Antibody testing Dairy H5N1 influenza

[RonO]

I posted this in the willful stupidity thread, but some posts are not
showing up.

https://www.cdc.gov/bird-flu/spotlights/h5n1-response-07192024.html

The CDC has released results of an initial screen in Michigan of 35
dairy workers for antibodies to H5N1. Something seems to be screwy.
They want to conclude there is no evidence of prior infection with H5N1
among these 35, but for some stupid reason they did not test the two
known positives that were identified in Michigan. The positive controls
may not have been included, so they do not know if their neutralizing
test is telling them anything about the dairy infections. If the two
positives were included in the 35 and were not found to have
neutralizing antibodies, that would negate their conclusions. The
previous studies that they cite that screened poultry workers for H5N1
were also negative for neutralizing antibodies, but some of those
studies found that even though the poultry workers did not pass the
neutralizing test some workers were detected to have antibodies against
H5N1. I do not know why they would not have the known positives in such
a study. The CDC claims that the study is being written up for peer review.


QUOTE:
Reporting the preliminary results of the Michigan-led seroprevalence
investigation. CDC analyzed sera (blood) collected from people who were
exposed to dairy cattle infected with highly pathogenic avian influenza
(HPAI) A(H5N1) clade 2.3.4.4b viruses causing outbreaks among animals in
the United States. These blood samples were collected as part of a type
of study called a seroprevalence study. Seroprevalence studies test
people’s blood for antibodies (an immune response) specific to a
pathogen of interest, in this case HPAI A(H5N1). These studies can tell
us whether someone has been previously infected.

Blood samples were collected in June 2024 from 35 people who work on
dairies in Michigan with herds that were confirmed positive for HPAI
A(H5N1) virus.

Study participants were from multiple counties and had different roles
on affected farms, but most worked with sick cows directly and fewer
than half reported using masks or goggles.

These samples were tested for antibodies against an avian influenza
A(H5N1) clade 2.3.4.4b virus and a seasonal influenza virus (control
virus) to measure antibodies.

Specimens were tested by two methods: microneutralization and
hemagglutination inhibition (HI) assays.

None of these 35 people showed neutralizing or HI antibodies (a sign of
prior infection) specific to avian influenza A(H5N1) virus.

Many of the people had neutralizing antibodies to seasonal flu.

The detection of antibodies to seasonal flu suggests that, not
unexpectedly, participants in the study had been previously infected or
vaccinated with seasonal influenza viruses and were able to generate an
immune response.
END QUOTE:

Ron Okimoto

[RonO]

Post by RonO
I posted this in the willful stupidity thread, but some posts are not
showing up.
https://www.cdc.gov/bird-flu/spotlights/h5n1-response-07192024.html
The CDC has released results of an initial screen in Michigan of 35
dairy workers for antibodies to H5N1.  Something seems to be screwy.
They want to conclude there is no evidence of prior infection with H5N1
among these 35, but for some stupid reason they did not test the two
known positives that were identified in Michigan.  The positive controls
may not have been included, so they do not know if their neutralizing
test is telling them anything about the dairy infections.  If the two
positives were included in the 35 and were not found to have
neutralizing antibodies, that would negate their conclusions.  The
previous studies that they cite that screened poultry workers for H5N1
were also negative for neutralizing antibodies, but some of those
studies found that even though the poultry workers did not pass the
neutralizing test some workers were detected to have antibodies against
H5N1.  I do not know why they would not have the known positives in such
a study.  The CDC claims that the study is being written up for peer
review.
Reporting the preliminary results of the Michigan-led seroprevalence
investigation. CDC analyzed sera (blood) collected from people who were
exposed to dairy cattle infected with highly pathogenic avian influenza
(HPAI) A(H5N1) clade 2.3.4.4b viruses causing outbreaks among animals in
the United States. These blood samples were collected as part of a type
of study called a seroprevalence study. Seroprevalence studies test
people’s blood for antibodies (an immune response) specific to a
pathogen of interest, in this case HPAI A(H5N1). These studies can tell
us whether someone has been previously infected.
Blood samples were collected in June 2024 from 35 people who work on
dairies in Michigan with herds that were confirmed positive for HPAI
A(H5N1) virus.
Study participants were from multiple counties and had different roles
on affected farms, but most worked with sick cows directly and fewer
than half reported using masks or goggles.
These samples were tested for antibodies against an avian influenza
A(H5N1) clade 2.3.4.4b virus and a seasonal influenza virus (control
virus) to measure antibodies.
Specimens were tested by two methods: microneutralization and
hemagglutination inhibition (HI) assays.
None of these 35 people showed neutralizing or HI antibodies (a sign of
prior infection) specific to avian influenza A(H5N1) virus.
Many of the people had neutralizing antibodies to seasonal flu.
The detection of antibodies to seasonal flu suggests that, not
unexpectedly, participants in the study had been previously infected or
vaccinated with seasonal influenza viruses and were able to generate an
immune response.
Ron Okimoto

https://www.nature.com/articles/s41586-024-07849-4

The article is paywalled, but you can get a prepublication copy via a
link in this NBC News article.

https://www.nbcnews.com/science/science-news/bird-flu-efficiently-spread-between-cows-mammals-rcna163487

Essentially the article just verifies what has been known since the
first genome sequences were made public. The dairy virus effectively
infects multiple different mammals and birds. The cases were known from
the beginning, and it was already known that the virus had pandemic
potential. It is just that the CDC and USDA just have not attempted to
contain the infection. They haven't even tried to identify all the
infected herds. A month ago the CDC claimed that it was giving up and
preparing for the worst, and just monitoring for if the virus ever
started to be transmitted between humans in a detectable manner. No
attempt was ever made to reduce human infections. Everyone has known
from the beginning in March that the way to limit human infection (the
most effective means to keep the virus from evolving into the next
pandemic) was to identify the infected herds and quarantine the herds
and the dairy workers. The CDC has recommendations that only apply to
known infected herds, and everyone with a clue understands that there
are a lot more infected herds than anyone is admitting to. It has to be
as stupid a response to this type of situation that could have possibly
occurred.

Ron Okimoto

[JTEM]

Post by RonO
Essentially the article just verifies what has been known since the
first genome sequences were made public.  The dairy virus effectively
infects multiple different mammals and birds.  The cases were known from
the beginning, and it was already known that the virus had pandemic
potential.  It is just that the CDC and USDA just have not attempted to
contain the infection.  They haven't even tried to identify all the
infected herds.  A month ago the CDC claimed that it was giving up and
preparing for the worst, and just monitoring for if the virus ever
started to be transmitted between humans in a detectable manner.

Yeah? And they had zero security stationed on that roof. Kind of a
pattern going here where they don't necessary do things, they just
let them happen.