Public Health Guidance for the Prevention and Management of Influenza-like-illness (ILI), including the Pandemic (H1N1) 2009 Influenza Virus, Related to Mass Gatherings

 

• Definition
• Introduction
• Canadian Situation Analysis
• 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). A gathering can be held at one location or spread over different sites.

A health related event is any event that would require health services.

Introduction

Mass gatherings have the potential to cause additional strain on the health care system when held during outbreaks of influenza-like-illness (ILI) as they can be a focal point to amplify and spread infectious disease if they are not planned and managed properly. Transmission can also occur during transit to and from the event and in participants home communities upon their return. 

Therefore it is important that planners of mass gatherings consult with public health officials to consider the capacity of the health care system to respond if a further increase in illness occurs or if another health-related event (e.g., accident resulting in multiple casualties) happens during or following a mass gathering event. For example, if the local health system is operating at capacity or overwhelmed with cases of ILI, communities may not be able to respond well to an increased demand for health services should increased illness transmission occur or should another health-related event during a mass gathering occur.

This document provides guidance that local public health officials can use to develop recommendations for organizers of mass gatherings in their communities. It is recommended that planning for mass gathering events be carefully evaluated taking into account such factors as the local level of influenza activity, especially the 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 influenza activity.

It is recommended that the decision to proceed with a mass gathering or to restrict, modify, postpone, or cancel the event due to pandemic influenza be based on a thorough risk assessment and that event planners undertake such an assessment in partnership with local and national public health authorities. The risk assessment may take into account available information about pandemic (H1N1) 2009 influenza at global, national, and local levels such as severity of illness, and periods of communicability and incubation. If the severity of illness is high and the periods of communicability or incubation are less than the length of the event, there is a greater risk of overwhelming the local health services; however, if the periods of communicability or incubation are of longer duration, the greater impact may be in the participants’ home communities upon their return home. It is recommended that these risks factors be assessed against the social disruption that may be caused by the cancellation of an event.

Canadian Situation Analysis

The pandemic (H1N1) 2009 influenza virus has rapidly spread across the world. Canadians experienced the first wave in the spring and early summer of 2009 with the peak appearing in June. While influenza activity is normally expected to wane during the summer months, the pandemic (H1N1) 2009 influenza virus continued to circulate at low levels in Canada throughout the summer and resurged in the fall. The epidemiology of this second wave is consistent with the first wave with pandemic (H1N1) 2009 influenza virus infections resulting in influenza like illness (ILI) similar to seasonal influenza.

The surveillance case definition for ILI in the general population is defined as the acute onset of respiratory illness with fever and cough 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.

It has been observed that gastrointestinal symptoms have been present in at least one third of the cases and a wider age range of individuals may not experience fever.

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 may also occur 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 approximately four days (range: one to seven days). The period of communicability is estimated to be seven days in uncomplicated cases; however, it may be longer in children (up to 10 days) and other individuals in whom symptoms and virus shedding may persist (i.e., immunocompromised and severely ill). Consistent with seasonal influenza, transmission of the pandemic (H1N1) 2009 influenza virus is most likely during the initial days of infection when cases are typically symptomatic and have high viral loads.

Like seasonal influenza, the pandemic influenza (H1N1) 2009 influenza infection in humans can vary in severity from mild to severe, with approximately two-thirds of hospitalized cases to date occurring in individuals with known risk factors for complications from influenza such as chronic illness, immunosuppression or pregnancy. This virus also appears to result in more severe disease in the 5-64 year old age group than does seasonal influenza; however, most individuals with pandemic (H1N1) 2009 influenza have not required hospitalization and have recovered in the community.

Recommendations

Based upon the current situational analysis, 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}

Promoting immunization, 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 of illness.

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 may make collaboratively. Recognizing that events may be cancelled for other reasons (e.g., economic, weather, etc.); event organizers are encouraged to communicate the reason for the event cancellation to the public.

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

It is recommended that public health officials promote key general public health prevention messages to the public using the variety of media available. The most important messages are:

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.  These individuals are advised to get vaccinated to protect themselves. If they are not immunized they 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; and
7. International travellers, who could 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 indicating where to find medical attention if they become ill.

Risk Assessment

Event planners and other stakeholders are advised to 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 that may be considered 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 a health-related event occur as a result of a mass gathering  (e.g., communities may not be able to respond to a health-related 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. Immunization coverage levels in the community;
4. The target audience of the mass gathering  (e.g., children, seniors, local vs. international);
5. The size and duration of the event;
6. 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);
7. The types of accommodation that will be used by event attendees (e.g., individual hotel rooms vs. dormitory style, tents or billeting arrangements);
8. The purpose of the mass gathering and the potential political, social, cultural and economic impacts of cancelling the event;
9. 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,
10. 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 importance of getting immunized
   2. the signs and symptoms of ILI
   3. the importance of having attendees stay home if ill with symptoms of ILI
   4. the potential for the spread of ILI at such events
   5. proper hand hygiene, cough & sneeze etiquette.
2. The promotion of key general public health messages (e.g., getting immunized , 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 - Material Safety Data Sheets and the product labels provide additional information regarding placement, storage and warnings associated with the product;
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/disinfecting of high-touch areas such as washroom facilities, handrails, door knobs etc.- many readily available household or commercial disinfectant cleaning products are effective against influenza viruses. Product specific information, including effectiveness against the H1N1 influenza virus, may be found on the cleaning product label and/or the manufacturer’s web site³.  If household or commercial disinfectant cleaning products are not readily available, hard surfaces can be cleaned using a mixture of 1 part bleach and 9 parts water.  Always use caution when using bleach as undiluted bleach is corrosive and could damage skin, fabrics, and other surfaces.
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;
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. Information on food safety can also be found at the following web link: http://www.phac-aspc.gc.ca/fs-sa/index-eng.php; and,
13. The importance of including social distancing measures to reducing crowding at a mass gathering during an influenza outbreak such as increasing the frequency of transport, staggering arrivals, diverting departures, and minimizing congregation at sanitary stations and food and water distribution areas.

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

Additional information can be found at:

• CDC
• WHO