Bird Flu News:

• USDA mandated testing of the nation’s milk supply for bird flu starting December 16th. (Washington Post)
• Arizona reports its first 2 cases of H5N1 in poultry workers, and California is investigating a potential second child infected in the Bay Area. (CIDRAP)
• Nevada reported its first bird flu infection in a dairy herd. (NV.gov)

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Health News:

• Flu activity is picking up the pace a bit with hot spots in Louisiana and D.C. (CIDRAP)
• WHO has sent experts to the Democratic Republic of Congo to help with their mysterious disease outbreak with nearly 400 cases and 30 deaths. (Reuters)
• Chikungunya costs reached nearly $50 billion over a decade. (Washington Post)
• Drinking enough water helps with migraines, weight loss, and more, a new study shows. (Fortune)
• To cut costs, some people are “microdosing” semaglutide weight loss drugs, but it’s not clear how effective small doses are. (NY Times)
• A surprising study of temperature-related deaths in Mexico found that heat actually kills far more young people under 35 than those older than 50. (AP)
• 300+ vials of a deadly virus went missing from an Australian lab in 2021, but they don’t appear to have been stolen, only misplaced or destroyed without proper paperwork. (Newsweek)

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Mental Health & Substance Use News:

• AI-powered self-harm alerts are a new, uncharted territory that some schools and employers are considering. (NY Times)
• Alcohol and substance use are contributing to the rising number of accidents on e-bikes and scooters. (NIH)

If you or someone you know may be considering suicide or need help, call or text 988.

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Best Questions:

Can the flu vaccine give you the flu? 

Nope! We haven't used live virus in the U.S. flu vaccine since back in 1945, so it can’t give you the actual flu. There are two possible explanations for symptoms after the flu shot. First, you might have already been infected with a cold or flu virus since they usually circulate by the time people get their annual shot, and it takes 2 weeks for immune protection to actually kick in. The second possible reason is that the flu shot does cause an immune reaction. This is why some people might get a fever, body aches, and fatigue for a day or so after their jab. That’s the bad news, but it actually means the shot is working by tricking your body into making the antigens that it will need to fight the flu in the future. The good news: it will be short and much more mild than any actual flu infection. 

Sources: YLE, Mayo Clinic

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Why have U.S. cases of bird flu been so mild while the other cases we hear about abroad are so severe?

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Over the past 20+ years that H5N1 has been circulating, the overall human mortality rate has been a whopping 50% in about 1,000 confirmed cases. That’s about as fatal as Ebola, for context. But in the U.S., we’ve seen nearly 60 confirmed cases since the dairy cattle outbreak first began, and all but one (the mysterious Missouri case) have been quite mild. 

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So what’s going on? We’re left with a few options:

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Possibility 1: Our estimates for case fatality rate are actually just wrong because so many people have mild symptoms and just never get tested. Only those with severe illness are counted among confirmed cases. 

• Why it doesn’t tell the full story: Many close contacts of severe cases have tested negative on blood tests. 

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Possibility 2: Most of these livestock-related cases are infections via the eyes because that’s where humans have bird-type flu receptors, and something about eye infections makes them milder and less likely to spread to the respiratory tract. 

• Why it doesn’t tell the full story: While dairy workers are spraying virus-laden milk into their eyes regularly, poultry cullers are likely breathing in large amounts of virus when they’re in enclosed spaces with millions of sick birds, but their cases are also still mild. 

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Possibility 3: There’s something about this specific strain (2.3.4.4b) circulating that just isn’t very good at infecting people.

• Why it doesn’t tell the full story: This strain is really, really good at infecting other mammals, from ferrets to bears to seals. We don’t understand what makes us so different (This one is also basically impossible to test.).

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Possibility 4: People have actually gained immunity due to exposure to other similar flu viruses (like H1N1, the swine flu that caused a pandemic in 2009).

• Why it doesn’t tell the full story: We still get sick all the time from flu viruses that we’ve already been exposed to. Plus, an outbreak in Egypt in 2014-2015, after the H1N1 pandemic, still had a 30% mortality rate. 

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Bottom Line: We really don’t understand what it is about this H5N1 virus that is making it so mild in the U.S. It may be a combination of these factors or just luck. Dr. Mike Osterholm at the Center for Infectious Disease Research and Policy, who has worked on this virus for over two decades, thinks there is just something about H5N1 that isn’t able to make the leap into human-to-human transmission and never will. We tend to think he’s right, though that doesn’t mean we shouldn’t monitor the situation carefully and be prepared. Even if it’s not H5N1, another flu pandemic is very likely in our lifetimes, and employers should have a pandemic plan in place. 

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Primary source: STAT ; Other sources: Lancet, CIDRAP

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Best Read:

Yes, the number of food recalls has been rising. Here's what you need to know - NPR

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