Post on 28-Dec-2015
Influenza is usually a respiratory infection
Transmission Regular person-to-person transmission Primarily through contact with respiratory
droplets Transmission from objects (fomites) possible
National Center for Disease Prevention and Control, DOH
Key CharacteristicsCommunicability
Viral shedding can begin 1 day before symptom onset
Peak shedding first 3 days of illness
Correlates with temperature Subsides usually by 5-7th
day in adults Infants, children and the
immuno-compromised may shed the virus longer
National Center for Disease Prevention and Control, DOH
Incubation period Time from exposure to onset of symptoms 1 to 4 days (average = 2 days)
Seasonality In temperate zones, sharp peaks in winter months In tropical zones, circulates year-round with
seasonal increases.
National Center for Disease Prevention and Control, DOH
Individuals at Increased Risk for Hospitalizations and Death
Elderly > 65 yearsChildren less than two yearsCertain chronic diseases
Heart or lung disease, including asthma Metabolic disease, including diabetes HIV/AIDs, other immuno-suppression Conditions that can compromise respiratory function or
the handling of respiratory secretionsPregnant women
National Center for Disease Prevention and Control, DOH
INTENSIVE-CARE PATIENTS WITH SEVERE NOVEL INFLUENZA A (H1N1)
VIRUS INFECTION --- MICHIGAN, JUNE 2009
10 patients wiith Influenza A(H1N1) and ARDS admitted at ICU. Of the 10 patients 9 were obese (BMI>30) including 7 who are extremely obese (BMI>40). Five had pulmonary emboli; Nine had MODS. 3 patients died. Clinicians should be aware of the potential for severe complications of H1N1 virus infection in extremely obese patients.
Conclusion
Predominance of malesHigh prevalence of obesityFrequency of clinically significant pulmonary
emboli and MODS
Influenza A VirusesInfluenza A viruses categorized by subtype
• Classified according to two surface proteins
Hemagglutinin (H) – 16 known
Neuraminidase (N) – 9 known
N
H
National Center for Disease Prevention and Control, DOH
A / Sydney / 05 / 97 (H3N2)
Nomenclature
Virus type
Strain number
Virus subtype
Place virusisolated
Year isolated
National Center for Disease Prevention and Control, DOH
Region
Cumulative total
as of 11 October 2009
Cases* Deaths WHO Regional Office for (AFRO) 12456 70 WHO Regional Office for the (AMRO) 153697 3406 WHO Regional Office for the (EMRO) 13855 90
WHO Regional Office for (EURO) Over
61000 At least
207 WHO Regional Office for (SEARO) 39522 530 WHO Regional Office for the Western Pacific (WPRO) 118702 432
Total Over
399232 At least
4735
Influenza A (H1N1) is a novel virus
Unusual combination of genetic material from pigs, birds & humans which have re-assorted
Affects all age groupsVaccines for human seasonal flu can not
protect humans against the novel virus
National Center for Disease Prevention and Control, DOH
Swine Influenza Viruses
RNA virusesPigs can be infected by avian influenza and
human influenza viruses as well as swine influenza viruses.
Re-assort and new viruses that are a mix of swine, human and avian influenza viruses can EMERGE
National Center for Disease Prevention and Control, DOH
Signs & Symptoms of Influenza A (H1N1)
FeverLethargyLack of appetiteCoughingRunny NoseSore throatNausea / VomitingDiarrhea
National Center for Disease Prevention and Control, DOH
Swine H1N1 vs. Human H1N1
swine H1N1 flu virus NOT the same as human H1N1 virus
antigenically very different from human H1N1 viruses
vaccines for human seasonal flu can not protect humans from swine H1N1
National Center for Disease Prevention and Control, DOH
Transmission: Food-Borne?
NOInfluenza A (H1N1) viruses are not
transmitted through food Safe to eat properly handled and cooked pork
and pork productsCook pork at an internal temperature of 70°C
(160°F)
National Center for Disease Prevention and Control, DOH
Diagnosis and Laboratory Confirmation
Clinically diagnosedRespiratory Specimen
• first 4 to 5 days of illness
• can shed for 10 days or longerSpecimens sent to US CDC
• ONLY laboratory that can isolate and identify swine influenza type A virus
National Center for Disease Prevention and Control, DOH
SpecimensUpper respiratory tract specimens as
recommended are the most appropriate. taken from the deep nostrils (nasal swab),
nasopharynx (nasopharyngeal swab), Nasopharyngeal aspirate, throat or bronchial aspirate.
Laboratory Diagnosis
Rapid Influenza Diagnostic Test
Antigen detection test that detect influenza viral nucleoprotein antigen
Can provide results within 30 minutes
Sensitivity 40-69%
Table 1. Comparison of Available Influenza Diagnostic Tests1 Influenza Diagnostic Tests
Method Availability TypicalProcessing Time2
Sensitivity3 for 2009 H1N1 influenza
Distinguishes 2009 H1N1 influenza from other influenza A viruses?
Rapid influenza diagnostic tests (RIDT)4
Antigen detection
Wide 0.5 hour 10 – 70% No
Direct and indirect immunofluorescence assays (DFA and IFA)5
Antigen detection
Wide 2 – 4 hours 47–93% No
Viral isolation in tissue cell culture
Virus isolation
Limited 2 -10 days - Yes 6
Nucleic acid amplification tests (including rRT-PCR) 7
RNA detection
Limited8 48 – 96 hours [6-8 hours to perform test]
86 – 100% Yes
Treatment
Influenza A (H1N1) is sensitive to: Oseltamivir (tamiflu) Zanamivir
Self medication is discouraged, may induce drug resistance
Chemoprophylaxis Oseltamivir
National Center for Disease Prevention and Control, DOH
Table 1. Antiviral medication dosing recommendations for treatment or chemoprophylaxis of novel influenza A (H1N1) infection.
(Table extracted from IDSA guidelines for seasonal influenza.)
Agent, group Treatment Chemoprophylaxis
Oseltamivir
Adults75-mg capsule twice per day
for 5 days75-mg capsule once per day
Children ≥ 12 months
15 kg or less60 mg per day divided into 2
doses30 mg once per day
16-23 kg90 mg per day divided into 2
doses45 mg once per day
24-40 kg120 mg per day divided into 2
doses60 mg once per day
>40 kg150 mg per day divided into 2
doses75 mg once per day
Zanamivir
AdultsTwo 5-mg inhalations (10 mg
total) twice per dayTwo 5-mg inhalations (10 mg
total) once per day
ChildrenTwo 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)
CDC Health Advisory Distributed via Health Alert Network July 09, 2009
Three Reports of Oseltamivir Resistant Novel Influenza A (H1N1) Viruses
ANTI VIRAL CHEMOPROPHYLAXIS
Post-exposure prophylaxis for health care workers, first responders and workers who did not have adequate PPE when in contact.
Anti-viral prophylaxis is not recommended to close contacts except when they belongto high risk group.
Vaccine
Process of production is underway, but may take 5 – 6 months
Seasonal influenza vaccine provides protection against the seasonal human influenza strains only
National Center for Disease Prevention and Control, DOH
Vaccine
Supplier Vaccine Form Mercury µg/0.5 mL
Age
MedImmune(nasal spray)
Live virus 0.2 mL(nasal spray sprayer)
0 2-49 yrsb
Sanofi (IM)a Inactivated0.25 mL prefilled syringe0.5 mL prefilled syringe5 mL multidose vial
00
25
6-35 mosb > 36 mosb > 6 mosb
Novartis (IM)a 5 mL multidose vial0.5 mL prefilled syringe
25< 1.0
≥ 4 yrsb > 4 yrsb
CSL Biotherapies, Inc (IM)a
0.5 mL prefilled syringe5.0 mL multidose vial
024.5
> 18 yrs> 18 yrs
0.5 mL doses contain 15 µg hemagglutinin of the vaccine strain A/California/7/2009 (H1N1)Two doses separated by 4 weeks for children 2-9 years
(CDC. Update on influenza A (H1N1) monovalent vaccines. MMWR Morb Mortal Wkly Rep. 2009;58:1100-1101.)
INTERIM GUIDELINES NO.2: INFECTION CONTROL AND USE OF PERSONAL PROTECTIVE EQUIPMENT IN
INFLUENZA A
HEALTH CARE PERSONNEL
Standard and droplet precautions when working in direct contact
If there is risk of splashes: particulate respirator; eye protection;clean, non-sterile, long sleeved gown; sterile gloves
Frequent and proper handwashing
Isolate patient in a single room.Reinforce standard precautions with droplet
and contact precautionUse appropriate Personal Protective
Equipment for all those entering patients rooms.
Restrict number of visitors.Healthcare workers on direct contact
should monitor their own temperature 2X a day and report any febrile event.
VaccinationInfluenza vaccine is the best prevention for
seasonal influenza.Inactivated viruses in the vaccine
developed from three circulating strains (generally 2 Type A and 1 Type B strain) Therefore, seasonal “flu shot” only works for 3
influenza subtypes and will not work on pandemic strains.
Live, intranasal spray vaccine for healthy non-pregnant persons 5-49 years
Inactivated, injectable vaccine for persons 6 months and olderNational Center for Disease Prevention and Control, DOH
Influenza Viruses
Classified into types A, B, and C
• Only Types A and B cause significant disease
• Types B and C limited to humans
• Type A viruses More virulent Affect many species
C Goldsmith, CDC
National Center for Disease Prevention and Control, DOH
The FDA has approved 4 vaccine preparations. The following data highlight relevant issues:All influenza vaccine preparations in the United States for the 2009-2010 season contain residual egg protein and none contain adjuvant;Children 6 months to 9 years of age who are given influenza A (H1N1) monovalent vaccine should receive 2 doses separated by about 4 weeks; persons ≥ 10 years of age should receive 1 dose;The influenza A (H1N1) monovalent vaccines were made according to standards used for seasonal and influenza vaccines and have the same age group indications, precautions, and contraindications as vaccines that are FDA-approved for seasonal flu; preliminary data indicate that the safety and efficacy of the 2009 Influenza A (H1N1) monoclonal vaccine is the same as winter;There is minimal evidence of significant antigenic change since the first characterization of the virus in April 2009, indicating that the virus continues to be well matched with the vaccine strain; andThe vaccines of the 4 suppliers have some differences that are important to recognize:for seasonal flu vaccines;Side effects, including local pain at the injection site, were reported in 46% of recipients, and systemic reactions (headache, malaise or myalgias) were reported in 45%; the safety profile is consistent with the experience with seasonal flu vaccine;Influenza activity due to influenza A (H1N1) increased in September 2009 and is expected to continue through fall and
Children 6 months to 9 years of age should receive 2 doses separated by 3 weeks. Children 10 years and older and adults should receive 1 dose.
The following groups should receive the vaccine as soon as it becomes available:•Pregnant women;•People who live with or care for infants younger than 6 months of age;•Healthcare workers (HCWs) and emergency medical personnel;•Persons 6 months to 24 years of age;•Persons 25-64 years of age who have chronic diseases (including immunodeficiency states) that pose risk for influenza.
When more vaccine becomes available, the following persons should be vaccinated:•Healthy persons ages 25-64 years; and•Adults 65 years of age and older.
S-top spreading panic acts / thoughts.
T-amiflu panic buying (Avoid).
O-ver-reacting with vaccines.
P-rotective Equipments
S-ocial Distancing.W-ASH YOUR HANDSI-solate voluntarily.N-o Unnecessary travel. E-arly Consult.
F-lu symptom declared.L-imit Crowded areas.U-pdate yourself.
H1N1 - Dos & DON’Ts !
N. Macalintal Jr. MD, FPCP, FPCCP