Novel H1N1 Influenza A Update. William Muth MD 2 Oct 2009

Transcription

1 Novel H1N1 Influenza A Update William Muth MD 2 Oct 2009

2 Novel H1N1 Influenza A Update Epidemiology Treatment Chemoprophylaxis Vaccine Infection Prevention

3 Novel H1N1 Influenza A International Epidemiology CDC

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5 Currently Virtually All Circulating Influenza is Novel H1N1 in U.S.

6 Epidemiology circa July 2009 Median age of laboratory confirmed infection with H1N1 influenza 12 years Median age of hospitalization for H1N1 influenza 20 years Median age of death due to H1N1 influenza 37 years As of July 2009 only 282 (5%) of 5,514 hospitalizations and 29 (8%) of the 353 reported deaths due to novel H1N1 influenza A had occurred among persons aged 65 years (CDC, unpublished data).

7 Novel H1N1 Confirmed and Probable Case Rate in the United States, By Age Group Median Age 12 CDC

8 Hospitalization Novel H1N1 vs. Seasonal Influenza Median Age 20 for Hospitalizations due to Novel H1N1

9 H1N1 Influenza A Deaths, United States (circa July 2009) Median Age 37 CDC

10 Influenza Pediatric Mortality CDC

11 Clinical Illness due to Novel H1N1 Influenza A* Typical influenza signs and symptoms fever, cough, sore throat, myalgias, headache, prostration Some reports have emphasized increased gastrointestinal symptoms. Complications have included post-influenza bacterial pneumonias. Roughly 2/3 of severe illness has occurred among those with traditional risk factors. Severe influenza viral pneumonia in young healthy individuals has occurred. *CDC Case Definition for influenza: Fever (temperature of 100 F [37.8 C] or greater) and a cough and/or a sore throat in the absence of a known cause other than influenza

12 Risk Groups for Influenza Complications Children younger than 2 years old Adults 65 years of age or older Pregnant women Persons with the following conditions: Chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic, hematological (including sickle cell disease), or metabolic disorders (including diabetes mellitus) Disorders that that can compromise respiratory function or the handling of respiratory secretions or that can increase the risk for aspiration (e.g., cognitive dysfunction, spinal cord injuries, seizure disorders, or other neuromuscular disorders) Immunosuppression, including that caused by medications or by HIV Persons younger than 19 years of age who are receiving long-term aspirin therapy, because of an increased risk for Reye syndrome.

13 Novel H1N1 Influenza A - Diagnosis Point of care rapid tests have a 10-70% sensitivity Can distinguish influenza A from influenza B Don t distinguish seasonal vs. novel influenza H1N1 PCR performed at Oregon State Public Health Laboratory Only available for hospitalized patients Definitive but not timely Outpatient diagnosis will depend upon clinical likelihood and current epidemiology.

14 Novel H1N1 Influenza Antiviral Treatment Antiviral Research 79 (2008)

15 Novel H1N1 Influenza Antiviral Treatment Treatment is recommended for all hospitalized patients with confirmed, probable or suspected 2009 H1N1 or seasonal influenza. Early empiric treatment should be considered for outpatients who are at higher risk for influenzarelated complications if initiated with first 48 hrs. Signs and symptoms of severe illness due to suspected influenza are in indication for immediate treatment, regardless of previous health or age. Because of limitations of diagnostic tests treatment decisions usually will have to be made empirically.

16 Novel H1N1 Influenza Chemoprophylaxis Consider for: Persons who are at higher risk (slide #11) for complications of influenza and are a close contact of a person with confirmed, probable, or suspected novel H1N1 influenza during that person s infectious period. Health care personnel, public health workers, or first responders who have had a recognized, unprotected close contact exposure to a person with confirmed, probable, or suspected novel H1N1 influenza during that person s infectious period if they are at higher risk (slide #11) of complications of influenza (SHS). Antiviral agents should not be used for post exposure chemoprophylaxis in healthy children or adults based on potential exposures in the community, school, camp or other settings. Chemoprophylaxis generally is not recommended if more than 48 hours have elapsed since the last contact with an infectious person.

17 Novel H1N1 Antiviral Treatment and Chemoprophylaxis Table 3. Antiviral medication dosing recommendations for treatment or chemoprophylaxis of novel influenza A (H1N1) infection. Oseltamivir Agent, group Treatment Chemoprophylaxis Adults 75-mg capsule twice per day for 5 days 75-mg capsule once per day 15 kg or less 60 mg per day divided into 2 doses 30 mg once per day Children 12 months kg kg 90 mg per day divided into 2 doses 120 mg per day divided into 2 doses 45 mg once per day 60 mg once per day >40 kg 150 mg per day divided into 2 doses 75 mg once per day Zanamivir Adults Two 5-mg inhalations (10 mg total) twice per day Two 5-mg inhalations (10 mg total) once per day Children Two 5-mg inhalations (10 mg total) twice per day (age, 7 years or older) Two 5-mg inhalations (10 mg total) once per day (age, 5 years or older) Oseltamivir can be prescribed for children <1 under an FDA emergency use authorization

18 Treatment/Chemoprophylaxis of Influenza when Oseltamivir-Resistant Viruses are Circulating Novel H1N1 influenza A oseltamivir (Tamiflu) resistance is very uncommon However, seasonal H1N1 influenza A has been oseltamivir resistant Therefore treatment/chemoprophylaxis when seasonal H1N1 flu is circulating may require: Zanamivir (Relenza) or Oseltamivir plus an adamantane (amantadine or rimantadine)

19 Novel H1N1 Influenza A Vaccine Prevention!

20 Vaccination for Seasonal Influenza Safe and effective May have even more benefit this year Protection of patients Decreased employee illness and absenteeism Decreased demands on limited quantities of antiviral medications Declination form required this year of SHS healthcare workers declining vaccination HCWs who decline vaccination may be required to wear surgical mask when providing patient care during the flu season.

21 Novel H1N1 Influenza A Vaccine Monovalent Manufactured by same methods as trivalent seasonal influenza vaccine No unusual safety issues identified in licensure trials Available as inactivated intramuscular injectable and live attenuated intranasal administrable vaccines Contraindicated in persons with severe egg allergy, history of Guillain Barre within 6 weeks of previous flu vaccine, moderate or severe acute illness (intranasal live vaccine has additional contraindications) Likely to be available in increments beginning in October Provided by U.S. government with distribution via local public health departments Two doses likely necessary for children < 10 years

22 ACIP Recommended Use of Influenza A (H1N1) 2009 Monovalent Vaccine* Initial Target Groups Pregnant women Persons who live with or provide care for infants aged <6 months (e.g., parents, siblings, and daycare providers) Health-care and emergency medical services personnel Persons aged 6 months--24 years Persons aged years who have medical conditions (slide #11) that put them at higher risk for influenza-related complications. *Order of target groups does not indicate priority

23 ACIP Subset of Target Groups During Limited Vaccine Availability Vaccinate* Pregnant women Persons who live with or provide care for infants aged <6 months Health-care and emergency medical services personnel who have direct contact with patients or infectious material Children aged 6 months--4 years Children and adolescents aged years who have medical conditions that put them at higher risk for influenzarelated complications Defer Vaccination Persons 5-24 years Persons years with high risk medical conditions *Order of target groups does not indicate priority

24 Inactivated Influenza Vaccine Adverse Reactions Local reactions 15%-20% Fever, malaise not common Allergic reactions rare Neurological very rare reactions

25 Live Attenuated Influenza Vaccine (LAIV)

26 Live Attenuated Influenza Vaccine (Flumist) Contraindications and Precautions Children younger than 2 years of age* Persons 50 years of age or older* Persons with chronic medical conditions (slide #11)* Children and adolescents receiving longterm aspirin therapy* *These persons should receive inactivated influenza vaccine

27 Live Attenuated Influenza Vaccine Contraindications and Precautions Immunosuppression from any cause* Pregnant women* Severe (anaphylactic) allergy to egg or other vaccine components History of Guillain-Barré syndrome Children younger than 5 years with recurrent wheezing* Moderate or severe acute illness *These persons should receive inactivated influenza vaccine

28 Live Attenuated Influenza Vaccine Adverse Reactions Children no significant increase in URI symptoms, fever, or other systemic symptoms significantly increased risk of asthma or reactive airways disease in children months of age Adults significantly increased rate of cough, runny nose, nasal congestion, sore throat, and chills reported among vaccine recipients no increase in the occurrence of fever No serious adverse reactions identified

29 Simultaneous Administration of LAIV and Other Vaccines Inactivated vaccines can be administered either simultaneously or at any time before or after LAIV Seasonal and novel H1N1 LAIV should not be administered on the same day Other live vaccines can be administered on the same day as LAIV Live vaccines not administered on the same day should be administered at least 4 weeks apart

30 Infection Prevention

31 Infection Prevention - General Hand hygiene and respiratory etiquette Signage Hygiene/respiratory etiquette stations Segregation of patients with influenza like illness (ILI) in waiting rooms, ERs, urgent cares Surgical masks for patients suffering with ILI and healthcare workers evaluating them

32 Novel H1N1 Influenza Infection Prevention - Hospital All hospitalized patients with influenza like illness* should be placed in contact/droplet isolation. Any healthcare workers (HCWs) entering the room should use PPE: Gowns, gloves, surgical masks Eye protection if anticipating contact within 3 feet HCWs should use N95 masks if involved in procedures likely to cause aerosolization intubation, bronchoscopy, nebulizer treatments, airway suctioning *Fever (temperature of 100 F [37.8 C] or greater) and a cough and/or a sore throat in the absence of a known cause other than influenza

33 Hospital Isolation for Influenza Isolation for confirmed or suspected influenza should be maintained for seven days from symptom onset or until symptoms abate whichever is longer. Isolation can be discontinued if a rapid test for influenza is negative and influenza is judged unlikely by the responsible physician. It is not necessary to have a negative H1N1 PCR result prior to discontinuing isolation if a physician judges infection unlikely.

34 Heathcare Worker Illness Healthcare workers with ILI should stay home until their illness subsides avoid presenteeism Healthcare workers who become ill with influenza like illness after unprotected exposure to a patient known definitely to have influenza should stay home for seven days from onset of illness or until symptoms abate whichever is longer. Those with risk factors for complications of influenza will be offered antiviral treatment.

35 Influenza Patient Triage* Influenza Like Illness Temperature>100 plus cough, myalgias, headache, sore throat, etc No Risk Factors for Complications of influenza Presence of Risk Factors for Complications of Influenza Pregancy, obesity, age <2 or >65, diabetes, neuromuscular disorders, cardiopulmonary disorders, immunosuppression, etc Difficulty Breathing Confusion Persistent inability to adequately eat or drink Stay home Drink liquids Rest Acetaminophen, symptomatic care Do not expose others Seek Medical Attention Such patients may be candidates for antiviral therapy Seek Emergency Medical Attention *Such a scheme could be employed in a medical office setting but only by persons skilled in medical assessment.

36 It wasn t our fault!!