David Bacsik

I'm not sure of the right mechanism, but maybe there's a creative way to give people a chance to learn more about their health if they affirmatively want to. (3/2)

Kristian's point about the implications for future WW studies. I wonder if there's a way to offer testing but maintain anonymity. Something like having DOH reach out to a largish number of potentially affected households and give people the chance to opt in for further testing, perhaps. (2/2)

Ah, I see. Thanks for closing the loop on that story! I've always been curious. In this case, for the informal poll, I would vote for finding some way to offer testing; it seems like a real opportunity cost to the patient to not have that information when it exists. I appreciate (1/2)

In the case of the Wisconsin lineage, what were potential patient's reactions when DOH reached out to the small number of people that used those bathrooms? IIRC, many had provided nasal swab samples and all of those were negative. Were folks not interested in providing follow-up stool samples?

The Webby paper also empirically tested oseltamivir and baloxavir against H5N5 viruses from this lineage, and they remained sensitive to both drugs, which I found reassuring.

Screening for Neuraminidase Inhibitor Resistance Markers among Avian Influenza Viruses of the N4, N5, N6, and N8 Neuraminidase Subtypes | Journal of Virology ABSTRACT Several subtypes of avian influenza viruses (AIVs) are emerging as novel human pathogens, and the frequency of related infections has increased in recent years. Although neuraminidase (NA) in...

This was the best reference I could find for N5-specific NA mutation effects: journals.asm.org/doi/10.1128/.... The test both antiviral resistance and stability of the mutation over a few passages.

The WA sequence looks like it does not have any resistance mutations to neuraminidase inhibitors.

Ecology and spread of the North American H5N1 epizootic - Nature The panzootic of highly pathogenic H5N1 since 2021 was driven by around nine introductions into the Atlantic and Pacific flyways, followed by rapid dissemination through wild migratory birds, primaril...

Our lab's paper describing the North American H5N1 epizootic is out now in Nature! So thrilled to have this out, and congratulations to @lambod50.bsky.social for all the fantastic work on this: www.nature.com/articles/s41...

Validation of H5 influenza virus subtyping RT-qPCR assay and low prevalence of H5 detection in 2024–2025 influenza virus season | Journal of Clinical Microbiology The spread of H5N1 influenza virus in the United States has led to the culling of almost 200 million birds, infected cow herds across 17 states, and resulted in 70 human infections as of July 2025. Ra...

8/ The final version of this manuscript is now published in the Journal of Clinical Microbiology. It includes updated results from 150 clinical tests performed through the end of April, none of which detected subtype H5 influenza A virus.

journals.asm.org/doi/10.1128/...

7/ Clinicians: The H5 subtyping PCR is available to order now through UW Medicine: testguide.labmed.uw.edu/view/FLUH5

Validation of H5 influenza virus subtyping RT-qPCR assay and low prevalence of H5 detection in 2024-2025 influenza virus season A sustained outbreak of H5N1 influenza virus among wild fowl and domestic livestock has caused more than 70 zoonotic infections in humans in the United States, including one death. The Centers for Dis...

6/ Read more in our manuscript from the
Greninger Lab
at UW Virology
: medrxiv.org/cgi/content/.... Many people contributed to this work, including
@margaretgracemills.bsky.social, Ailyn Perez-Osorio, and
@pavitrarc.bsky.social.

5/ The CDC recommends subtyping all hospitalized flu A+ cases. With H5N1 still circulating widely in birds & cattle, monitoring remains critical—especially for patients with close animal contact, who face the highest risk.

4/ This suggests that, in Seattle, the 2024-2025 flu season has been driven by seasonal strains, with no H5N1 detected among this cohort of patients with lab-confirmed influenza A infections.

3/ So far, none of the samples tested have been H5-positive. All sequenced samples contained seasonal H3N2 or H1N1 viruses.

2/ In Dr. Alex Greninger’s lab at UW Virology, we developed a clinical RT-qPCR assay for H5 subtyping. We used it to differentiate seasonal influenza A infections from subtype H5 infections during Seattle’s 2024-2025 influenza season.

1/ How has H5N1 affected this year’s flu season in Seattle? Despite ongoing outbreaks in birds & cattle nationally, we detected zero H5N1 cases in 675 influenza A-positive specimens tested at UW Medicine.

RSV F evolution escapes some monoclonal antibodies but does not strongly erode neutralization by human polyclonal sera Vaccines and monoclonal antibodies targeting the respiratory syncytial virus (RSV) fusion protein (F) have recently begun to be widely used to protect infants and high-risk adults. Some other viral pr...

In study led by @csimonich.bsky.social & Teagan McMahon, we quantify antigenic evolution of RSV F

Important because:

1️⃣ RSV top cause of infant hospitalization in USA

2️⃣ New antibodies & vax can prevent hospitalizations

3️⃣ Will virus evolution erode their efficacy?

www.biorxiv.org/content/10.1...

I agree with Scott. This is important because:

1. This shows that cattle are susceptible to other H5N1 viruses, not just B3.13.
2. D1.1 viruses are currently transmitting really efficiently through wild birds in North America, and are very widespread.
...