Source: Emerging Infectious Diseases Journal, https://wwwnc.cdc.gov/eid/article/30/11/24-0892_article

Abstract
Since 2013, a total of 167 human infections with swine-origin (variant) influenza A viruses of A(H1N1)v, A(H1N2)v, and A(H3N2)v subtypes have been reported in the United States. Analysis of 147 genome sequences revealed that nearly all had S31N substitution, an M2 channel blocker-resistance marker, whereas neuraminidase inhibitor–resistance markers were not found. Two viruses had a polymerase acidic substitution (I38M or E199G) associated with decreased susceptibility to baloxavir, an inhibitor of viral cap-dependent endonuclease (CEN). Using phenotypic assays, we established subtype-specific susceptibility baselines for neuraminidase and CEN inhibitors. When compared with either baseline or CEN-sequence–matched controls, only the I38M substitution decreased baloxavir susceptibility, by 27-fold. Human monoclonal antibodies FI6v3 and CR9114 targeting the hemagglutinin’s stem showed variable (0.03 to >10 µg/mL) neutralizing activity toward variant viruses, even within the same clade. Methodology and interpretation of laboratory data described in this study provide information for risk assessment and decision-making on therapeutic control measures.

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https://etidioh.wordpress.com/2024/10/09/antiviral-susceptibility-of-swine-origin-influenza-a-viruses-isolated-from-humans-usa/

#abstract #antivirals #baloxavir #drugsResistance #h1n1v #h1n2v #h3n2v #influenzaA #oseltamivir #peramivir #research

2 #human #infections with novel #influenza A viruses were reported by #Minnesota Dept of Health. #US #CDC #FluView: https://jasem.chiachoob.com/fluview/surveillance/2024-week-37.html

Patients were infected with flu #H3N2v virus. Patients are <18 yrs, sought care during wk ending Sept 7 (Wk 36), not hospitalized, & recovered from illnesses. Investigation by state officials found that both patients, {not contacts}, attended same agricultural #fair prior to their illness onset, where 1rst child had indirect swine contact & 2nd had.

#USA, #Michigan DHHS confirms detection of #influenza A #H3N2v #variant (#swine flu) in Ingham County, https://www.michigan.gov/mdhhs/inside-mdhhs/newsroom/2024/08/09/swine-flu-detection

The individual tested positive for influenza A H3N2v in late July. Specimen was forwarded to MDHHS Bureau of Laboratories for enhanced influenza virus sequence monitoring as part of CDC’s Emerging Infections Program where it again tested presumptive positive for influenza A H3N2v; later confirmed by CDC.

#USA. A #human #infection with a novel #influenza A #H3N2v virus was reported by #Colorado #CDC: https://www.cdc.gov/flu/weekly/index.htm

Patient was infected with an influenza H3N2v variant virus, is < 18 yrs of age, sought healthcare during wk ending July 13, 24 (Wk 28), & was not hospitalized. An investigation by public health officials found patient attended an agricultural event prior to their illness onset. Investigation didn't identify illness among close contacts of patient. Investigation is ongoing