Influenza infection
- Overview
- Theory
- Diagnosis
- Management
- Follow up
- Resources
Treatment algorithm
Your Organisational Guidance
ebpracticenet urges you to prioritise the following organisational guidance:
Prévention de l’InfluenzaPublished by: Groupe de travail Développement de recommandations de première ligneLast published: 2018Preventie van influenzaPublished by: Werkgroep Ontwikkeling Richtlijnen Eerste Lijn (Worel)Last published: 2018Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
exposure to infected individual(s) in at-risk population
prophylactic antiviral therapy
Consider post-exposure antiviral chemoprophylaxis for: people at high risk of developing complications of influenza if illness develops shortly after influenza vaccination, before an adequate immune response develops; people in whom the vaccine is contraindicated (this may include anaphylaxis to egg or allergy to other components of the vaccine, febrile illness, or history of Guillain-Barre syndrome within 6 weeks of previously administered influenza vaccine); people who have not received the vaccine but present with acute respiratory symptoms during a known influenza outbreak; unvaccinated people in close contact with those at high risk of developing complications of influenza during an influenza outbreak; all residents of long-term facilities or nursing homes, including those already vaccinated, if an outbreak of influenza occurs in the community where they are living; people who have highest risk of complications, including death (this may include immunocompromised people); people who were unable to receive vaccine due to shortage, if they are at high risk of developing complications of influenza.[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47.
https://academic.oup.com/cid/article/68/6/e1/5251935
http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com
[112]National Institute for Health and Care Excellence. Oseltamivir, amantadine (review) and zanamivir for the prophylaxis of influenza. Sep 2008 [internet publication].
https://www.nice.org.uk/Guidance/TA158
[113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication].
https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm
[ ]
If there is an outbreak of influenza A in the community, do amantadine and rimantadine given prophylactically prevent the development of influenza in the elderly?/cca.html?targetUrl=https://cochranelibrary.com/cca/doi/10.1002/cca.23/fullShow me the answer
Both oseltamivir and zanamivir have been shown to be effective as prophylaxis against infection when given early after exposure to an infected individual.
[ ]
What are the benefits and harms of neuraminidase inhibitors for the prevention of influenza in adults?/cca.html?targetUrl=https://cochranelibrary.com/cca/doi/10.1002/cca.991/fullShow me the answer One meta-analysis has shown that oseltamivir used prophylactically may reduce the spread of symptomatic influenza within households.[127]Jefferson T, Jones M, Doshi P, et al. Oseltamivir for influenza in adults and children: systematic review of clinical study reports and summary of regulatory comments. BMJ. 2014 Apr 9;348:g2545.
https://www.bmj.com/content/348/bmj.g2545.long
http://www.ncbi.nlm.nih.gov/pubmed/24811411?tool=bestpractice.com
Another systematic review and meta-analysis suggests that post-exposure prophylaxis probably decreases the risk of symptomatic seasonal influenza in individuals at high risk for severe disease.[141]Zhao Y, Gao Y, Guyatt G, et al. Antivirals for post-exposure prophylaxis of influenza: a systematic review and network meta-analysis. Lancet. 2024 Aug 24;404(10454):764-72.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11369964
http://www.ncbi.nlm.nih.gov/pubmed/39181596?tool=bestpractice.com
In phase 3 trials, single-dose baloxavir marboxil was effective in preventing influenza in household contacts (both adults and children) of patients with influenza.[142]Ikematsu H, Hayden FG, Kawaguchi K, et al. Baloxavir marboxil for prophylaxis against influenza in household contacts. N Engl J Med. 2020 Jul 23;383(4):309-20.
https://www.nejm.org/doi/10.1056/NEJMoa1915341
http://www.ncbi.nlm.nih.gov/pubmed/32640124?tool=bestpractice.com
[143]Baker J, Block SL, Matharu B, et al. Baloxavir marboxil single-dose treatment in influenza-infected children: a randomized, double-blind, active controlled phase 3 safety and efficacy trial (miniSTONE-2). Pediatr Infect Dis J. 2020 Aug;39(8):700-5.
https://journals.lww.com/pidj/Fulltext/2020/08000/Baloxavir_Marboxil_Single_dose_Treatment_in.12.aspx
http://www.ncbi.nlm.nih.gov/pubmed/32516282?tool=bestpractice.com
Oseltamivir can be used in adults and children of all ages, and is given for 10 days (up to 6 weeks during an epidemic) for this indication. It should be started within 2 days of exposure.
Zanamivir is given for 10 days in adults and children aged ≥5 years for this indication, and should be started within 2 days of exposure.
Baloxavir marboxil is given as a single dose to those aged 5 years or older (it is approved for patients 1 year and older in Europe). It should be given as soon as possible and within 2 days of exposure. Baloxavir is not recommended in people who are severely immunosuppressed.[113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm
Pregnant women can be offered oseltamivir.[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47. https://academic.oup.com/cid/article/68/6/e1/5251935 http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com [34]Influenza in pregnancy: prevention and treatment: ACOG committee statement no. 7. Obstet Gynecol. 2024 Feb 1;143(2):e24-30. https://journals.lww.com/greenjournal/fulltext/2024/02000/influenza_in_pregnancy__prevention_and_treatment_.25.aspx http://www.ncbi.nlm.nih.gov/pubmed/38016152?tool=bestpractice.com [113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm
Primary options
oseltamivir: children <3 months of age: consult specialist for guidance on dose; children 3 months to <1 year of age: 3 mg/kg orally once daily; children ≥1 year of age and ≤15 kg body weight: 30 mg orally once daily; children ≥1 year of age and 15-23 kg body weight: 45 mg orally once daily; children ≥1 year of age and 23-40 kg body weight: 60 mg orally once daily; children ≥1 year of age and >40 kg body weight and adults: 75 mg orally once daily
OR
zanamivir inhaled: children ≥5 years of age and adults: 10 mg (two inhalations) once daily
OR
baloxavir marboxil: children ≥5 years of age (body weight <20 kg): 2 mg/kg orally as a single dose; children ≥5 years of age and adults (body weight 20-79 kg): 40 mg orally as a single dose; children ≥5 years of age and adults (body weight ≥80 kg): 80 mg orally as a single dose
adults
antipyretic/analgesic
Antipyretics/analgesics are recommended for symptom relief of headache, fever, and myalgia.
Ibuprofen carries a greater risk of potentially serious adverse effects compared with paracetamol.
Primary options
paracetamol: 500-1000 mg orally every 4-6 hours when required, maximum 4000 mg/day
OR
ibuprofen: 200-400 mg orally every 4-6 hours when required, maximum 2400 mg/day
antiviral therapy
Additional treatment recommended for SOME patients in selected patient group
The US Centers for Disease Control and Prevention (CDC) recommends that antiviral treatment is given as soon as possible for patients with confirmed or suspected influenza who have severe, complicated, or progressive illness, or who require hospitalisation, as well as for patients who are at higher risk for complications.[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47. https://academic.oup.com/cid/article/68/6/e1/5251935 http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com [113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm Antivirals have been documented to reduce hospital length of stay and mortality in adults.[116]Katzen J, Kohn R, Houk JL, et al. Early oseltamivir after hospital admission is associated with shortened hospitalization: a 5-Year analysis of oseltamivir timing and clinical outcomes. Clin Infect Dis. 2019 Jun 18;69(1):52-8. https://academic.oup.com/cid/article/69/1/52/5124354?login=false http://www.ncbi.nlm.nih.gov/pubmed/30304487?tool=bestpractice.com [117]Tenforde MW, Noah KP, O'Halloran AC, et al. Timing of influenza antiviral therapy and risk of death in adults hospitalized with influenza-associated pneumonia, Influenza Hospitalization Surveillance Network (FluSurv-NET), 2012-2019. Clin Infect Dis. 2025 Feb 24;80(2):461-8. https://pmc.ncbi.nlm.nih.gov/articles/PMC11847407 http://www.ncbi.nlm.nih.gov/pubmed/39172994?tool=bestpractice.com [118]Gao Y, Guyatt G, Uyeki TM, et al. Antivirals for treatment of severe influenza: a systematic review and network meta-analysis of randomised controlled trials. Lancet. 2024 Aug 24;404(10454):753-63. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(24)01307-2/fulltext http://www.ncbi.nlm.nih.gov/pubmed/39181595?tool=bestpractice.com However, the effects of antivirals on mortality and other patient outcomes are uncertain due to scarce data from randomised controlled trials.[118]Gao Y, Guyatt G, Uyeki TM, et al. Antivirals for treatment of severe influenza: a systematic review and network meta-analysis of randomised controlled trials. Lancet. 2024 Aug 24;404(10454):753-63. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(24)01307-2/fulltext http://www.ncbi.nlm.nih.gov/pubmed/39181595?tool=bestpractice.com While antivirals are approved by the US Food and Drug Administration (FDA) for uncomplicated acute illness, guidelines tend to recommend these drugs for complicated illness as well as for those at risk of complications. Local guidelines may vary and should be consulted.[119]UK Health Security Agency. Influenza: treatment and prophylaxis using anti-viral agents. Dec 2021 [internet publication]. https://www.gov.uk/government/publications/influenza-treatment-and-prophylaxis-using-anti-viral-agents
The benefits of treatment are greatest when drugs are initiated in the first 24-30 hours of symptom onset.[135]Stiver G. The treatment of influenza with antiviral drugs. CMAJ. 2003 Jan 7;168(1):49-56. https://www.cmaj.ca/content/168/1/49.full http://www.ncbi.nlm.nih.gov/pubmed/12515786?tool=bestpractice.com
Oseltamivir and zanamivir should be given within 2 days of onset of symptoms and given for 5 days for this indication. Peramivir is given as a single intravenous dose within 2 days of onset of symptoms.[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47. https://academic.oup.com/cid/article/68/6/e1/5251935 http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com [113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm Peramivir may be recommended for those who are unable to take oral or inhaled neuraminidase inhibitors.
Inhaled and intravenous formulations of zanamivir are approved in Europe. Intravenous zanamivir is indicated for the treatment of complicated and potentially life-threatening influenza where other treatments for influenza, including the inhaled formulation of zanamivir, are unsuitable, and/or the patient's influenza virus is known or suspected to be resistant to other treatments. The recommended treatment course of intravenous zanamivir is 5-10 days.
Baloxavir marboxil, a polymerase acidic endonuclease inhibitor, is active against both influenza A and B and is given as a single oral dose. The FDA has approved baloxavir marboxil for the treatment of acute uncomplicated influenza in patients aged ≥5 years who have been symptomatic for no more than 48 hours, and who are otherwise healthy or at high risk of developing influenza-related complications. Use of baloxavir is not recommended in people who are severely immunosuppressed.[113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm
Antivirals are not a substitute for the seasonal influenza virus vaccine.
Pregnant women presenting with uncomplicated illness due to influenza, and who have no evidence of systemic disease, can be offered oseltamivir.[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47. https://academic.oup.com/cid/article/68/6/e1/5251935 http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com [34]Influenza in pregnancy: prevention and treatment: ACOG committee statement no. 7. Obstet Gynecol. 2024 Feb 1;143(2):e24-30. https://journals.lww.com/greenjournal/fulltext/2024/02000/influenza_in_pregnancy__prevention_and_treatment_.25.aspx http://www.ncbi.nlm.nih.gov/pubmed/38016152?tool=bestpractice.com [113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm
Primary options
oseltamivir: 75 mg orally twice daily
OR
zanamivir inhaled: 10 mg (two inhalations) twice daily
OR
peramivir: 600 mg intravenously as a single dose
OR
baloxavir marboxil: body weight 20-79 kg: 40 mg orally as a single dose; body weight ≥80 kg: 80 mg orally as a single dose
antibiotic therapy
Treatment recommended for ALL patients in selected patient group
Antibiotics should be reserved for certain complications of acute influenza, such as bacterial pneumonia or sinusitis. Most patients with influenza do not require antibiotic therapy, as bacterial superinfections are rare, particularly early in the disease course. The World Health Organization (WHO) recommends not administering antibiotics in patients with nonsevere influenza virus infection with a low probability of bacterial coinfection.[138]World Health Organization. Clinical practice guidelines for influenza. Sep 2024 [internet publication]. https://www.who.int/publications/i/item/9789240097759
The choice of antibiotics should be guided by Gram stain and culture, or provide empirical antibiotics effective against the most common bacterial pathogens following influenza, namely Streptococcus pneumoniae, Staphylococcus aureus, or Haemophilus influenzae (e.g., ceftriaxone, cefotaxime, cefuroxime, or a fluoroquinolone such as levofloxacin or moxifloxacin). Fluoroquinolones are not typically used first line.[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47. https://academic.oup.com/cid/article/68/6/e1/5251935 http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com Treatment can be instituted as an outpatient if the patient is not in respiratory distress and is haemodynamically stable. However, close monitoring and follow-up is required to assess if the patient needs admission for inpatient care.
Systemic fluoroquinolone antibiotics may cause serious, disabling, and potentially long-lasting or irreversible adverse events. This includes, but is not limited to: tendinopathy/tendon rupture; peripheral neuropathy; arthropathy/arthralgia; aortic aneurysm and dissection; heart valve regurgitation; dysglycemia; and central nervous system effects including seizures, depression, psychosis, and suicidal thoughts and behaviour.[144]Rusu A, Munteanu AC, Arbănași EM, et al. Overview of side-effects of antibacterial fluoroquinolones: new drugs versus old drugs, a step forward in the safety profile? Pharmaceutics. 2023 Mar 1;15(3):804. https://pmc.ncbi.nlm.nih.gov/articles/PMC10056716 http://www.ncbi.nlm.nih.gov/pubmed/36986665?tool=bestpractice.com Prescribing restrictions apply to the use of fluoroquinolones, and these restrictions may vary between countries. In general, fluoroquinolones should be restricted for use in serious, life-threatening bacterial infections only. Some regulatory agencies may also recommend that they must only be used in situations where other antibiotics, that are commonly recommended for the infection, are inappropriate (e.g., resistance, contraindications, treatment failure, unavailability). Consult your local guidelines and drug information source for more information on suitability, contraindications, and precautions.
Cephalosporins are suitable for use in pregnant women.
Treatment course is generally 7-14 days.
Primary options
ceftriaxone: 2 g intravenously once daily
OR
cefotaxime: 1-2 g intravenously every 6-8 hours
OR
cefuroxime: 750-1500 mg intravenously every 6-8 hours
Secondary options
levofloxacin: 500 mg orally/intravenously once daily for 7-14 days; or 750 mg orally/intravenously once daily for 5 days
OR
moxifloxacin: 400 mg orally/intravenously once daily
antibiotic therapy
Treatment recommended for ALL patients in selected patient group
Anti-staphylococcal coverage should be added when Staphylococcus aureus is a suspected source of infection. Suspicion for S aureus infection should be considered in patients with influenza and superimposed pneumonia on chest x-ray.
If S aureus infection is confirmed, broad-spectrum antibiotic therapy should be stopped and treatment continued with either oxacillin or nafcillin.
If MRSA is confirmed, broad-spectrum antibiotic therapy should be stopped and treatment ideally continued with either vancomycin or linezolid. However, local guidelines should be consulted to see which antibiotic is available and is most effective.
Treatment course is generally 10-14 days; longer courses (up to 21 days) may be required for MRSA infection.
Primary options
oxacillin: 2 g intravenously every 4 hours
OR
nafcillin: 2 g intravenously every 4 hours
OR
vancomycin: 1 g intravenously every 12 hours
OR
linezolid: 600 mg intravenously/orally every 12 hours
antibiotic therapy
Additional treatment recommended for SOME patients in selected patient group
Antibiotic therapy may be considered for patients with otitis media. Initial antibiotic treatment is with amoxicillin. Lack of improvement by 48-72 hours suggests that the initial therapy was not adequate. This is usually related to infection with an organism resistant to beta-lactam antibiotics (Haemophilus influenzae and drug-resistant Streptococcus pneumoniae), thus indicating the need for a beta-lactam-sensitive drug such as amoxicillin/clavulanate or a cephalosporin.
Either azithromycin or clarithromycin may be used as an alternative in penicllin-allergic patients. However, resistant pneumococcal isolates may not respond to this therapy.[145]Dowell SF, Butler JC, Giebink GS, et al. Acute otitis media: management and surveillance in an era of pneumococcal resistance - a report from the Drug-resistant Streptococcus Pneumoniae Therapeutic Working Group. Pediatr Infect Dis J. 1999 Jan;18(1):1-9. http://www.ncbi.nlm.nih.gov/pubmed/9951971?tool=bestpractice.com
Amoxicillin and cephalosporins are considered safe in pregnant women.
Primary options
amoxicillin: 500-875 mg orally every 12 hours for 7 days
OR
amoxicillin/clavulanate: 500-875 mg orally every 12 hours for 7 days
More amoxicillin/clavulanateDose refers to amoxicillin component.
Secondary options
cefdinir: 300 mg orally every 12 hours for 10 days
OR
cefuroxime: 250-500 mg orally every 12 hours for 10 days
Tertiary options
azithromycin: 500 mg orally once daily for 3 days
OR
clarithromycin: 250-500 mg orally every 12 hours for 7 days
children
antipyretic/analgesic
Antipyretics/analgesics are recommended for symptom relief of headache, fever, and myalgia.
Ibuprofen carries a greater risk of potentially serious adverse effects compared with paracetamol.
Aspirin should not be administered to children aged <16 years due to the risk of Reye syndrome.
Primary options
paracetamol: 10-15 mg/kg orally every 4-6 hours when required, maximum 75 mg/kg/day
OR
ibuprofen: 5-10 mg/kg orally every 6-8 hours when required, maximum 30 mg/kg/day
antiviral therapy
Additional treatment recommended for SOME patients in selected patient group
The US Centers for Disease Control and Prevention (CDC) recommends antiviral treatment is given as soon as possible for children with confirmed or suspected influenza who have severe, complicated, or progressive illness, or who require hospitalisation, as well as for children who are at higher risk for complications.[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47. https://academic.oup.com/cid/article/68/6/e1/5251935 http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com [113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm While antivirals are approved by the US Food and Drug Administration (FDA) for uncomplicated acute illness, guidelines tend to recommend these drugs for complicated illness as well as for those at risk of complications. Local guidelines may vary and should be consulted.[119]UK Health Security Agency. Influenza: treatment and prophylaxis using anti-viral agents. Dec 2021 [internet publication]. https://www.gov.uk/government/publications/influenza-treatment-and-prophylaxis-using-anti-viral-agents
The benefits of treatment are greatest when drugs are initiated in the first 24-30 hours after symptom onset.[135]Stiver G. The treatment of influenza with antiviral drugs. CMAJ. 2003 Jan 7;168(1):49-56. https://www.cmaj.ca/content/168/1/49.full http://www.ncbi.nlm.nih.gov/pubmed/12515786?tool=bestpractice.com [136]Heinonen S, Silvennoinen H, Lehtinen P, et al. Early oseltamivir treatment of influenza in children 1-3 years of age: a randomized controlled trial. Clin Infect Dis. 2010 Oct 15;51(8):887-94. http://www.ncbi.nlm.nih.gov/pubmed/20815736?tool=bestpractice.com
Oseltamivir and zanamivir should be given within 2 days of onset of symptoms and given for 5 days for this indication. Peramivir may be given to children aged ≥6 months who have been symptomatic for no more than 2 days.[18]Committee on Infectious Diseases. Recommendations for prevention and control of influenza in children, 2024-2025: policy statement. Pediatrics. 2024 Oct 1;154(4):e2024068507. https://publications.aap.org/pediatrics/article/154/4/e2024068507/199041/Recommendations-for-Prevention-and-Control-of?autologincheck=redirected http://www.ncbi.nlm.nih.gov/pubmed/39183669?tool=bestpractice.com [113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm Peramivir may be recommended for those who are unable to take oral or inhaled neuraminidase inhibitors.
Inhaled and intravenous formulations of zanamivir are approved in Europe. Intravenous zanamivir is indicated for the treatment of complicated and potentially life-threatening influenza in children aged ≥6 months where other treatments for influenza, including the inhaled formulation of zanamivir, are unsuitable, and/or the patient's influenza virus is known or suspected to be resistant to other treatments. The recommended treatment course of intravenous zanamivir is 5-10 days.
Baloxavir marboxil, a polymerase acidic endonuclease inhibitor, is active against both influenza A and B and is given as a single oral dose. The FDA has approved baloxavir marboxil for the treatment of acute uncomplicated influenza in children aged ≥5 years who have been symptomatic for no more than 48 hours, and who are otherwise healthy or at high risk of developing influenza-related complications. Use of baloxavir is not recommended in people who are severely immunosuppressed.[113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm In Europe, baloxavir marboxil is approved for patients 1 year of age and older.
Antivirals are not a substitute for the seasonal influenza virus vaccine.
Children aged <1 year who have symptoms of seasonal influenza should be treated with oseltamivir.[113]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html?CDC_AAref_Val=https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm
Primary options
oseltamivir: children <14 days of age: consult specialist for guidance on dose; children 14 days to 1 year of age: 3 mg/kg orally twice daily; children ≥1 year of age and ≤15 kg body weight: 30 mg orally twice daily; children ≥1 year of age and >15-23 kg body weight: 45 mg orally twice daily; children ≥1 year of age and >23-40 kg body weight: 60 mg orally twice daily; children ≥1 year of age and >40 kg body weight and children ≥13 years of age: 75 mg orally twice daily
OR
zanamivir inhaled: (inhaled) children ≥7 years of age: 10 mg (two inhalations) twice daily
OR
peramivir: children 6 months to 12 years of age: 12 mg/kg intravenously as a single dose, maximum 600 mg/dose; children ≥13 years of age: 600 mg intravenously as a single dose
OR
baloxavir marboxil: children ≥5 years of age (body weight <20 kg): 2 mg/kg orally as a single dose; children ≥5 years of age (body weight 20-79 kg): 40 mg orally as a single dose; children ≥5 years of age (body weight ≥80 kg): 80 mg orally as a single dose
antibiotic therapy
Treatment recommended for ALL patients in selected patient group
Antibiotics should be reserved for certain complications of acute influenza, such as bacterial pneumonia or sinusitis. Most patients with influenza do not require antibiotic therapy, as bacterial superinfections are rare, particularly early in the disease course. The World Health Organization (WHO) recommends not administering antibiotics in patients with nonsevere influenza virus infection with a low probability of bacterial coinfection.[138]World Health Organization. Clinical practice guidelines for influenza. Sep 2024 [internet publication]. https://www.who.int/publications/i/item/9789240097759
The choice of antibiotics should be guided by Gram stain and culture, or provide empirical antibiotics effective against the most common bacterial pathogens following influenza, namely Streptococcus pneumoniae, Staphylococcus aureus, or Haemophilus influenzae (an example of suitable empirical option is listed here).[2]Uyeki TM, Bernstein HH, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America: 2018 update on diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2019 Mar 5;68(6):e1-47. https://academic.oup.com/cid/article/68/6/e1/5251935 http://www.ncbi.nlm.nih.gov/pubmed/30566567?tool=bestpractice.com Treatment can be instituted as an outpatient if the patient is not in respiratory distress and is haemodynamically stable. However, close monitoring and follow-up is required to assess if the patient needs admission for inpatient care.
Treatment course is generally 7-14 days.
Primary options
ceftriaxone: 50-75 mg/kg/day intravenously
antibiotic therapy
Treatment recommended for ALL patients in selected patient group
Anti-staphylococcal coverage should be added when Staphylococcus aureus is a suspected source of infection. S aureus infection should be suspected in patients with influenza and superimposed pneumonia on CXR.
If S aureus infection is confirmed, broad-spectrum antibiotic therapy should be stopped and treatment continued with either oxacillin or nafcillin.
If MRSA is confirmed, broad-spectrum antibiotic therapy should be stopped and treatment ideally continued with either vancomycin or linezolid.
Treatment course is generally 10-14 days; longer courses (up to 21 days) may be required for MRSA infection.
Primary options
oxacillin: 100-200 mg/kg/day intravenously given in divided doses every 6 hours, maximum 12 g/day
OR
nafcillin: 50-200 mg/kg/day intravenously given in divided doses every 4-6 hours, maximum 12 g/day
OR
vancomycin: 10-15 mg/kg intravenously every 6 hours, maximum 2000 mg/day
OR
linezolid: 10 mg/kg intravenously/orally every 8 hours, maximum 600 mg/dose
antibiotic therapy
Additional treatment recommended for SOME patients in selected patient group
Antibiotic therapy may be considered for patients with otitis media.[146]Venekamp RP, Sanders SL, Glasziou PP, et al. Antibiotics for acute otitis media in children. Cochrane Database Syst Rev. 2015 Jun 23;(6):CD000219. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD000219.pub4/full http://www.ncbi.nlm.nih.gov/pubmed/26099233?tool=bestpractice.com See Acute otitis media.
Initial antibiotic treatment is with amoxicillin.
Lack of improvement by 48-72 hours in a patient treated with antimicrobial therapy suggests that the initial therapy was not adequate. This is usually related to infection with an organism resistant to beta-lactam antibiotics (Haemophilus influenzae and drug-resistant Streptococcus pneumoniae), thus indicating the need for a beta-lactam-sensitive drug such as amoxicillin/clavulanate or a cephalosporin.
Either azithromycin or clarithromycin may be used as an alternative in penicillin-allergic patients. However, resistant pneumococcal isolates may not respond to this therapy.[145]Dowell SF, Butler JC, Giebink GS, et al. Acute otitis media: management and surveillance in an era of pneumococcal resistance - a report from the Drug-resistant Streptococcus Pneumoniae Therapeutic Working Group. Pediatr Infect Dis J. 1999 Jan;18(1):1-9. http://www.ncbi.nlm.nih.gov/pubmed/9951971?tool=bestpractice.com
Primary options
amoxicillin: 80-90 mg/kg/day orally given in divided doses every 12 hours for 10 days
OR
amoxicillin/clavulanate: >3 months of age: 80-90 mg/kg/day orally given in divided doses every 12 hours for 10 days
More amoxicillin/clavulanateDose refers to amoxicillin component.
Secondary options
cefdinir: >6 months of age: 14 mg/kg/day orally for 10 days
OR
cefuroxime: 30 mg/kg/day orally given in divided doses every 12 hours for 10 days
Tertiary options
azithromycin: >6 months of age: 10 mg/kg/day orally on the first day, followed by 5 mg/kg/day for 4 days; or 10 mg/kg/day orally for 3 days; or 30 mg/kg/day orally as a single dose
OR
clarithromycin: >6 months of age: 15 mg/kg/day orally given in divided doses every 12 hours for 10 days
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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer
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