Influenza Management

Evaluation 

Clinical Presentation of Seasonal Influenza

The typical signs and symptoms of seasonal influenza include an abrupt onset of fever, severe myalgia and/or arthralgia, severe dry cough, pleuritic chest pain, loss of appetite, abdominal pain, diarrhea, headache, malaise, fatigue, sore throat, and rhinitis.  

Physical examination of patients with seasonal influenza may present with flushing, pain on eye movement, nonexudative pharyngitis, and scattered rales or rhonchi. Elderly patients may have hot, dry, or diaphoretic skin.  

Clinical Presentation of Zoonotic Influenza

Avian Influenza A(H5N1) Should Be Suspected in the Following:

• Documented temperature of >38°C and 
•   ≥1 of the following: Cough, sore throat, and/or shortness of breath and
•   Contact history:
  • History of contact with sick or dead poultry, family members with suspected or confirmed H5N1 infection, healthcare workers of suspected or confirmed H5N1 patients, laboratory workers handling specimens or viral cultures of H5N1 viruses
  • History of living in an endemic area or an environment with sick or dead poultry
  • If the patient only has a history of travel to endemic areas, a risk assessment will need to be individualized

Avian Influenza A (H7N9)  

Avian influenza A (H7N9) is a subtype of influenza virus first reported in March 2013 in China. Transmission is by direct contact with infected poultry or exposure to the environment of infected poultry. No human-to-human transmission has been recorded yet. Signs and symptoms are the same as seasonal influenza, but it is most often accompanied by a history of severe pneumonia.  

Other Reported Presentations of Avian Influenza in Humans  

Other presentations include typical influenza-like symptoms (abrupt onset with headache, high-grade fever, sore throat, chills, dry cough, malaise, myalgia, anorexia), dyspnea or bloody sputum, chest pain, bleeding from the nose and gums, gastrointestinal upset (vomiting, diarrhea, abdominal pain), neurological symptoms (eg stupor, convulsions), conjunctivitis, pneumonia or pneumonitis, and acute respiratory distress.

Management Decision

The initial management of influenza in adults is based on clinical presentation and epidemiological data. 

Seasonal Influenza*  

Seasonal influenza may present as a mild respiratory illness similar to the common cold or it may present without any characteristic signs and symptoms. Diagnosis based on typical symptoms may be difficult because other pathogens cause similar symptoms. Identification is made easier when it is known that the influenza virus is present in the community.  

Course of Illness  

The course of illness for uncomplicated influenza typically resolves for most patients after 3 to 7 days. Cough and malaise can persist for more than 2 weeks.  

*Please see Etiology and Laboratory Tests and Ancillaries for further information.

Avian Influenza*  

During the initial stages of illness that are caused by avian influenza infection, the clinical examination does not accurately distinguish it from other causes of community-acquired pneumonia, influenza-like illness, acute gastroenteritis, or acute encephalitis.  

Course of Illness  

The course of illness of avian influenza often presents as a rapidly progressive pneumonia with respiratory failure ensuing over several days. Hospital care is warranted during the initial stages. The incubation period for human H5N1 and H7N9 infection following exposure to infected poultry is ≤7 days and is often 2-5 days.  

Risk Stratification  

High-risk exposure groups are currently defined as household or close family contacts of a strongly suspected or confirmed H5N1 patient because of potential exposure to a common environmental or poultry source as well as exposure to the index case.  

Moderate-risk exposure groups are currently defined as personnel handling sick animals or decontaminating affected environments (including animal disposal) if personal protective equipment is not used properly. Individuals with unprotected and very close direct exposure to sick or dead animals infected with the H5N1 virus or to particular birds that have been directly implicated in human cases are likewise considered under moderate-risk exposure groups. Healthcare personnel in close contact with strongly suspected or confirmed H5N1 patients such as during intubation or performing tracheal suctioning, delivering nebulized drugs, or handling inadequately screened or sealed body fluids without any or with insufficient personal protective equipment is also under moderate-risk exposure groups. This group also includes laboratory personnel who might have unprotected exposure to virus-containing samples.  

Low-risk exposure groups are currently defined as healthcare workers not in close contact (distance >1 m) with a strongly suspected or confirmed avian influenza patient and having no direct contact with the infectious material from that patient. Healthcare workers who used appropriate personal protective equipment during exposure to infected patients, personnel involved in culling non-infected or likely non-infected animal populations as a control measure, and personnel involved in handling sick animals or decontaminating affected environments (including animal disposal), who used proper personal protective equipment are also considered as low-risk exposure groups.  

*Please see Etiology and Laboratory Tests and Ancillaries for further information.

Pharmacological therapy 

Symptomatic Therapy

Fever and myalgia may be treated with analgesics (non-opioids) and antipyretics (eg Paracetamol). Avoid salicylates in children ≤18 years of age because of the risk of Reye’s syndrome. Cough and colds may be treated with cough and cold preparations (eg expectorants, mucolytics).  

Antivirals for Seasonal Influenza

Prophylaxis

Antiviral agents (eg Baloxavir marboxil, Oseltamivir, Zanamivir) may be used to prevent the spread of influenza among unvaccinated high-risk household members and during an influenza outbreak in an institutionalized setting. 

They may be used in persons who cannot be vaccinated due to contraindications to the vaccine and do not start until the influenza epidemic has begun and stop only when the epidemic is over. They may also be used in persons at high risk for complications who have been vaccinated after an outbreak of influenza begun but should be given for 2 hourly starting from the day of vaccination to give sufficient time for immunity to develop. 

Treatment 

Empirical antiviral treatment should be started as soon as possible for all patients with progressive disease highly suspected of influenza, and those at high risk for complications, regardless of illness duration and even without influenza test results. When used within 48 hours of symptom onset, antiviral agents may reduce the duration of symptoms. They should not be used if there is uncertainty about the diagnosis or if a bacterial infection cannot be ruled out. Data are limited concerning the effectiveness of the antiviral agents for the treatment of patients at high risk of serious complications of influenza. 

Baloxavir marboxil 

Baloxavir marboxil is the first approved influenza virus-specific enzyme polymerase acidic (PA) protein-targeting drug used for the treatment of acute uncomplicated seasonal influenza in patients ≥12 years old who exhibited symptoms for no more than 48 hours. It may also be used as a single-dose post-exposure prophylaxis agent in children ≥12 years of age. Based on several studies, the therapeutic effect of a single dose of Baloxavir marboxil is comparable to that of the 5-day twice-daily treatment with Oseltamivir. 

M2 Inhibitors

Example drugs: Amantadine, Rimantadine  

M2 inhibitors are active against influenza A viruses, but not against influenza B viruses. High resistance to adamantanes is continuing among influenza A (H3N2) and influenza A (H1N1) pdm09 viruses. Thus, Amantadine and Rimantadine are not recommended for treatment and chemoprophylaxis of currently circulating influenza A viruses.  

Its effect as a treatment is apparent when used within 48 hours of illness onset in otherwise healthy adults as it can reduce the duration of uncomplicated influenza. As chemoprophylaxis, both drugs are 70-90% effective in preventing illness from influenza A infection. They prevent illness while allowing subclinical infection and the development of protective antibodies. Additionally, therapy does not interfere with the antibody respiratory response to the vaccine.  

The incidence of central nervous system (CNS) side effects is higher among persons taking Amantadine than those taking Rimantadine.  

Neuraminidase Inhibitors

Example drugs: Oseltamivir, Peramivir, Zanamivir  

Oral Oseltamivir and inhaled Zanamivir are used for the treatment and prophylaxis of infection with influenza A or B viruses. IV Peramivir is used for the treatment of influenza A and B viruses, especially for those who are intolerant to oral medications. Combination treatment with neuraminidase inhibitors is not recommended.  

As a treatment, they can reduce the duration of uncomplicated influenza A and B illness by approximately 1 day compared with a placebo when used within 2 days of illness onset. Both drugs are effective, 82% Oseltamivir and 84% Zanamivir, in preventing febrile, laboratory-confirmed influenza illness in otherwise healthy individuals. As chemoprophylaxis, the experience in preventing the spread of influenza within institutions is limited when compared to the M2 inhibitors.

Antivirals for Avian Influenza

Prophylaxis  

In areas where neuraminidase inhibitors are not available, Amantadine or Rimantadine might be administered for chemoprophylaxis if local surveillance data show that the virus is known or likely to be susceptible to these drugs among high- or moderate-risk exposure groups. In low-risk exposure groups, Amantadine and Rimantadine should not be administered for chemoprophylaxis. In pregnant women, Amantadine and Rimantadine should not be administered for chemoprophylaxis as well. In the elderly, people with impaired renal function, and individuals receiving neuropsychiatric medication, or with neuropsychiatric or seizure disorders, Amantadine should not be administered for chemoprophylaxis.  

Treatment  

It is recommended that treatment with a neuraminidase inhibitor is started as early as possible in the clinical course. Data regarding the effectiveness of these antiviral medications against H5N1 infections is limited.  

Oseltamivir  

Oseltamivir is the primary antiviral agent of choice for the treatment of influenza A(H5N1) and A(H7N9) virus infections. The cultivable virus generally disappears within 2 to 3 days after initiation of Oseltamivir among avian influenza survivors, although clinical progression has been reported. The standard duration of therapy is 5 days but may be extended to 10 days if with no clinical improvement.  

Other Neuraminidase Inhibitors

Example drugs: Peramivir, Zanamivir  

Peramivir and Zanamivir are highly active in vitro and in animal models, including those that are due to the Oseltamivir-resistant influenza A(H5N1) virus.  

Orally inhaled Zanamivir has low systemic absorption and may not be useful if extrapulmonary dissemination has occurred. Intravenous Zanamivir may be considered for inpatients with suspected or confirmed resistance to Oseltamivir and Peramivir therapy. Zanamivir monotherapy is associated with a rapid emergence of resistance. 

They may be used as an off-label treatment option in patients with confirmed or strongly suspected infection if Oseltamivir is unavailable especially if the virus is known or likely to be susceptible. 

M2 Inhibitors

Example drugs: Amantadine, Rimantadine  

Early Amantadine treatment of patients with adamantane-susceptible influenza A(H5N1) virus infections in Hong Kong in 1997 may have been associated with clinical benefit. They are not recommended for patients with avian influenza A(H7N9) virus infection and should only be considered in H5N1 influenza as a treatment option if with treatment failure after neuraminidase inhibitors.

Combination Therapy  

Combinations of Oseltamivir and M2 inhibitors have enhanced antiviral activity and reduced the emergence of resistance. It demonstrated greater antiviral effects and increased survival compared to monotherapy in animal models. In areas where neuraminidase inhibitors are available, in high-risk exposure groups, including pregnant women, Oseltamivir should be administered as chemoprophylaxis continuing for 7-10 days after the last exposure. Zanamivir could be used in the same way as an alternative. In moderate-risk exposure groups, including pregnant women, Oseltamivir might be administered as chemoprophylaxis continuing for 7-10 days after the last exposure. Zanamivir might be used in the same way. In low-risk exposure groups and pregnant women, Oseltamivir or Zanamivir should not be administered for chemoprophylaxis. Amantadine or Rimantadine should also not be administered as chemoprophylaxis.

Nonpharmacological

Rest is recommended for patients with influenza. Strenuous physical activities (eg running) should be avoided until complete recovery. Patients are advised not to go to work or school and to avoid crowded places to reduce transmission. They may return to full activity gradually after the illness has resolved, especially if it has been severe. 

Advise patients to wear masks in public areas, cover their nose or mouth when coughing or sneezing, and perform frequent hand washing. Advise patients that adequate fluid intake is necessary to prevent dehydration and that adequate nutrition will assist in recovery. Advise the patient, if necessary, to stop smoking.

Other Therapy: Supportive Therapy for Hospitalized Patients

Oxygen (O₂) Therapy  

Administer oxygen by face mask rather than nasal prongs. The goal is to maintain >80 mmHg partial arterial pressure of oxygen (PaO₂) and >90% (95% for pregnant women) oxygen saturation (SaO₂).  

Continuous oxygen therapy is indicated for patients with PaO₂ of <80 mmHg, hypotension, metabolic acidosis with bicarbonate of <18 mmol/L, or respiratory distress with a respiratory rate of >24 breaths per minute.  

As a caution, the use of nebulizers and high airflow oxygen masks have been potentially implicated in the nosocomial spread of severe acute respiratory syndrome. Use these measures only if clinically justified and apply them under strict infection control including airborne transmission precautions. 

Hydration and Nutrition  

It is vital to assess volume depletion in patients with influenza and consider administering intravenous (IV) fluids if necessary. Patients who are hospitalized for prolonged periods may require increased nutritional support (enteral, parenteral). 

Prevention

Influenza Vaccines

The following recommendations apply to seasonal influenza only; vaccines against avian influenza are still being developed.  

Vaccines are the primary preventive measure against influenza, and it decreases morbidity and mortality caused by influenza. It is vital in reducing the impact of influenza-related respiratory illnesses on the population and resulting burdens on the healthcare system during the COVID-19 pandemic. Vaccines used should comply with the current WHO recommendations.  

Influenza vaccine should be given annually for persons ≥6 months with no contraindication/s to any of its components. An age-appropriate formulation of inactivated influenza vaccine (IIVs), recombinant influenza vaccine (RIV), or live attenuated influenza vaccine (LAIV) should be given.  

Special populations that may be given the influenza vaccine include those with a history of egg allergy who only have hives after exposure, those with a history of egg allergy other than hives (ie angioedema, lightheadedness, recurrent emesis, respiratory distress, and those who required Epinephrine or other emergency medical intervention), and pregnant women including those who want to become pregnant.  

Patients with a history of egg allergy of any severity may receive any licensed, recommended, and age-appropriate IIV, RIV4, or LAIV4 influenza vaccine but should be observed for 15 minutes post-vaccination to reduce the risk of injury in patients who experience syncope. Severe allergic reaction is a contraindication for vaccination with any form of influenza vaccine. 

Composition  

For the 2023/2024 northern hemisphere flu season, the recommended egg-based trivalent vaccine should contain an A/Victoria/4897/2022 (H1N1)pdm09-like virus, an A/Darwin/9/2021 (H3N2)-like virus, and a B/Austria/1359417/2021 (B/Victoria lineage)-like virus. Quadrivalent vaccines will contain the mentioned three viruses, plus a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.  

For the 2023/2024 northern hemisphere flu season, the recommended cell culture- or recombinant-based trivalent vaccine should contain an A/Wisconsin/67/2022 (H1N1)pdm09-like virus, an A/Darwin/6/2021 (H3N2)-like virus, and a B/Austria/1359417/2021 (B/Victoria lineage)-like virus. Quadrivalent vaccines will contain the mentioned three viruses, plus a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.  

For the 2023 southern hemisphere flu season, the recommended egg-based trivalent vaccine should contain an A/Sydney/5/2021 (H1N1)pdm09-like virus, an A/Darwin/9/2021 (H3N2)-like virus, and a B/ Austria/1359417/2021 (B/Victoria lineage)-like virus. Quadrivalent vaccines will contain the mentioned three viruses, plus a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.

For the 2023 southern hemisphere flu season, the recommended cell- or recombinant-based trivalent vaccine should contain an A/Sydney/5/2021 (H1N1)pdm09-like virus, an A/Darwin/6/2021 (H3N2)-like virus, and a B/ Austria/1359417/2021 (B/Victoria lineage)-like virus. Quadrivalent vaccines will contain the mentioned three viruses, plus a B/Phuket/3073/2013 (B/Yamagata lineage)-like virus.  

LAIV4 is an option for patients ≥2-49 years of age without contraindications (eg anatomic and functional asplenia, cerebrospinal fluid leak, cochlear implants).

Trivalent Flu Vaccines  

Trivalent flu vaccines contain two type A strains and one type B strain of influenza. The standard-dose trivalent shots (IIV3) are manufactured using virus-grown eggs and are recommended for 18 to 64 years old. The high-dose trivalent shot is approved for people ≥65 years of age. The trivalent shot with adjuvant is also approved for people ≥65 years of age.  

Quadrivalent Flu Vaccines  

Quadrivalent flu vaccines contain two type A strains and two type B strains of influenza. Intradermal doses are approved for people 18 to 64 years of age. Two new quadrivalent vaccines (high-dose and standard dose with adjuvant) were recently approved by the United States Food and Drug Administration for patients ≥65 years of age. The quadrivalent flu shot with a virus grown in cell culture is recommended for children ≥4 years of age.  

Coadministration with Other Vaccines  

IIVs and RIV4 may be administered simultaneously or sequentially with other inactivated or live vaccines. LAIV4 may be administered simultaneously with other inactivated or live vaccines. For live vaccines given sequentially, an interval of at least 4 weeks is recommended. Current guidelines indicate that COVID-19 vaccines can be administered with influenza vaccines. 

Inactivated Influenza Vaccine (IIV)  

IIV is given intramuscularly and contains killed or inactivated viruses; hence it cannot cause influenza. It is licensed for use among persons aged >6 months, including those who are healthy and those with chronic medical conditions.  

In terms of effects, if the vaccine used contains the predominant circulating influenza strains, it can be 70-90% effective in preventing illness in healthy adults aged <65 years. It is approximately 50-77% effective when the vaccine strains were antigenically dissimilar to the majority of circulating strains.            

Patients with concurrent medical conditions may have a reduced rate of severe respiratory illness and death (up to 50%). The main benefit of vaccination in these patients is the prevention of severe consequences of infection rather than preventing uncomplicated illness. Vaccines that conform to international standards of purity and potency are usually free from systemic side effects. 

Live Attenuated Influenza Vaccine (LAIV4)  

LAIV is given intranasally and contains live attenuated viruses that may cause mild signs and symptoms. It is licensed for use among nonpregnant persons aged 2-49 years including healthcare personnel and other close contacts of high-risk persons (except severely immunocompromised persons who require care in a protected environment). It may be used postpartum and is recommended for healthy children 2 to 8 years with no contraindications or precautions. 

In terms of effects, it significantly reduces the incidence of severe febrile illnesses, number of sick days, frequency of physician visits, and antibiotic use. Effects include a 55% reduction in culture-confirmed influenza among children who received LAIV compared with those who received IIV, a 52% greater efficacy than TIV in preventing influenza among children aged 6-71 months who had previously experienced recurrent respiratory tract infection, and a 32% increased protection in preventing culture-confirmed influenza in children and adolescents aged 6-17 years with asthma. 

LAIV should not be used in children and adolescents who are receiving Aspirin or Aspirin-containing products, persons who have experienced severe allergic reactions to the vaccine or any of its components and previous dose of any influenza vaccine, pregnant women, immunosuppressed children and adults (includes immunosuppression caused by medication and human immunodeficiency virus [HIV]), caregivers and close contacts of immunocompromised individuals who require a protected environment, children 2 to 4 years with asthma or with a wheezing episode, and persons who took influenza antiviral medications within the previous 48 hours. 

Recombinant Influenza Vaccine (RIV)  

The RIV is a recently approved influenza vaccine that is neither inactivated nor weakened. It is recommended for patients aged ≥18 years allergic to egg protein with no other contraindications as it does not contain any egg protein. It uses recombinant DNA technology and an insect virus expression system to produce an egg protein-less vaccine against seasonal influenza.  

Recommendations for Influenza Vaccination and COVID-19  

Reducing the prevalence of influenza through vaccination may help the symptoms that are confused with those of COVID-19. For patients with mild or asymptomatic COVID-19, vaccination should be deferred to avoid confusing COVID-19 illness symptoms with postvaccination reactions. For patients with moderate to severe COVID-19, vaccination should be deferred until fully recovered. For individuals who are unvaccinated or partially vaccinated against COVID-19 with COVID-19 infection or had close contact exposure with a COVID-19-positive individual, influenza vaccination should be delayed until the quarantine or isolation period has been fulfilled. Symptomatic individuals should have fully recovered prior to going to a vaccination site.  

For patients already admitted to a healthcare facility, the following should be followed:

• Patients who have been fully vaccinated and with no known recent exposure to individuals with suspected or confirmed COVID-19 infection may proceed to receive the influenza vaccine
• Influenza vaccine may be given to patients in quarantine due to close contact exposure with a COVID-19-positive individual if another opportunity to be vaccinated is not likely; vaccination may be deferred until quarantine has been completed if possible symptoms of COVID-19 infection may cause diagnostic confusion
• Vaccination should be delayed for symptomatic individuals with suspected or confirmed COVID-19 infection until the criteria to discontinue isolation is fulfilled (at least 10 days after symptom onset and 24 hours afebrile without the use of fever-reducing medications) and COVID-19 symptoms are improving, and the person is no longer moderately to severely ill
• Vaccination may be given to asymptomatic or presymptomatic individuals with suspected or confirmed COVID-19 infection, or those who have fully recovered and are now asymptomatic, even if criteria to discontinue isolation has not been fulfilled, especially if another opportunity to be vaccinated is not likely 

Timing of Vaccination

During vaccination, it is essential to follow the local programs for control of priority diseases, if available.  

Timing of Seasonal Influenza Vaccination  

The influenza vaccine is administered yearly to provide optimal protection against influenza virus infection. Vaccine should be administered before influenza activity in the community begins and should commence throughout the flu season due to its varying duration.   

Vaccination campaigns may start earlier (July-August or as soon as vaccines are available) to ensure that there is sufficient time for the community to be vaccinated against influenza while adapting to the social distancing practices implemented in different countries to reduce the spread of SARS-CoV-2.   

Northern Hemisphere   

In the northern hemisphere, annual vaccinations are typically administered to high-risk individuals and their close contacts by the end of October. Vaccinations that are given in December or later might be considered in most influenza seasons. Influenza activity typically occurs from October to May.   

Southern Hemisphere   

In the southern hemisphere, annual vaccinations are typically administered to high-risk individuals and their close contacts between March to May. Influenza activity typically occurs from April to September.   

Tropical or Subtropical Regions   

In tropical or subtropical regions, laboratory-confirmed influenza can occur anytime throughout the year. The peaks of influenza activity can occur 1-2 times in a year. Epidemics often coincide with the rainy season. Public health programs where high-risk individuals and their close contacts are vaccinated should be performed at the same time each year if >1 peak of influenza activity occurs within a year. The latest available vaccine formulation should be used.   

Recommended Target Groups for Seasonal Influenza Vaccination 

For individual protection, the administration of seasonal influenza vaccination is recommended for the following persons at higher risk for complications secondary to severe influenza:

• All persons aged ≥6 months without contraindications
• Children aged 6-59 months
• Adults aged ≥50 years
• Those who are immunocompromised, including those caused by HIV and medications
• Individuals with chronic pulmonary (including asthma, chronic obstructive pulmonary disorder, cystic fibrosis), cardiovascular (congenital heart disease, congestive heart failure, coronary artery disease except for isolated hypertension), renal, hepatic, hematologic (sickle cell anemia), and metabolic disorders (including diabetes mellitus) 
• Individuals who are morbidly obese (ie body mass index [BMI] ≥40 kg/m²)
• Children and adolescents 6 months to 18 years of age currently receiving Aspirin- or salicylate-containing medications who will be at increased risk for Reye's syndrome after a bout of flu 
• Women anticipating pregnancy and pregnant women during the flu season
  • WHO considers the vaccine safe at any gestational age of pregnancy
• Poultry workers, pig farmers, and those in the pig-slaughtering industry
• Caregivers or other individuals who live with high-risk individuals (eg healthy household members and caregivers of high-risk individuals, healthcare workers)
• Residents of institutions for the physically and mentally disabled and other long-term care facilities
• Members of other groups are advised to consult their physician should they wish to obtain seasonal influenza vaccine

Infection Control or Isolation

Infection Control Measures for Outpatients  

It is highly advised that outpatients frequently wash their hands with soap and water, cover their nose and mouth when sneezing or coughing, and dispose of nasal and mouth discharge and used tissue papers properly. It is recommended that ill persons use surgical masks since paper masks are not recommended. All members of the household should be educated on personal hygiene and infection control measures (eg hand washing, use of surgical mask) and be advised to avoid sharing utensils, towels, and beddings between patients and others. Advise them to clean all environmental surfaces soiled by body fluids with a household disinfectant according to the manufacturer’s instructions and make sure to wear gloves during this activity.   

For adults, there should be restrictions on social contacts (patients should not go to work, school, or other public areas). Advise them to continue infection control precautions until 21 days after the resolution of fever and improved or absent respiratory symptoms.   

For children under 12 years, there should likewise be restrictions on social contacts (patients should not go to school or other public areas). Advise them to continue infection control precautions until 21 days after the resolution of fever and improved or absent respiratory symptoms.   

Household members or other close contacts of diagnosed avian influenza patients who develop fever or respiratory symptoms should immediately contact the local public health authority or WHO hotlines.   

Isolation Precautions for Hospitalized Patients  

Isolation precautions implemented for all hospitalized patients with confirmed or suspected influenza A should include standard, droplet, or airborne precautions.   

Standard precautions require scrupulous hand hygiene before and after patient contact along with appropriate use of gloves or gowns when needed. Droplet precautions require wearing a surgical mask if within 1 meter of the patient. Airborne precautions are controversial and are only warranted for selected patient care procedures. If available, place the patient in an airborne isolation room (ie monitored negative air pressure in relation to the surrounding areas with 6 to 12 air exchanges per hour). When entering the room, use a high-efficiency mask, if available, or a surgical mask.   

During isolation, restrictions should be followed. If a single room is not available, place patients separately in designated multibed rooms or wards. Beds should be placed 1 meter apart from other beds and preferably separated by a physical barrier (eg curtain or partition). Limit the number of healthcare workers who have direct contact with the patient. These healthcare workers should not look after other patients. Restrict the number of visitors and provide them with the appropriate personal protective equipment (mask, gown, gloves, face shield, or goggles) and instruct them in their use.   

Hospitalized patients discharged after less than 14 days should implement the necessary isolation precautions as mentioned above for outpatients.   

Clinicians should check with the local health authority for the latest updates because recommendations will change as new information becomes available.