This is an official

CDC HEALTH ADVISORY

Distributed via the CDC Health Alert Network

December 14, 2022, 4:00 PM ET

CDCHAN-00482

illnesses, 120,000 hospitalizations, and 7,300 deaths from influenza (Weekly U.S. Influenza Surveillance

Report | CDC). While the Food and Drug Administration (FDA) has not indicated shortages of oseltamivir

(generic or Tamiflu) in any of its forms (capsules, oral suspension), CDC has received numerous

anecdotal reports of availability issues for generic oseltamivir in some locations [1]. This may continue to

occur in some communities as influenza activity continues.

This Health Alert Network (HAN) Health Advisory provides clinicians and public health officials with

guidance for prioritizing oseltamivir for treatment and information on other influenza antivirals that are

recommended for treating influenza in areas where oseltamivir is temporarily unavailable.

and deaths, particularly among people at increased risk of complications such as older adults, very young

children, pregnant people, and people of all ages with certain chronic medical conditions [2].

Four FDA approved prescription antiviral medications (oseltamivir, baloxavir, zanamivir, and peramivir)

are available for use for early treatment of outpatients with influenza. These antivirals have different

formulations, routes of administration, dosing, duration of treatment, and recommendations for

administration by age group. The clinical benefit of antiviral treatment of influenza is greatest when

treatment is started early (within 2 days of illness onset) in people with mild, uncomplicated illness [3-4].

Oseltamivir treatment also is recommended as soon as possible for suspected or confirmed influenza

requiring hospitalization, and to help control institutional influenza outbreaks [4].

does not exclude COVID-19, and a positive SARS-CoV-2 test result without influenza testing does not

exclude influenza.

CDC recommends annual influenza vaccination of people aged 6 months and older as the first and most

important tool to prevent influenza [2]. For people aged 65 years and older, high-dose, recombinant, or

adjuvanted influenza vaccines are recommended if available [2]. Healthcare providers should strongly

encourage people who have not yet received influenza vaccination this season to get vaccinated as they

can still benefit.

used for early treatment of outpatients at increased risk for complications who present with

uncomplicated influenza, depending upon age and contraindications.

• When there is limited availability of oseltamivir or other antivirals, antiviral treatment should target

patients with influenza who are at the highest risk of severe disease and those who are

hospitalized.

• Antiviral treatment of outpatients should be prioritized for persons who test positive for influenza

within 2 days of illness onset.

• When there is limited availability of oseltamivir or other antivirals, patients with clinically mild

influenza who are otherwise healthy and not at increased risk of influenza complications can be

managed with supportive care without antiviral treatment.

• When there are limited supplies of antivirals, treatment of suspected influenza without a positive

test result should be limited to those who are being hospitalized with suspected influenza, or

patients highly suspected to have influenza (e.g., an ill patient who has a household member with

laboratory-confirmed influenza).

Clinicians, hospitals, healthcare systems, and public health officials are encouraged to use all available

information and their best judgment to prioritize oseltamivir and other antivirals for treating patients with

influenza, depending upon their local situation. The following are considerations for antiviral treatment

prioritization when antivirals such as oseltamivir are in short supply.

patients [4]. Because observational studies have shown that early initiation of oseltamivir

treatment has significant clinical benefit [5-7], oseltamivir treatment is recommended to

be started as soon as possible without waiting for results of influenza testing, such as in

the emergency department or in admitted patients with high suspicion for influenza.

o There are limited data for using inhaled zanamivir, intravenous peramivir, or baloxavir for

treating influenza in hospitalized patients.

o In a recent clinical trial, the addition of baloxavir to a neuraminidase inhibitor (primarily

oseltamivir) did not show clinical benefit compared to neuraminidase inhibitor treatment

alone in hospitalized patients with influenza aged 12 years and older [8].

Outpatients

Among outpatients, prioritize antiviral treatment for patients who test positive for influenza as follows:

o People with multiple conditions that place them at increased risk for complications from

influenza (e.g., several co-morbidities, age <2 years, and 65 years and older) and those

with severe uncontrolled chronic disease might be at highest risk of influenza

complications.

• Patients who have progressive or severe influenza not requiring hospitalization, even if

they test positive for influenza more than 2 days from illness onset.

• Patients who are pregnant, less than 2 weeks postpartum, or immunocompromised.

o Substantial data from observational studies indicate that oseltamivir treatment of

because the optimal duration of treatment is unknown and there is concern for

emergence of influenza viruses resistant to baloxavir during or after treatment.

• Children less than 5 years of age.

o Oseltamivir is the only recommended oral antiviral for treatment of influenza in children

less than 5 years of age.

o If oseltamivir suspension is unavailable for treating influenza in young children, clinicians

can request that pharmacists compound a suspension from oseltamivir capsules.

o In areas where generic oseltamivir is unavailable, baloxavir can be used for early

treatment of influenza in otherwise healthy children aged 5 years and older, and for

influenza in residents of congregate settings such as long-term care facilities (LTCFs),

who test positive for influenza.

• In the setting of laboratory confirmed influenza outbreaks in LTCFs:

o Early empiric antiviral treatment of suspected influenza in residents is recommended [4].

Once an influenza diagnosis is confirmed through testing, post-exposure antiviral

chemoprophylaxis of exposed residents is recommended [4].

o Because institutional outbreaks can be prolonged, consider using a limited duration

treatment dosage (twice daily for 5 days) for post-exposure oseltamivir instead of

extended use of oseltamivir chemoprophylaxis (once daily), with ongoing active daily

monitoring and influenza testing for all residents with new illness signs and symptoms.

o If oseltamivir is not available, baloxavir, zanamivir, or peramivir may be used for

treatment of influenza.

o Although baloxavir may be used for treatment, there are no available data on using

baloxavir in LTCFs for treatment or post-exposure chemoprophylaxis.

nasogastric tube. For hospitalized patients who cannot absorb enterically-administered

oseltamivir (e.g., due to gastric stasis, malabsorption, or gastrointestinal bleeding), or when

oseltamivir is not available, intravenous peramivir is an option.

double-blind, placebo-controlled, superiority trial. Lancet Infect Dis. 2022 May;22(5):718-730. DOI:

https://doi.org/10.1016/S1473-3099(21)00469-2