Teaching Resource for Primary Health Care professionals Pandemic Influenza

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Teaching Resourcefor Primary Health Care
professionalsPandemic Influenza
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Influenza Viruses

• Three types A, B and C.
• Influenza type B cause seasonal influenza
  epidemics that are clinically similar but with
  higher attack rates in children.
• Influenza type C these viruses cause only mild
  disease, and are not considered clinically
  important to diagnose or treat.

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Influenza Type A

• Type A viruses infect a range of hosts and are
  responsible for pandemics.
• The subtype of the Influenza A virus is
  determined by the two glycoproteins on the virus
  coat
• Haemagglutinin (HA)
• Neuraminidase (NA).

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Antigenic Drift and Shift

• The influenza virus has a very simple genetic
  structure with its genes in eight
• segments of single stranded RNA.
• RNA replication leads to increased susceptibility
  to mutations. Mutation and reassortment are the
  genetic basis for the two types of changes
  antigenic drift and shift.

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Antigenic Drift and Shift cont

• Antigenic drift
• Constantly occurring in both types A and B
  viruses.
• The HA and/or NA of the new strain are
  sufficiently different to evade (at least
  partially) the pre-existing human immunity.
• This leads to the seasonal epidemics.

• Antigenic shift
• Occurs only in type A virus.
• Is the emergence of an entirely new virus
  subtype.
• When this new subtype emerges it can cause a
  pandemic, because there is no pre-existing
  immunity
• in humans.

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Seasonal, Avian and Pandemic
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Seasonal

• A common viral respiratory illness in people.
• Seasonal outbreaks affect 10 - 20 of the New
  Zealand population yearly.
• Classical symptoms are sudden onset of fever,
  headache, and body aches with cough and runny
  nose developing later

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Avian (bird flu)

• Influenza A
• a disease of wild water birds
• Birds carry virus in intestine, oro-faecal spread
• Close exposure to birds can, rarely, lead to
  human infection
• Not present in NZ birds
• Other animals can be infected including pig,
  horse
• Current concerns H5N1, H7N7 and H9N2

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Pandemic

• A pandemic, (a global epidemic), arises when a
  new subtype of influenza A arises via antigenic
  shift or drift.
• The new sub-type displaces the previously
  circulating type A virus and becomes the seasonal
  influenza virus that continues circulating until
  the next pandemic.
• An average of three influenza pandemics per
  century since 1510.
• With bird and human population explosions,
  potential for pandemics is higher than ever.

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1918 Pandemic

• The 1918 virus (H1N1) is inappropriately called
  the "Spanish flu" as it most likely originated in
  the USA.
• The parent viruses may have been circulating for
  several years, accumulating the necessary changes
  to become adapted to humans.
• It emerged by direct mutation from an avian
  influenza virus.
• Caused an estimated 50 million deaths worldwide,
  8250 deaths in NZ of which 2160 were in the
  Maori population!

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1957 and 1968 pandemics

• 1957 Asian Flu, H2N2
• 1968 Hong Kong Flu, H3N2
• Re-assortments i.e. bird/human
• Less severe than 1918

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Current Situation

• Avian H5N1 virus highly pathogenic and spreading
  from Asia and across to Europe and Africa.
• First seen in 1996,
• first infected humans in 1997, also H7N7 and H9N2
• Bird to human spread with close contact
• Human to human transmission very rare
• Pandemic possibility unknown
• Other avian viruses also pandemic potential H7,
  H9

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Bird Flu hits Europe
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Influenza The Disease
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Influenza the Disease

• Contagious, viral illness
• Droplet spread
• And via contact with infected surfaces/hands etc
• Airborne spread unlikely
• Incubation period 1-3 days, but can range up to 7
  days
• Peak viral shedding after 1-3 days, lasts
  considerably longer in children

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Symptoms

• Sudden onset high fever, chills, headaches, body
  aches
• Fever (38 400) peaks within 24 hours of onset
• Infants/children more non-specific symptoms
• Main complications pneumonia, exacerbation of
  underlying conditions

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Diagnosis

• Not reliable on clinical features
• Need viral nasopharyngeal swab for confirmation

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NISG Dec 2002
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New Zealand Pandemic Planning
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Potential Scale of Pandemic

• Scenarios used to gauge the impact of an
  influenza pandemic in NZ estimate a maximum 40
  incidence, potentially resulting in 83 influenza
  consultations per GP/week (likely more owing to
  GP sickness), and 33,000 deaths over an 8 week
  period (compared with a usual total numbers of
  deaths for all reasons in an 8 week period of
  4,400).

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Preparation (prior to Pandemic)

• Promote influenza vaccination
• Development of national and local plans
• Focus on effective national
• surveillance system

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NZ 5 Stage Strategy
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Keep it Out

• Stopping pandemic influenza entering NZ borders
• Potential measures include
• Border control/management
• Quarantine measures
• High level of alert for Index cases in NZ
• Communication with public

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Stamp it Out

• Pandemic influenza in NZ, identified at the
  border or from community surveillance
• Potential measures include
• Rapid identification of cases
• Isolation and contact tracing
• Treat/prophylaxis with anti-virals
• Can declare emergency powers
• Can restrict movements

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Manage it

• The pandemic is widespread in the community
• Potential measures include
• Reduce/stop public meetings
• People to stay at home
• Can close schools
• Reorganisation of local primary health care eg
  move to key practices, outreach services,
  telephone triage
• Antiviral distribution via distribution centres
  or outreach services
• Support infrastructure

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Primary Health Care Preparedness
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Current Preparation

• Understand the key principles of infection
  control
• Be on alert for an index case
• Communication with staff
• Develop a practice plan
• Communication with patients

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Scenario

• Mr T makes a routine morning appointment.
• Arrives at the surgery and takes a seat in the
  waiting room with other patients
• 15 minute wait.
• History unwell 48 hours, fever, cough,
  headache, returned yesterday from 5 day visit in
  Jakarta. Fever 40.1, cough, signs in R lung field
• Nasopharyngeal swab taken in the practice
• Sent for CXR

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Points for Discussion

• Issues
• How could reception staff have better identified
  the nature of the problem either when he phoned
  for an appointment, or when he presented in an
  unwell condition to the surgery?
• What steps could have been taken to reduce risk
  of cross-infection while waiting for his
  appointment?
• How could the doctor have reduced the risk of
  infection to himself during the consultation, and
  the taking of the throat swab?

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Points for Discussion cont

• Should a pernasal nasopharyngeal swab have been
  taken?
• How could the radiology clinic staff have been
  better prepared to deal with the risk of
  infection?
• If Tamiflu had been available, should this have
  been offered to the patient?
• Was the prescription of an antibiotic
  appropriate?
• How could the doctor have ensured that the
  hospital laboratory was prepared for the
  processing of the specimen?
• What management would have been appropriate for
  the patient's wife and direct contact family
  members?
• Should the doctor have discussed the problem with
  the medical officer of health?

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Infection Control Key Points

• Organisational respiratory disease policy
• Sending ill people home
• Respond to early symptoms
• Enabling staff to work in more isolated settings
• Ventilation of internal spaces
• Cough hygiene
• Hand hygiene
• HANDWASHING SINGLE MOST IMPORTANT ISSUE
• Physical distancing
• Protective barriers

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Infection Control for Primary Healthcare Practice
in the Pandemic Influenza Setting
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Infection Control in Primary Health Care

• Keeping distance
• Hand Hygiene
• Surgical mask (patient, support people and staff)
  , eye protection, /- gloves
• Ventilation
• Respiratory hygiene and cough etiquette
• Extra PPE packs for very close contact
• (Particulate respirator mask(N95), gown, eye
  protection, gloves)

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Alert for an Index Case

• Be vigilant for the possibility of a case
• Plan how to identify and manage a high-risk
  patient when they present
• Keeping distance between the patient, staff,
  other patients
• Practising infection control in all practice
  activities
• Wearing surgical masks and gloves, mask for
  patient and support people
• Identifying areas to isolate these patients from
  others
• Rigorous, frequent hand washing , or the use of
  alcohol-base hand gel if no water available.
• Good ventilation in the practice
• Use the Ministry of Health posters
• Protect and Prevent as a resource for staff
  information
• Travel Health patient poster

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Alert for an Index Case cont

• Case Identification
• On suspicion immediately ring the local Medical
  Officer of Health for advice.
• Diagnosis will require obtaining a good quality
  viral nasopharyngeal swab. There are high risks
  of spreading the virus in doing a nasopharyngeal
  swab so it is advised to TAKE ADVICE in your
  local area as to the best way of obtaining an
  urgent specimen, rather than taking your own
  sample.

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Development of a Practice Plan

• Preparedness
• Communication to all the team
• Routine influenza vaccination
• Alert for an index case
• Antiviral use advice
• Supplies
• Infection control training

• In the Pandemic
• Coping with patient demand
• Continuation of routine services
• Personal protection for staff
• Staff illness
• Communication
• Security
• Vaccination

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Communications With Patients

• Preparedness
• Awareness of travel and need to screen
• Advice available
• Key PPE messages
• Preparation with regular meds
• ?Database sharing

• Pandemic Phase
• Communication channels re
• Regular services
• Access to influenza treatment/advice

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Local Responsiveness

• Be aware of the local plan, and triggers
• Reorganising practices in localities
• Key practices for regular work
• Patients with influenza go elsewhere
• Telephone (and possible internet) triage
• Community Based Assessment Centres
• Outreach Services

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Community Preparedness

• What is the local community capacity?
• Is there any local community plan of action?
• Who are the most vulnerable groups/individuals
  within your community?

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Anti-Viral Drugs

• Licensed amantadine, zanamavir (Relenza), and
  oseltamivir (Tamiflu)
• Amantadine resistance increasing, not to be used
  first line
• Zanamavir (Relenza) is currently not available
  in New Zealand, however it is licensed in New
  Zealand, and may be available on the private
  market in the future.

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OSELTAMIVIR(Tamiflu)

• Licensed for treatment and prophylaxis
• Over a year of age
• Treatment 75mg bd 5/7 best with early usage
  (within 48 hours)
• Post-exposure prophylaxis 75mg daily 10/7
  reduces incidence by 92
• Can still develop immunity while on prophylaxis
• Minor side effects nausea, vomiting, headache

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National Stockpile

• Current national stockpile sufficient for
  treatment of 21 of country (Jan 2006)
• Currently no stocks for children, ongoing
  discussions
• It is expected that this stockpile will be used
  for
• KEEP IT OUT border control - treatment and
  prophylaxis for contacts
• STAMP IT OUT case/cluster control - treatment
  and post-exposure prophylaxis for contacts
• MANAGE IT pandemic management - treatment
  courses for the community plus there may be some
  held back for treatment of essential service
  staff.

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Vaccines

• Pandemic Vaccine
• NZ has agreement with CSL for pandemic vaccine
  supply
• Development will take 15 27 weeks after
  pandemic virus is isolated till availability in
  NZ
• 2 dose course ?4 weeks apart, but may be earlier

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Prototype Vaccine

• A vaccine that anticipates and mimics the
  characteristics of a pandemic virus
• Contains antigens to which humans are
  immunologically naïve
• Currently developing H5N1 prototype vaccine
  internationally
• NZ considering the benefits of purchasing some
  supplies of a prototype vaccine

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Common Questions

• What is the difference between seasonal and
  pandemic influenza?
• What is avian influenza (bird flu)?
• What is Tamiflu?
• Is there a vaccine available?
• How will a pandemic affect us?
• Should I be concerned about bird flu?
• What can be done to prevent a pandemic starting
  from H5N1?
• Any advance warning for a pandemic?
• Can the spread of H5N1 in birds be stopped?

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Resources

• National
• Ministry of Health phone line 0800 AVNFLU (286
  358)
• Ministry of Health pandemic influenza Web site
  www.moh.govt.nz/pandemicinfluenza
• For information for businesses re preparing for
  pandemic influenza, see the Ministry of Economic
  Development Guide online at www.med.govt.nz
• Ministry of Agriculture and Fisheries Hotline
  (for suspected animal cases) 0800809966
• Pandemic Postings - from Auckland Regional Public
  Health Service. 
• International
• World Health Organization www.who.int/csr/disease
  /avian_influenza/en/
• USA CDC www.cdc.gov/flu/avian/
• UK Influenza Pandemic Contingency Plan
  www.dh.gov.uk
• World Health Organization Writing Group.
  Nonpharmaceutical interventions for pandemic
  influenza, international measures. Emerg Infect
  Dis serial on the Internet. 2005 Jan.
  Available from http//www.cdc.gov/ncidod/EID/vol1
  2no01/05-1370.htm
• http//www.cdc.gov/ncidod/EID/index.htm  - Jan
  2006 Edition of Emerging Infetious Diseases (Vol
  12, No 1)