Extra Extra Read all about it in the Petri Dish

Some on my mind and chest

Couple days since my last posting but I came across something that have captured my brain synapses and set them ablaze. Hence the extra edition Petri Dish.

What lit the fuse?

Seasonal Flu Shot: First Defense Against an Eventful Avian Influenza Pandemic…. (?)*

https://www.medscape.com/viewarticle/seasonal-flu-shot-first-defense-against-eventful-avian-2025a10000ym

This article is a summary of this study:

Are we serologically prepared against an avian influenza pandemic and could seasonal flu vaccines help us?

https://journals.asm.org/doi/full/10.1128/mbio.03721-24?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org

So I fixed the medscape header by adding a *question mark and admittedly misread eventful as eventual. A prognostication of things to come? Nevertheless, this is a fascinating concept that is worth a deeper dive into the world of Hemagglutinins, Neuraminidase and Receptor-mediated endocytosis. Maybe writing this now will stave off that hyperactive brain 2AM wake up call. Hey, one can dream on, right?

So the basics

hemagglutinin (the H)

Glycoprotein https://www.britannica.com/science/hemagglutinin

Neuraminidase (the N)

Enzyme https://www.britannica.com/science/neuraminidase

Both are short but provide important information, especially on neuraminidases.

Antigenic neuraminidases occurring on influenza viruses have been well characterized. Following host-cell infection, these viruses manipulate the cell machinery to replicate themselves. When the replicated viruses bud from the host cells, they remain attached to the host-cell surface by binding between hemagglutinin (another antigenic protein on the surface of the virus) and sialic acid. Neuraminidase cleaves the sialic acid molecule, thereby freeing the virus to infect other cells in the host organism. Antibodies against neuraminidase that are generated by the host’s immune system following infection bind to a portion of the neuraminidase antigen known as an epitope. This binding targets the virus particles for immune destruction. The genes encoding the neuraminidases of influenza viruses are highly susceptible to genetic mutations that modify the epitopes of the antigen. The emergence of a new neuraminidase epitope enables an influenza virus to escape immune recognition, at least until new, matching antibodies have been generated against it. Genetic alterations affecting neuraminidase may arise through antigenic drift or antigenic shift—processes that can give rise to influenza viruses capable of causing epidemics or pandemics. There are 9 different forms of neuraminidase, designated N1 through N9, that are associated with influenza type A viruses. Together with various forms of hemagglutinin, neuraminidase is used to distinguish between subtypes of influenza A viruses (e.g., H1N1, H5N1).

To help visualize a short video, ( I am a very visual type of person myself.)

Receptor-mediated endocytosis

The virus enters the cell through a process called receptor-mediated endocytosis. The process was unknown until shortly after the turn of the 21st century. This paper is the result of those researches.

Endocytosis of influenza viruses

https://www.sciencedirect.com/science/article/pii/S1286457904001753?via%3Dihub

Another short video

So the “in practice” conclusion in Medscape:

"The results of our study indicate that probably the best vaccination strategy during the early stages of an AIV [avian influenza virus] pandemic will likely involve immunization first with seasonal IIV [inactivated influenza vaccine], followed, when it becomes available, with an AlV-specific vaccine or with specific newly designed H5N1 vaccines. This would lead to a more robust seroprotection compared with the single administration of the monovalent H5N1 vaccine," the authors wrote.

My Take

This is an observational study that seems more hypothetical than practical. Given that neuraminidases is highly susceptible to antigenic shift/drift, perhaps not a cross protective as suggested. From: https://pmc.ncbi.nlm.nih.gov/articles/PMC6005355/

From Annual vaccination is one of the most efficient and cost-effective strategies to prevent and control influenza epidemics. Most of currently available influenza vaccines are strong inducer of antibody responses against viral surface proteins, hemagglutinin (HA) and neuraminidase (NA), but are poor inducers of cell-mediated immune responses against conserved internal proteins. Moreover, due to the high variability of viral surface proteins because of antigenic drift or antigenic shift, many of the currently licensed vaccines confer little or no protection against drift or shift variants.

I do not see any licensed next gen vaccines yet. Further, with declining flu vaccine uptake, I do not see this as a public health tool against Avian Influenza. Don’t see any mandates either, seeing what happened to COVID. Even if H5N1 vaccines may not do better in uptake. A positive note though, we do have antivirals that are currently effective. I rate this study as, meh…

Another concern is, bitterly, politics.

Biden Health Officials Say They Built Up Pandemic Defenses. Trump Promises Changes.

— The outgoing administration releases a "roadmap" for defenses against infectious diseases

The Biden administration on Tuesday released a "roadmap" for maintaining government defenses against infectious diseases, just as President-elect Donald Trump pledges to dismantle some of them.

The 16-page report recaps steps taken in the last 4 years against COVID-19, mpox, and other diseases, including vaccination efforts and the use of wastewater and other measures to spot signs of erupting disease outbreaks. It's a public version of a roughly 300-page pandemic-prevention playbook that Biden officials say they are providing to the incoming administration.

https://www.medpagetoday.com/publichealthpolicy/washington-watch/113771

This is a must and face palm read.

DISCUSSION TIME

Would really like to hear from you on this.

Now for something a little different

Why the ‘Ferrari of viruses’ is surging through the Northern Hemisphere

Norovirus, which causes explosive diarrhea and vomiting, may be on the rise because of an antibody-dodging variant and post–COVID-19 socializing

https://www.science.org/content/article/why-ferrari-viruses-surging-through-northern-hemisphere

Never thought of or heard of Norovirus as the “Ferrari of viruses”. However, post–COVID-19 socializing contribution is debatable.