Guidance for Ambulatory Care of Influenza-Like Illness in the context of Pandemic (H1N1) 2009 influenza virus

Revised: March 23, 2010

This guidance is based on current, available scientific evidence and expert opinion about this emerging virus and is subject to review and change as new information becomes available. It should be read in conjunction with relevant provincial and territorial guidance documents. The Public Health Agency of Canada will be posting regular updates and related documents at www.phac-aspc.gc.ca.

Introduction

This guidance document has been prepared by the Public Health Agency of Canada (PHAC) to assist clinicians in the management of patients presenting with clinical influenza-like illness (ILI) symptoms in an ambulatory care setting in the context of pandemic (H1N1) 2009 virus (pH1N1). Please note that this document replaces previous versions of the guidance for clinicians in Ambulatory Care Settings. The following guidance should be read in conjunction with the information contained in the Clinical Recommendations for Patients Presenting with Respiratory Symptoms During the 2009-2010 influenza season^[1], Annex E of the Canadian Pandemic Influenza Plan^[2] and H1N1 PHAC Guidelines for Health Professionals.^[3] This document provides information related to infection prevention and control measures, clinical assessment, laboratory testing and ongoing collaboration with public health and clinical management.

Background

The pH1N1 virus continues to circulate in Canada and around the world. Recent evidence suggests that pH1N1 has an incubation period of approximately 4 days, with a range of 1-7 days. The period of communicability is 7 days in uncomplicated cases. This may be longer in children (up to 10 days) and other individuals in whom symptoms and viral shedding may persist (i.e. those who are immunocompromised or severely ill). Consistent with seasonal influenza, transmission is most likely during the initial days of infection when the individual is symptomatic and has a high viral load. To date, the pH1N1 virus has spread almost exclusively in the community setting. It generally causes a mild disease. However, patients who initially present with uncomplicated influenza may progress rapidly to more severe disease. Although the majority of patients who progress to severe illness have underlying risk factors for complications, recent data indicates that approximately one third of ICU cases in Canada did not have any underlying medical conditions.^[4]

Infection Prevention And Control

Initial triage

It is recommended that all patients who present to a primary care setting should be screened for fever and respiratory symptoms. This includes passive screening (e.g. posters that alert patients to report cough and fever) and/or active screening (e.g. reception staff asking about fever and respiratory symptoms).

Infection prevention and control for patients

Patients who report fever and respiratory symptoms may be instructed to:

1. perform hand hygiene using either 60-90% alcohol-based hand rub or soap and water,
2. employ respiratory hygiene practices: cough into sleeve; use tissues to control secretions (including proper disposal); wear a surgical or high-quality procedure mask if tolerated,
3. sit at least 2 metres (6 feet) away from others. If this is not possible in the waiting room setting, it is recommended that the patient be moved immediately to an examining room.

Routine practices and contact precautions for clinicians
Before a clinical assessment, it is recommended that clinicians:

1. perform hand hygiene using either 60-90% alcohol-based hand rub or soap and water,
2. put on gloves; wear a gown only when there is a risk of clothing or skin contamination, and
3. wear a surgical mask and eye/face protection (goggles, safety glasses or face shield) to prevent droplet contamination. An N95 respirator is recommended when a patient is coughing forcefully and unable or unwilling to wear a surgical or high-quality procedure mask and/or when there is a risk of aerosol transmission, such as during an aerosol-generating medical procedure (AGMP).^{[5] ±}

During a clinical assessment, it is recommended that clinicians:

1. ensure coughing patients continue to wear a surgical mask over their nose and mouth. If a nasopharyngeal swab is indicated, the mask can be temporarily lowered to expose the nose while still covering the mouth to provide protection if the patient coughs.

After a clinical assessment, it is recommended that clinicians:

1. remove gloves and gown before leaving room and dispose in hands-free waste receptacle;
2. after leaving room, remove eye or face protection first, then remove mask by the straps (do not touch mask) and dispose of in hands-free waste receptacle or separate receptacle for reprocessing.
3. perform hand hygiene before and after removing mask, respiratory protection and face/eye protection and after leaving the patient’s care area
4. ensure surfaces that have been touched by the patient or that are within droplet range are cleaned with a hospital-grade cleaning and disinfecting agent.

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Clinical Assessment

Clinical assessment of ILI, in the context of pH1N1 and other viruses of concern, requires ongoing knowledge of which respiratory viruses are circulating in the community. This information can be obtained through local/regional public health authorities or by assessing the geographic map of influenza in the weekly FluWatch reports.^[6] Although the pH1N1 virus is expected to predominate, seasonal H1N1, H3N2 and other respiratory viruses may also circulate during the 2009-10 influenza season.

History

It is recommended that patients presenting with respiratory symptoms should be assessed for the clinical features of ILI which may include the following symptoms:

Atypical presentations of pH1N1 are most common in infants, the elderly and immunocompromised persons. People with chronic lung conditions may present with a new or worsening cough. Those over age 65 may present without fever and rarely have GI symptoms.

It is advised that clinicians enquire about contact with ill people; it may reveal an unusual cluster of cases (such as a school outbreak) that would increase the possibility of infection with the H1N1 flu virus. An occupational history may be relevant in the case of laboratory personnel who work directly with influenza or other respiratory viruses, and health care workers exposed to patients linked to a community or health care facility outbreak.

If the patient is found to have the clinical features of ILI and pH1N1 is known to be circulating in the community, it is recommended that the clinician further assess for the presence of risk factors for complications from influenza and/or severity indicators, as listed below. The risk factors are based on Canadian and international epidemiologic data related to the pH1N1 virus.

Patients who initially present with uncomplicated influenza may progress rapidly to more severe disease. Severe or progressive disease requires immediate medical attention and hospitalization. Severity indicators and signs of disease progression are listed below.

Laboratory Best Practices

Collection of a nasopharyngeal (NP) swab for viral diagnosis is appropriate when assessing treatment decisions in the following situations: in patients who may require hospitalization; those with ILI who have been on prophylaxis; or when there is no response to treatment. Throat and nasal swabs may be accepted by some laboratories but are generally not recommended. Decisions to test for viruses may be affected by epidemiological factors (e.g., sudden onset of cough and fever in the summer may warrant a test but not in the middle of flu season). It is recommended that clinicians ensure that both the specimen and the requisition are clearly labeled and clinical symptoms are noted on the laboratory requisition. NP swabs should be sent for RT-PCR testing at a public health laboratory or tertiary care hospital as directed by local or regional public health authorities. In critically ill patients, NP swabs may be negative and an endotracheal aspirate is indicated. Point of care (POC) tests are generally not recommended due to their low sensitivity (i.e. high false negative rate) but may be useful in detecting pH1N1 outbreaks in remote and isolated communities.

Collaboration With Public Health

Clinicians are advised to report any respiratory infections of concern, such as severe disease or unusual clusters of illness, to local public health authorities. Surveillance of H1N1 flu virus and any other respiratory viruses of concern will be addressed through the enhanced FluWatch^[6] program which includes laboratory testing by sentinel physicians in the community.

Clinical Management

For otherwise healthy patients, with ILI and no risk factors, the basic therapy is supportive. It is recommended that these individuals self-isolate until they are feeling well and able to fully participate in all normal day to day activities. It is advised that the patient be reminded to use good respiratory and hand hygiene practices. Patients need to be informed of the risk of rapid deterioration and to seek reassessment if their symptoms worsen. The antivirals that have been found to be effective for pH1N1 are oseltamivir (Tamiflu^®)^[7] for adults and children of all ages and zanamivir (Relenza^®)^[8] for adults and children age 7+. For oseltamivir (Tamiflu^®) dosing recommendations for children under the age of one, refer to the Guidance for expanded use of Tamiflu^® for children under one year of age.^[9]

Treatment with antivirals is recommended for persons with ILI in the following circumstances:

• If the patient presents with any severity indicators, antiviral medications and hospitalization are needed.
• If the patient has any of the risk factors or ‘other considerations’ (see Clinical Assessment), antivirals and close follow up are indicated.
• For all children under 2 years of age.
• For children 2-5 years of age with any other risk factors.
• For children aged 2-5 with no other risk factors; clinical discretion regarding treatment is indicated.

Antiviral medications are most effective if started within 24-48 hours of the onset of symptoms. Post-exposure prophylaxis is generally not recommended in Canada although is recommended in the control of outbreaks in closed facilities.^[10]

Adverse reaction reporting

Reports of adverse reactions to antiviral medications are an important source of information that will help guide their safest and most effective use. Please promptly report any suspected serious adverse reactions involving an antiviral medication as per local or provincial/territorial requirements to Health Canada at: Adverse Reaction Reporting, Marketed Health Products or call: 1-866-234-2345.

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