold under several additional brand names this past week (more info)
Fabalish Kickin’ Carrot Falafel Bites (related to the carrot recall above) (more info)
Gaines Family Farmstead Chicken Chips for Dogs. While not for human consumption, humans may be infected by Salmonella if they do not adequately wash their hands or contaminated surfaces after handling the product (more info)
Hollywood Feed Carolina Raised Chicken Chips [for Dogs]. Same as above (more info)
Previously reported:
Soft ripened cheeses, including brie, sold under multiple brand names, including Aldi, La Bonne Vie, and Glenview Farms (more info)
Prepackaged turkey sandwiches with spreadable brie sold under multiple brand names (more info)
Ready-to-eat poultry and meat products sold by Yu Shang Food, including pork belly, beef shank, and whole chicken (more info)
If you have food allergies, you may wish to review these FDA safety alerts and USDA alerts for foods with undeclared allergens.
In other news
Researchers have found that the H5N1 avian influenza virus infecting a teenager in British Columbia has mutations that could make it easier for the virus to infect humans. The teenager, hospitalized in critical condition since November 8, is not thought to have transmitted the virus to others, and the infection likely represents an isolated case. Scientists believe the mutations likely developed during the teen's infection. These changes in the virus's hemagglutinin protein enhance its ability to bind to human receptors. While H5N1 cases in North America have largely been mild, this severe case underscores the risk posed by ongoing human exposure to the virus.
The CDC has confirmed the first U.S. case of H5 avian influenza in a child, following initial presumptive reports announced by the California Department of Public Health. The infection was identified through California’s flu surveillance system, though follow-up testing showed low levels of viral material and also detected other common respiratory viruses. The child is recovering, and all family members have tested negative for H5. There is no evidence of human-to-human transmission. The CDC continues to investigate the source of the child's exposure to H5N1.
The Global Polio Eradication Initiative reported new polio cases in three countries this week. Pakistan recorded one additional wild poliovirus type 1 case, bringing its 2024 total to 49. Chad reported five cases of circulating vaccine-derived poliovirus type 2 (cVDPV2), raising its yearly total to 20. Nigeria identified one more cVDPV2 case in September, increasing its 2024 count to 81. Additionally, an environmental sample in Warsaw, Poland, tested positive for cVDPV2, linked to an outbreak originating in, Nigeria. However, there is no evidence of local circulation in Poland, which maintains high vaccination coverage.
Two new CDC studies published in Morbidity and Mortality Weekly Report reveal low vaccination rates for flu, Covid-19, and RSV among U.S. adults, including nursing home residents, as of early November. Among adults, 34.7% reported receiving a flu vaccine, 17.9% had an updated Covid-19 vaccine, and RSV vaccine coverage for older adults ranged from 31.6% (ages 60-74) to 39.7% (ages 75+). In nursing homes, 29.7% had received a Covid-19 vaccine, 58.4% a flu vaccine, and 17.9% an RSV vaccine.
If you’re looking for something to read over the holiday weekend, check out my debut book, CRISIS AVERTED. It’s about the hidden science of fighting outbreaks, told through a series of suspenseful and touching stories.
Want more local information? Regional editions are now available to paid subscribers. These versions of Outbreak Outlook are specific to the West, South, Northeast, and Midwestern regions of the country. They contain more localized trends and updates.
Oops, typo. Today is Nov 25th :)
I think Covid is under the radar and much higher than is being reported. My son just contracted it again and he masks a lot. He is in college and he most likely let his guard down. This is non sustainable the long run. He got the vaccine 4 weeks ago and I know it does not prevent illness that is why he continues to mask. My worry is long term effects. This summer he has two weeks apart fevers of unknown origin of 104 - 104.2 . We saw infectious disease specialist etc he also had blood in his urine. He is only 21 . We can’t keep going like this in society and with the in coming administration we will be dying in large numbers when the bird flu hits. I feel no one takes the public health seriously at all. We had serious long repercussions from 1918 flu. Sequelae diseases from Covid I feel will and are worst. The young population is being hit hard. I fear from their future.