Outbreak Outlook - National - October 23

Oct 23, 2023

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Respiratory diseases

Influenza-like illness

Influenza-like illness activity remained about the same this week, with 2.3% of visits to the doctor being for fever and cough or sore throat. National ILI activity is higher than it normally is this time of year, but activity is nonetheless still low.

The overall map looks good, although Alaska is now in the high category. Several states, such as Florida, Georgia, and New Mexico, remain in the 'low' category. However, I won’t be surprised if they reach the 'moderate' level in the coming weeks.

As usual, young children have the highest rates of ILI. Now 8.2% of visits to the doctor were for ILI symptoms, up from 7.6% last week. The rates for older age groups also saw a slight increase this week, but they all remain below 4%.

Covid-19

Covid-19 activity fell again last week for most of the country. We have now seen several weeks of consistent declines. The number of new weekly hospitalizations was around 16,200, down from the recent peak of 20,700. Test positivity and metrics related to emergency department visits also continue to decline.

Upon closer inspection, however, there are multiple states throughout the country where activity is actually increasing, which makes me concerned that improvements may be reversing. For example, Louisiana, Washington, Iowa, and Massachusetts all have increasing rates of hospitalization. I’ll be keeping a closer eye in the weeks ahead.

The current mix of Covid-19 variants is diverse. E.G.5 is the most prevalent, but it only makes up around 24% of sampled variants. Next up is HV.1, which is expected to grow to nearly 20% of cases. I don’t think either of these variants will significantly change the current trends or severity of the disease, but I plan to look more into this for clues about why activity is increasing in some states.

RSV

RSV activity is still climbing, putting us well into RSV season. At the national level, test positivity is now 4.2%. Test positivity has been climbing week over week, up from recent lows of less than 0.5%. There are now signs of increase in every region of the country, but the South remains most heavily affected. RSV can be dangerous to older adults and infants, in particular.

FYI: The demand for the infant RSV shot has outpaced supply, such that the Federal government has moved from allowing providers to place their own orders to a more centrally rationed system. If you are looking for the shot, don’t give up.

Others

I'm monitoring several other respiratory viruses. Here's the current status:

Seasonal coronavirus, human metapneumovirus, and adenovirus all seem to be under control, with no concerning increases. Parainfluenza is drifting up, but I don’t see anything that concerns me too much right now.
Rhinovirus/enterovirus activity (one cause of the common cold) has actually come down recently, according to data from Biofire. Activity has been quite high the last few weeks.

Stomach bugs

Norovirus

Norovirus activity is low in most of the country. Current test positivity is about 6%, up from a recent low of 4.8% but still much lower than what we see in the winter. However, there has been a small uptick recently, which could be normal variation or could indicate the start of “stomach bug” season. I’ll keep an eye on it.

The big exception is the Midwest. Norovirus test positivity is fairly high and rising in that region of the country. The best way to prevent norovirus is handwashing — and stay home if you are ill, so you don’t pass it to others!

Food recalls

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

New this week:

Bagged collard greens sold at Kroger (more info)
Frozen, ready to eat carne asada burritos (more info)

Previously reported:

Ready-to-eat ham produced by Sunnyvalley Smoked Meats (more info)
Ion and Restore brands Sinus Spray (more info)
Organic Chicken and Beef Broth sold at Costco and Whole Foods (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

Since the outbreak began in December 2022, over 600 people, predominantly children, have succumbed to diphtheria in Nigeria, with Kano state in northern Nigeria being the hardest hit. This outbreak, with 14,000 suspected cases, is significantly more severe than the 2011 episode, which reported 98 cases. Diphtheria is a highly contagious disease affecting the nose and throat, spread through coughs, sneezes, or close contact. While preventable through vaccination, many victims in Nigeria were unvaccinated.
Flu cases in Japan have surpassed the warning level, with the number of cases per monitored medical institution reaching 11.07 in the week ending Sunday, exceeding the threshold of 10, according to the health ministry. This rise suggests a potential major outbreak within the next month. In total, 17 out of 47 prefectures exceeded the warning level.