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Neonatal Nursing Education Briefs

H1N1 Influenza

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Purpose and Goal: CEARP #1097

  • Describe the clinical manifestations of H1N1 influenza during pregnancy.
  • Identify at least 2 infection control practices that protect newborn infants from H1N1 influenza.

None of the planners, faculty or content specialists has any conflict of interest or will be presenting any off-label product use. This presentation has no commercial support or sponsorship, nor is it co-sponsored. 

Requirements for Successful completion

  • Successfully complete the post-test
  • Complete the evaluation form

Date

  • March 2014 – March 2016

Learning Objectives

  • Describe the clinical manifestations of H1N1 influenza during pregnancy.
  • Describe the prevention and treatment of H1N1 influenza during pregnancy.
  • Identify at least two infection control practices that protect newborn infants from H1N1 influenza.

Introduction

  • H1N1 influenza originated in Mexico.
  • First detected in the United States in March 2009
  • Peak United States incidence was in October 2009.
  • All 50 states reported infection.
  • Outbreak rapidly spread worldwide.
  • H1N1 remains an annual seasonal risk.
  • Pregnant women are at highest risk.
  • Newly delivered women are also at high risk.

H1N1 Influenza

  • H1N1 influenza is a subtype of influenza A.
    • Most common subtype
  • H1N1 is also known as “swine influenza.”
  • H1N1 represents four strains of influenza
    • Two swine strains
    • One human strain
    • One avian strain
  • Influenza illness in pigs first recognized in 1918
  • Swine virus first isolated from humans in 1974
  • It is unclear how H1N1 was transmitted to humans.
  • H1N1 influenza primarily affects the young.
  • Pregnant women have highest rate of infection.
  • H1N1 influenza uncommon >64 years old

Clinical Presentation

  • Fever
  • Chills
  • Cough
  • Rhinorrhea
  • Sore throat
  • Malaise
  • Headache
  • Shortness of breath
  • Vomiting
  • Diarrhea
  • Myalgia
  • Arthralgia

Transmission

  • Person-to-person contact
  • Large droplet contact
    • Coughing
    • Sneezing
    • Speaking
  • Nosocomial transmission
    • Patient to patient
    • Patient to healthcare provider
    • Healthcare provider to healthcare provider
  • Viral shedding
  • Begins a day before onset of symptoms
    • Can last for five to seven days or longer
    • Greatest rate of shedding in first two days
  • Incubation period after exposure is one and a half to three days.
  • H1N1 environmental survival
    • 24 to 48 hours on nonporous surfaces
    • 12 hours on porous surfaces
    • Hand washing is critical to avoid exposure.

Diagnosis

  • Real-time reverse transcriptase (rRT)-PCR
    • Polymerase chain reaction – uses DNA
    • PCR is most sensitive and specific.
    • Not always immediately available
  • Influenza culture
    • Definitely diagnostic
    • Slower results
  • Rapid antigen test
    • Can distinguish between A and B viruses
    • Cannot distinguish subtypes like H1N1
  • Immunofluorescent antibody testing
    • Can distinguish between A and B viruses
    • Cannot distinguish subtypes like H1N1
  • Serology
    • Useful for influenza surveillance only
    • Can diagnose past influenza illness

Prevention

  • Vaccination
    • Inactivated influenza vaccine
    • Live attenuated influenza vaccine
    • Vaccine includes both influenza A and B
    • Single vaccine provides protection.
    • Protection occurs within two weeks of vaccine.
    • Center for Disease Control recommendations
      • Healthcare workers
      • Emergency workers
      • Pregnant women
      • Young children after six months
      • Young adults before 24 years
      • Adults 25 to 64 with medical conditions
        • Diabetes
        • Asthma
        • Chronic lung disease
        • Heart disease
  • Antiviral prophylaxis
    • Can be started for any exposure
    • Antiviral medications
      • Oseltamivir (Tamiflu)
      • Zanamivir (Relenza)
  • Personal hygiene
    • Hand hygiene
    • Respiratory hygiene
      • Covering nose and mouth
      • During coughing or sneezing

Treatment

  • Prompt empiric treatment most beneficial
  • Can be started at any time during illness
  • Decreases severity of illness
  • Antiviral medications
    • Oseltamivir (Tamiflu)
      • Neuraminidase inhibitor
      • 75 mg twice daily for 5 to 10 days 
    •  Zanamivir (Relenza)
      • Neuraminidase inhibitor
      • 10 mg (two inhalations) daily for 5 to 10 days
  • Tamiflu may be preferred due to systemic absorption.

H1N1 Influenza and Pregnancy

  • Pregnant women are at high risk.
    • High risk for severe illness
    • High risk for severe complications
    • High risk for preterm birth
    • High risk for SGA infants
    • High risk for death
  • Newly delivered women also at high risk
    • Up to two weeks post-partum
    • Includes pregnancy losses
  • Physiological changes during pregnancy
    • Decreased immunity
      • Prevents rejection of fetus
      • Increases risk of illness
    • Enlarging uterus
      • Compresses diaphragm
      • Compresses lung tissue
      • Reduces lung volume
      • Predisposes to respiratory infection
  • Live attenuated vaccine is not recommended.
    • Weakened live virus nasal spray
    • Increases chance of illness
    • Safe for newly delivered women
  • Influenza vaccination during pregnancy
    • Protects the pregnant woman
    • Protects the developing fetus
    • Protects the newborn for up to six months
      • Increases maternal IgG antibodies
      • Increases IgA antibodies in breast milk
  • CDC recommends treatment with antiviral medications.
    • All pregnant women with illness
    • All newly delivered women with illness
      • Up to two weeks post-partum
    • Tamiflu is the preferred treatment
      • Enhanced systemic absorption
      • Improved immune response
      • Improved protection of fetus
  • Treatment considered safe at any stage of pregnancy
    • Safe during first trimester
    • Best protection if started at first sign of illness
    • Should be started within 48 hours of illness
  • Increased body temperature from fever
    • Can be harmful to developing fetus
    • Fever should be treated with acetaminophen.
  • Rest and increased fluid intake are important.
  • Increased incidence of severe complications
    • Delay in antiviral treatment >48 hours
    • Severe illness and death
      • Pneumonia
      • Adult respiratory distress syndrome

H1N1 and the Newborn Infant

  • Newborn infants at high risk of illness
    • At risk for severe complications
  • Influenza vaccine not recommended <6 months
  • Healthy newborns born to infected mothers
    • Considered exposed
    • Not considered infected
  • CDC recommendation and guidelines
    • Temporary separation of mother and infant
      • All mothers with suspected influenza
      • All mothers with confirmed influenza
    • Length of separation
      • Until mother treated for 48 hours
      • Until mother afebrile for 24 hours
        • Without use of antipyretics
      • Until mother able to control cough
        • Including respiratory secretions
  • Healthy newborns can be cared for in the nursery.
    • Infants need to be monitored closely. 
  • If separation is not feasible or acceptable
    • Infant should be kept six feet from mother.
    • Healthy family members should care for infant.
  • All feedings should be done by healthy caregivers. 
  • If the mother becomes ill with influenza after discharge
    • Infants should be cared for by healthy family member.
      • If a healthy family member not available
        • Masks should be worn.
        • Hand hygiene is critical.
    • The mother can pump and express breast milk.
    • Breast milk can be safely fed by family member.
    • Antiviral medications are safe to use while breastfeeding.
  • All family members should receive influenza vaccine.
    • Immediate family members
    • Extended family members
    • All household contacts
    • All infant caregivers

Infection Control Practices

  • Control and prevention of influenza outbreak
    • Optimal prevention means prompt identification.
    • Multiple infection control measures are required.
  • CDC guidelines for healthcare settings
    • Promote and administer influenza vaccination.
    • Take steps to minimize exposures.
    • Monitor and manage ill healthcare workers.
    • Adhere to strict standard precautions.
    • Adhere to strict droplet precautions.
    • Manage visitor access and movement.
    • Monitor influenza activity in hospital.
    • Implement environmental infection control.
    • Implement engineering controls.
    • Train and educate healthcare workers.
    • Administer antiviral medications.
      • Healthcare workers
      • Patients and family members
    • Educate patients and family members.

References

  1. Dunlap, M.M. H1N1 Influenza: Implications for Pregnancy. 2010. Growing Families, 14(2), p. 1-4. 
  2. UpToDate: Influenza and Pregnancy
  3. UpToDate: Clinical Manifestations and Diagnosis of H1N1 Influenza   
  4. UpToDate: Treatment and Prevention of H1N1 Influenza
  5. UpToDate: Infection Control Measures to Prevent Seasonal Influenza in Healthcare Settings

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