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A National Framework For Responding To An Influenza Pandemic

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4 PLANNING OUR RESPONSE

4.1 Introduction

The Scottish Executive and UK Government response is based on a set of key planning assumptions and modelling information about the scale and impact of an influenza pandemic, which is set out below. This is fundamental to our approach to planning for a pandemic across the UK. Local planning should also be based on these key assumptions so that all planning begins from a common approach and common understanding.

Of course, we will not know the exact nature and shape of a pandemic until the virus emerges, but we can make assumptions based on the best available evidence to assist our planning. Since these are estimates, planning must be flexible enough to allow adjustment once the characteristics of the virus are known. This must include the capacity to scale up or indeed scale down.

Scientific and modelling analysis will continue as the virus emerges and the pandemic progresses and this may help us to adjust our response as more information becomes available.

4.2 The WHO International Phases and UK alert levels

The World Health Organization ( WHO) has defined phases in the evolution of a pandemic that allow a step by step escalation in planning and response proportionate to the risk from first emergence of a novel influenza virus. This global classification is used internationally. Once a pandemic is declared, action will depend on whether cases are identified in the UK and the extent of spread. For UK purposes, four additional alert levels have therefore been included within WHO Phase 6 consistent with those used for other communicable disease emergencies.

Inter-pandemic Period

1

No new influenza virus subtypes detected in humans

2

Animal influenza virus subtype poses substantial risk

Pandemic Alert Period

3

Human infection(s) with a new subtype, but no (or rare) person-to-person spread to a close contact

4

Small cluster(s) with limited person-to-person transmission but spread is highly localised, suggesting that the virus is not well adapted to humans

5

Large cluster(s) but person-to-person spread still localised,

suggesting that the virus is becoming increasingly better adapted to humans

Pandemic Period

6

Increased and sustained transmission in general population

UK alert level

1 Virus/cases only outside the UK

2 Virus isolated in the UK

3 Outbreak(s) in the UK

4 Widespread activity across UK

Post Pandemic Period

Return to Inter-pandemic Period

4.3 Key planning assumptions

Origins of a pandemic

  • A new pandemic will be caused by a new subtype of influenza A virus.
  • The emergence of new influenza A viruses is highly probable.
  • Although an influenza virus with potential to cause a pandemic could develop anywhere, it is most likely to emerge from the Far East.
  • The virus may be a re-emerging previously-known human subtype that has not recently been in circulation, or a new virus - most likely of avian origin - emerging either through 'adaptation' to humans or through a process of genetic 're-assortment' between the genes of an animal and a human virus.
  • The close proximity of humans to poultry and pigs in many parts of the world facilitates mingling of human and animal viruses and increases the risk that they may then exchange genetic material resulting in a new 're-assorted' human strain. The wide dissemination of the avian A/H5N1 virus in domestic poultry and water-fowl provides one seedbed for such re-assortment, but such viruses may also re-emerge from reservoirs in other animal species.
  • From time to time, avian influenza viruses will infect people directly exposed to infected poultry but will not necessarily evolve into pandemic viruses.
  • Whenever such a virus is detected following human infection, its potential to spread directly from person to person needs assessment.
  • The pandemic potential of a new virus must remain under consideration until it can be determined whether person-to-person spread has occurred.

Timing and duration

  • A future influenza pandemic could occur at any time (intervals between the most recent pandemics have varied from about 10 to 40 years with no recognisable pattern, the last being in 1968/9).
  • A new virus may emerge at any time of the year.
  • Initially pandemic influenza activity in the UK may last for three to five months, depending on the season, and there may be subsequent waves, weeks or months apart.

Geographical spread

  • Although it may be theoretically possible to contain the initial spread of a pandemic virus originating in rural parts of the Far East, this is likely to be difficult in practice. It may also be difficult to document the early stages of spread accurately.
  • Spread from an origin in the Far East is likely to follow the main routes of travel and trade.
  • Spread from the source country to the UK through movement of people is likely to take around a month. Modern travel may result in even more rapid international spread.
  • It is unlikely that we could prevent the virus getting into the UK except by closing all borders - even a 99.9% restriction of travel into the country can only be expected to delay importation of the virus by up to two months.
  • From arrival in the UK it will take a further one to two weeks until sporadic cases and small clusters are occurring across the country.

Infectivity and mode of spread

  • Influenza spreads through the respiratory route by droplets of infected respiratory secretions produced when an infected person talks, coughs or sneezes.
  • It may also spread by hand/face contact after touching a person or surface contaminated with infectious respiratory droplets.
  • Finer respiratory aerosols (which stay in the air for longer and are therefore more effective at spreading infection) may occur in some circumstances such as nebulisers, some dental procedures etc.
  • People may be infectious between 24 and 48 hours before the onset of symptoms and are highly infectious for four to five days from the onset of symptoms (longer in children and those who are immunocompromised).
  • Children have been shown to secrete virus for longer and at higher levels than adults.
  • Some people can be infected without showing symptoms and may excrete the virus and therefore be able to pass on the infection.
  • Incubation period is in the range of 1 to 4 days (typically 2-3).
  • Without intervention, and with no significant immunity in the population, historical evidence suggests one person infects about 1.4 to 1.8 people on average (the Ro or 'basic reproduction number'). This number is likely to be higher in closed communities such as prisons, residential homes and boarding schools.

The severity (clinical attack rate) of illness and deaths

  • Pandemic flu is likely to be far more severe than normal seasonal flu with higher attack rates and case fatality rates and differences in age distribution and severity of illness
  • Most people will be susceptible, but not all will become ill. Previous experience suggests that roughly equal numbers will be asymptomatic (infected but with no symptoms) as develop symptomatic infection (illness).
  • All ages are likely to be affected, but children and otherwise fit adults could be at relatively greater risk, particularly if the elderly have some residual immunity from previous exposure to a similar virus earlier in their lifetime.
  • Any age-specific differential attack rate will affect the overall impact. If working age adults are predominantly affected this will have a more serious impact on provision of services and business continuity, while illness in the very young and elderly is likely to present a greater burden on health and community services.
  • Although potential for age-specific differences in clinical attack rate should be noted, they are impossible to predict and a uniform attack rate across all age groups is assumed for planning purposes.
  • More severe illness may include severe prostration and rapidly fatal overwhelming viraemia, viral pneumonia or secondary complications.
  • Up to 4% of those who are symptomatic may require hospital admission if sufficient capacity were available.
  • In previous pandemics, the overall UK clinical attack rate has been between 25% to 35%, compared to the usual seasonal range of 5% to 15%. Cumulative clinical attack rates of up to 50% of the population in total are possible spread over one or more waves of around 15 weeks, each some weeks or months apart. Response plans should consider both the lower and upper ends of the attack rate.
  • If they occur a second or subsequent waves could possibly be more severe than the first.
  • Seasonal flu causes around 1200 deaths in Scotland annually. The UK case fatality rate for previous pandemics was of the order of 0.2 to 2% of those who became ill.
  • To inform planning the following table shows the potential impact of a 25%, 35% and 50% clinical attack rate and overall case fatality rates of 0.4%,1%,1.5% and 2.5%.

Range of possible excess deaths based on various permutations of case fatality and clinical attack rates, based on Scotland and UK populations

Case fatality rate

Clinical attack rate

25%

35%

50%

Scotland

UK

Scotland

UK

Scotland

UK

0.40%

5,100

55,500

7,100

77,700

10,200

111,000

1.00%

12,700

150,000

17,800

210,000

25,400

300,000

1.50%

19,000

225,000

26,700

315,000

38,100

450,000

2.50%

31,700

375,000

44,400

525,000

63,700

750,000

4.4 UK planning presumptions

The following table outlines the UK's current planning presumptions for developing response plans and maintaining essential services during a possible influenza pandemic. These presumptions are based on provisional decisions by Ministers and on-going planning across essential services. They will be revised regularly, reviewed when the nature of the virus is known and may be altered because of international actions or evolving advice from the World Health Organisation ( WHO).

Area of Policy Response

Phase 4

Small cluster of cases with limited person to person transmission

Phase 5

Large cluster(s) of cases with person to person transmission.

Phase 6

Increased and sustained transmission in general population (pandemic confirmed)

UK alert level 1

cases outside UK

UK alert levels 2-4 cases in UK

Transport/ Travel

International travel advice

In formulating travel advice, the Government will consider WHO advice. Consular staff will give advice to British Nationals as the situation develops and risks increase, to ensure their awareness that the travel advice may change soon, and should they wish to return to the UK, they should act quickly.

Advice against non-essential travel to affected areas

Advice against non-essential travel to affected areas

Advice against non-essential travel to areas where pandemic confirmed. In certain circumstances, the advice may be against all travel to an affected country or region - if law and order has broken down, and/or the health care is unable to treat British Nationals, and/or the British Embassy/consulate is closed; such advice would be subject to agreement between FCO, DfT, DH and CO and ministerial clearance.

International travel restrictions

Based on the evidence currently available, the Government would not recommend or impose any other international travel restrictions

Border

closures

Based on expectation of limited public health benefit and considerable downsides from closure as well as implementation and enforcement difficulties, planning presumption is against closure of UK borders. Other countries may close their borders.

Airport closures

No imposed closures in the UK, but airports may find they have operational difficulties in Phase 6 if staff are absent and/or if airports overseas have operational difficulties or close.

Health screening

Based on available evidence, no entry or exit screening will be imposed in the UK. If recommended by WHO, or other countries impose requirements (such as a country requiring all incoming flights to undergo exit screening), the Government would consider screening on a case by case basis, bearing in mind the lack of evidence to support screening.

Financial assistance to airlines / travel industry

No plans for Government assistance. Subject to extent of impact, the Government may consider at the time and/or during the recovery phase.

Domestic travel restrictions

Business as usual as far as possible

Subject to nature and spread of virus, the Government may advise against non-essential travel but not impose restrictions.

Hygiene measures on public transport

Public advice from the Scottish Executive Health Department and HPA will encourage general good hygiene practice in reducing spread of infectious diseases e.g. regular hand washing

Advice to keep using public transport whilst adopting basic hygiene measures and staggering journeys where possible. May also want to consider limiting non-essential travel.

International

Repatriation of dead bodies

Normal arrangements will apply at airports to receive any dead British nationals who may be part of the early clusters. Family/insurance to meet costs.

Ports of entry may need to supplement reception arrangements. Family/insurance to meet costs.

Repatriation issues (live/well)

Subject to extent of disruption to air travel, British nationals may be stranded overseas at any Phase (although more likely at 5 and 6). Given the potential scale & numbers of countries involved, the Government is unlikely to arrange repatriation.

Advice from embassies to British nationals overseas

Plan for Phase 6, including whether to stay or leave and local access to health care. British Nationals may wish to return to UK in Phases 4/5. Flights and/or consular support may be reduced in Phase 6.

Plan for arrival of the virus in host country, or, if already arrived, review local access to healthcare. Flights and/or consular support may be reduced.

Medical assistance to British Nationals overseas

British nationals will be advised to plan for a potential pandemic including medical arrangements if not entitled to treatment from the host country

Government liaison with other countries

Foreign and Commonwealth Office ( FCO) will lead on liaising with Governments in other countries to ensure full understanding of impacts and response measures during each phase.

Essential services

Health care

Normal service levels

NHS plans to care for large numbers of cases and will provide essential care

Community Care

Normal service levels

Disruption expected from staff absence and ill carers, particularly at pandemic peak. Prioritisation of services required. Local co-ordination will be required to ensure appropriate step down care.

Domestic travel/ public transport

Normal service levels

Business as usual as far as possible. Some disruption expected from staff absence particularly at the peak of the pandemic. Relaxation of working time regulations may be considered if required to maintain services.

Essential repairs or maintenance of power lines, telecoms, gas pipelines and energy supply

Normal service levels

Essential repairs will continue. Routine repairs may be curtailed by staff shortfalls - particularly at peak of the pandemic.

Capacity of telecoms/ level of service

Normal service levels

Near normal service levels expected. Staffing shortfalls may result in a gradual increase in time taken to respond to customer calls and routine repairs. 1

Availability of fuel

Normal service levels

Fuel supplies expected to be maintained. May be occasional local shortages if peak absences coincide with technical or weather-related supply difficulties.

Maintenance in the energy, telecoms and fuel sectors

Maintenance programs as normal

Routine programmes may be disrupted if peak absences coincide with technical or weather-related supply difficulties.

Provision of water and sewerage services

Normal service levels

Near normal levels. Essential repairs to maintain water and sewerage pipework, but non-essential work may be curtailed.

Food / supplies

Normal service levels

Near-normal service levels, but may be reduced choice and localised short-term disruption to availability due to staff absences.

Finance - cash circulation, banking and payment systems

Normal service levels

Near-normal service levels, but may be some disruption due to staff absence at peak.

Post Office

Normal service levels

May be some disruption due to staff absence at peak of the pandemic, but daily deliveries and collections will be sustained as far as possible

Provision of local services e.g. refuse collection

Normal service levels

Subject to staff absences particularly at peak of the pandemic, there may be some short-lived disruption to essential services such as refuse collection.

Education/social mixing

Schools, nurseries and group childcare settings

Business as usual

Subject to impact of the virus, the Executive may recommend that Strategic Co-ordinating Groups (and Local Authorities) close schools and child-care settings to children, when the first clinical cases are confirmed locally and remain closed until pandemic is over. 2

Further and Higher Education

Business as usual

No plans to advise further education establishments to close. Decision for each institution based on a risk assessment and its situation.

Advice on social gatherings, such as attending UK sporting, arts events and conferences

Business as usual

Business as usual, as far as possible, subject to sensible basic hygiene precautions including robust advice to their customers that they should stay at home if they are ill or have flu-like symptoms. If schools and child-care facilities are shut to reduce spread of the virus, children should not mix with other children and adults for the duration of closures. In early stages of Phase 6, the Government may advise against international events held in the UK if delegates/ teams/ performers expected from affected countries

Advice on use of public places

Public advice from the Scottish Executive and HPS will encourage good hygiene practices in reducing the spread of the disease eg regular hand washing

Business as usual as far as possible. The public will need to apply sensible hygiene precautions.

Broadcasting

Public service broadcasts

Business as usual

Business as usual, as far as practicable. May be some re-adjustment of services.

Benefits

Sickness absence policy, including statutory sick pay

Business as usual

Guidance regarding Statutory Sick Pay ( SSP) will be issued by HMRC at time of pandemic. Most employers will be paying Occupational Sick Pay ( OSP) that must be at least as generous as SSP. Rules for controlling payments are for employers to determine.

Benefits payments

Business as usual

Business as usual, as far as practicable.

Pharmaceutical and other interventions

Antiviral

Medicines

Antivirals given preferably within 12 hours (but up to 48hrs) is the main medical countermeasure and will be used mainly for treatment. National stockpile allows for treatment of some 25% of population. Initially all patients symptomatic for less than 48 hrs will be given antivirals unless contraindicated. Consumption will be monitored and prioritisation introduced only if that becomes necessary.

Access to antivirals

Normal supply may remain available for seasonal influenza cases at Phase 4 and 5. Limited amounts of the national stockpile are predistributed to Health Boards currently (5% to mainland boards and 10% to the islands). Main stock would be distributed to NHS Boards at Phases 5 or 6 but not made available until UK alert level 2.

Antiviral may be used initially to treat cases and for containment. When infection is widespread for treatment only following telephone based assessment/ authorisation and collection from distribution points by friends/ relatives

Face masks

Advice provided to public and business regarding Government policy. Specific infection control guidance provided for a number of sectors.

Protection advised for health workers and others in close/regular contact with infectious patients or considered at occupational risk

Antibiotics

SEHD will seek to enhance stocks

For secondary infections/

complications as per guidelines

Pre-pandemic vaccines

270,000 doses of H5N1 vaccine has been ordered for healthcare workers. Final decisions will be made on the timing of inoculations.

May offer limited protection if used as a pre-pandemic vaccine prior to cases in the UK, depending on match with pandemic virus but stocks are limited

Pandemic -specific vaccine

A specific vaccine can only be produced once the pandemic virus has been isolated and the vaccine developed and manufactured (4-6 months).

The UK will secure sufficient vaccine for the entire population as soon as that is available. Likely to be at least 4-6 months i.e. well after the first wave strikes the UK. Delivery schedule would make prioritisation inevitable.

Other consumables and essential medicines

SEHD will seek to enhance stocks and supply of those essential medicines for which there is likely to be a greater demand.

Implement changes to medicines legislation or regulations where necessary, to ensure ease of access.

Communications

Isolation of cases/ stay at home.

Possible implications for returning travellers with symptoms and their contacts in Phases 4, 5 and UK alert level 1 of Phase 6 i.e. isolation of confirmed cases and voluntary quarantine at home of suspect cases and/or their close contacts .

Those who believe they are ill will be asked to stay at home in voluntary isolation. Voluntary home isolation may be recommended for close contacts at early stages to contain/slow the spread.

Health messages to public

Significant increase in public information at Phase 4 - proportionate to levels of risk. Different communication products such as leaflets, door drops used during Phases 4 & 5 emphasising basic hygiene measures and re-assuring the public. Regional/local communications to be consistent with national messages

Main messages to include: stay at home if ill, basic hygiene, how to obtain help and antivirals. Other areas may include advice on use of face masks and other Health and Safety advice on issues such as air-conditioning in the workplace. Messages to be consistent.

Information to public.

WHO updates on location(s) and areas affected and advice will be reflected in overseas travel advice.

A national door drop and advertising campaign will take place in Phase 5 alerting the public to the heightened risk, emphasising the need for personal preparation and socially responsible behaviour. A public information film will demonstrate how to slow the spread of the virus and a dedicated action line will be available. Information materials will also be available through primary care, pharmacies and on the Scottish Executive website.

WHO will provide Department of Health ( DH) with regular updates on countries affected. DH will maintain liaison and cascade.

The Scottish Executive will report to DH the numbers ill. DH will provide these on a regional basis to CCC. This may be made available to the public via DH, Scottish Executive and/or Health Protection Agencies websites & media briefings.

A second wave of advertising will run in Phase 6 providing basic facts and advice on the measures people can take to help slow the spread. The dedicated information line will continue to operate and an updated public information film made

Excess deaths

Managing excess deaths

Planning will continue in preparation for the arrival of the pandemic in Scotland and consequent additional deaths expected to occur (scale will be dependent upon nature of the virus).

Planning is underway to minimise delays to the death certification and registration processes. Further measures are being considered for the reasonable worse case scenario (63,700 deaths)

Response and co-ordination

Response, planning and coordination of response across central and local government

The Ministerial Group on Civil Contingencies ( MGCC) will meet as required to agree early policy decisions in Scotland and to urge completion of planning. Strategic Coordinating Groups will meet as required to promulgate policy decisions/advice and maintain overview of response.

The Justice Department will assume responsibility for coordination across the Scottish Executive. The MGCC will meet regularly to maintain an overview of the impacts on Scotland, agree policy and allocate resources. Strategic Coordinating Groups will meet regularly to maintain overview of regional impacts, identify resource issues and promulgate policy and information to the public

Civil Contingencies Act 2004

Emergency regulations may be used if it is necessary and proportionate to do so and if the legal safeguards in the Act are met. The scope and content of emergency regulations will be dependent on circumstances at the time.

Liaison with business community and Financial Authorities

Government would liaise and share information with business community and financial authorities through established stakeholder groups.

At local level, business community and financial authorities would work with the Strategic Co-ordinating Groups ( SGCs)

4.5 Research and development

Research and development into animal and human influenza viruses has made - and continues to make - an important contribution to shaping and informing pandemic preparedness planning and remains particularly vital to improving understanding of the health and wider impacts of any new virus, which by definition are difficult to predict.

Pandemic influenza research is coordinated across UK government departments, including the Research Councils. The government actively supports national and international programmes of work in this area, encourages the exchange of information and experiences at all levels and contributes to efforts to support those countries whose plans and preparations are less developed. The UK participates in World Health Organization ( WHO), World Organisation for Animal Health ( OIE) and European Union ( EU) research programmes and jointly leads the influenza pandemic work stream of the G8 countries. It also hosts one of the four WHO Collaborating Centres for Influenza at the National Institute for Medical Research. That institute receives viruses for detailed virological analysis and its laboratories - with those of the National Institute for Biological Standards and Control and the National Influenza Reference Laboratory at the Health Protection Agency. All Scottish virus laboratories are closely linked to the HPA National Influenza Reference Laboratory and send specimens here for detailed analysis. Industry and governments are also devoting considerable research efforts into developing pharmaceutical countermeasures and finding ways of reducing the time taken for testing and production.

Epidemiological models help us to understand how the disease might spread and the likely effectiveness of countermeasures, whilst operational models look at how we might best implement those countermeasures. Where possible, assumptions for models derive from data from previous pandemics but where that is not available information about known influenza viruses provides a source for estimates. UK modellers are amongst the world leaders in this work. Health Protection Scotland in liaison with the Statistical team in Applied Mathematics ( STAMS) Strathclyde University work closely with colleagues across the UK in the development of such models for use by the NHS in Scotland.

Continuing to improve the evidence base - and to apply the results of research and modelling to the development of plans - is of critical importance to the UK's strategic and operational approach to an influenza pandemic. As knowledge and information are constantly advancing regular reviews and revisions of plans at all levels are essential. To ensure that the best scientific advice is fed into policy, the Department of Health is advised by a Pandemic Influenza Scientific Advisory Group (to which SEHD & HPS contribute), whose meeting minutes are published on the DH website together with a regularly updated summary of the current position on mathematical modelling.

Further information on research and modelling is available from

www.dh.gov.uk/pandemicflu and www.hps.scot.nhs.uk/

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Page updated: Thursday, March 15, 2007