Public Health Guidance for the prevention and management of Influenza-like-illness (ILI), including the Pandemic (H1N1) 2009 Influenza Virus, related to mass gatherings

9 September 2009

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Table of Content

• Definition
• Background Information
• Introduction
• Recommendations
• Communication to the Public
• Risk Assessment
• Event Planning

Definition

Mass gatherings are the temporary collection of large numbers of people at one site or location for a common purpose.  Gatherings can be short-term (for a few hours as in a sporting event or concert) or longer (for several days to weeks as in the Olympic Games).  The gathering can be held at one location or spread over different sites.

Mass gatherings held during outbreaks of influenza-like-illness (ILI) may strain the capacity of the health system to respond to an adverse health event.  Given the extra burden pandemic (H1N1) 2009 influenza virus may place on the health care system of a community and given that mass gatherings have the potential to become a focal point for illness transmission, consideration should be given to the capacity of the health care system to respond if a further increase in illness occurs or if an adverse health event happens during or following a mass gathering event.  For example, if the local health system is at capacity or overwhelmed with cases of pandemic (H1N1) influenza virus, communities may not be able to respond well to an increased demand for health service should increased illness transmission occur or should an adverse health event at a mass gathering (e.g., an accident resulting in multiple casualties) occur.

Background Information

The pandemic (H1N1) 2009 influenza virus has rapidly spread across the world.  While influenza activity would normally be expected to wane almost entirely during the summer months, the pandemic (H1N1) 2009 influenza virus has continued to circulate at low levels in Canada and the potential for resurgence in the fall remains.

To date, infection with the pandemic (H1N1) 2009 influenza virus has resulted in ILI similar to seasonal influenza.

• The surveillance case definition for ILI is defined as the acute onset of respiratory illness with fever and cough and with one or more of the following - sore throat, muscle aches, joint pain or weakness which could be due to influenza virus.  In children under 5, gastrointestinal symptoms may also be present.  In patients under 5 or 65 and older, fever may not be prominent.
• The clinical case definition for ILI for treatment or isolation purposes in a given setting should be adapted to ensure appropriate sensitivity and specificity for this setting.

This pandemic (H1N1) 2009 influenza virus is thought to be spread from person-to-person in the same way as seasonal influenza where transmission occurs predominantly through droplets produced from coughing or sneezing.  Indirect transmission also likely occurs through self-inoculation after contact with surfaces or objects contaminated with the virus from infected persons.

The incubation period for pandemic (H1N1) 2009 influenza virus is understood to be up to four days and the period of communicability up to seven days from onset of symptoms in uncomplicated cases.  This may be longer (up to ten days) in individuals with severe illness and children in whom symptoms and virus shedding may persist.  Consistent with seasonal influenza, transmission of the pandemic H1N1 (2009) influenza virus is most likely during the initial days of infection when the individual is symptomatic and has a high viral load.

Like seasonal influenza, the pandemic (H1N1) 2009 influenza infection in humans can vary in severity from mild to severe, with the most severe disease occurring mainly in individuals with known risk factors for complications from influenza such as chronic illness, immunosuppression or pregnancy (especially second or third trimesters).  This virus also appears to result in more severe disease in the 5-55 year old age group than does seasonal influenza; however, most individuals with pandemic (H1N1) 2009 influenza virus infection have not required hospitalization and have recovered in the community.

Introduction

This document provides guidance that local public health officials can use in developing recommendations for organizers of large gatherings in their communities.  Planning for mass gathering events should be carefully evaluated taking into account such factors as the local situation of pandemic (H1N1) 2009 influenza virus, the type of event, the participating population, and the ability of the host community to respond to and mitigate the impacts of the disease. 

At this time the Public Health Agency of Canada does not recommend the cancellation of mass gatherings as a control measure to limit the spread of pandemic (H1N1) 2009 influenza virus as there is insufficient evidence to support cancelling or restricting mass gatherings as an effective control measure when pandemic influenza virus is circulating in a community.¹,² . 

Encouraging ill people not to attend gatherings and ensuring processes are in place to safely isolate and transport ill persons off-site remain the most important measures to prevent transmission.

Recommendations

The decision to cancel, postpone or modify a mass gathering event due to the pandemic (H1N1) 2009 influenza virus is a local decision public health officials and event organizers should make collaboratively.  Recognizing that events may be cancelled for other reasons (e.g., economic); event organizers should communicate the reason for the event cancellation to the public.

Other factors that may be considered when making such a decision include the local pandemic (H1N1) 2009 influenza virus activity, severity of the illness and the public health capacity of the community hosting the mass gathering to monitor and respond to local outbreaks of pandemic (H1N1) 2009 influenza virus.  These factors should be weighed against the social disruption that may be caused by the cancellation of an event.

Public health officials are encouraged to connect with local municipalities to ensure they are included in the planning and approval process for mass gatherings.  The three areas for which public health officials may provide guidance related to the planning and hosting of mass gatherings are:

• To the public; on public health prevention measures using a variety of communication tools,
• To event organizers and other stakeholders; on conducting risk assessments of an event as part of the planning process and,
• To event organizers; on measures to mitigate the transmission of ILI during an event.

Communication to the Public

Public health officials should promote key general public health prevention messages to the public using a variety of media available.  The most important message should be:

Other important public health prevention messages include information for and regarding:

1. Individuals who have an underlying illness that puts them at risk for severe illness or complications from the pandemic (H1N1) 2009 influenza virus may wish to consider not attending mass gatherings because of their own personal risk.
2. Practising frequent hand cleaning (i.e., after sneezing or coughing, before and after eating, after recreation times, after going to the washroom, etc.),
3. Using the correct hand washing technique,
4. Practising cough and sneeze etiquette
   
5. Recognizing the signs and symptoms of ILI.
6. Avoiding travel if experiencing symptoms of ILI.
7. International travellers, who should be made aware that they may be subject to isolation and quarantine measures while travelling.

Public health officials should consider providing posters and leaflets at places such as airports, tourist information centres, bus depots, train stations, etc., with information that contains the above key messages and includes phone numbers for visitors on where to find medical attention if they become ill.

Risk Assessment

Event planners and other stakeholders should work in close collaboration with local public health officials when planning events, taking into account local factors while conducting a risk assessment of the event.  Conducting a risk assessment of a planned event will assist event planners, stakeholders, and local public health officials to determine if an event should be cancelled, modified, or postponed.  Factors to consider when conducting a risk assessment of an event include:

1. The capacity of the health care system to respond (or access adequate health care services if such services are not available in the host community) should an adverse health event occur as a result of a mass gathering  (e.g. communities may not be able to respond to an adverse health event such as an accident resulting in multiple casualties, should one occur at a mass gathering, if the local health system is overwhelmed with cases of pandemic (H1N1) 2009 influenza virus);
2. The morbidity and mortality of the pandemic (H1N1) 2009 influenza virus illness within the community;
3. The target audience of the mass gathering  (e.g., children, seniors, local vs. international);
4. The size and duration of the event;
5. The types of transportation that will be used, if the event includes transportation, and the degree of isolation from medical attention (e.g., cars vs. buses);
6. The types of accommodation that will be used by event attendees (e.g., individual hotel rooms vs. dormitory style, tents or billeting arrangements);
7. The purpose of the mass gathering and the potential political, social, cultural and economic impacts of cancelling the event;
8. The season the event is to be held in and the type of venue  (e.g., an outdoor summer event vs. an indoor winter event); and
9. The ability of the event organizer to provide adequate hygiene & sanitation facilities.

Event Planning

To help mitigate the spread of ILI during an event, public health officials can provide guidance to event organizers regarding:

1. The importance of providing information prior to the event (e.g., with event tickets, announcements on radio & TV, etc.) on:

   1. the signs and symptoms of ILI;
   2. the importance of attendees to stay home if ill with symptoms of ILI;
   3. the potential for the spread of ILI at such events; and
   4. proper hand hygiene, cough & sneeze etiquette. 
2. The promotion of key general public health messages (e.g., hand hygiene, cough and sneeze etiquette, not to share cups, cigarettes, etc.) during the event via the display of posters at the event, inclusion of relevant information in event brochures, and making announcements at the event;
3. The importance of planning for the safe assessment of people who become ill with symptoms of ILI at the event and a mechanism for isolating ill attendees or safely transporting ill attendees from the site;
4. The importance of, and how to consult with public health authorities if clusters of ILI are identified at events with a longer duration, (e.g., a few days or more);
5. The importance of providing hand wash stations throughout the event venue and in a manner that will help encourage hand cleaning;
6. The importance of ensuring a constant supply of soap and paper towels for hand washing purposes and providing advice (e.g., include posters at hand wash stations) regarding  correct hand cleaning procedure);
7. The benefits of locating temporary toilet and hand washing facilities, if used, throughout the site rather than in one area, to reduce queuing;
8. The use of alcohol based rub stations to supplement (or in lieu of) hand washing stations and information (e.g., posters) showing correct hand cleaning procedures at alcohol based rub stations;
9. The importance of ensuring that tissues and closed waste receptacles are located throughout the venue and that posters promoting hand hygiene and respiratory etiquette are visible in order to encourage appropriate infection prevention practices;
10. The importance of frequent cleaning, using routine cleaning products, of high-touch areas (e.g., washroom facilities, handrails, door knobs etc.);
11. The importance of frequent emptying of waste receptacles - no special waste handling is required for influenza.  Waste handling should be carried out according to usual standards; and
12. The importance of, and how to, contact local public health or health protection offices for information on food safety and sanitation issues at mass gathering events.

The information provided by event organizers should be tailored for the event attendees and may need to be provided in additional languages. 

Additional information can be found at:

• CDC
• WHO