Treatment , Prophylaxis and prevention of Influenza

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Treatment , Prophylaxis and prevention of
Influenza

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symptom-based therapy(In uncomplicated)

• acetaminophen for the relief of headache, myalgia
  and fever(use of salicylates should be avoided in
  childrenlt18 years of age association of
  salicylates with Reye's syndrome.
• Treatment with cough suppressants generally is
  not indicated, although codeine-containing
  compounds may be employed if the cough is
  particularly troublesome.
• rest and maintain hydration during acute illness

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Specific Antiviral Agent for influenaza

• neuraminidase inhibitors Oseltamivir (tamiflu)
• Zanamivir (relenaz)

• M2 Inhibitors
• Amantadine (symmetrol)
• Rimantadine

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Specific antiviral therapy (continued)

• If begun within 48 h of the onset of illness,
  reduced the duration of systemic and respiratory
  symptoms of influenza by 50

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Specific antiviral therapy (drug)

• amantadine and rimantadine for influenza A
• Zanamivir and oseltamivir for both influenza A
  and influenza B

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Specific antiviral therapy (M2 Inhibitors)

• amantadine and rimantadine inhibit by
  interfering with the uncoating of virus after
  infection of the cell , interaction with the
  influenza A M2 matrix protein, during which the
  ion channel function of M2 is inhibited.
• A substitution of a single amino acid at
  critical sites in the M2 protein can result in a
  virus that is resistant to amantadine and
  rimantadine

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Specific antiviral therapy (M2 Inhibitors)

• 5 to 10 who receive amantadine mild CNS side
  effects, primarily jitteriness , anxiety,
  insomnia, or difficulty in concentrating
  (disappear upon cessation of the drug)( with old
  age , TMP/SMZ , antihistamine anticholnegic ).
• Rimantadine equally efficacious , less frequent
  CNS side effects than is amantadine.
• In adults, the usual dose of amantadine
  (cap100mg) or rimantadine is 200 mg/d for 3 to 7
  days.

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Specific antiviral therapy (M2 Inhibitors)

• For prophylaxis, the compounds must be
  administered daily for the period at risk (i.e.,
  the peak duration of the outbreak). For therapy,
  amantadine or rimantadine is generally
  administered for 5 to 7 days
• excreted via the kidney, the dose should be
  reduced to lt100 mg/d in elderly and in renal
  insufficiency (creatinine clearance (Cr,) rate of
  lt50 mL/min)

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Specific antiviral therapy (M2 Inhibitors)

• Amantadine is not metabolized and is excreted
  almost entirely by the kidney,
• Rimantadine is extensively metabolized to
  hydroxylated derivatives

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Specific antiviral therapy (neuraminidase
inhibitors )

• Both zanamivir and oseltamivir act through
  competitive and reversible inhibition of the
  activesite of influenza A and B viral
  neuraminidases (essential for release of the
  virus from infected cell) and have relatively
  little effect on mammalian cell enzymes.
• zanamivir and oseltamivir are active against
  strains resistant to amantadine and rimantadine.

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Specific antiviral therapy (neuraminidase
inhibitors )

• Zanamivir(has low oral bioavailability)
  (belister pack 5 mg), inhaled orally 10 mg
  twice a day for 5 days,
• oseltamivir (cap 75) , orally 75 mg twice a
  day for 5 days,
• Zanamivir may exacerbate bronchospasm in
  asthmatic patients, and oseltamivirhas been
  associated with nausea and vomiting, ( reduced by
  drug administration with food)

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Specific antiviral therapy (neuraminidase
inhibitors )

• Zanamivir and oseltamivir treatment of
  influenza in adults and in children (those gt_7
  years old for zanamivir and those gt 1 year old
  for oseltamivir) who have been symptomatic for
  lt_2 days.
• Oseltamivir is approved for prophylaxis of
  influenza in individuals gt 13 years of age

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Specific antiviral therapy (continued)

• Resistant viruses
• frequently during treatment with amantadine or
  rimantadine and can be transmitted among family
  members.
• resistance infrequent with zanamivir or
  oseltamivir

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therapy (primary influenza pneumonia )

• maintaining oxygenation and is most appropriately
  undertaken in an intensive care unit, with
  aggressive respiratory and hemodynamic support as
  needed.
• When an acute respiratory distress syndrome
  develops, fluids must be administered cautiously,
  with close monitoring of blood gases and
  hemodynamic function

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therapy (bacterial complications )

• secondary bacterial pneumonia.
• Gram's staining and culture of respiratory
  secretions, such as sputum or transtracheal
  aspirates.(or empirical antibiotics effective
  against the most common bacterial pathogens (S.
  pneumoniae, S. aureus, and H. influenzae)

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clinical management of human infection with avian
influenzaA (H5N1)
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Summary of treatment modalities for human A(H5N1)
virus infection
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Summary of treatment modalities for human
A(H5N1)virus infection
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Summary of treatment modalities for human
A(H5N1)virus infection
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Summary of treatment modalities for human
A(H5N1)virus infection
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Summary of treatment modalities for human
A(H5N1)virus infection
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Summary of treatment modalities for human
A(H5N1)virus infection
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Summary of treatment modalities for human
A(H5N1)virus infection
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Summary of treatment modalities for human
A(H5N1)virus infection
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PROPHYLAXIS
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PROPHYLAXIS(vaccines)

• inactivated influenza vaccines(highly purified)
  influenza A and B viruses circulated during the
  previous influenza season.
• 50 to 80 protection.
• reactions. 5 of individuals low-grade fever and
  mild systemic symptoms 8 to 24 h
• one-third mild redness or tenderness at the
  vaccination site
• (produced in eggs,)individuals with true
  hypersensitivity to egg products should be
  desensitized or not be vaccinated.

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PROPHYLAXIS(vaccines)

• 1976 swine influenza vaccine increased
  frequency of Guillain-Barre syndrome, ( since
  1976 generally have not been)
• during the 19921993 and 19931994 influenza
  seasons, slightly more than one case per million
  among vaccine recipients.

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PROPHYLAXIS(vaccines)

• recommends for any individual gt6 months of age
  who is at an increased risk for complications of
  influenza, (Table).
• inactivated ("killed"), safely to
  immunocompromised patients.
• not associated with exacerbations of chronic
  nervous-system diseases such as multiple
  sclerosis.
• administered early in the autumn before influenza
  outbreaks occur and then annually

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PROPHYLAXIS(vaccines)

• a live attenuated influenza vaccine intranasal
  spray.
• by reassortment of currently circulating strains
  of influenza A and B virus with a cold-adapted,
  attenuated master strain.
• well tolerated and highly efficacious (92
  protective)
• protection against a circulating influenza virus
  that had drifted antigenically away from the
  vaccine strain.
• for use in healthy children and adults from 5 to
  49years of age.

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PROPHYLAXIS(vaccines)

• a live attenuated influenza vaccine 0.5 ml
  sprayer , 5-9 years 1 or 2 doses interanasal
  (4-10 w) , 9-49 1 2 doses interanasal
• inactivated influenza vaccines IM
• agegt 13 years0.5 ml 1
• age 4-12 years0.5 ml 2 (4 w)
• age 6- 48 m. 0.25 ml 2 (4 w)

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PROPHYLAXIS(Chemoprophylaxis)

• amantadine or rimantadine, 100 to 200 mg/d, (
  70 to 100 against influenza A infection) .
• Chemoprophylaxis with oseltamivir (75 mg/d by
  mouth) ( 84 to 89 against influenza A and B).
• for high-risk individuals who have not received
  influenza vaccine or in a situation where the
  vaccines previously administered are relatively
  ineffective because of antigenic changes in the
  circulating virus.

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PROPHYLAXIS(Chemoprophylaxis)

• During an outbreak antiviral chemoprophylaxis
  with inactivated vaccine,(drugs do not interfere
  with an immune response to the vaccine. In fact,
  there is evidence that the protective effects of
  chemoprophylaxis and vaccine may be additive.)
• concurrent administration of chemoprophylaxis and
  the live attenuated vaccine may interfere with
  the immune response to the vaccine.

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PROPHYLAXIS(Chemoprophylaxis)

• Chemoprophylaxis control nosocomial outbreaks
  of influenza.
• For prophylaxis, administration should be
  instituted promptly when influenza activity is
  detected and must be continued daily for the
  duration of the outbreak.
• Amantadine and rimantadine are approved for
  prophylaxis in adults and in children(gt1years)
  oseltamivir is approved for prophylaxis in adults
  and in children(gt13 years old) .

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PROPHYLAXIS(Chemoprophylaxis)

• Persons at High Risk Who Are Vaccinated After
  Influenza Activity Has Begun(for persons at high
  risk during the time from vaccination until
  immunity has developed. Children aged lt9 years
  who receive influenza vaccine for the first time
  can require 6 weeks of chemoprophylaxis (i.e.,
  chemoprophylaxis for 4 weeks after the first dose
  of vaccine and an additional 2 weeks of
  chemoprophylaxis after the second dose).)

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PROPHYLAXIS(Chemoprophylaxis)

• Persons Who Provide Care to Those at High Risk
  (employees of hospitals, clinics, and
  chronic-care facilities household members
  visiting nurses and volunteer workers)
• Persons Who Have Immune Deficiencies (HIV,
  chiefly those with advanced HIV disease)

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PROPHYLAXIS(Chemoprophylaxis)

• When outbreaks occur in institutions,
  chemoprophylaxis should be administered to all
  residents, regardless of whether they received
  influenza vaccinations during the previous fall,
  and should continue for a minimum of 2 weeks. If
  surveillance indicates that new cases continue to
  occur, chemoprophylaxis should be continued until
  approximately 1 week after the end of the outbreak

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PROPHYLAXIS(Chemoprophylaxis)

• Chemoprophylaxis also can be offered to
  unvaccinated staff members who provide care to
  persons at high risk.
• Chemoprophylaxis should be considered for all
  employees, regardless of their vaccination
  status, if the outbreak is suspected to be caused
  by a strain of influenza virus that is not
  well-matched to the vaccine

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PROPHYLAXIS(Chemoprophylaxis)

• In addition to nursing homes, chemoprophylaxis
  also can be considered for controlling influenza
  outbreaks in other closed or semiclosed settings
  (e.g., dormitories or other settings in which
  persons live in close proximity).

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Household Contact Treatment

• Frequent handwashing
• N95 masks/eye protection (feasible?)
• Monitor temperature twice daily for 7 days
• Quarantine

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Influenza Prevention What Can We Do?

• Stay home when sick
• Respiratory hand hygiene
• Cover your cough
• Wash hands and/or
• use alcohol hand gel
• Avoid touching eyes, nose, mouth
• Implement social distancing measures
• Masks?
• Pandemic preparedness planning

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Health Care Worker Surveillance

• Record temperature twice daily

Prophylaxis
Normal
Abnormal Symptoms
Remove from workplace
Evaluate for influenza
Treatment
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Infection control considerations /Isolation
facilities

• appropriate precaution measures
• wear eye protection, gowns, gloves and
  particulate respirators that are at least as
  effective as the NIOSH-certified N95, EU FFP2 or
  equivalent
• an airborne precaution room (mechanically or
  naturally ventilated rooms with at least 12 air
  exchanges/hour and safe airflow), in a single
  well-ventilated room, or in a negative pressure
  room when available.

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Special infection control considerations during
ventilatory support therapy

• endotracheal intubation, as well as possibly NPPV
  and oxygen therapy, were risk factors for SARS
  nosocomial transmission, although inconsistent
  use of PPE is a key confounding variable in such
  studies

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Special infection control considerations during
ventilatory support therapy

• supplemental oxygen via mask dispersion of
  potentially infectious aerosols
• Oxygen masks with an expiratory port and HEPA
  filter will reduce aerosol production

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Special infection control considerations during
ventilatory support therapy

• HEPA filters should be attached to the expiratory
  ports of ventilators, and a closed tracheal
  suctioning system used for aspiration of
  respiratory secretions to reduce generation and
  spread of infectious aerosols.

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Special infection control considerations during
ventilatory support therapy

• To minimize the risk of nosocomial infection, it
  is important to maintain adequate medical ward
  ventilation during application of oxygen therapy
  or NPPV. If NPPV is to be used, a closed system
  with a head helmet and an expiratory port HEPA
  filter is recommended whenever possible

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CONTROL
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VACCINATION
CONTROL
DEPOPULATIO
QURANTINE
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Transmission of AI virus A/H5N1 to humans

• From infected animals to humans
• contact with respiratory secretions, faeces,
  contaminated feathers, blood from infected birds.
• Environmental contamination
• Raw food consumption (?)
• From a patient to health care
• personnel/family members

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Asias particularities Live Animal Markets
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AI Transmission issues

• Need to better understand the kind of close
  contacts with poultry that pose a risk to public
  health.
• Clear need to improve biosecurity and hygiene at
  live animal markets

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Control of animal outbreaks

• Stamping out policies
• Destruction of infected flocks and surrounding
  flocks.
• Strengthening disease surveillance
• Delay of 3-6 months before restocking
• Vaccination
• Need for biosecurity capabilities
• Implications for trade

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Benefits of fit testing

• Study 25 volunteers, 21 models of N-95
  respirators
• Without fit testing, 95 of the tests had up to
  33 leakage
• With fit testing, 95 of the tests had no more
  than 4 leakage

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REFERENCES

• Treanor J. Influenza Virus. In Mandell, Douglas,
  and Bennett's Principles and Practice of
  Infectious diseases. 6th ed. New York
  Elsevier/Churchill Livingstone 2005chap 162
• Kasper,HARRISONS Principles of Internal
  Medicine 16th ed.2005 chap.171
• Clinical management of human infection with avian
  influenza A (H5N1) virus ,Updated advice 15
  August 2007 ,wold health organization
• Prevention and Control of Influenza
  Recommendations of the Advisory Committee on
  Immunization Practices (ACIP) , Morbidity and
  Mortality Weekly Report , July 28, 2006 / Vol. 55
  / No. RR-10, department of health and human
  services Centers for Disease Control and
  Prevention