IT’S THAT TIME OF YEAR: FLU QUICKHITS (PART 2)

Part two will cover the important basics about the flu treatment, chemoprophylaxis, high risk patient population w/ the flu management. This is a compilation of information provided by the CDC along with reference papers that have been clinically relevant as they have been referenced multiple times over the last few weeks during my rotation in the ED. 

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Note that Tamiflu is now FDA approved for patients age 2-weeks and older (FDA NEWS RELEASE link)

 

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Pregnant women

Oseltamivir is preferred for treatment of pregnant women. Pregnant women are recommended to receive the same antiviral dosing as nonpregnant persons

  • Zanamivir might be preferred by some providers because of its limited systemic absorption; however, respiratory complications that might be associated with zanamivir because of its inhaled route of administration need to be considered, especially in women at risk for respiratory problems
  • Pregnant women are known to be at higher risk for complications from infection with seasonal influenza viruses and severe disease among pregnant women was reported during past pandemics
  • Oseltamivir, zanamivir, rimantadine, and amantadine are “Pregnancy Category C” medications, indicating that data from clinical studies are not adequate to assess the safety of these medications for pregnant women

Persons w/ impaired renal function

Oseltamivir: For patients with creatinine clearance of 10–30 mL per minute, a reduction of the treatment dosage of oseltamivir to 75 mg once daily and in the chemoprophylaxis dosage to 75 mg every other day is recommended

  • Serum concentrations of oseltamivir carboxylate, the active metabolite of oseltamivir, increase with declining renal function.

Person w/ Immunosuppression

  • oseltamivir was safe and well tolerated when used during the control of an influenza outbreak among hematopoietic stem cell transplant recipients living in a residential facility
  • Source: (retrospective study: Vu D, Peck AJ, Nichols WG, et al. Safety and tolerability of oseltamivir prophylaxis in hematopoietic stem cell transplant recipients: a retrospective casecontrol study. Clin Infect Dis 2007;45:187–93.)

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SUMMARY FOR TREATMENT RECOMMENDATIONS:

  • Clinical trials and observational data show that early antiviral treatment can shorten the duration of fever and illness symptoms, and may reduce the risk of complications from influenza
  • Persons at higher risk for influenza complications recommended for antiviral treatment include:
    • children aged younger than 2 years;*
    • adults aged 65 years and older;
    • persons who are morbidly obese (i.e., body-mass index is equal to or greater than 40)
    • persons with immunosuppression, including that caused by medications or by HIV infection;
    • women who are pregnant or postpartum (within 2 weeks after delivery);
    • persons aged younger than 19 years who are receiving long-term aspirin therapy;
    • persons with chronic pulmonary (including asthma), cardiovascular (except hypertension alone), renal, hepatic, hematological (including sickle cell disease), metabolic disorders (including diabetes mellitus), or neurologic and neurodevelopment conditions (including disorders of the brain, spinal cord, peripheral nerve, and muscle such as cerebral palsy, epilepsy [seizure disorders], stroke, intellectual disability [mental retardation], moderate to severe developmental delay, muscular dystrophy, or spinal cord injury);
    • American Indians/Alaska Natives;
    • residents of nursing homes and other chronic-care facilities.
  • When indicated, antiviral treatment should be started as soon as possible after illness onset, ideally within 48 hours of symptom onset. However, antiviral treatment might still be beneficial in patients with severe, complicated or progressive illness and in hospitalized patients when started after 48 hours of illness onset, as indicated by observational studies.
  • When indicated, antiviral treatment should be started as soon as possible after illness onset, ideally within 48 hours of symptom onset. However, antiviral treatment might still be beneficial in patients with severe, complicated or progressive illness and in hospitalized patients when started after 48 hours of illness onset, as indicated by observational studies.
  • Decisions about starting antiviral treatment should not wait for laboratory confirmation of influenza
  • The recommended duration of treatment is 5. Longer treatment regimens might be necessary in severely ill hospitalized patients or persons with immunosuppression

SUMMARY FOR CHEMOPROPHYLAXIS

  • Antiviral medications are approximately 70% to90% effective in preventing influenza and are useful adjuncts to influenza vaccination (** CDC does not recommend routine use of antiviral meds for chemophrophylaxis to limit possibilities of antiviral resistance)
  • An emphasis on close monitoring and early initiation of antiviral treatment is an alternative to chemoprophylaxis after a suspected exposure for some persons.
  • To be effective as chemoprophylaxis, an antiviral medication must be taken each day for the duration of potential exposure to a person with influenza and continued for 7 days after the last known exposure.
  • Antiviral chemoprophylaxis generally is not recommended if more than 48 hours have elapsed since the last exposure to an infectious person.

SUMMARY OF INFLUENZA VACCINATION

  • All persons aged 6 months and older should be vaccinated annually.
  • Protection of persons at higher risk for influenza-related complications should continue to be a focus of vaccination efforts.
  • When vaccine supply is limited, vaccination efforts should focus on delivering vaccination to persons who:
    • are aged 6 months–4 years (59 months);
    • are aged 50 years and older;
    • have chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus);
    • are immunosuppressed (including immunosuppression caused by medications or by human immunodeficiency virus);
    • are or will be pregnant during the influenza season;
    • are aged 6 months–18 years and receiving long-term aspirin therapy and who therefore might be at risk for experiencing Reye syndrome after influenza virus infection;
    • are residents of nursing homes and other chronic-care facilities;
    • are American Indians/Alaska Natives;
    • are morbidly obese (body-mass index is 40 or greater);
    • are health-care personnel;
    • are household contacts and caregivers of children aged younger than 5 years and adults aged 50 years and older, with particular emphasis on vaccinating contacts of children aged younger than 6 months; and
    • are household contacts and caregivers of persons with medical conditions that put them at higher risk for severe complications from influenza.

VACCINATION IN PERSONS ALLERGIC TO EGGS

Generally, egg allergic patients can safely receive TIV. Individuals with a history of severe (life threatening) allergy to eating eggs should consult with a specialist with expertise allergy prior to receiving TIV

Updated recommendations based on 2011 morbidity and mortality report from CDC:

Recommendations regarding influenza vaccination for persons who report allergy to eggs — Advisory Committee on Immunization Practices (ACIP), 2011–12 influenza season

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1. Persons who have experienced only hives following exposure to egg should receive influenza vaccine with the following additional measures:

a) Because studies published to date involved use of TIV, TIV rather than LAIV should be used.

b) Vaccine should be administered by a health-care provider who is familiar with the potential manifestations of egg allergy.

c) Vaccine recipients should be observed for at least 30 minutes for signs of a reaction following administration of each vaccine dose.

 Other measures, such as dividing and administering the vaccine by a two-step approach and skin testing with vaccine, are not necessary.

2. Persons who report having had reactions to egg involving angioedema, respiratory distress, lightheadedness, or recurrent emesis, or persons who required epinephrine or other emergency medical intervention, particularly those that occurred immediately or within minutes to hours after egg exposure are more likely to have a serious systemic or anaphylactic reaction upon reexposure to egg proteins. Before receipt of vaccine, such persons should be referred to a physician with expertise in the management of allergic conditions for further risk assessment

3. All vaccines should be administered in settings in which personnel and equipment for rapid recognition and treatment of anaphylaxis are available. ACIP recommends that all vaccination providers be familiar with the office emergency plan

4. Some persons who report allergy to egg might not be egg allergic. Those who are able to eat lightly cooked egg (e.g., scrambled eggs) without reaction are unlikely to be allergic. Conversely, egg-allergic persons might tolerate egg in baked products (e.g., bread or cake); tolerance to egg-containing foods does not exclude the possibility of egg allergy (35). Egg allergy can be confirmed by a consistent medical history of adverse reactions to eggs and egg-containing foods, plus skin and/or blood testing for immunoglobulin E antibodies to egg proteins.

5. A previous severe allergic reaction to influenza vaccine, regardless of the component suspected to be responsible for the reaction, is a contraindication to receipt of influenza vaccine.

References:

Compiled by: Sakib Motalib

Miss anything? Forgot to include something important? Leave a comment and help us improve our knowledge base for medical students!

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