Transcript Slide 1

H1N1 virus -update
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Dr Anna Sharma
MBBS MSc MRCP(paeds)
FRCPCH
Consultant paediatrician
Immunisation clinical leadHillingdon PCT
Structure of Influenza virus
• H=haemaglutinin
• N=neuraminidase
• Family of
orthomyxoviridae
RNA viruses
• Infect humans pigs
birds and horses
H1N1 virus -epidemiology
Flu pandemics
Name
Year
Deaths (millions) Subtype
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1889-90
1918-20
1957-58
1968-69
1976
2009 -
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40 (?)
1-1.5
0.75
Russian Flu
Spanish Flu
Asian Flu
Hong Kong Flu
New Jersey Flu
Swine Flu
possibly H2N2
H1N1
H2N2
H3N2
H1N1
H1N1
What is a pandemic?
• Greek-pan=all,demos=people
• WHO definition
– Emergence of a new infectious disease
– Agents infect humans causing serious illness
– Agents spread easily and sustainably among
humans
• Pandemic phasesWHO definitions
The 1918 pandemic
• 1918- a severe haemmorhagic disease
• Deaths by secondary infection- mainly
pneumonia
• ‘Cytokine storm’ overwhelms healthy
immune sytems
• Severe forms spread widely due to
transport of infected soldiers in crowded
trains to field hospitals
1918-19 epidemic-comparision of age
profile with 1917 seasonal flu age
profile
Rate per 100,000 of new cases of
pandemic influenza in England by
week and age group (17/09/09-HPA)
Antiviral prescriptions as of
17/09/09 (HPA)
Previous flu pandemics
‘Spanish flu’ 1918-19
– H1N1
• Infected a third of the
worlds population
• Killed 50 million in 6
months
• 200,000 died in UK
• 2-3% mortality
‘Asian flu’ 1956-57
– H2N2
• Mainly young children
• Clinical attack rate 30%
• Mortality<0.2%
UK mortality 1918
figure taken from Center for Disease Control and Prevention USA
Pandemic of 1918 and nowcomparision
• Started in one military
installation in US
• Weakened population at end of
war
• Affected mainly young adults
• More serious cases often
travelled in crowded trains and
in field hospitals- spreading
infection
• Very rapid spread throughout
the world
• Began to subside when
doctors started to treat
pneumonia with antibiotics
• Started in multiple generational
community in Mexico
• Antivirals available before
vaccine
• Heightened emergency
preparedness due to alerts on
anthrax/bioterrorism in 9/11
• Open and prompt monitoring of
cases
• Recognised rating system to
declare a pandemic
• Digital media communications
• Containment of cases early on
• Only milder cases tend to
travel and spread infection
• Milder infection
Case Definition/Diagnostic criteria
• Fever >38 C or a history
of fever
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• Influenza like illnessTWO or more of
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Cough
Sore throat
Rhinorrhoea
Joint /limb pains
Headache
Vomiting
Diarrhoea
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OR
Fever >38C
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Severe and/or life
threatening illness
suggestive of an
infection
Antivirals
• Tamiflu (Oseltamivir)
• Relenza (nasal-more suitable for pregnant
women)
• Not suitable for
– Pregnant women
– Children under 1
– Those in risk groups
– Prophylaxis
– Hot Line
Dose to prescribe antivirals in
children
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Over 1 year
Oseltamivir capsules
<15 kg =30mg bd 5/7
15-23 kg=45mg bd 5/7
23-40 kg=60mg bd 5/7
>40 kg =75mg bd 5/7
Renal impairment
Possibly zanamivir
Under 1 year
Prescribe made up
solution
• 15 mg in 1 ml
• (Bitter taste)-syringe
graduated in ml
Can get Tamiflu
suspension
• 12 mg in 1 ml -syringe
graduated in mg
• 2mg/kg bd 5/7
• Not licensed
• Potential
neurotoxicity/
• Encephalopathy
• Could be ineffective in
<4 weeks old
• RCPCH consensus
statement
• So weigh up risks and
benefits
Side effects of oral antivirals
• Gastroenterological
– Nausea
– Abdominal pain
– diarrhoea
• Neuropsychiatric
– Irritability
– Reduced concentration
– Bad dreams
– delusions
H1N1 virus -vaccines
Introducing a new vaccine
• Burden of disease
• Availability of timely and safe treatment for
disease
• Availability and efficacy of vaccine
• Safety profile of vaccine
• Disease profile (age/clinical groups)
• Acceptability
• Cost/effectiveness
Vaccine characteristics
Vaccine characteristics
Vaccine characteristics
1976-New Jersey strain H1N1
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40 million people vaccinated
Vaccine withdrawn after 10 weeks
500 cases of Guillain Barre syndrome
25 deaths
8 fold increase in baseline incidence of
Guillain Barre
Gullian barre syndrome
• Acute flaccid paralysis
• Muscle weakness, loss of
sensation
• due to demyelination
• caused by autoimmunity
to myelin sheath of nerve
cells.
• 80% recover. Some
progress. Mortality 2-3%
Fisher syndrome
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Variant of Guillain Barre
Abnormal muscle co-ordination
Paralysis of eye muscles
Absent tendon reflexes
Specific autoantibodies.
Prognosis good
Recovery within 2-4 weeks
• http://bpna.org.uk/audit/GBS/home.htm
• http://www.ich.ucl.ac.uk/clinical_informatio
n/clinical_guidelines/cmg_guideline_00007
Guillaine barre syndrome
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Presenting problem(s)
History- ask about:
Onset and progression of weakness
Distribution and symmetry of weakness
Sensory symptoms (pain, parasthaesia)
Cranial nerve involvement (particularly
bulbar dysfunction, diplopia)
Gait disturbance
Sphincter disturbance
Symptoms of autonomic dysfunction
(sweating, palpitations)
Respiratory symptoms
History of recent infection/diarrhoea/fever
Medications (antibiotics, analgesics)
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Examination:
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Primary assessment (ABCDE)
Conscious level (use modified Glasgow Coma
Scale)
Cranial nerve function including
Eye movements
Facial weakness
Bulbar function (speech, swallow, gag, cough,
drooling)
Peripheral neurological examination to include
evaluation of:
Motor deficit (tone, power, reflexes)
Ataxia
Sensory dysfunction (location, sensory level if
present)
Neck and spine (rigidity, tenderness, bruising)
Respiratory examination (include respiratory rate,
vital capacity, O2 sats)
Cardiovascular examination (include pulse, blood
pressure)
Abdominal examination (palpable bladder,
constipation, sensation, abdominal reflexes)
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Guillain Barre-investigations
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Blood tests
Full blood count
Urea& electrolytes, liver function tests
ESR
CRP
Blood culture
Swine flu antibody
Serology for mycoplasma, EBV, CMV,
Borrelia, VZV, coxsackie,
campylobacter
If indicated:
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antiganglioside antibodies (anti-GQ1b
in MDS, anti-GM1 in AMAN)
Polio serology
Toxicology
Heavy metals (lead, mercury, arsenic)
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CSF (may be normal within 7 days of
onset of symptoms)
Cells
Protein
Glucose
Stool
M,C&S
Virology
Consider botulinum toxin
Urine
Consider toxicology, porphyrins
Throat swab
M,C&S
Viral culture
Guillain Barre- management
• Indications for PICU
• Vital capacity <20mg/kg
or rapidly deteriorating
• Rapidly progressive
tetraparesis with loss of
head control
• Severe bulbar palsy
• Severe autonomic
cardiovascular instability
• Indications for
Immunoglobulin (see
infusion schedule)
• Progressive deterioration
at time of presentation
• Non-ambulent patient
• Bulbar dysfunction
• Respiratory compromise
Guillain Barre
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Other management considerations
Physiotherapy
Pain relief
S/C Heparin, anti-thrombotic stockings
Feeding/nutrition
Bed sore prevention, skin care
Eye care
Communication aids
Psychology
H1N1 virus –2009/10 vaccine
programme
CMO letter dated 13th August 2009
Influenza vaccination plan in
Hillingdon
• August/September 09
– Vaccine programme planning
– Health professionals’ training
• October 09
– Delivery of vaccine, syringes and needles to
• Hillingdon Hospital
• Mount Vernon Hospital
• 2 other community sites
– Vaccination of health and social care workers, priority
groups
• Seasonal flu vaccine to be offered with second dose of H1N1
flu vaccine
Vaccine uptake
• Uptake in 2008/9
– 74.1% in over 65’s
– 47.1% in clinical risk groups under 65
– 16.5% in Staff nationally
– WHO target is 75%
Vaccination of health and social
care professionals
• Occupational Health Services Programme via
Hillingdon Hospital and Hillingdon Council.
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GP’s, Practice Nurses
Hospital Staff (including cleaners)
PCT staff
Volunteer workers
Dentists, Community Pharmacists
Social care staff
Students, trainees in direct contact with patients
Staff in nursing care homes
Vaccination of priority groups
• People age 6 months to 65 years in
clinical high risk groups to be offered
seasonal flu vaccine and swine flu
vaccine.
– Identification and call/recall in primary care
– ‘Primary care clusters’ to operate in the event
of staff shortage due to sickness/surge
– Trained PCT nursing staff to be deployed to
assist vaccination sessions.
– Records to be entered onto EMIS
Clinical risk groups
Definition of ‘High risk’ groups
• Immunosuppressed
• Long term respiratory illness
• Long term renal illness
Clinical risk groups-contd
Clinical risk groups-contd
Vaccination of Priority groups
• ‘All pregnant women subject to licensing
conditions’ Pregnant women in their 2nd
and 3rd trimester
– Identification and call/recall in primary care
assisted by midwives (community/hospital)
– Information given by midwives
– Vaccination in primary care
– Data entry onto EMIS checked by midwives.
Priority groups
• Household contacts of the
immunosupressed
Priority groups contd
• Over 65’s in clinical risk groups
Data recording/consent
• PGD to cover vaccine
• Staff trained to national minimum
standards for immunisation
• Consent informed via leaflet/discussion
• Immunisation data recorded on patient
record (pchr/card)
• And on EMIS/Occupational health data
base
Monitoring side effects
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Record in notes
MHRA ‘yellow card’ system
BPSU ‘orange card’ surveillance system
BNSU
Notification of new cases-europe
-WHO update
Notification of new cases- world
-WHO update