Influenza Pandemic – an outline guide

Introduction

There is considerable current concern that avian flu, which can be caught by humans from infected birds, may mutate and develop into a form of infectious influenza which can be passed from human to human. When this happens over a wide area it becomes known as a flu pandemic. Flu pandemic has been identified as a ‘very high’ risk by the Devon and Cornwall Local Resilience Forum in its Community Risk Register.

Below are some extracts from official information on flu pandemic and links to relevant websites, designed to inform of the dangers of flu pandemic and the counter measures which can be taken.

Background

Avian influenza is a highly infectious disease affecting many species of birds, including commercial, wild and pet birds. It may also affect people and other animals in certain circumstances. It is caused by a Type A influenza virus. For Questions and Answers on Avian Flu.

There is concern that the virus may change (re-assort or mutate) to emerge as a new virus that is easily transmissible between people and capable of causing disease in people, birds and other animals. Influenza A viruses occur worldwide in man and a wide range of mammals.

The high pathogenic H5N1 AI strain involved in most of the Asian outbreaks during the last 18 months has shown the ability to jump the species barrier occasionally and cause severe disease, with high mortality, in humans. It has not shown the ability to move easily between humans.

Avian and human influenza viruses can exchange genetic material when a person or other animal susceptible to infection with both viruses is simultaneously infected with both viruses. This could create a completely new subtype of the influenza virus to which few, if any, humans would have immunity and which might be able to spread between humans.

Impact

Official figures indicate that there have been 170 cases of people contracting the H5N1 virus, resulting in 92 deaths (to March 06), experts point out that cross-infection to humans is still relatively rare, and usually occurs where people have been in close contact with infected birds. There have been no reported cases of avian flu in humans in the EU, to date.

Controlling the spread of influenza:

Vaccination and Immunisation

Vaccines offer the best line of defence in reducing illness and deaths during a flu pandemic. However, currently available flu vaccines are likely to provide little or no immunity in a pandemic situation. A new vaccine must be developed to match the pandemic strain of virus. This work can only begin once that strain has been identified, although preparatory work can shorten the lead time in production.

Once a pandemic virus had been identified, even with the preparatory work under way, it will probably take around four to six months to produce a vaccine, and possibly longer to produce the vaccine itself. Vaccines are unlikely to be available during the early stages of a pandemic and even then will not offer 100% protection.

When a vaccine is available, the aim will be to immunise the whole population as quickly as possible as vaccine supplies increase

Groups prioritised for vaccination are as follows:

• health care workers most at risk: health care workers are essential to the health service response and are likely to be at increased risk of infection through their contact with patients
• essential services workers: to prevent disruption to key services through absence due to illness
• ‘at risk groups’: to prevent serious illness, reduce hospitalisations and deaths
• enclosed communities: to reduce the spread of flu in communities where it might spread particularly rapidly such as residential care homes, schools and prisons
• general population: to prevent illness in the population as a whole.

Anti-viral drugs

Antiviral drugs are likely to have an important role in the prevention and treatment of pandemic flu, especially when sufficient vaccine supplies are not available. However, it is important to note the following:

• the effectiveness of antiviral drugs in a pandemic, and in particular in reducing mortality in cases of severe disease, is not known
• it is recommended that antiviral drugs should be given to treat those at risk of serious illness. However, until the pandemic is under way, we cannot say for certain who will benefit most
• the pandemic flu virus may develop resistance to antiviral drugs.

Antiviral drugs are expensive, take time to manufacture, have a limited shelf life and will be in high international demand at the time of a pandemic. The UK is building up a stockpile of antiviral drugs against the contingency of a flu pandemic. As with other medicines it will be necessary to use them in the most effective way.

The UK plan has identified strategies and prioritised groups for receipt of antiviral drugs. However, since it is impossible to identify with absolute certainty those who would benefit most from antiviral treatment, these recommendations are not final and will be reviewed according to advice from expert bodies on the emerging epidemiology of the pandemic and other information. The priority groups are likely to be:

• health care workers: if and when they develop fever or other flu symptoms - to minimise impact on the health service response.
• Un-immunised people in high risk groups - to ameliorate illness and reduce complications, hospital admissions and deaths
• other un-immunised groups
• immunised people: if emerging information suggests the vaccine is not effective at reducing serious illness, complications or deaths.

Personal interventions

Some basic measures can be taken at the individual level to reduce the risk of infection:

• respiratory hygiene: covering the mouth and nose with a tissue when coughing or sneezing
• disposing of dirty tissues promptly and carefully – bagging and binning them
• avoiding non-essential travel and large crowds, where possible
• handwashing frequently with soap and water: reduces acquiring the virus from contact with infected surfaces and from passing it on
• cleaning hard surfaces (e.g. kitchen worktops, door handles) frequently, using a normal cleaning product
• making sure your children follow this advice.

Population-wide interventions

Other interventions at the national level may also be introduced at various stages during the pandemic:

• restrictions of mass gatherings: this will probably only be effective early on and could include the prohibition of large international gatherings such as pop concerts and sporting events. It may also include local gatherings.
• travel restrictions: travel to or from infected areas may be restricted. However, this measure cannot be enforced. Recommendations on restricting national travel may also apply.
• school closure: schools may be closed to prevent the spread of infection.
• voluntary home isolation of cases
• voluntary quarantine of contacts of known cases.

Screening of people entering UK ports

This is unlikely to be effective because of the highly infectious nature of the flu virus. Screening can only detect people who are showing symptoms. Pandemic flu victims may be infectious even before they exhibit symptoms yet would not be detected by port screening systems.

Wearing of masks

The widespread wearing of masks by the general public during a pandemic is unlikely to be effective in preventing people from becoming infected with the virus. However, they may have some limited use for those already infected with the virus in order to prevent them spreading it.

Contingency Planning

A flu pandemic will place great pressure on health and social services due to the increased burden of patients with flu requiring treatment and the depletion of the work force due to illness and other disruption. This could mean delays in dealing with other medical conditions, as sometimes occurs during a particularly bad epidemic of ‘ordinary’ flu. Non-urgent work will have to be prioritised during the peak weeks and some work cancelled because of pressure on beds, staff and resources.

NHS specific contingency plans will include planning for large and sudden increases in the numbers of patients and the minimising of staff absenteeism due to illness. NHS staff are currently being trained in how to cope with an outbreak of pandemic flu and how to manage the increased demands that will be placed on them.

Planning assumptions

A flu pandemic is likely to affect all age groups, with more than 10% of the population likely to lose working days. The UK plan assumes that 25% of the UK workforce will take 5 to 8 working days off over a three month period.

Business continuity

During the peak of the pandemic, estimates suggest that absenteeism will double in the private sector and increase by two thirds in the public sector.

This has important implications for business continuity. Advice for employers on how to maintain business continuity is available at:

Emergency Planning Business Continuity

Pandemic flu is likely to spread rapidly in schools and other closed communities leading to potential closures. Schools could also be affected by staff absenteeism and disruption to transport services.  

Pandemic flu will impact all services including police, fire, the military, fuel supply, food production, distribution and transport, prisons, education and businesses. All are likely to be affected by staff sickness, travel restrictions and other potentially disruptive counter measures.

The civil emergency response is covered by other contingency plans which will come into effect should they be required. These will ensure the maintenance of essential services, transport, food distribution, pharmaceutical supplies, utilities and communications, the maintenance of public order and the role of the police and armed services.

Responding to the threat of pandemic flu

The UK was one of the first European countries to have a pandemic flu contingency plan in place. It set out specific measures and actions required from health and other government departments and organisations at national and local levels to support an effective response to a flu pandemic.

The UK Pandemic Influenza Contingency Plan was published in March 2005. Replacing the Multiphase Contingency Plan for Pandemic Influenza published in 1997, the current plan has been updated to take account of new scientific developments, changes in the health service, lessons learned from the 1997 outbreak of avian flu in Hong Kong and from the 2003 SARS outbreak and experience in emergency planning since the events of 11 September 2001.

The UK plan has been developed in accordance with international recommendations issued by WHO and adapted to meet national needs. Its overall objective is to minimise the impact of a flu pandemic on the UK population.

Devon County Council has a pandemic flu plan, part of its approach to business continuity planning, based on a framework developed by the multi-agency Devon Influenza Multi-Agency Planning Group.

Also on devon.gov.uk

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