Influenza Update for the 2020 - 2021 Flu Season
Key Points
Key Points
- Seasonal influenza A and B virus epidemics are associated with significant morbidity and mortality each year in the United States and worldwide. During 2010-2019, annual seasonal influenza epidemics of variable severity were associated with an estimated 9.3 million to 45 million illnesses, 140,000 to 810,000 hospitalizations, and 12,000 to 61,000 deaths in the U.S. Source: [ cdc.gov/flu/about/burden/index.html ]
- Most people recover from uncomplicated influenza, but influenza can cause complications that result in severe illness and death, particularly among very young children, older adults, pregnant and postpartum women within 2 weeks of delivery, people with neurologic disorders, and people with certain chronic medical conditions including chronic pulmonary, cardiac, and metabolic disease, and those who are immunocompromised.
- Early treatment with antivirals reduces the duration of symptoms and risk of some complications (bronchitis, otitis media, and pneumonia) and hospitalization, and may decrease mortality among high-risk populations.
- Annual vaccination is the best method for preventing or mitigating the impact of influenza, but in certain situations chemoprophylaxis with antiviral medications can be used for pre-exposure or post-exposure prevention and can help control outbreaks in certain populations.
- Because prevention and control of influenza is a dynamic field, clinicians should consult the website of the Centers for Disease Control and Prevention (CDC) [ cdc.gov/flu/index.htm ] for the latest information about influenza vaccines, influenza tests, and approved antiviral medications.
Testing and Treatment of Influenza When SARS-CoV-2 and Influenza Viruses are Co-circulating
- Consolidated Clinical Algorithm for Outpatient Clinic or Emergency Department Patients with Acute Respiratory Illness Symptoms (With or Without Fever): cdc.gov/flu/professionals/diagnosis/testing-guidance-for-clinicians.htm
- Clinical Algorithm for Outpatient Clinic or Emergency Department Patients with Acute Respiratory Illness Symptoms (With or Without Fever) Not Requiring Hospital Admission: cdc.gov/flu/professionals/diagnosis/testing-guidance-for-outpatient.htm
- Clinical Algorithm for Patients with Acute Respiratory Illness Symptoms Requiring Hospital Admission (With or Without Fever): cdc.gov/flu/professionals/diagnosis/testing-guidance-for-clinicians-hospitaized.htm
- Testing and Management Considerations for Nursing Home Residents: cdc.gov/flu/professionals/diagnosis/testing-management-considerations-nursinghomes.htm
- NIH COVID-19 Treatment Guidelines on Influenza and COVID-19: covid19treatmentguidelines.nih.gov/special-populations/influenza/
Prevention
...vention...
...e 1. Influenza Vaccines — United...
...Contraindications and Precautions to the Use o...
...e 3. Dose Volumes for Inactivated...
...re 1. Influenza Vaccine Dosing Alg...
...vention...
...oprophylaxis...
Antiviral drugs should NOT be used for r...
Clinicians can consider antiviral chemoprop...
Clinicians can consider antiviral chemop...
...linicians can consider short-term antiviral chemo...
...linicians can consider short-term antiviral chem...
...Clinicians can consider educating...
...icians should use an NAI (oral oseltamivir or inh...
...cians should administer pre-exposur...
...ians should test for influenza and switc...
...can consider post-exposure antiviral che...
...n consider post-exposure antiviral chemoprophylax...
...ans can consider educating patients an...
...If chemoprophylaxis is given, clinicians...
...Clinicians should not administer onc...
...ns should administer post-exposure antiviral...
...ans should test for influenza and switch to ant...
...ans should administer an NAI (inhaled z...
Treatment
...atment...
Antiviral Dosing
...f any age who are hospitalized with influen...
...Outpatients of any age with severe or...
...tpatients who are at high risk of complicatio...
...younger than 2 years and adults ≥65 yea...
...nt women and those within 2 weeks postp...
...Outpatients with illness onset ≤2 days before...
...Symptomatic outpatients who are h...
...atic healthcare providers who care for pati...
...reatment for Suspected or Confirmed I...
...Clinicians should start antiviral treatmen...
...nicians should NOT routinely use higher...
...inicians should treat uncomplicate...
...cians can consider longer duration of antivir...
...erial Coinfection...
...nicians should investigate and emp...
...ians should investigate and empirica...
...nicians can consider investigating bacterial co...
...iviral Failu...
...should investigate other causes besides...
Antiviral-resistant Infection Testin...
...who develop laboratory-confirmed influen...
...with an immunocompromising condition...
...ients with laboratory-confirmed influenza who i...
...ith severe influenza who do not imp...
...s should remain informed on current CDC and W...
...ctive Therapy...
...should NOT administer corticosteroid adjun...
...should NOT routinely administer immunomodula...
...able 4. Antiviral Agents and Dosing Recommendation...
Institutional Outbreak Control
...ional Outbreak Control...
...tutional Outbrea...
...surveillance for additional cases should be i...
...eak control measures should be impl...
...ementation of outbreak control measures can b...
...n an influenza outbreak has been iden...
...mpiric antiviral treatment should be administered...
...chemoprophylaxis should be administer...
...moprophylaxis should be administere...
...s can consider antiviral chemoprophylaxis fo...
...ans can consider antiviral chemoprophyl...
Clinicians can consider antiviral chemo...
...Clinicians should administer antivira...
...e 5. Control Measures for Managing In...
Diagnosis
Diagnos...
...sting
...utpatients (including emergency depar...
...icians should test for influenza in high-risk pati...
...uld test for influenza in patients who p...
...can consider influenza testing for p...
...nfluenza activity without any link to an in...
Hospitalized P...
...ians should test for influenza on ad...
...icians should test for influenza on...
...hould test for influenza on admission in all...
Clinicians should test for influenza in all p...
...s should test for influenza on admission...
...nicians can consider testing for influ...
...ble 6. Signs and Symptoms of Uncomplicated In...
...nical Manifestations and Complications Associa...
...ons Who Are at High Risk of Complications...
...Groups in Whom to Consider a Diagnosis of Influenz...
Table 10. Influenza Diagnostic Tests for Respirato...
...plex Assays Authorized for Simultaneous Det...
...able 12. Interpretation of Influenza Testing Resul...
...ble 13. List of Differential Diagnoses to Conside...
Figure 2. Guide for Considering Influe...
...pecimen...
...should collect upper respiratory tract sp...
...ns should collect nasopharyngeal (optimal...
...hould collect endotracheal aspirate or bronchoalve...
Clinicians should NOT collect or...
...ns should NOT collect serum specimens, including...
...ostic Tests...
...ians should use rapid molecular assays (i.e., nu...
...cians should use reverse-transcription polymeras...
...linicians should use multiplex RT-PCR assays t...
...ians can consider using multiplex RT-...
...should NOT use immunofluorescence assays for...
...llow-up testing with RT-PCR or othe...
...d NOT use RIDTs in hospitalized patients excep...
...w-up testing with RT-PCR or other mo...
Clinicians should NOT use viral culture fo...
...ulture can be considered to confirm n...
...ns should NOT use serologic testing for dia...