CDC: Updated Interim Guidance On Handling & Treatment Of Novel Flu Infections

Photo Credit – Wikipedia

 

 

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Although HPAI H7N9 and HPAI H5N1 human infections remain almost exclusively an Asian or Middle Eastern problem, the potential for seeing an imported case (as we already have with two H7N9 & 1 H5N1 cases in Canada) certainly exists, as does the possibility of infection by one of the recently arrived (and reassorted) HPAI H5 viruses in North America.

This winter’s unprecedented H5N1 outbreak in Egypt, in particular, raises the risks of seeing cases here, and so the CDC has released new, updated (Interim) guidance on the handling of patients (and their contacts) who may have been exposed to, or infected by, novel influenza A viruses.

 

These new guidance documents essentially consolidate, and update, earlier individual guidance documents for the handling of H5N1 and H7N9 (see H7N9: Updated CDC Guidance For Antiviral Treatment and CDC Interim Guidance On Antiviral Chemoprophylaxis For Persons With Exposure To Avian Flu).

 

Wth the rapid expansion of novel avian flu types over the past two years it has become unwieldy and counter productive to maintain separate guidance documents for each subtype, when the advice is essentially the same across the board.

 

As these are long and detailed documents, I’ve only posted the links and the opening section of each. Clinicians will want to follow the links to read them in their entirety.

 

 

Interim Guidance on the Use of Antiviral Medications for Treatment of Human Infections with Novel Influenza A Viruses Associated with Severe Human Disease

Summary

This document provides guidance for antiviral treatment of human infection with novel influenza A viruses associated with severe human disease; these viruses currently include influenza A (H7N9) virus and highly pathogenic avian influenza A (H5N1) virus.¹

This guidance merges and replaces the previously posted guidance on the use of antiviral agents for treatment of human infections with avian influenza A (H7N9) and avian influenza A (H5N1). This antiviral treatment guidance is consistent with current CDC and World Health Organization (WHO) recommendations, and provides updated recommendations for treatment of novel influenza A infections associated with severe human disease in the United States.

This guidance reflects recently updated novel influenza A case definitions (see H7N9 case definitions and H5N1 case definitions).This guidance recommends antiviral treatment as soon as possible for all hospitalized cases of human infection with novel influenza A viruses associated with severe human disease, and for confirmed and probable outpatient cases.² Outpatient cases under investigation who have had recent close contact with a confirmed or probable case of human infection with a novel influenza A virus that can cause severe disease should receive antiviral treatment, whereas outpatient cases under investigation meeting only the travel exposure criteria for a case under investigation are not recommended to receive antiviral treatment. (For guidance on investigation of close contacts of confirmed or probable cases, see Interim Guidance on Follow-up of Close Contacts of Persons Infected with Novel Influenza A Viruses Associated with Severe Human Disease and the Use of Antiviral Medications for Chemoprophylaxis.)

These recommendations are based on expert opinion and available published and unpublished data on the treatment of infection caused by influenza viruses, including seasonal, pandemic, and novel viruses. This guidance will continue to be updated as additional information on virus transmissibility, epidemiology, and antiviral susceptibility patterns becomes available for novel influenza A viruses that cause severe disease.

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Interim Guidance on Follow-up of Close Contacts of Persons Infected with Novel Influenza A Viruses Associated with Severe Human Disease and on the Use of Antiviral Medications for Chemoprophylaxis

This document provides guidance for follow-up and antiviral chemoprophylaxis of close contacts of cases of human infection with novel influenza A viruses associated with severe human disease, which currently includes avian influenza A (H7N9) virus and highly pathogenic avian influenza A (H5N1) virus.¹ This guidance merges previously posted guidance on the use of antiviral agents for chemoprophylaxis of human infections with avian influenza A (H7N9) and avian influenza A (H5N1).

This interim guidance is based on expert opinion and currently available published and unpublished data for antiviral treatment and chemoprophylaxis of seasonal, pandemic, and novel influenza. These recommendations are based on the following considerations:

• Novel influenza A viruses have caused severe human disease and substantial mortality among detected cases to date.
• Limited, non-sustained human-to-human transmission cannot be excluded in some case clusters.
• Sufficient supplies of antiviral agents that are expected to be effective against novel influenza A viruses are available.

The public health goal of this interim guidance is to prevent further spread of novel influenza A viruses associated with severe human disease if there is introduction/travel of infected persons into the United States. It is specific to a scenario where there are sporadic cases associated with poultry exposure and possible limited, non-sustained human-to-human virus transmission.

This guidance will be updated as additional information on epidemiology and transmissibility becomes available for novel influenza A viruses causing severe human disease.

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CDC Interim Guidance On Antiviral Chemoprophylaxis For Persons With Exposure To Avian Flu

Photo Credit – FAO

 

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Last night the CDC released a pair of interim guidance documents for clinicians and public health officials on how to deal with patients suspected of being exposed to novel (primarily avian) influenza. I blogged about the first guidance document earlier today in CDC Interim Guidance For Testing For Novel Flu.

Although we haven’t had to deal with HPAI much in North America, the standard procedure it to treat – prophylactically with antivirals – anyone with known exposure to infected birds. 

 

Often in Asia or the Middle East, this has included cullers who have been charged with destroying an infected flock of poultry, or family members of someone diagnosed with H5N1 or H7N9.  With the recent arrival of HPAI H5 viruses in migratory and wild birds to North America, it is possible that some North American poultry workers (or hunters) may be exposed to infected birds. 

 

While the HPAI H5 viruses currently circulating in North America have not been directly associated with human infection, viruses evolve over time, and the CDC is wisely considering them a potential human health hazard.  The CDC has therefore released the following interim guidance.

 

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

• Español
• Background
• Exposure to Birds Infected with Avian Influenza
• Monitoring of Exposed Persons
• Post-exposure Chemoprophylaxis of Exposed Persons
• Footnotes

Background

This document provides interim guidance for clinicians and public health professionals in the United States on follow-up and influenza antiviral chemoprophylaxis of persons exposed to birds infected with avian influenza A viruses associated either with severe human disease or thought to have the potential to cause severe human disease. Examples of viruses associated with severe human disease include Asian avian influenza A (H5N1) and A (H7N9) viruses. Examples of viruses with the potential to cause severe human disease include avian influenza A (H5N2) and (H5N8) viruses, and a new reassortant avian influenza A (H5N1) virus¹, all of which were detected in wild and domestic birds in North America in December 2014 and January 2015. There is limited experience with these newly detected viruses to inform public health guidance. However, these viruses are thought to have the potential to infect people and cause severe illness. To date no human avian influenza infections have been documented in the U.S. CDC will update this guidance as additional information becomes available.

Exposure to Birds Infected with Avian Influenza

An exposed person is defined as a person with contact² in the past 10 days³ to infected sick or dead birds, or infected flocks. Infected refers to infection with avian influenza A viruses associated with severe human disease or which have the potential to cause severe human disease.

Top of Page

Monitoring of Exposed Persons

Exposed persons should monitor themselves for new illness for 10 days after the last known exposure. The presence of fever and respiratory symptoms (e.g., cough, sore throat, shortness of breath, difficulty breathing) should be assessed daily during this period.

Any exposed person who has a new fever or respiratory symptoms should be referred for prompt medical evaluation, antiviral treatment, and testing for avian influenza (A) virus infection.

Post-exposure Chemoprophylaxis of Exposed Persons

Chemoprophylaxis with influenza antiviral medications can be considered for all exposed persons. Decisions to initiate antiviral chemoprophylaxis should be based on clinical judgment, with consideration given to the type of exposure and to whether the exposed person is at high risk for complications from influenza.

If antiviral chemoprophylaxis is initiated, treatment dosing for the neuraminidase inhibitors oseltamivir or zanamivir (one dose twice daily) is recommended in these instances instead of the typical antiviral chemoprophylaxis regimen (once daily).⁴ For specific dosage recommendations for treatment by age group, please see Influenza Antiviral Medications: Summary for Clinicians. Physicians should consult the manufacturer’s package insert for dosing, limitations of populations studied, contraindications, and adverse effects.

Chemoprophylaxis is not routinely recommended for personnel involved in culling non-infected or likely non-infected bird populations as a control measure or personnel involved in handling sick birds or decontaminating affected environments (including animal disposal) who used proper personal protective equipment.

See CDC guidance for follow-up and antiviral chemoprophylaxis of contacts of cases of human infection with avian influenza A viruses associated with severe human disease.

Footnotes

¹ The H5N1 virus isolated from a US wild bird is a new mixed-origin virus (a “reassortant”) that is genetically different from the avian H5N1 viruses that have caused human infections with high mortality in several other countries (notably in Asia and Africa). No human infections with this new reassortant H5N1 virus have been reported.

² This direct exposure may include: contact with birds (e.g., handling, slaughtering, defeathering, butchering, preparation for consumption); direct contact with surfaces contaminated with feces or bird parts (carcasses, internal organs, etc.); or prolonged exposure to birds in a confined space.

³ The potential incubation period is unknown for avian influenza A viruses which are not yet known to cause human disease. Available data suggest that the estimated incubation period for human infection with H5N1 and H7N9 viruses is generally 3 to 7 days, but has been reported to be as long as 10 days.

⁴ This recommendation for twice daily antiviral chemoprophylaxis dosing frequency is based on limited data that support higher chemoprophylaxis dosing in animals for avian A(H5N1) virus (Boltz DA, et al JID 2008;197:1315) and the desire to reduce the potential for development of resistance while receiving once daily dosing ( BazM, et al NEJM 2009;361:2296; Cane A et al PIDJ 2010;29:384; MMWR 2009;58:969).

CDC Interim Guidance For Testing For Novel Flu

 

Credit NIAID 

 

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While the risk to the public remains low, the importation this month of two cases of H7N9 into Canada from China, the ongoing outbreak of H5N1 in Egypt, and the recent introduction of HPAI H5 viruses via wild and migratory birds into North America are all reasons why doctors around the country need to be aware of the potential for seeing novel flu cases.

The HPAI H5 viruses currently circulating in North America have not been associated with human infection - but they are related to H5 viruses that have - and so they are deserving of extra scrutiny and vigilance.  

Last night the CDC published extensive interim guidelines on the handling of suspected novel flu patients for clinicians and public health entities, excerpts of which I’ve posted below:  They also published Interim Guidance on Influenza Antiviral Chemoprophylaxis of Persons Exposed to Birds with Avian Flu, which I will cover in my next blog.

 

 

Interim Guidance on Testing, Specimen Collection, and Processing for Patients with Suspected Infection with Novel Influenza A Viruses with the Potential to Cause Severe Disease in Humans

On this Page

• Background and Purpose
• Recommendations for Surveillance, Testing, and Investigation
• When Specimens Should Be Collected
• Infection Control when Collecting Specimens
• Preferred Respiratory Specimens
• Swabs
• Storing Clinical Specimens
• Shipping Clinical Specimens to State Public Health Laboratories
• Diagnostic Testing
• Testing at State Health Departments
• Antiviral Treatment
• Shipping Clinical Specimens to CDC

Background and Purpose

This document provides interim guidance for clinicians and public health professionals in the United States on appropriate testing, specimen collection and processing for patients who may be infected with novel influenza A viruses with the potential to cause severe illness in people. Examples of such viruses include Asian-lineage avian influenza A (H5N2), (H5N8), and (H5N1)¹ viruses, which were detected in wild and domestic birds in North America in December 2014 and January 2015; these viruses may have some or all of their genes from Asian avian influenza viruses, but for simplicity will all be referred to as “newly detected avian influenza A H5” viruses in this guidance document. Other newly detected avian influenza A H5 viruses also may have the potential to cause severe disease in humans. For a list of avian influenza A H5 virus infections identified in birds in the United States, and their locations, please see an update on avian influenza findings maintained by the US Department of Agriculture. CDC will update this guidance as additional information becomes available.

The appearance of newly detected avian influenza A H5 viruses in North America may increase the likelihood of human infection with these viruses in the United States. Because these newly identified avian influenza A H5 viruses are related to avian influenza A viruses associated with severe disease in humans (e.g., highly pathogenic Asian-lineage avian influenza A (H5N1) virus), they should be regarded as having the potential to cause severe disease in humans until shown otherwise. Other CDC guidance provides recommendations for influenza viruses known to be associated with severe disease in humans.

¹ The H5N1 virus isolated in the United States in January 2015 is a new mixed-origin virus (a “reassortant”) that is genetically different from the H5N1 virus found in several other countries (notably in Asia and Africa), which has caused human infections with high mortality. Although it is related to the H5N1 virus that has caused human infections with high mortality, the ability of this new reassortant H5N1 virus to cause severe disease is currently unknown.

Recommendations for Surveillance, Testing, and Investigation

Clinicians and public health personnel should consider the following recommendations for surveillance and testing:

1. Consider the possibility of infection with novel influenza A viruses with the potential to cause severe disease in humans in patients with medically-attended influenza-like illness (ILI) and acute respiratory infection (ARI) who have had recent contact¹ (<10 days prior to illness onset) with sick or dead birds in any of the following categories²:
   1. Domestic poultry (e.g., chickens, turkeys, ducks)
   2. Wild aquatic birds (e.g., ducks, geese, swans)
   3. Captive birds of prey (e.g., falcons) that have had contact with wild aquatic birds
2. If infection with a novel influenza A virus with the potential to cause severe disease in humans is possible, respiratory specimens should be collected with appropriate infection control precautions and sent to the state or local health department for immediate testing (see guidance below).
3. If infection with a novel influenza A virus with the potential to cause severe disease in humans is suspected, state health departments are encouraged to initiate a public health investigation with animal health partners and should notify CDC promptly.

¹ Contact may include: direct contact with birds (e.g., handling, slaughtering, defeathering, butchering, preparation for consumption); or direct contact with surfaces contaminated with feces or bird parts (carcasses, internal organs, etc.); or prolonged exposure to birds in a confined space.

² For questions or concerns about possible human infection in patients with exposures to birds not listed here, please contact CDC. Exposures that occur in geographic regions in the United States where newly detected avian influenza A H5 viruses have been identified are of most concern.

When Specimens Should Be Collected

The duration of shedding of novel influenza A viruses in humans is largely unknown, and there are currently limited data describing prolonged shedding of people infected with these viruses. Therefore, the estimated duration of viral shedding is based upon seasonal influenza virus infection. Specimens should be obtained for novel influenza A virus testing as soon as possible after illness onset, ideally within 7 days of illness onset. However, as some persons who are infected with seasonal influenza viruses are known to shed virus for longer periods (e.g., children and immunocompromised persons), specimens should be tested for novel influenza A virus even if obtained after 7 days from illness onset. Note that prolonged shedding of influenza virus in the lower respiratory tract has been documented for critically ill patients with highly-pathogenic avian influenza A H5N1 virus and avian influenza A H7N9 virus infections.

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