Purpose
This document summarizes current key public health prevention recommendations for state, tribal, local, and territorial jurisdictions and provides links to resources for additional information on how to reduce the risk of infection and severe illness from highly pathogenic avian influenza (HPAI) A(H5N1) virus (hereafter “HPAI A(H5N1)”)
CDC Update
- HPAI A(H5N1) virus is widespread in wild birds worldwide and is causing outbreaks in poultry and U.S. dairy cows, with two recent human cases in U.S. dairy farm workers.
- Since 1997, more than 900 sporadic human cases of HPAI A(H5N1) have been reported from 23 countries and more than 50% of these human cases have died.
- CDC is working with the U.S. Department of Agriculture (USDA), the Food and Drug Administration (FDA), the Administration for Strategic Preparedness and Response (ASPR), public health and animal health officials in states, and other partners using a One Health approach to respond to the public health challenge posed by the multistate outbreak of HPAI A(H5N1) in dairy cows and other animals in the United States.
- While CDC believes the current risk to the general public is low, some people (e.g., those who work with infected or presumed infected animals) are at greater risk of infection and CDC is monitoring for changes that might indicate the potential for increased transmission of the virus to humans or among humans.
- CDC has recommended that state and local public health agencies monitor people with exposures to infected animals.
- Information on the current HPAI A(H5N1) situation is available at H5N1 Bird Flu: Current Situation Summary.
Protecting farm workers
- Employers and workers should take action to reduce the risk of infection when working with infected or potentially infected animals or materials, including raw milk contaminated or potentially contaminated with HPAI A(H5N1) virus.
- Employers should conduct a site-specific risk assessment and select the engineering and administrative controls and personal protective equipment (PPE) that best address the hazards present.
- Workers who have direct or close contact with animals or materials, including raw milk, that are infected or contaminated or potentially infected or contaminated with HPAI A(H5N1) virus, should wear appropriate PPE.
- All PPE should be used in accordance with Occupational Safety and Health Administration (OSHA) regulations.
- Employers should train workers and ensure that they can demonstrate an understanding of when to use PPE, what PPE is necessary, what it looks like when PPE is properly fitted, how to properly disinfect reusable PPE, and how to properly dispose of damaged or single-use PPE.
- The following links contain more information on worker safety and PPE:
- Updated Interim Recommendations for Worker Protection and Use of Personal Protective Equipment (PPE) to Reduce Exposure to Novel Influenza A Viruses Associated with Disease in Humans
- Protect Yourself From H5N1 When Working With Farm Animals [2 MB, 1 page] | Spanish [2 MB, 1 page] | K'iche' [2.1 MB, 1 page] | Nahuatl [2.2 MB, 1 page]
- Updated Interim Recommendations for Worker Protection and Use of Personal Protective Equipment (PPE) to Reduce Exposure to Novel Influenza A Viruses Associated with Disease in Humans
Monitoring and testing farm workers
- Monitor workers and other people with direct or close contact with cows, birds, or other domestic or wild animals infected, or potentially infected, with HPAI A(H5N1) viruses to rapidly identify any human cases, provide appropriate treatment, and prevent onward spread.
- Monitoring is coordinated at the state or local level and should begin with first exposure and continue for 10 days past the last known exposure.
- CDC will collect weekly aggregate monitoring reports from states and summarize information
- CDC will collect weekly aggregate monitoring reports from states and summarize information
- To determine whether an illness is from HPAI A(H5N1) virus infection, testing of exposed symptomatic people is being done by state or local officials, and CDC conducts confirmatory testing when needed.
- Workers who are being monitored could also develop symptoms from other causes, including seasonal influenza or other respiratory infections, allergies, or other environmental exposures.
- Commercially available influenza tests in clinical settings can detect HPAI A(H5N1) virus as an influenza A positive result, but not specifically identify or distinguish HPAI A(H5N1) virus from seasonal influenza A or other novel influenza A viruses. If exposed workers present to a clinical setting and test positive there for influenza, specimens should be sent to the public health laboratory for further testing.
- The following links contain more information on testing:
- Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations
- Interim Guidance on Testing and Specimen Collection for Patients with Suspected Infection with Novel Influenza A Viruses with the Potential to Cause Severe Disease in Humans
- Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations
- Workers who are being monitored could also develop symptoms from other causes, including seasonal influenza or other respiratory infections, allergies, or other environmental exposures.
Use of oseltamivir (generic or brand name Tamiflu™) for treatment and post-exposure prophylaxis of human infections
- Oseltamivir treatment is recommended as soon as possible for people with HPAI A(H5N1) virus infection.
- People confirmed or suspected to have HPAI A(H5N1) virus infection should be isolated, with recommended clinical specimens collected for influenza A and A(H5) virus testing, and they should be started on empiric oseltamivir treatment as soon as possible (even before testing results are available). See: Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations and Interim Guidance on the Use of Antiviral Medications for Treatment of Human Infections with Novel Influenza A Viruses Associated with Severe Human Disease
- People confirmed or suspected to have HPAI A(H5N1) virus infection should be isolated, with recommended clinical specimens collected for influenza A and A(H5) virus testing, and they should be started on empiric oseltamivir treatment as soon as possible (even before testing results are available). See: Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations and Interim Guidance on the Use of Antiviral Medications for Treatment of Human Infections with Novel Influenza A Viruses Associated with Severe Human Disease
- Oseltamivir is recommended for post-exposure prophylaxis (at treatment dosing frequency of twice daily x 5 days) of close contacts (e.g., household members) of a patient with probable or confirmed HPAI A(H5N1) virus See: Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations;
- Oseltamivir treatment dosing (twice daily x 5 days) is recommended because of the potential for HPAI A(H5N1) virus infection to cause severe human disease with high mortality, and to avoid sub-therapeutic drug levels that increase the risk of oseltamivir resistance if infection is established.
- Close contacts should be monitored for signs and symptoms of illness for 10 days after the last known exposure to a patient with probable or confirmed HPAI A(H5N1) virus infection.
- Oseltamivir treatment dosing (twice daily x 5 days) is recommended because of the potential for HPAI A(H5N1) virus infection to cause severe human disease with high mortality, and to avoid sub-therapeutic drug levels that increase the risk of oseltamivir resistance if infection is established.
- Oseltamivir is recommended for post-exposure prophylaxis (at treatment dosing frequency of twice daily x 5 days) for certain people with HPAI A(H5N1) virus exposure.
- Decisions should be based on clinical judgment, with consideration for the type of exposure, duration of exposure, time since exposure, and known infection status of the birds or animals to which the person was exposed.
- Antiviral chemoprophylaxis is not routinely recommended for people who used proper PPE and experienced no breaches while working with infected or potentially infected birds or other animals or when decontaminating affected environments, including animal disposal.
- Decisions should be based on clinical judgment, with consideration for the type of exposure, duration of exposure, time since exposure, and known infection status of the birds or animals to which the person was exposed.
- The following links contain more information on the use of oseltamivir:
- Interim Guidance on Influenza Antiviral Chemoprophylaxis of Persons Exposed to Birds with Avian Influenza A Viruses Associated with Severe Human Disease or with the Potential to Cause Severe Human Disease
- Interim Guidance on Follow-up of Close Contacts of Persons Infected with Novel Influenza A Viruses and Use of Antiviral Medications for Chemoprophylaxis
- Interim Guidance on Influenza Antiviral Chemoprophylaxis of Persons Exposed to Birds with Avian Influenza A Viruses Associated with Severe Human Disease or with the Potential to Cause Severe Human Disease