Outbreak Outlook - National - April 1

Flu and Covid-19 down, but I'm watching H5N1 closely

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Respiratory Diseases

ILI

Influenza-like illness is on its way out across the country. Nationwide, 3.2% of outpatient visits are for fever and cough or sore throat, down from this season’s peak of 6.3%. The baseline that marks the beginning and end of flu season is 2.9%, so I expect we will reach it in one to two weeks.

By age: All age groups saw improvements again this week. As always, children 0-4 remain most affected, at 9%. They have improved from this season’s high of over 15%, but they will likely remain above 5% year round. Older age groups are doing better, currently at or below around 5%.

By region: All four regions of the country are enjoying steady improvements. The South is in the best shape, though still above baseline. The Northeast lags a bit, coming in around 3.4%. The Midwest and Western regions are also seeing improvements.

Source: CDC

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COVID-19

Covid-19 activity is also declining. The rate of new weekly hospitalizations is headed toward 2 per 100,000, which is generally the low point for the year. Wastewater concentration for SARS-CoV-2 is also steeply declining, both at the national level and across all four regions of the country.

At the regional level, the Northeastern region is in the best shape, with the rate of new weekly hospitalizations now below 2.4. The South lags a bit, with hospitalizations a full point higher at 3.4. However, the region has been heading in the right direction for several weeks now, so I expect continued declines in the weeks ahead.

It’s worth noting that Covid-19 remains a major cause of mortality. The number of new weekly deaths has remains above 1,000 since late August¹.

Throughout the pandemic, there have been only a few weeks when the death toll fell below 1,000. The peak of fatalities occurred in one week of January 2021, with nearly 26,000 deaths reported.

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Other bugs

• Seasonal coronavirus activity is down, bringing welcome relief as we move into allergy season (the fewer causes of stuffy noses, the better). The seasonal coronaviruses cause cold-like symptoms. It looks like this year’s peak was in February.

• Human metapneumovirus activity is rising; last year saw an early April peak, and this year looks like it might be similar. Metapneumovirus is a respiratory pathogen known to cause symptoms ranging from mild cold-like signs to severe lung infections, especially in children, the elderly, and immunocompromised individuals. The Southern, Midwestern and Western regions are also seeing rising activity.

• Parainfluenza and adenovirus look fine.

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Stomach Bugs

It continues to be peak norovirus season, with test positivity rising in most regions of the country. The only exception is the Northeast, which is finally seeing slight easing. At the national level, test positivity rose this week from 11.9% to 13.2%. Nationwide peak occurred in mid-April last year, so we likely have several weeks yet to go.

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Food recalls

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

New

• Helados Mexico mango bars (more info)

Previously reported:

• Trader Joe’s 50% Less Salt Roasted & Salted Whole Cashews (more info)

• Multiple brands of cinnamon sold at discount stores, for lead contamination. The best resource I found to quickly survey affected products is here.

• Robitussin Honey CF Max cough syrup products (more info)

• Tons of different granola and oatmeal products from Quaker (more info).

• If you have food allergies, you may wish to review these FDA safety alerts and USDA alerts for foods with undeclared allergens.

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In other news

• U.S. officials have detected avian influenza A(H5N1) in dairy cows in New Mexico, Texas, Michigan, Idaho and Kansas. H5N1 has been spreading widely in wild birds for several years now, as I’ve reported in previous newsletters. Symptoms in dairy cows include reduced milk production and low appetite. This development follows a recent report of goats contracting bird flu in Minnesota, which marked the first known instance of the virus in domestic ruminants. The U.S. Department of Agriculture and the Food and Drug Administration have determined that the commercial milk supply remains safe, because milk from sick animals is discarded. Moreover, pasteurization is effective at inactivating viruses and bacteria.

  • This situation is worrisome because it affects multiple farms across different states and includes infections in animals not previously affected. While there are clear implications for agriculture, my major concern is the potential for the virus to evolve to spread easily between humans. There is no evidence that this is happening, but any time we see a change in the epidemiology of the virus, I take notice. I’ll be watching this situation closely in the days and weeks ahead.

• The FDA has granted emergency use authorization for pemivibart (Pemgarda) as a Covid-19 pre-exposure prophylaxis for immunocompromised peoples aged 12 and older. Pre-exposure prophylaxis means it must be given before exposure to be effective in providing protection.

  • Pemivibart is a long-acting monoclonal antibody that is intended for those with moderate-to-severe immune compromise due to medical conditions or immunosuppressant medications.

  • It is administered via a single intravenous infusion administered over 60 minutes. Subsequent doses are given every three months for continued protection.

  • This EUA follows the withdrawal of authorization for Evusheld earlier due to its ineffectiveness against certain SARS-CoV-2 variants.

Photo by Carly Kewley on Unsplash

1. Through the week of March 2nd. Data from more recent weeks is still being collected.