Publication - Strategy/plan

Pandemic Flu: A Scottish framework for responding to an influenza pandemic

Published: 22 Nov 2007
Part of:
Health and social care
ISBN:
9780755955022

Pandemic Flu: A Scottish framework for responding to an influenza pandemic. This guidance was superseded by the UK Influenza Pandemic Preparedness Strategy 2011.

Pandemic Flu: A Scottish framework for responding to an influenza pandemic
5 PLANNING OUR RESPONSE

5 PLANNING OUR RESPONSE

5.1 Introduction

The Scottish Government 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 us to adjust our response 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. Our response will be adjusted as more information becomes available.

5.2 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 (see table 1). 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 the spread. For UK purposes, four additional alert levels have been included within WHO Phase 6. These are consistent with those used for other communicable disease emergencies.

Table 1 - WHO influenza pandemic phases

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

5.3 Key planning assumptions

5.3.1 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 South East Asia, the Middle East or Africa.
  • 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, pigs and domestic animals in many parts of the world facilitates mingling of human and animal viruses. This 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 or animals but will not necessarily evolve into pandemic viruses.
  • When 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.

5.3.2 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.

5.3.3 Geographical spread

  • Although it may be theoretically possible to contain the initial spread of a pandemic virus originating in rural parts of Asia, the Middle East or Africa; this is likely to be difficult in practice. It may also be difficult to document the early stages of spread accurately.
  • Spread from the country of origin is likely to follow the main routes of travel and trade.
  • Increasing use of routes where surveillance is not as well developed may result in the failure to document the early stages of a virus' spread.
  • Spread from the source country to the UK through movement of people is likely to take two to four weeks. 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 - modelling suggests that 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.

5.3.4 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 (nose, mouth or eyes) 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 during the use of 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 two other people on average (the Ro or 'basic reproduction number'). This number is likely to be higher in closed communities such as prisons, residential homes or boarding schools.

5.3.5 The severity (clinical attack rate) of illness and deaths

  • Pandemic influenza is likely to be far more severe than normal seasonal influenza 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 direct impact on provision of services and business continuity, while illness in the very young and elderly is likely to have an indirect impact and will 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 is 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.
  • Subsequent waves, if they occur, could possibly be more severe than the first.
  • The UK case fatality rate for previous pandemics was of the order of 0.2 to 2% of those who became ill.
  • The current avian A/H5N1 virus has raised concerns as a potential origin of a pandemic virus. Although it is not necessarily the most likely virus to lead to a pandemic, we need to be concerned because of its potential severity.
  • The reported mortality for humans infected with this avian virus is currently over 50%. However, it should be noted that this is primarily an avian virus with its own specific characteristics and treatment has often been delayed.
  • Diverse views regarding the link between virulence and ability to transmit between humans have been published, although a majority of scientists currently believe virulence to be independent from transmission ability.
  • The likelihood of the current (avian) H5N1, or any other virus, developing pandemic potential cannot be quantified. In the face of these uncertainties, most experts agree that accepting the evidence from previous influenza pandemics suggesting a maximum case fatality of 2.5% is a reasonable worst case scenario for planning purposes.
  • 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%.

Table 2 - 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

5.4 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 WHO.

Table 1 - UK planning presumptions

Area of policy response

WHO phase 4

Small cluster of cases with limited person-to-person transmission.

WHO phase 5

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

WHO phase 6

Increased and sustained transmission in general population (pandemic confirmed).

UK alert level 1
Cases outside the UK.

UK alert levels 2-4
Outbreaks in the UK.

Transport/travel

Foreign and Commonwealth Office ( FCO) travel advice for other countries

FCO travel advice will take as its starting point the advice issued by WHO at each stage of a developing pandemic. British missions overseas will consider a full range of options for informing British nationals of the developing situation and its associated risks. This will include ensuring that British nationals continue to monitor FCO travel advice. From WHO phase 4, the FCO will recommend that British nationals in affected and neighbouring countries consider returning to the UK.

Advice against non-essential travel to affected and neighbouring countries.

If the situation in a country is judged severe enough to significantly affect British nationals (eg the healthcare system is unable to treat them or there has been a breakdown in law and order), a decision may be made to advise against all travel. Where possible, travellers will be given a timeframe for moving from advising against all but essential travel to advising against all travel, based on the predicted spread of the pandemic. Such a decision would be subject to agreement between the FCO, the Department for Transport and the Department of Health and would be subject to Ministerial clearance.

International travel restrictions/
Border closures

The possible health benefits that may accrue from international travel restrictions or border closures need to be considered in the context of the practicality, proportionality and potential effectiveness of imposing them, and balanced against their wider social and economic consequences. Given the complexity of this issue, the Government will keep under review the evidence on the benefits and disadvantages of various approaches.

Airport closures

No imposed closures in the UK (subject to the above) but airports may find they have operational difficulties in phase 6 if staff are absent and/or if airports or carriers 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 if other countries impose requirements (such as requiring outgoing flights to undergo exit screening), the Government will consider screening on a case-by-case basis, bearing in mind the lack of evidence to support it.

Financial assistance to airlines/travel industry

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

Domestic travel restrictions

Business as usual.

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

Hygiene measures on public transport

Public advice from the Scottish Government Health Directorates and Health Protection Scotland ( HPS) will encourage general good hygiene practice in reducing the spread of infectious diseases, e.g. regular hand washing.

Advice to keep using public transport whilst adopting good hygiene measures and staggering journeys where possible.

International

Repatriation issues

Subject to the extent of disruption to air travel, British nationals may be stranded overseas at any phase (although this is more likely at phases 5 and 6). Given the potential scale and number of countries involved, the Government is unlikely to arrange repatriation. The FCO already advises British nationals, through its avian influenza fact sheet on its website and its missions overseas, that the Government will not be in a position to offer repatriation.

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.

Repatriation may be difficult due to circumstances in other countries and possible flight disruption. Ports of entry will continue to provide normal arrangements for as long and as far as that is practical. Family/insurance to meet costs.

Advice from British missions to British nationals overseas Plan for phase 6, including whether to stay or leave and local access to healthcare. Advise British nationals to consider returning to the UK at phases 4/5 in affected or neighbouring countries. Plan for arrival of the virus in host country or, if it has 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 arranging for their own medical care and discussing with their healthcare provider whether they will have access to antiviral treatment during a pandemic. The FCO is already advising British nationals, through the avian influenza fact sheet on its website and through its missions overseas, that British diplomatic missions cannot provide medical treatment or antiviral drugs.
Government liaison with other countries The FCO will lead on liaison with governments in other countries to ensure full understanding of impacts and response measures during each phase.
Assistance to foreign nationals in the UK The current policy will apply during a pandemic, i.e. no assistance apart from emergency healthcare. For public health reasons, visitors who develop influenza symptoms whilst in the UK will be given emergency treatment with antiviral medicines if necessary.

Essential services

Healthcare

Normal service levels.

Disruption expected from staff absence and ill carers, particularly at pandemic peak. The NHS plans to care for large numbers of cases and will only 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 for as long and as far as that is possible. Some disruption expected at the peak of a pandemic. Relaxation of regulations on drivers' hours may be considered if required to maintain services.

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

Normal service levels.

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

Capacity of tele-communications/ level of service

Normal service levels.

Near-normal service levels expected. Staff shortfalls may result in a gradual increase in time taken to respond to customer calls and routine repairs. Organisations planning to increase home working should discuss plans with their service provider at an early stage (see section 10.5.1).

Availability of fuel

Normal service levels.

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

Maintenance in the energy, telecommunications and fuel sectors

Maintenance programmes 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 service levels. Essential repairs to maintain water/sewerage pipe-work. Non-essential work may be curtailed.

Food/supplies

Normal service levels.

Near-normal service levels; 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 there may be some disruption to customer-facing services due to staff absence at peak. Demand for cash in circulation will be met, but there may be some short-lived disruption if bank branches are closed and cash machines take longer to restock.

Postal services

Normal service levels.

May be some disruption due to staff absence at the 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 the peak, there may be some short-lived disruption to essential services such as refuse collection.

Education/social mixing

School and early years/ childcare setting closures

Business as usual.

Subject to the impact of the pandemic, the Scottish Government may recommend that schools and early years childcare settings close to children when the first clinical cases are confirmed in the SCG area and that they remain closed until the local epidemic is over.

Further and higher education

Business as usual.

No plans to advise further/higher education establishments to close. Each institution to decide how it operates based on a risk assessment and its situation.

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

Business as usual.

Business as usual for as long and as far as that is possible, subject to good hygiene precautions including robust advice to customers that they should stay at home if they are ill or have influenza-like symptoms. If schools and early years childcare facilities are advised to close to children, information will be made available to parents and carers to enable them to assess the risks of infection linked with out of school activities so that they can act appropriately to protect children. In the early stages of phase 6, the Government may advise against holding international events in the UK if delegates, teams or performers are expected from affected countries.

Advice on use of public places

Public health advice from the Scottish Government Health Directorates and HPS will encourage general good hygiene practice to reduce the spread of infectious diseases, e.g. regular hand washing.

Business as usual for as long and as far as that is possible. The public will need to take good hygiene precautions.

Broadcasting

Public service broadcasts

Business as usual.

Business as usual, for as long and as far as that is possible. May be some readjustment of services.

Benefits

Sickness absence policy, including statutory sick pay

Business as usual.

Business as usual for as long and as far as that is possible. Advice may be issued as pandemic develops.

Benefits payments

Business as usual.

Business as usual, for as long and as far as that is possible.

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 antiviral medicines

Normal supply may remain available for seasonal influenza cases at Phase 4 and 5. Limited amounts of the national stockpile have been predistributed to NHS Boards (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.

Antivirals 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

Personal Protective Equipment ( PPE)

Advice to public and business regarding government policy (face masks necessary for healthcare workers dealing with suspect cases or others at particular risk). Occupational risk assessments in other settings should be conducted jointly with staff. General wearing of face masks in public places by those who do not have influenza symptoms will not be recommended and the Government will not supply facemasks for that purpose.

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

Antibiotics

Scottish Government will seek to enhance stocks

Administered for secondary infection complications as per guidelines.

Pre-pandemic vaccines

270,000 doses of H5N1 vaccine have been purchased 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 has been developed and manufactured (four to six months).

The UK will secure sufficient vaccine to protect the population as soon as it is available (likely to be at least four to six months, i.e. well after the first wave strikes the UK). Delivery of supplies would make clinical prioritisation inevitable.

Other consumables and essential medicines

The Scottish Government 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.

The Government will consider the relaxation of medicines and NHS regulations where necessary to ensure ease and speed of access.

Communications

Isolation of cases/stay at home if ill

Possible implications for returning travellers with symptoms and their contacts, 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 also be recommended for close contacts at early stages to contain/slow the spread.

Health messages to the public

Increase in public information at phase 4 - proportionate to levels of risk. Different communication products such as leaflets and door drops, will be used during phases 4 and 5, emphasising good hygiene measures and reassuring the public. Regional/local communications to be consistent with national messages.

Main messages to include: stay at home if ill; adopt good hygiene practices; and how to obtain help and antiviral medicines. Other messages may include information on face masks and health and safety advice on issues such as air conditioning in the workplace. Messages must be consistent.

Information to the public

WHO advice and updates on location(s) and areas affected will be reflected in FCO 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 the national flu line service (see 9.8.5) will be available. Information materials will also be available through primary care, pharmacies and on the Scottish Government website.

WHO will provide the Department of Health ( DH) with regular updates on countries affected. DH will cascade to other government departments, Devolved Administrations and the NHS.

The Scottish Government will report the numbers ill on a regional basis to the Civil Contingencies Committee.

This information may be made available via the national flu line service, websites and 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 will be made.

Excess deaths

Managing excess deaths

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

Planning is under way to minimise delays in burials or cremations. Further measures are being considered for the reasonable worst case scenario.

Response and coordination

Response, planning and coordination across central and local government

The Cabinet Sub-Committee on Civil Contingencies ( SEER- CSC) will meet as required to agree early policy decisions in Scotland and to urge completion of planning. Strategic Coordinating Groups ( SCGs) will meet as required to promulgate policy decisions/advice and maintain overview of response.

The Justice and Communities Directorates will assume responsibility for coordination across the Scottish Government. SEER- CSC will meet regularly to maintain an overview of the impacts on Scotland, agree policy and allocate resources. SCGs will meet regularly to maintain overview of regional impacts, identify resource issues and promulgate policy and information to the public.

Civil Contingencies Act 2004

The Government will rely on voluntary compliance with national advice and is unlikely to invoke emergency or compulsory powers unless they become necessary, in which case the least restrictive measures will be applied first.

Liaison with the business community

The Government will liaise and share information with the business community through established stakeholder groups. At local level, the business community will work with the SCGs.

Support from the Armed Services

As with guidance for other major emergencies, planners should not assume that military support will be available. Such assistance might be available in exceptional circumstances if life and property are in immediate danger, but planning for an influenza pandemic should take into account that support may not be available if local units are deployed on operations, that they may not have personnel available with either the skill or equipment to undertake specialist tasks and that military personnel will themselves be vulnerable to the illness.

5.5 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. Behavioural science is also important to our understanding of how people are likely to react.

UK pandemic influenza research is coordinated across Government Departments and research councils by the Pandemic Influenza Research Funders Coordination Group. 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 WHO, World Organisation for Animal Health and European Union 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 - together with those of the National Institute for Biological Standards and Control and the National Influenza Reference Laboratory ( NIRL) at the Health Protection Agency - work closely together. All Scottish virus laboratories are closely linked to the NIRL and send specimens there 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. HPS, in liaison with the Statistical Team in Applied Mathematics at Strathclyde University, work closely with colleagues across the UK in the development of such models for use by the NHS in Scotland. Further information on research and modelling is available from: www.hps.scot.nhs.uk and www.dh.gov.uk/pandemicflu.