A third case of mammal-to-human transmission of the highly pathogenic H5N1 bird flu virus has been reported in the United States. This latest case, involving a dairy worker in Michigan, raises concerns due to the individual exhibiting respiratory symptoms, highlighting the pandemic potential of this virus. U.S. hospitals need to prepare for the worst and hope for the best.
The three human cases of H5N1 in the U.S. — the first one in Texas and the others in Michigan — are not connected to each other. Fortunately, all three individuals experienced mild symptoms and have fully recovered, with no additional cases detected. These infections are part of a broader epidemic affecting dairy cattle, with more than 90 herds infected across 12 states. Wastewater surveillance has shown increased detections of influenza A in certain areas. Bird flu is in the family of influenza A so any increase observed can be implicated with H5N1 or other influenza A viruses, such as H1N1 and H3N2 that routinely circulate in people. While there is yet no evidence of human-to-human transmission of the H5N1 virus, this could emerge at any time, underscoring the urgent need for hospitals to bolster their preparedness for potential additional human cases of H5N1.
The current risk to the general public is low, though individuals with job-related or recreational exposure to infected birds, cattle, or other animals are at higher risk for infection. To date, no severe illness or deaths from H5N1 have been reported in the U.S., though the virus is known to be deadly. Since the first human outbreak in 1997 in Hong Kong, more than 900 sporadic cases have been reported in 23 countries, with more than half resulting in death.
As leaders in health care and public health, we recognize the important role hospitals play in outbreak detection and response, and mitigating the spread of infectious diseases. With H5N1 posing a potentially significant public health threat, hospitals must adopt proactive, comprehensive strategies to prepare for, reduce the threat of, and respond to potential cases. Here are four strategies we recommend hospitals implement:
Actively check people for H5N1 infection
Testing is the first step in detecting and managing people with H5N1 bird flu. Clinicians should consider testing people showing signs or symptoms of acute respiratory illness or conjunctivitis with relevant exposure history, especially anyone who has had contact with potentially infected sick or dead birds, livestock, or other animals within 10 days of the onset of symptoms. Clinical presentations can range from mild conjunctivitis and upper respiratory symptoms to severe pneumonia and multi-organ failure.
It is crucial for clinicians to understand that cases of H5N1 bird flu can occur without any known links to infected animals, animal products, or contaminated sources (such as equipment), so it’s important to test individuals who exhibit H5N1 symptoms, regardless of their exposure history.
Public health authorities, who control whether testing for H5N1 should be conducted at a public health laboratory, should be flexible and allow clinicians to test patients for H5N1 based on their own clinical judgement and who may not fit the specific criteria for H5N1 — like being in direct contact with an infected animal — as the risk for being infected with H5N1 is evolving.
Strengthen communication and coordination with local public health partners
Through the national and state Influenza Surveillance Report currently in place, hospitals, clinics, and community providers are essential for public health surveillance for seasonal influenza, including detecting novel strains like H5N1. Identifying various viral subtypes is typically done in public health laboratories. As such, effective communication and coordination between clinicians and local health departments are crucial for diagnosing and managing human H5N1 cases.
Increased awareness of H5N1 among clinicians is important for recognizing potential infections in humans and initiating public health investigations. For individuals directly exposed to dairy cows, birds, or other animals that can carry H5N1, or those in at-risk groups, clinicians should be thinking H5N1 if there are signs, symptoms, and a positive influenza A test and immediately contact their local public health departments for subtyping.
All hospitals have the ability to test for influenza A, since this family of viruses includes the normally circulating flu strains they see every flu season. Individuals who do not have obvious exposure to H5N1 but have flu strains that are not H1N1 or H3N2, the typical seasonal flu strains, should be evaluated for H5N1 at public health laboratories. Testing for other causes of acute respiratory illness, including SARS-CoV-2, should also be considered based on local epidemiology of circulating respiratory viruses.
Educate health care workers
Health care workers are the frontline defenders in responding to outbreaks, acting as public health eyes and ears in the fight against infectious diseases. Their preparedness is vital for public health. To ensure effective monitoring and response to potential H5N1 cases, all clinicians must be educated on CDC guidelines for identifying infections, initiating antiviral treatment, and notifying health departments for testing. Training should cover H5N1 criteria and definition of risk factors for infection with H5N1, proper notification procedures to the health department to initiate testing, and the use of personal protective equipment (PPE) to prevent transmission.
Early identification of infections is essential to control spread and protect health care workers. The CDC’s updated webpage is a valuable resource for current outbreak information.
Incorporate public education and outreach
Public education is vital for a hospital’s preparedness strategy. While the CDC states the current risk to the general public from H5N1 is low, preventive measures are essential, especially with the increased consumption of raw milk, a potential means of transmission. Public recommendations include avoiding contact with infected or dead animals and potentially contaminated surfaces or equipment, using PPE when necessary, and avoiding undercooked or raw foods such as unpasteurized milk. Hospitals should engage in community outreach to disseminate this information and encourage individuals to seek medical care if they suspect an infection.
The emergence of an H5N1 bird flu epidemic in the U.S. highlights the persistent threat of this virus. Hospitals must beef up their preparedness by implementing robust screening protocols, strengthening communication with public health partners, educating health care workers, and engaging in public outreach. These steps support the public health response to H5N1 and mitigate risks. Ongoing vigilance and readiness are crucial to protecting public health and health care workers.
Syra Madad, D.HSc., is the chief biopreparedness officer at NYC Health + Hospitals and a fellow at the Belfer Center for Science and International Affairs. Carlos del Rio, M.D., is Distinguished Professor of Medicine in the Division of Infectious Diseases at Emory University School of Medicine in Atlanta. Scott J. Becker, M.S., is the chief executive officer of the Association of Public Health Laboratories, where Ewa King, Ph.D., is the chief program officer.