Respiratory Syncytial Virus Concerns and Control - PowerPoint PPT Presentation


PPT – Respiratory Syncytial Virus Concerns and Control PowerPoint presentation | free to view - id: 3c4fa8-MDQ3M


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation

Respiratory Syncytial Virus Concerns and Control


Respiratory Syncytial Virus Concerns and Control Pediatrics in Review Vol. 24 No. 9 Sept. 2003 Respiratory Syncytial Virus : Introduction Virology Epidemiology ... – PowerPoint PPT presentation

Number of Views:217
Avg rating:3.0/5.0
Slides: 32
Provided by: medicalAb


Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Respiratory Syncytial Virus Concerns and Control

Respiratory Syncytial Virus Concerns and
  • Pediatrics in Review Vol. 24 No. 9
  • Sept. 2003

Respiratory Syncytial Virus
  • Introduction
  • Virology
  • Epidemiology
  • Pathogenesis Immunity
  • Complications Long term Effects
  • Diagnosis
  • Therapy Prevention

RSV Introduction
  • RSV is responsible for outbreaks of lower
    respiratory tract disease in young children.
  • Bronchiolitis pneumonia from RSV are frequent
    causes of hospitalization.
  • Recent conformation of the significance of RSV in
    causing respiratory tract illness throughout
  • Therapy prevention based on increased
    understanding of the virus host response .
  • Control of RSV infection.

RSV Virology
  • RSV Paramyxovirus, pneumovirus.
  • RSV chimpanzee coryza agent.
  • RSV Isolated from infants with respiratory
    symptoms , renamed because of its characteristic
    syncytial pattern.
  • Enveloped virus, -ve single stranded RNA genome
  • Genome codes for 10 m RNAs, each codes for a
    specific protein.
  • Viral envelop F, G ,SH, M ,M2
  • Neucleocapsid L, N, P
  • NS1, NS2

RSV Virology
  • Two major groups A B
  • PH 7.5, Temperature sensitive.
  • Stable in hospital environment recovered
  • from countertops rubber gloves.
  • Nosocomial Pathogen

RSV Epedemiology
  • Present world wide, yearly epidemics.
  • Appears in Nov. or Dec. persists till Apr. or
  • A strain predominant , the two strains circulate.
  • Strain variation does not significantly affect
    the clinical severity.
  • Peak incidence 2-5 months.

RSV Epidemiology
  • In the 1st two years of life one or more RSV
  • More severe Boys , lower socioeconomic classes.
  • Reinfection throughout life is common.
  • Milder than primary infection.

RSV Pathogenesis Immunity
  • Incubation period 2-8 days.
  • Ocular, nasal contact with infected secretions.
  • Upper airway cough rhinorrhea.
  • 50 primary infection spreads to lower tract.
  • Bronchiolitis lymphocyte infiltrate epithelial
  • Obstruction mucus epithelium .
  • Hyperinflation.
  • Interstitial infiltrates Pneumonia.

RSV Immunity
  • Immune response not well understood.
  • Different parts of immune system are involved.
  • Antibodies
  • Higher levels of maternal Abs , lower infection
  • Prophylactic Abs reduce but do not eliminate
    severe disease.
  • No level of serum Abs provides protection.
  • Type of Ab generated may be critical.

RSV Immunity
  • Cell mediated immunity
  • Integral in clearance recovery.
  • T- cell deficiency severe infection prolonged
  • Type of T-cell response influences control.
  • Type extent of cytokine production determines
    response to RSV.

RSVClinical Features
  • Wide range of illness , rarely asymptomatic.
  • Illness begins cough , nasal congestion
  • Ottitis Media
  • LRT disease 50
  • LRT disease tachypnea , dyspnea, retractions.
  • Feeding difficulty, hypoxemia.

RSV Clinical Manifestations
  • LRT disease
  • Bronchiolitis VS. Pneumonia
  • Bronchiolitis Pneumonia
  • Overwhelming Sepsis
  • Young infants
  • Apnea
  • Preterm infants
  • Croup
  • Fewer than 10

RSV Clinical manifestations
  • High risk infants
  • Preterm infants
  • Chronic lung disease
  • Congenital Heart disease
  • Immunocompromised
  • Neurological disorders
  • Multiple congenital Anomalies.

RSV Clinical manifestations Children Adults
  • Repeated Infections milder , localized to URT.
  • LRTI uncommon, may be followed by airway
  • Immunocompromised BMT severe , fatal disease
  • URT symptoms suspect RSV
  • Early therapeutic measures.

Complications long term Effects
  • Acute
  • Respiratory Failure
  • Apnea
  • Secondary bacterial infection
  • Long Term Effects
  • Reactive Airway Disease??

  • Young Children
  • Season
  • Typical history
  • Physical examination
  • Children Adults
  • Signs Symptoms are less specific.
  • Chest x ray nonspecific
  • Chest X rays
  • Hyperinflation
  • Peribronchial thickening
  • Increased interstitial markings
  • Consolidation, Atelectasis

RSV Diagnosis
  • In children with mild disease, definitive
    diagnosis may not be necessary.
  • In hospitalized patients those with severe
    disease ,an accurate diagnosis may limit further
    lab. evaluation and antibiotic use.
  • RSV may be identified by viral isolation or by
    one of numerous rapid assays.

RSV Diagnosiscont.
  • Infants
  • Nasal wash
  • Children adults
  • Swab from nasal turbinatespharynx
  • or bronchoalveolar lavage are the most likely to
    be positive Specimens obtained by endotracheal
  • Specimens for culture should be placed in viral
    culture media kept cold during transport.
  • RSV grows in multiple cell lines ( Hep-2 HeLa)
  • Typical pattern syncytial giant cell , 3-7
  • Fluorescein-labled Ab are applied to cultures.

RSV Diagnosis
  • Rapid assays
  • Fluorescent antibody tests
  • Enzyme immunoassays
  • Reverse transcriptase PCR
  • Tissue Biopsies
  • Serologic testing for RSV is not useful for
  • Has been used in epidemiological studies.
  • Difficult to interpret in the very young

RSV Therapy
  • RSV therapy remains largely supportive
  • Supplemental oxygen, IV fluids
  • Bronchodilators??
  • Corticosteroids??
  • Vitamin A??

RSV Ribavirin
  • Ribavirin the only antiviral agent currently
    licensed for treatment of RSV infection.
  • It is a synthetic nucleoside analog that
    interferes with expression of mRNA prtn
  • Nebulized Ribavirin is associated with clinical
    improvement,but a decrease in hospital stay has
    not been documented.
  • Efficacy vs. Cost
  • Toxicity adverse reactions
  • Ventilated patients

RSV Therapy Ribavirin
  • AAP Decisions regarding Ribavirin therapy are
    to be based on individual clinical situation
    physicians experience
  • Ribavirin is licensed for treatment by aerosol
    route by O2 hood, tent or mask until
  • Usually 3-7 days, or longer in severe cases.
  • No guidelines regarding administration to adults

RSV Therapy Others
  • IV inhaled Igs have bee used in small numbers
    but with no significant benefit.
  • Immunocompromised patients , in combination with
  • Other Agents
  • IM alpha 2a interferon
  • Surfactant
  • Rh-DNA ase
  • Drugs affecting cytokine production alone or with
  • New Antiviral agents

Infection control Procedures During RSV season
  • Educate hospital staff patients families about
  • Emphasize maintain good hand washing
  • Use contact isolation for patients with RSV.
  • Cohort children RSV infection.
  • Identify RSV by using rapid accurate assays.
  • Use mask for staff who have respiratory symptoms.

Infection Control
  • Cohort staff , if possible , to infected
    uninfected patients
  • Limit visitors during RSV season.
  • Postpone elective admissions for high risk
    patients in RSV season.
  • Identify uninfected infants who may benefit from

RSV Prevention
  • Prophylactic Antibodies to RSV has been shown to
    decrease severe disease.
  • Two products have been approved for use in
    selected children at high risk for RSV.
  • Neither product currently is licensed for use in
    infants with cyanotic congenital heart disease.
  • Prophylaxis may be beneficial in
    Immunocompromised children.
  • Expenses of prophylaxis.
  • Regional analysis is required.
  • Impact on long term complications is yet unknown.

RSV Prevention RSV IGIV
  • Approved in 1996, after multicenter PREVENT
  • Patients received monthly infusions of RSV-IVIG,
    or placebo during RSV season.
  • Those receiving RSV-IVIG had a 41 reduction in
    rate of hospitalization,fewer hospital days
    less frequent O2 requirements.

RSV Prevention Palivizumab
  • It is a humanized IgG-1 monoclonal Ab, that binds
    to the F prtn of RSV.
  • It is estimated to have 50 - 100X more activity
    than RSV IGIV.
  • Given IM.
  • Approved in 1998 after placebo controlled
    multicenter trial ( Impact Study)
  • Administration resulted in 55 reduction in
  • RSV IVIG vs. Palivizumab.

AAP Recommendations for prophylaxis
  • Childrenlt 2yeras ,chronic lung disease received
    medical therapy in the last 6 months.
  • Infants lt 32 wks gestation
  • lt 28 wks
  • 32 gt age gt 28
  • 35gt age gt32

RSV prevention Vaccines
  • Development of an effective vaccine remains a
  • A variety of approaches to Vaccine development
    have been studied.
  • Types of candidate vaccines include inactivated
    ,live attenuated subunit vaccines.
  • Successful immunization against RSV may require
    different individualized approaches.
  • Maternal immunization may be protective , but not
    for LBW infants

RSV prevention
  • Additional strategies are needed to provide
    protection shortly after birth.
  • In older individuals vaccines that the existing
    to RSV maybe beneficial or more feasible to
  • Possible therapeutic preventive measures are
    evolving rapidly, portending that the burden of
    RSV disease soon may be lessened.