Resources with keywords: Influenza Virus
Sporadic H5N1 human infections continue; all linked to direct animal contact. Agricultural research workers, poultry handlers, and veterinary staff conducting field work face the highest occupational risk. Clade 2.3.4.4b dominant globally. Research staff working with live avian influenza virus must comply with FSAP registration requirements (H5N1 is a Select Agent). No sustained human-to-human transmission detected as of 18 May 2026.
Cumulative 172 influenza-associated pediatric deaths this season; ~85% in unvaccinated or incompletely vaccinated individuals. HCWs remain at occupational risk from undiagnosed febrile patients. Hospitals should verify HCW influenza vaccination rates. Influenza A(H3N2) subclade K dominates nationally; influenza B increasing in recent weeks. End-of-season transition period warrants continued HCW respiratory precautions.
First peer-reviewed report of H5N5 human infection in a 75-year-old immunocompromised patient. Nasal swab RT-PCR was initially negative; confirmed only via deep sequencing. This has direct implications for laboratory workers: standard influenza diagnostic assays may miss novel subtypes in immunocompromised patients. Biosafety officers should review subtype-specific testing protocols and PPE for novel subtype specimen processing.
Genotype D1.1 H5N1 viruses replicate significantly more efficiently in human nasal epithelium organoids than genotype B3.13. This finding has direct biosafety implications for laboratory workers: D1.1 strains pose greater occupational infection risk and may require enhanced containment measures beyond current BSL-3 enhanced (Ag) standards. Dual-use research of concern (DURC) policies apply. Biosafety officers at labs conducting avian influenza research should review containment adequacy for D1.1 strains.
Tobolowsky FA, Morris E, Castro L, et al.
Although antibodies against influenza A(H5N1) were detected in the index patient, serologic testing of a convenience sample of nine close contacts identified no detectable A(H5)-specific antibodies. Despite an extensive investigation, the infection source remains unknown; no human-to-human transmission was identified among close contacts by rRT-PCR and serologic testing.
Recommendations made by the ACIP are reviewed by the CDC Director, and if adopted, are published as official CDC/HHS recommendations in the Morbidity and Mortality Weekly Report.
OSHA Influenza QuickCards (by Occupation)General Precautions (English/Español)
Healthcare Workers (English/Español)
Laboratory Workers (English/Español)
Poultry Workers (English/Español)
Animal Handlers (English/Español)
Food Handlers (English/Español)
Iincludes Guidance for Poultry Employees , Animal Handlers other than Poultry Employees, Laboratory Employees, Healthcare Workers Who Treat Patients with Known or Suspected AI, Guidance for Food Handlers, etc.
Naraharisetti R, Weinberg M, Stoddard B, et al.
HPAI A(H5N1) virus was detected in two indoor domestic cats with respiratory and neurologic illness that lived in homes of dairy workers but had no known direct exposure to HPAI A(H5N1)–affected farms.
Leonard J, Harker EJ, Szablewski CM, et al.
These findings suggest the possible benefit of systematic surveillance for rapid identification of HPAI A(H5) virus in dairy cattle, milk, and humans who are exposed to cattle to ensure appropriate hazard assessments.
