Based on hospital laboratory and emergency department surveillance data, influenza and influenza-like illnesses (ILI) are increasing in Philadelphia (figure). Influenza A(H3N2), the predominant strain currently circulating is known to cause significant morbidity in children and adults 65 years and older. This season, roughly 50% of Philadelphians hospitalized for influenza are 65 years and older.
Vaccination and Treatment:
With the 2017-18 influenza season underway, the Philadelphia Department of Public Health Division of Disease Control (DDC) is reminding clinicians to continue to offer influenza vaccination to all patients 6 months and older. Vaccination remains the best form of prevention. Clinicians should also provide neuraminidase inhibitor antiviral treatment – oral oseltamivir (Tamiflu), inhaled zanamivir (Relenza), or intravenous peramivir (Rapivab) – to patients suspected of having or confirmed to have influenza, particularly persons requiring hospitalization, persons with severe or progressively worsening illnesses, and those at high risk for complications, including:
- Persons over 65 or under 2 years of age
- Pregnant women, or those who have given birth, or had a miscarriage or abortion in the previous 2 weeks
- Persons with metabolic disorders (including diabetes), chronic lung, heart, kidney, liver or blood disorders, neurological or neurodevelopmental conditions, morbid obesity (i.e., body-mass index ≥ 40)
- Persons who are immunocompromised (from illness or medications)
- Persons under 19 years who are on long-term aspirin therapy
- Residents of nursing homes and other chronic-care facilities
- American Indians/Alaska Natives
Antiviral treatment should be provided within 48 hours of symptom onset, though initiation of treatment after 48 hours can still provide modest benefit.
Diagnostic Testing and Reporting:
Recommended diagnostic tests include viral culture, rapid antigen testing, immunofluorescence, and molecular assays such as RT-PCR, and multiplex PCR. Rapid antigen diagnostic tests can have poor sensitivity and a negative result does not exclude a diagnosis of influenza in a sick patient. For hospitalized patients with suspected influenza or unexplained respiratory failure, molecular testing is recommended. However, decisions for treatment of any symptomatic patient should not wait for laboratory confirmation of influenza. Severe influenza cases (hospitalizations and fatalities), suspect novel influenza infection, and institutional outbreaks of respiratory illness should be reported to DDC at 215-685-6742. DDC can also assist with coordinating laboratory testing of specimens from suspected novel influenza A patients or specimens found to be influenza A non-subtypeable. For more information including testing algorithms, treatment recommendations, and local activity updates, please visit https://hip.phila.gov.
Originally released by the Philadelphia Department of Public Health on January 12, 2018.