Antibody negative testing

https://www.cdc.gov/bird-flu/spotlights/h5n1-response-07192024.html#:~:text=Pasteurization%20kills%20avian%20influenza%20A,and%20should%20take%20proper%20precautions.
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.
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Ron Okimoto