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Unvaccinated or <2wk after vaccination or unlikely to respond to vaccine If unvaccinated, <2wk since vaccination,1 or unlikely to respond to vaccine:1 Consider chemoprophylaxis w/ PO oseltamivir, inhaled zanamivir, or PO baloxavir in high-risk pts2 if ≤48h since 1st exposure to infectious person;3 close monitoring/early initiation of antiviral tx if fever and/or resp sx develop is alternative to chemoprophylaxis after a suspected exposure for some pts. - 75 mg PO once daily x7 days after last known exposure
- >40 kg: 75 mg PO once daily x7 days after last known exposure
- >23 to 40 kg: 60 mg PO once daily x7 days after last known exposure
- >15 to 23 kg: 45 mg PO once daily x7 days after last known exposure
- ≤15 kg: 30 mg PO once daily x7 days after last known exposure
- 3 mg/kg/dose PO once daily x7 days after last known exposure
- Not recommended, unless situation judged critical
- 10 mg (two 5-mg inhalations) once daily x7 days after last known exposure
- ≥5 yo AND weighs <20 kg: 2 mg/kg (suspension) PO x1
- ≥5 yo AND weighs 20 kg to <80 kg: 40 mg (tab or susp) PO x1
- ≥5 yo AND weighs ≥80 kg: 80 mg (tab or susp) PO x1
Not recommended for influenza prophylaxis:
- peramivir
- amantadine
- rimantadine
Footnotes 1 Antibody development after vaccination takes ≈2wk in adults; may take longer in children. Pts w/ severe immune deficiencies or on immunosuppressive meds may not respond to influenza vaccination.
2 Pts at higher risk for influenza complications (for whom antiviral tx is recommended):
• children <2 yo*
• adults ≥65 yo
• asthma
• neurological/neurodevelopmental conditions
• blood disorders (e.g., sickle cell dz)
• chronic lung dz (e.g., COPD, cystic fibrosis)
• endocrine disorders (e.g., DM)
• heart dz (e.g., congenital heart dz, CHF, CAD)
• kidney and liver disorders
• metabolic disorders (e.g., inherited metabolic disorders, mitochondrial disorders)
• pts who are obese w/ BMI ≥40
• pts <19 yo on long-term aspirin- or salicylate-containing meds
• pts w/ immunocompromise due to dz (e.g., HIV/AIDS, some cancers such as leukemia) or meds (e.g., chemo or radiation tx for cancer, or pts requiring chronic corticosteroids or other immunosuppressants)
• stroke
• pregnancy and up to 2wk postpartum
• nursing or long-term care facility residents
• Non-Hispanic Black persons, Hispanic/Latino persons, and American Indian/Alaska Native persons
*Although all children <5 yo are considered at higher risk for flu complications, the highest risk is for those <2 yo, w/ highest hospitalization and death rates among those <6 mo. Because many children w/ mild febrile resp illness might have other viral infxns (e.g., RSV, rhinovirus, parainfluenza virus, or human metapneumovirus), knowledge of other resp viruses as well as influenza virus strains circulating in the community is important for tx decisions.
3 Encourage pts receiving antiviral chemoprophylaxis to seek medical eval as soon as they develop a febrile resp illness that might indicate influenza.
4 oseltamivir renal dosing in adults:
• CrCl 61-90 mL/min: 75 mg PO once daily
• CrCl 31-60 mL/min: 30 mg PO once daily
• CrCl 11-30 mL/min: 30 mg PO every other day
• ESRD on hemodialysis only (CrCl ≤10 mL/min): 30 mg PO after alternate HD cycles (can administer initial dose prior to start of dialysis)
• CAPD (CrCl ≤10 mL/min): 30 mg PO once weekly immediately after dialysis exchange
5 oseltamivir adverse events: nausea, vomiting, HA. Postmarketing reports of serious skin rxns and sporadic, transient neuropsychiatric events.
6 zanamivir renal dosing: no dose adjustment recommended for pts w/ renal impairment.
7 Zanamivir not recommended if underlying resp dz (asthma, COPD, etc.) or allergy to lactose or milk protein.
zanamivir adverse events: bronchospasm risk, esp. if underlying airways dz; sinusitis, and dizziness. Postmarketing reports of serious skin rxns and sporadic, transient neuropsychiatric events.
8 baloxavir marboxil adverse events: none more common than placebo in clinical trials.
Don’t administer w/ dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc).
One study of baloxavir postexposure prophylaxis (PEP) of flu in household members reported 86% lower risk of lab-confirmed flu among those who received baloxavir PEP vs. placebo.
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Institutional settings (hospitals, long-term care facilities)
Give antiviral chemoprophylaxis (PO oseltamivir or inhaled zanamivir) to all non-ill residents (regardless of vaccination status) during influenza outbreak. - 75 mg PO once daily x minimum 14 days and up to 1wk after last known case identified
- >40 kg: 75 mg PO once daily x minimum 14 days and up to 1wk after last known case identified
- >23 to 40 kg: 60 mg PO once daily x minimum 14 days and up to 1wk after last known case identified
- >15 to 23 kg: 45 mg PO once daily x minimum 14 days and up to 1wk after last known case identified
- ≤15 kg: 30 mg PO once daily x minimum 14 days and up to 1wk after last known case identified
- 3 mg/kg/dose PO once daily x minimum 14 days and up to 1wk after last known case identified
- Not recommended, unless situation judged critical
- 10 mg (two 5-mg inhalations) once daily x minimum 14 days and up to 1wk after last known case identified
- ≥5 yo AND weighs <20 kg: 2 mg/kg (suspension) PO x1
- ≥5 yo AND weighs 20 to <80 kg: 40 mg (tab or susp) PO x1
- ≥5 yo AND weighs ≥80 kg: 80 mg (tab or susp) PO x1
Footnotes 1 oseltamivir renal dosing in adults:
• CrCl 61-90 mL/min: 75 mg PO once daily
• CrCl 31-60 mL/min: 30 mg PO once daily
• CrCl 11-30 mL/min: 30 mg PO every other day
• ESRD on hemodialysis only (CrCl ≤10 mL/min): 30 mg PO after alternate HD cycles (can administer initial dose prior to start of dialysis)
• CAPD (CrCl ≤10 mL/min): 30 mg PO once weekly immediately after dialysis exchange
2 oseltamivir adverse events: nausea, vomiting, HA. Postmarketing reports of serious skin rxns and sporadic, transient neuropsychiatric events.
3 zanamivir renal dosing: no dose adjustment recommended for pts w/ renal impairment.
4 Zanamivir not recommended if underlying resp dz (asthma, COPD, etc.) or allergy to lactose or milk protein.
zanamivir adverse events: bronchospasm risk, esp. if underlying airways dz; sinusitis, and dizziness. Postmarketing reports of serious skin rxns and sporadic, transient neuropsychiatric events.
5 baloxavir marboxil adverse events: none more common than placebo in clinical trials.
Don’t administer w/ dairy products, calcium-fortified beverages, polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc).
One study of baloxavir postexposure prophylaxis (PEP) of flu in household members reported 86% lower risk of lab-confirmed flu among those who received baloxavir PEP vs. placebo.
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