Human infections with highly pathogenic avian influenza A(H5N1) viruses in the United States from March 2024 to May 2025.

Between March 2024 and October 2024, 46 human cases of highly pathogenic avian influenza (HPAI) A(H5N1) had been detected in the United States. The persistent panzootic spread of HPAI A(H5N1) viruses and continued detection of human cases presents an ongoing threat to public health. In this study, between November 2024 and May 2025, an additional 24 cases have been reported for a total of 70 human cases of HPAI A(H5N1): 41 were exposed to dairy cows, 24 to commercial poultry, two to backyard poultry and three had an unidentified source of exposure.

Neutralizing Antibody Response to Influenza A(H5N1) Virus in Dairy Farm Workers, Michigan, USA.

Since March 2024, highly pathogenic avian influenza A(H5N1) viruses have caused outbreaks in dairy cattle and poultry in the United States, and they continue to spill over into humans. However, data on human immune response to those viruses is limited. We report neutralizing antibody responses in 2 dairy farm worker H5N1 cases.

Highly Pathogenic Avian Influenza A(H5N1) Virus Infections in Humans.

Background: Highly pathogenic avian influenza A(H5N1) viruses have caused widespread infections in dairy cows and poultry in the United States, with sporadic human cases. We describe characteristics of human A(H5N1) cases identified from March through October 2024 in the United States.

Methods: We analyzed data from persons with laboratory-confirmed A(H5N1) virus infection using a standardized case-report form linked to laboratory results from the Centers for Disease Control and Prevention influenza A/H5 subtyping kit.

Update: Characteristics of Health Care Personnel with COVID-19 - United States, February 12-July 16, 2020.

As of September 21, 2020, the coronavirus disease 2019 (COVID-19) pandemic had resulted in 6,786,352 cases and 199,024 deaths in the United States.* Health care personnel (HCP) are essential workers at risk for exposure to patients or infectious materials (1). The impact of COVID-19 on U.

Trends in Morbidity, Mortality, and Cost of Hospitalizations Associated With Infectious Disease Sequelae of the Opioid Epidemic.

Background: Increases in fatal drug poisonings and hepatitis C infections associated with the opioid epidemic are relatively well defined, because passive surveillance systems for these conditions exist. Less described is the association between the opioid epidemic and skin, soft-tissue, and venous infections (SSTVIs), endocarditis, sepsis, and osteomyelitis.

Methods: Michigan hospitalizations between 2016 and 2018 that included an International Classification of Diseases, Tenth Revision, Clinical Modification, code indicating substance use were examined for codes indicative of infectious conditions associated with injecting drugs.

Characteristics of Persons Who Died with COVID-19 - United States, February 12-May 18, 2020.

During January 1, 2020-May 18, 2020, approximately 1.3 million cases of coronavirus disease 2019 (COVID-19) and 83,000 COVID-19-associated deaths were reported in the United States (1). Understanding the demographic and clinical characteristics of decedents could inform medical and public health interventions focused on preventing COVID-19-associated mortality.

Age-Related Differences in Hospitalization Rates, Clinical Presentation, and Outcomes Among Older Adults Hospitalized With Influenza-U.S. Influenza Hospitalization Surveillance Network (FluSurv-NET).

Background: Rates of influenza hospitalizations differ by age, but few data are available regarding differences in laboratory-confirmed rates among adults aged ≥65 years.

Methods: We evaluated age-related differences in influenza-associated hospitalization rates, clinical presentation, and outcomes among 19 760 older adults with laboratory-confirmed influenza at 14 FluSurv-NET sites during the 2011-2012 through 2014-2015 influenza seasons using 10-year age groups.

Results: There were large stepwise increases in the population rates of influenza hospitalization with each 10-year increase in age.

Outcomes of Immunocompromised Adults Hospitalized With Laboratory-confirmed Influenza in the United States, 2011-2015.

Background: Hospitalized immunocompromised (IC) adults with influenza may have worse outcomes than hospitalized non-IC adults.

Methods: We identified adults hospitalized with laboratory-confirmed influenza during 2011-2015 seasons through CDC's Influenza Hospitalization Surveillance Network. IC patients had human immunodefiency virus (HIV)/AIDS, cancer, stem cell or organ transplantation, nonsteroid immunosuppressive therapy, immunoglobulin deficiency, asplenia, and/or other rare conditions.

Text-Based Illness Monitoring for Detection of Novel Influenza A Virus Infections During an Influenza A (H3N2)v Virus Outbreak in Michigan, 2016: Surveillance and Survey.

Background: Rapid reporting of human infections with novel influenza A viruses accelerates detection of viruses with pandemic potential and implementation of an effective public health response. After detection of human infections with influenza A (H3N2) variant (H3N2v) viruses associated with agricultural fairs during August 2016, the Michigan Department of Health and Human Services worked with the US Centers for Disease Control and Prevention (CDC) to identify infections with variant influenza viruses using a text-based illness monitoring system.

Objective: To enhance detection of influenza infections using text-based monitoring and evaluate the feasibility and acceptability of the system for use in future outbreaks of novel influenza viruses.

Effects of Influenza Vaccination in the United States During the 2017-2018 Influenza Season.

Background: The severity of the 2017-2018 influenza season in the United States was high, with influenza A(H3N2) viruses predominating. Here, we report influenza vaccine effectiveness (VE) and estimate the number of vaccine-prevented influenza-associated illnesses, medical visits, hospitalizations, and deaths for the 2017-2018 influenza season.

Methods: We used national age-specific estimates of 2017-2018 influenza vaccine coverage and disease burden.

Increased Antiviral Treatment Among Hospitalized Children and Adults With Laboratory-Confirmed Influenza, 2010-2015.

(See the Editorial Commentary by Martin on pages 368-9.)Using population-based surveillance data, we analyzed antiviral treatment among hospitalized patients with laboratory-confirmed influenza. Treatment increased after the influenza A(H1N1) 2009 pandemic from 72% in 2010-2011 to 89% in 2014-2015 (P < .

Outbreak of Influenza A(H3N2) Variant Virus Infections Among Persons Attending Agricultural Fairs Housing Infected Swine - Michigan and Ohio, July-August 2016.

On August 3, 2016, the Ohio Department of Health Laboratory reported to CDC that a respiratory specimen collected on July 28 from a male aged 13 years who attended an agricultural fair in Ohio during July 22-29, 2016, and subsequently developed a respiratory illness, tested positive by real-time reverse transcription-polymerase chain reaction (rRT-PCR) for influenza A(H3N2) variant* (H3N2v). The respiratory specimen was collected as part of routine influenza surveillance activities. The next day, CDC was notified of a child aged 9 years who was a swine exhibitor at an agricultural fair in Michigan who became ill on July 29, 2016, and tested positive for H3N2v virus at the Michigan Department of Health and Human Services Laboratory.