Influenza outbreaks during World Youth Day 2008 mass gathering

Sacred journeys and pilgrimages: health risks associated with travels for religious purposes

BACKGROUND

Pilgrimages and travel to religious mass gatherings (MGs) are part of all major religions. This narrative review aims to describe some characteristics, including health risks, of the more well-known and frequently undertaken ones.

METHODS

A literature search was conducted using keywords related to the characteristics (frequency of occurrence, duration, calendar period, reasons behind their undertaking and the common health risks) of Christian, Muslim, Hindu, Buddhist and Jewish religious MGs.

RESULTS

About 600 million trips are undertaken to religious sites annually. The characteristics vary between religions and between pilgrimages. However, religious MGs share common health risks, but these are reported in a heterogenous manner. European Christian pilgrimages reported both communicable diseases, such as norovirus outbreaks linked to the Marian Shrine of Lourdes in France, and non-communicable diseases (NCDs). NCDs predominated at the Catholic pilgrimage to the Basilica of Our Lady of Guadalupe in Mexico, which documented 11 million attendees in 1 week. The Zion Christian Church Easter gathering in South Africa, attended by ~10 million pilgrims, reported mostly motor vehicle accidents. Muslim pilgrimages such as the Arbaeen (20 million pilgrims) and Hajj documented a high incidence of respiratory tract infections, up to 80% during Hajj. Heat injuries and stampedes have been associated with Hajj. The Hindu Kumbh Mela pilgrimage, which attracted 100 million pilgrims in 2013, documented respiratory conditions in 70% of consultations. A deadly stampede occurred at the 2021 Jewish Lag BaOmer MG.

CONCLUSION

Communicable and NCD differ among the different religious MGs. Gaps exists in the surveillance, reporting and data accessibility of health risks associated with religious MGs. A need exists for the uniform implementation of a system of real-time monitoring of diseases and morbidity patterns, utilizing standardized modern information-sharing platforms. The health needs of pilgrims can then be prioritized by developing specific and appropriate guidelines.

Protection enhancement strategies of potential outbreaks during Hajj

OBJECTIVE

This study aimed to assist governments and organizers of mass gathering events in reviewing existing preventive measures for disease outbreaks to inform the adoption of enhanced strategies for risk reduction and impacts on public health.

DESIGN

A cross-sectional, quantitative, descriptive study.

SETTING

This study was conducted in a mass gathering of Hajj, an annual religious event in Mecca, Saudi Arabia.

PARTICIPANTS

A convenience sample of 70 personnel working in government ministries of Saudi Arabia (Ministry of Health, Ministry of Hajj, and Ministry of Interior) and the Saudi Red Crescent Authority involved in health management in Hajj, including policy formulation and implementation.

MAIN OUTCOME MEASURES

Perception and knowledge of health risks and outbreaks associated with Hajj.

RESULTS

The majority of the respondents (60 percent) expressed concern about the potential for infection transmission during Hajj. The respondents also reported having or knowing a colleague, a friend, or a family member with a history of infection during or after Hajj. However, the respondents' knowledge of the possible modes of infection of various diseases was limited.

CONCLUSIONS

Hajj is associated with various risks of outbreaks, and thus, better protection-enhancing measures are required. Training personnel involved in health management, including planners, coordinators, and healthcare providers, can help reduce the risks and prevent potential outbreaks.

Modelling disease mitigation at mass gatherings: A case study of COVID-19 at the 2022 FIFA World Cup

The 2022 FIFA World Cup was the first major multi-continental sporting Mass Gathering Event (MGE) of the post COVID-19 era to allow foreign spectators. Such large-scale MGEs can potentially lead to outbreaks of infectious disease and contribute to the global dissemination of such pathogens. Here we adapt previous work and create a generalisable model framework for assessing the use of disease control strategies at such events, in terms of reducing infections and hospitalisations. This framework utilises a combination of meta-populations based on clusters of people and their vaccination status, Ordinary Differential Equation integration between fixed time events, and Latin Hypercube sampling. We use the FIFA 2022 World Cup as a case study for this framework (modelling each match as independent 7 day MGEs). Pre-travel screenings of visitors were found to have little effect in reducing COVID-19 infections and hospitalisations. With pre-match screenings of spectators and match staff being more effective. Rapid Antigen (RA) screenings 0.5 days before match day performed similarly to RT-PCR screenings 1.5 days before match day. Combinations of pre-travel and pre-match testing led to improvements. However, a policy of ensuring that all visitors had a COVID-19 vaccination (second or booster dose) within a few months before departure proved to be much more efficacious. The State of Qatar abandoned all COVID-19 related travel testing and vaccination requirements over the period of the World Cup. Our work suggests that the State of Qatar may have been correct in abandoning the pre-travel testing of visitors. However, there was a spike in COVID-19 cases and hospitalisations within Qatar over the World Cup. Given our findings and the spike in cases, we suggest a policy requiring visitors to have had a recent COVID-19 vaccination should have been in place to reduce cases and hospitalisations.

The impact of mass gatherings on the local transmission of COVID-19 and the implications for social distancing policies: Evidence from Hong Kong

Mass gatherings provide conditions for the transmission of infectious diseases and pose complex challenges to public health. Faced with the COVID-19 pandemic, governments and health experts called for suspension of gatherings in order to reduce social contact via which virus is transmitted. However, few studies have investigated the contribution of mass gatherings to COVID-19 transmission in local communities. In Hong Kong, the coincidence of the relaxation of group gathering restrictions with demonstrations against the National Security Law in mid-2020 raised concerns about the safety of mass gatherings under the pandemic. Therefore, this study examines the impacts of mass gatherings on the local transmission of COVID-19 and evaluates the importance of social distancing policies. With an aggregated dataset of epidemiological, city-level meteorological and socioeconomic data, a Synthetic Control Method (SCM) is used for constructing a 'synthetic Hong Kong' from over 200 Chinese cities. This counterfactual control unit is used to simulate COVID-19 infection patterns (i.e., the number of total cases and daily new cases) in the absence of mass gatherings. Comparing the hypothetical trends and the actual ones, our results indicate that the infection rate observed in Hong Kong is substantially higher than that in the counterfactual control unit (2.63% vs. 0.07%). As estimated, mass gatherings increased the number of new infections by 62 cases (or 87.58% of total new cases) over the 10-day period and by 737 cases (or 97.23%) over the 30-day period. These findings suggest the necessity of tightening social distancing policies, especially the prohibition on group gathering regulation (POGGR), to prevent and control COVID-19 outbreaks.

The population attributable fraction of cases due to gatherings and groups with relevance to COVID-19 mitigation strategies

Many countries have banned groups and gatherings as part of their response to the pandemic caused by the coronavirus, SARS-CoV-2. Although there are outbreak reports involving mass gatherings, the contribution to overall transmission is unknown. We used data from a survey of social contact behaviour that specifically asked about contact with groups to estimate the population attributable fraction (PAF) due to groups as the relative change in the basic reproduction number when groups are prevented. Groups of 50+ individuals accounted for 0.5% of reported contact events, and we estimate that the PAF due to groups of 50+ people is 5.4% (95% confidence interval 1.4%, 11.5%). The PAF due to groups of 20+ people is 18.9% (12.7%, 25.7%) and the PAF due to groups of 10+ is 25.2% (19.4%, 31.4%). Under normal circumstances with pre-COVID-19 contact patterns, large groups of individuals have a relatively small epidemiological impact; small- and medium-sized groups between 10 and 50 people have a larger impact on an epidemic. This article is part of the theme issue 'Modelling that shaped the early COVID-19 pandemic response in the UK'.

Novel Respiratory Viruses in the Context of Mass-Gathering Events: A Systematic Review to Inform Event Planning from a Health Perspective

BACKGROUND

Mass-gathering events (MGEs) occur regularly throughout the world. As people congregate at MGEs, there is an increased risk of transmission of communicable diseases. Novel respiratory viruses, such as Severe Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1), Influenza A Virus Subtype H1N1 Strain 2009 (H1N1pdm09), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), or Coronavirus Disease 2019 (COVID-19), may require specific infection prevention and control strategies to minimize the risk of transmission when planning MGEs. This literature review aimed to identify and analyze papers relating to novel respiratory viruses with pandemic potential and to inform MGE planning.

METHOD

This paper used a systematic literature review method. Various health care databases were searched using keywords relating to MGEs and novel respiratory viruses. Information was extracted from identified papers into various tables for analysis. The analysis identified infection prevention and control strategies used at MGEs to inform planning before, during, and following events.

RESULTS

In total, 27 papers met the criteria for inclusion. No papers were identified regarding SARS-CoV-1, while the remainder reported on H1N1pdm09 (n = 9), MERS-CoV (n = 15), and SARS-CoV-2 (n = 3). Various before, during, and after event mitigation strategies were identified that can be implemented for future events.

CONCLUSIONS

This literature review provided an overview of the novel respiratory virus epidemiology at MGEs alongside related public health mitigation strategies that have been implemented at these events. This paper also discusses the health security of event participants and host communities in the context of cancelling, postponing, and modifying events due to a novel respiratory virus. In particular, ways to recommence events incorporating various mitigation strategies are outlined.

Narrative review of non-pharmaceutical behavioural measures for the prevention of COVID-19 (SARS-CoV-2) based on the Health-EDRM framework

INTRODUCTION

Non-pharmaceutical measures to facilitate a response to the COVID-19 pandemic, a disease caused by novel coronavirus SARS-CoV-2, are urgently needed. Using the World Health Organization (WHO) health emergency and disaster risk management (health-EDRM) framework, behavioural measures for droplet-borne communicable diseases and their enabling and limiting factors at various implementation levels were evaluated.

SOURCES OF DATA

Keyword search was conducted in PubMed, Google Scholar, Embase, Medline, Science Direct, WHO and CDC online publication databases. Using the Oxford Centre for Evidence-Based Medicine review criteria, 10 bottom-up, non-pharmaceutical prevention measures from 104 English-language articles, which published between January 2000 and May 2020, were identified and examined.

AREAS OF AGREEMENT

Evidence-guided behavioural measures against transmission of COVID-19 in global at-risk communities were identified, including regular handwashing, wearing face masks and avoiding crowds and gatherings.

AREAS OF CONCERN

Strong evidence-based systematic behavioural studies for COVID-19 prevention are lacking.

GROWING POINTS

Very limited research publications are available for non-pharmaceutical measures to facilitate pandemic response.

AREAS TIMELY FOR RESEARCH

Research with strong implementation feasibility that targets resource-poor settings with low baseline health-EDRM capacity is urgently needed.

Comprehensive metagenomic insights into a unique mass gathering and bathing event reveals transient influence on a riverine ecosystem

The religious mass gathering and bathing can pose a multitude of significant public health challenges and lead to severe alterations in the river microbial ecology. The Pandharpur Wari is an annual pilgrimage of Maharashtra, India, where millions of devotees carry the footprints of the saint-poets and pay their obeisance to Lord Vitthal on the 11th day of moon's waxing phase (Ashadi Ekadashi). As a part of the ritual, the engrossed devotees, walk over 250 km, take a first holy dip in a sacred river Indrayani at Alandi and secondly in Bhima River at Pandharpur. The MinION-based shotgun metagenomic approach was employed to examine the impact of spiritual mass bathing on environmental changes (concerning the river microbial community structure and functions); and public health aspects (in terms of changes in the pathogenic potential and antibiotic resistance). The analysis of bathing and post-bathing samples of both the rivers revealed alterations in the alpha and beta diversity, indicating significant spatiotemporal variations in the overall microbial structure and function. Furthermore, the analysis revealed up to 80% of differences in the abundance of virulence genes between the bathing and post bathing samples. We observed parallel increase of priority skin and enteric pathogens (ranging from 11% to 80%) such as Acinetobacter baumannii, Staphylococcus aureus, Streptococcus pyogenes, Mycobacterium tuberculosis, and Pseudomonas aeruginosa during the bathing event. Moreover, we observed a significant increase in the antibiotic resistance in the bathing samples of Bhima and Indrayani rivers respectively. Altogether, this is the first comprehensive metagenomic study unravelling the influence of religious mass-bathing on the riverine ecosystem.

Incorporating calendar effects to predict influenza seasonality in Milwaukee, Wisconsin

Social outings can trigger influenza transmission, especially in children and elderly. In contrast, school closures are associated with reduced influenza incidence in school-aged children. While influenza surveillance modelling studies typically account for holidays and mass gatherings, age-specific effects of school breaks, sporting events and commonly celebrated observances are not fully explored. We examined the impact of school holidays, social events and religious observances for six age groups (all ages, ⩽4, 5–24, 25–44, 45–64, ⩾65 years) on four influenza outcomes (tests, positives, influenza A and influenza B) as reported by the City of Milwaukee Health Department Laboratory, Milwaukee, Wisconsin from 2004 to 2009. We characterised holiday effects by analysing average weekly counts in negative binomial regression models controlling for weather and seasonal incidence fluctuations. We estimated age-specific annual peak timing and compared influenza outcomes before, during and after school breaks. During the 118 university holiday weeks, average weekly tests were lower than in 140 school term weeks (5.93 vs. 11.99 cases/week, P < 0.005). The dampening of tests during Winter Break was evident in all ages and in those 5–24 years (RR = 0.31; 95% CI 0.22–0.41 vs. RR = 0.14; 95% CI 0.09–0.22, respectively). A significant increase in tests was observed during Spring Break in 45–64 years old adults (RR = 2.12; 95% CI 1.14–3.96). Milwaukee Public Schools holiday breaks showed similar amplification and dampening effects. Overall, calendar effects depend on the proximity and alignment of an individual holiday to age-specific and influenza outcome-specific peak timing. Better quantification of individual holiday effects, tailored to specific age groups, should improve influenza prevention measures.

World's Largest Mass Bathing Event Influences the Bacterial Communities of Godavari, a Holy River of India

Kumbh Mela is one of the largest religious mass gathering events (MGE) involving bathing in rivers. The exponential rise in the number of devotees, from around 0.4 million in 1903 to 120 million in 2013, bathing in small specified sites can have a dramatic impact on the river ecosystem. Here, we present the spatiotemporal profiling of bacterial communities in Godavari River, Nashik, India, comprising five sites during the Kumbh Mela, held in 2015. Assessment of environmental parameters indicated deterioration of water quality. Targeted amplicon sequencing demonstrates approximately 37.5% loss in microbial diversity because of anthropogenic activity during MGE. A significant decrease in phyla viz. Actinobacteria, Chloroflexi, Proteobacteria, and Bacteroidetes was observed, while we noted substantial increase in prevalence of the phylum Firmicutes (94.6%) during MGE. qPCR estimations suggested nearly 130-fold increase in bacterial load during the event. Bayesian mixing model accounted the source of enormous incorporation of bacterial load of human origin. Further, metagenomic imputations depicted increase in virulence and antibiotic resistance genes during the MGE. These observations suggest the striking impact of the mass bathing on river ecosystem. The subsequent increase in infectious diseases and drug-resistant microbes pose a critical public health concern.

A systematic review of emerging respiratory viruses at the Hajj and possible coinfection with Streptococcus pneumoniae

Background

The annual Hajj to the Kingdom of Saudi Arabia attracts millions of pilgrims from around the world. International health community's attention goes towards this mass gathering and the possibility of the development of any respiratory tract infections due to the high risk of acquisition of respiratory viruses.

Method

We searched MEDLINE/PubMed and Scopus databases for relevant papers describing the prevalence of respiratory viruses among Hajj pilgrims.

Results

The retrieved articles were summarized based on the methodology of testing for these viruses. A total of 31 studies were included in the quantitative/qualitative analyses. The main methods used for the diagnosis of most common respiratory viruses were polymerase chain reaction (PCR), culture and enzyme-linked immunosorbent assay (ELISA). Influenza, rhinovirus and parainfluenza were the most common viruses detected among pilgrims. Coronaviruses other than MERS-CoV were also detected among pilgrims. The acquisition of MERS-CoV remains very limited and systematic screening of pilgrims showed no infections.

Conclusions

Well conducted multinational follow-up studies using the same methodology of testing are necessary for accurate surveillance of respiratory viral infections among Hajj pilgrims. Post-Hajj cohort studies would further evaluate the impact of the Hajj on the acquisition of respiratory viruses.

Mass Gatherings and the Spread of Respiratory Infections. Lessons from the Hajj

The mass gathering of people is a potential source for developing, propagating, and disseminating infectious diseases on a global scale. Of the illnesses associated with mass gatherings, respiratory tract infections are the most common, the most easily transmitted, and the most likely to be spread widely beyond the site of the meeting by attendees returning home. Many factors contribute to the spread of these infections during mass gatherings, including crowding, the health of the attendees, and the type and location of meetings. The annual Hajj in the Kingdom of Saudi Arabia is the largest recurring single mass gathering in the world. Every year more than 10 million pilgrims attend the annual Hajj and Umrah. Attendees assemble in confined areas for several days. People with a wide range of age, health, susceptibility to illness, and hygiene sophistication come in close contact, creating an enormous public health challenge. Controlling respiratory infections at the Hajj requires surveillance, rapid diagnostic testing, and containment strategies. Although the Hajj is without equal, other mass gatherings can generate similar hazards. The geographic colocalization of the Zika virus epidemic and the 2016 Summer Olympic Games in Brazil is a current example of great concern. The potential of international mass gatherings for local and global calamity calls for greater global attention and research.

Estimating the frequency and characteristics of respiratory disease outbreaks at mass gatherings in the United States: Findings from a state and local health department assessment

Mass gatherings create environments conducive to the transmission of infectious diseases. Thousands of mass gatherings are held annually in the United States; however, information on the frequency and characteristics of respiratory disease outbreaks and on the use of nonpharmaceutical interventions at these gatherings is scarce. We administered an online assessment to the 50 state health departments and 31 large local health departments in the United States to gather information about mass gathering-related respiratory disease outbreaks occurring between 2009 and 2014. The assessment also captured information on the use of nonpharmaceutical interventions to slow disease transmission in these settings. We downloaded respondent data into a SAS dataset for descriptive analyses. We received responses from 43 (53%) of the 81 health jurisdictions. Among these, 8 reported 18 mass gathering outbreaks. More than half (n = 11) of the outbreaks involved zoonotic transmission of influenza A (H3N2v) at county and state fairs. Other outbreaks occurred at camps (influenza A (H1N1)pdm09 [n = 2] and A (H3) [n = 1]), religious gatherings (influenza A (H1N1)pdm09 [n = 1] and unspecified respiratory virus [n = 1]), at a conference (influenza A (H1N1)pdm09), and a sporting event (influenza A). Outbreaks ranged from 5 to 150 reported cases. Of the 43 respondents, 9 jurisdictions used nonpharmaceutical interventions to slow or prevent disease transmission. Although respiratory disease outbreaks with a large number of cases occur at many types of mass gatherings, our assessment suggests that such outbreaks may be uncommon, even during the 2009 influenza A (H1N1) pandemic, which partially explains the reported, but limited, use of nonpharmaceutical interventions. More research on the characteristics of mass gatherings with respiratory disease outbreaks and effectiveness of nonpharmaceutical interventions would likely be beneficial for decision makers at state and local health departments when responding to future outbreaks and pandemics.

Multiple Sources of Genetic Diversity of Influenza A Viruses during the Hajj

Outbreaks of respiratory virus infection at mass gatherings pose significant health risks to attendees, host communities, and ultimately the global population if they help facilitate viral emergence. However, little is known about the genetic diversity, evolution, and patterns of viral transmission during mass gatherings, particularly how much diversity is generated by in situ transmission compared to that imported from other locations. Here, we describe the genome-scale evolution of influenza A viruses sampled from the Hajj pilgrimages at Makkah during 2013 to 2015. Phylogenetic analysis revealed that the diversity of influenza viruses at the Hajj pilgrimages was shaped by multiple introduction events, comprising multiple cocirculating lineages in each year, including those that have circulated in the Middle East and those whose origins likely lie on different continents. At the scale of individual hosts, the majority of minor variants resulted from de novo mutation, with only limited evidence of minor variant transmission or minor variants circulating at subconsensus level despite the likely identification of multiple transmission clusters. Together, these data highlight the complexity of influenza virus infection at the Hajj pilgrimages, reflecting a mix of global genetic diversity drawn from multiple sources combined with local transmission, and reemphasize the need for vigilant surveillance at mass gatherings.IMPORTANCE Large population sizes and densities at mass gatherings such as the Hajj (Makkah, Saudi Arabia) can contribute to outbreaks of respiratory virus infection by providing local hot spots for transmission followed by spread to other localities. Using a genome-scale analysis, we show that the genetic diversity of influenza A viruses at the Hajj gatherings during 2013 to 2015 was largely shaped by the introduction of multiple viruses from diverse geographic regions, including the Middle East, with only little evidence of interhost virus transmission at the Hajj and seemingly limited spread of subconsensus mutational variants. The diversity of viruses at the Hajj pilgrimages highlights the potential for lineage cocirculation during mass gatherings, in turn fuelling segment reassortment and the emergence of novel variants, such that the continued surveillance of respiratory pathogens at mass gatherings should be a public health priority.

Community Mitigation Guidelines to Prevent Pandemic Influenza - United States, 2017

When a novel influenza A virus with pandemic potential emerges, nonpharmaceutical interventions (NPIs) often are the most readily available interventions to help slow transmission of the virus in communities, which is especially important before a pandemic vaccine becomes widely available. NPIs, also known as community mitigation measures, are actions that persons and communities can take to help slow the spread of respiratory virus infections, including seasonal and pandemic influenza viruses.These guidelines replace the 2007 Interim Pre-pandemic Planning Guidance: Community Strategy for Pandemic Influenza Mitigation in the United States - Early, Targeted, Layered Use of Nonpharmaceutical Interventions (https://stacks.cdc.gov/view/cdc/11425). Several elements remain unchanged from the 2007 guidance, which described recommended NPIs and the supporting rationale and key concepts for the use of these interventions during influenza pandemics. NPIs can be phased in, or layered, on the basis of pandemic severity and local transmission patterns over time. Categories of NPIs include personal protective measures for everyday use (e.g., voluntary home isolation of ill persons, respiratory etiquette, and hand hygiene); personal protective measures reserved for influenza pandemics (e.g., voluntary home quarantine of exposed household members and use of face masks in community settings when ill); community measures aimed at increasing social distancing (e.g., school closures and dismissals, social distancing in workplaces, and postponing or cancelling mass gatherings); and environmental measures (e.g., routine cleaning of frequently touched surfaces).Several new elements have been incorporated into the 2017 guidelines. First, to support updated recommendations on the use of NPIs, the latest scientific evidence available since the influenza A (H1N1)pdm09 pandemic has been added. Second, a summary of lessons learned from the 2009 H1N1 pandemic response is presented to underscore the importance of broad and flexible prepandemic planning. Third, a new section on community engagement has been included to highlight that the timely and effective use of NPIs depends on community acceptance and active participation. Fourth, to provide new or updated pandemic assessment and planning tools, the novel influenza virus pandemic intervals tool, the Influenza Risk Assessment Tool, the Pandemic Severity Assessment Framework, and a set of prepandemic planning scenarios are described. Finally, to facilitate implementation of the updated guidelines and to assist states and localities with prepandemic planning and decision-making, this report links to six supplemental prepandemic NPI planning guides for different community settings that are available online (https://www.cdc.gov/nonpharmaceutical-interventions).

Community Mitigation Guidelines to Prevent Pandemic Influenza - United States, 2017

When a novel influenza A virus with pandemic potential emerges, nonpharmaceutical interventions (NPIs) often are the most readily available interventions to help slow transmission of the virus in communities, which is especially important before a pandemic vaccine becomes widely available. NPIs, also known as community mitigation measures, are actions that persons and communities can take to help slow the spread of respiratory virus infections, including seasonal and pandemic influenza viruses.These guidelines replace the 2007 Interim Pre-pandemic Planning Guidance: Community Strategy for Pandemic Influenza Mitigation in the United States - Early, Targeted, Layered Use of Nonpharmaceutical Interventions (https://stacks.cdc.gov/view/cdc/11425). Several elements remain unchanged from the 2007 guidance, which described recommended NPIs and the supporting rationale and key concepts for the use of these interventions during influenza pandemics. NPIs can be phased in, or layered, on the basis of pandemic severity and local transmission patterns over time. Categories of NPIs include personal protective measures for everyday use (e.g., voluntary home isolation of ill persons, respiratory etiquette, and hand hygiene); personal protective measures reserved for influenza pandemics (e.g., voluntary home quarantine of exposed household members and use of face masks in community settings when ill); community measures aimed at increasing social distancing (e.g., school closures and dismissals, social distancing in workplaces, and postponing or cancelling mass gatherings); and environmental measures (e.g., routine cleaning of frequently touched surfaces).Several new elements have been incorporated into the 2017 guidelines. First, to support updated recommendations on the use of NPIs, the latest scientific evidence available since the influenza A (H1N1)pdm09 pandemic has been added. Second, a summary of lessons learned from the 2009 H1N1 pandemic response is presented to underscore the importance of broad and flexible prepandemic planning. Third, a new section on community engagement has been included to highlight that the timely and effective use of NPIs depends on community acceptance and active participation. Fourth, to provide new or updated pandemic assessment and planning tools, the novel influenza virus pandemic intervals tool, the Influenza Risk Assessment Tool, the Pandemic Severity Assessment Framework, and a set of prepandemic planning scenarios are described. Finally, to facilitate implementation of the updated guidelines and to assist states and localities with prepandemic planning and decision-making, this report links to six supplemental prepandemic NPI planning guides for different community settings that are available online (https://www.cdc.gov/nonpharmaceutical-interventions).

Epidemiology of influenza B in Australia: 2001-2014 influenza seasons

Background

Influenza B is characterised by two antigenic lineages: B/Victoria and B/Yamagata. These lineages circulate together with influenza A during influenza seasons, with varying incidence from year to year and by geographic region.

Objective

To determine the epidemiology of influenza B relative to influenza A in Australia.

Methods

Laboratory‐confirmed influenza notifications between 2001 and 2014 in Australia were obtained from the Australian National Notifiable Diseases Surveillance System.

Results

A total of 278 485 laboratory‐confirmed influenza cases were notified during the study period, comprising influenza A (82.2%), B (17.1%) and ‘other and untyped’ (0.7%). The proportion of notifications that were influenza B was highest in five‐ to nine‐year‐olds (27.5%) and lowest in persons aged 85 years and over (11.5%). Of all B notifications with lineage determined, 77.1% were B/Victoria and 22.9% were B/Yamagata infections. Mismatches between the dominant B lineage in a season and the trivalent vaccine B lineage occurred in over one‐third of seasons during the study years. In general, influenza B notifications peaked later than influenza A notifications.

Conclusion

The proportion of circulating influenza B in Australia during 2001‐2014 was slightly lower than the global average and was dominated by B/Victoria. Compared with influenza A, influenza B infection was more common among older children and young adults and less common in the very elderly. Influenza B lineage mismatch with the trivalent vaccine occurred about one‐third of the time.

Uptake and effectiveness of facemask against respiratory infections at mass gatherings: a systematic review

•

Approximately half of the attendees of mass gatherings use facemask

•

Facemask seems to be effective against respiratory infections at Hajj

•

Effectiveness of facemask against specific respiratory infections is not proven

Objectives

The risk of acquisition and transmission of respiratory infections is high among attendees of mass gatherings (MGs). Currently used interventions have limitations yet the role of facemask in preventing those infections at MG has not been systematically reviewed. We have conducted a systematic review to synthesise evidence about the uptake and effectiveness of facemask against respiratory infections in MGs.

Methods

A comprehensive literature search was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines using major electronic databases such as, Medline, EMBASE, SCOPUS and CINAHL.

Results

Of 25 studies included, the pooled sample size was 12710 participants from 55 countries aged 11 to 89 years, 37% were female. The overall uptake of facemask ranged from 0.02% to 92.8% with an average of about 50%. Only 13 studies examined the effectiveness of facemask, and their pooled estimate revealed significant protectiveness against respiratory infections (relative risk [RR] = 0.89, 95% CI: 0.84-0.94, p < 0.01), but the study end points varied widely.

Conclusion

A modest proportion of attendees of MGs use facemask, the practice is more widespread among health care workers. Facemask use seems to be beneficial against certain respiratory infections at MGs but its effectiveness against specific infection remains unproven.

Communicable diseases as health risks at mass gatherings other than Hajj: what is the evidence?

Mass gatherings are characterized by the concentration of people temporally and spatially, and may lead to the emergence of infectious diseases due to enhanced transmission between attendees. This is well-demonstrated in the context of the Hajj and Umrah pilgrimages in Saudi Arabia. The goal of this review was to present the available evidence on outbreaks associated with a variety of pathogens, or also the lack thereof, as assessed by thorough surveillance at any mass gatherings with the exception of those in Saudi Arabia. A systematic search for relevant articles in the literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Sixty-eight studies were identified. Although outbreaks have not been reported frequently in or after mass gatherings outside the Hajj and Umrah pilgrimages, they have sometimes occurred at Muslim, Christian, and Hindu religious events, at sports events, and at large-scale open air festivals. In this review it was found that the most common outbreaks at these mass gatherings involved vaccine preventable diseases, mainly measles and influenza, but also mumps and hepatitis A. Meningococcal disease has rarely been recorded. Additionally it was found that the transmission of various communicable diseases that may not be prevented by vaccination has been recorded in association with mass gatherings. These were mainly gastrointestinal infections, caused by a variety of pathogens. It was also noted that some outbreaks occurring at mass gatherings have resulted in the international spread of communicable diseases.

Burden of vaccine preventable diseases at large events

BACKGROUND

Large events or mass gatherings (MGs) are known to amplify the risk of infectious diseases, many of which can be prevented by vaccination. In this review we have evaluated the burden of vaccine preventable diseases (VPDs) in MGs.

METHODS

Major databases like PubMed and Embase, Google Scholar and pertinent websites were searched by using MeSH terms and text words; this was supplemented by hand searching. Following data abstraction, the pooled estimate of the burden of VPDs was calculated when possible; otherwise a narrative synthesis was conducted.

RESULTS

In the past, at religious MGs like Hajj and Kumbh Mela, cholera caused explosive outbreaks; but currently respiratory infections, notably influenza, are the commonest diseases not only at Hajj but also at World Youth Day and Winter Olympiad. The recent cumulative attack rate of influenza at Hajj is 8.7% (range 0.7-15.8%), and the cumulative prevalence is 3.6% (range: 0.3-38%). Small outbreaks of measles (13-42 cases per event) have been reported at sport, entertainment and religious events. A sizeable outbreak (>200 cases) was reported following a special Easter Festival in Austria. An outbreak of hepatitis A occurred following the 'Jam bands' music festival. Other VPDs including pneumococcal disease, pertussis and tuberculosis have been reported in relation to MG attendance.

CONCLUSION

VPDs not only affect the participants of MGs but also their contacts; vaccine uptake is variable and vaccine implementation is likely to have beneficial effects. Research to address the knowledge gaps surrounding VPDs at MGs is needed.

Changes in the prevalence of influenza-like illness and influenza vaccine uptake among Hajj pilgrims: A 10-year retrospective analysis of data

BACKGROUND

Influenza is an important health hazard among Hajj pilgrims. For the last ten years, pilgrims are being recommended to take influenza vaccine before attending Hajj. Vaccination coverage has increased in recent years, but whether there has been any change in the prevalence of influenza-like illness (ILI) is not known. In this analysis, we examined the changes in the rate of ILI against seasonal influenza vaccine uptake among Hajj pilgrims over the last decade.

METHOD

Data for this analysis is a synthesis of raw and published data from eleven Hajj seasons between 2005 and 214. For seven Hajj seasons the data were obtained from studies involving pilgrims of UK, Saudi Arabia and Australia; and for the remaining four Hajj seasons data were abstracted from published studies involving pilgrims from multiple countries. The data from both sources were synthesised to estimate the relative risk (RR) of acquisition of ILI in vaccinated versus unvaccinated pilgrims.

RESULTS

The pooled sample size of the included studies was 33,213 with most pilgrims being in the age band of 40-60 years (range: 0.5 to 95 years) and a male to female ratio of 1.6. The pilgrims originated, in order of frequency, from Iran, Australia, France, UK, Saudi Arabia, Indonesia, India, Algeria, Ivory Coast, Nigeria, Somalia, Turkey, Syria, Sierra Leone and USA. Except for one year (2008), data from individual years did not demonstrate a noticeable change in the rate of ILI against influenza vaccine coverage, however the combined data from all studies suggest that the prevalence of ILI decreased among Hajj pilgrims as the vaccine coverage increased over the last decade (RR 0.2, P<0.01).

CONCLUSION

This analysis suggests that influenza vaccine might be beneficial for Hajj pilgrims. However, controlled trials aided by molecular diagnostic tools could confirm whether such an effect is real or ostensible.

Using Geographic Information for Disease Surveillance at Mass Gatherings

Mass gatherings present the medical community with an excellent window of opportunity to study infectious diseases that can be transmitted over long distances. This is because the venue of a mass gathering usually does not change year-to-year. As a result, special attention can be given to the public health risks that are introduced by travelers from around the world into these mass gatherings. Travelers can also be infected with diseases that are endemic in the host country and transport the locally acquired infectious diseases to their home environments. Therefore, mass gatherings can be thought of as global-to-local-to-global events because of the initial convergence of global populations and the subsequent divergence of populations throughout the world. This chapter discusses three active areas of geographic research that have emerged from our understanding of disease surveillance at mass gatherings: the role of transportation and population geographies in disease surveillance; the spatial and temporal dimensions of environmental geography in the spread of disease; and the advances in GIScience that provide real-world surveillance and monitoring of disease and injuries at mass gatherings.

Viral respiratory infections among Hajj pilgrims in 2013

Middle East respiratory syndrome coronavirus (MERS-CoV) has emerged in the Arabian Gulf region, with its epicentre in Saudi Arabia, the host of the 'Hajj' which is the world's the largest mass gathering. Transmission of MERS-CoV at such an event could lead to its rapid worldwide dissemination. Therefore, we studied the frequency of viruses causing influenza-like illnesses (ILI) among participants in a randomised controlled trial at the Hajj 2013. We recruited 1038 pilgrims from Saudi Arabia, Australia and Qatar during the first day of Hajj and followed them closely for four days. A nasal swab was collected from each pilgrim who developed ILI. Respiratory viruses were detected using multiplex RT-PCR. ILI occurred in 112/1038 (11%) pilgrims. Their mean age was 35 years, 49 (44%) were male and 35 (31%) had received the influenza vaccine pre-Hajj. Forty two (38%) pilgrims had laboratory-confirmed viral infections; 28 (25%) rhinovirus, 5 (4%) influenza A, 2 (2%) adenovirus, 2 (2%) human coronavirus OC43/229E, 2 (2%) parainfluenza virus 3, 1 (1%) parainfluenza virus 1, and 2 (2%) dual infections. No MERS-CoV was detected in any sample. Rhinovirus was the commonest cause of ILI among Hajj pilgrims in 2013. Infection control and appropriate vaccination are necessary to prevent transmission of respiratory viruses at Hajj and other mass gatherings.

A cluster-randomised controlled trial to test the efficacy of facemasks in preventing respiratory viral infection among Hajj pilgrims

BACKGROUND

Cost-effective interventions are needed to control the transmission of viral respiratory tract infections (RTIs) in mass gatherings. Facemasks are a promising preventive measure, however, previous studies on the efficacy of facemasks have been inconclusive. This study proposes a large-scale facemask trial during the Hajj pilgrimage in Saudi Arabia and presents this protocol to illustrate its feasibility and to promote both collaboration with other research groups and additional relevant studies.

METHODS/DESIGN

A cluster-randomised controlled trial is being conducted to test the efficacy of standard facemasks in preventing symptomatic and proven viral RTIs among pilgrims during the Hajj season in Mina, Mecca, Saudi Arabia. The trial will compare the 'supervised use of facemasks' versus 'standard measures' among pilgrims over several Hajj seasons. Cluster-randomisation will be done by accommodation tents with a 1:1 ratio. For the intervention tents, free facemasks will be provided to be worn consistently for 7days. Data on flu-like symptoms and mask use will be recorded in diaries. Nasal samples will be collected from symptomatic recruits and tested for nucleic acid of respiratory viruses. Data obtained from questionnaires, diaries and laboratory tests will be analysed to examine whether mask use significantly reduces the frequency of laboratory-confirmed respiratory viral infection and syndromic RTI as primary outcomes.

CONCLUSIONS

This trial will provide valuable evidence on the efficacy of standard facemask use in preventing viral respiratory tract infections at mass gatherings. This study is registered at the Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN: ACTRN12613001018707 (http://www.anzctr.org.au).

Health and safety issues for travelers attending the World Cup and Summer Olympic and Paralympic Games in Brazil, 2014 to 2016

IMPORTANCE

Travelers from around the globe will attend the 2014 Fédération Internationale de Football Association (FIFA) World Cup and the 2016 Olympic and Paralympic Games in Brazil. Travelers to these mass gathering events may be exposed to a range of health risks, including a variety of infectious diseases. Most travelers who become ill will present to their primary care physicians, and thus it is important that clinicians are aware of the risks their patients encountered.

OBJECTIVE

To highlight health and safety concerns for people traveling to these events in Brazil so that health care practitioners can better prepare travelers before they travel and more effectively diagnose and treat travelers after they return.

EVIDENCE REVIEW

We reviewed both peer-reviewed and gray literature to identify health outcomes associated with travel to Brazil and mass gatherings. Thirteen specific infectious diseases are described in terms of signs, symptoms, and treatment. Relevant safety and security concerns are also discussed.

FINDINGS

Travelers to Brazil for mass gathering events face unique health risks associated with their travel.

CONCLUSIONS AND RELEVANCE

Travelers should consult a health care practitioner 4 to 6 weeks before travel to Brazil and seek up-to-date information regarding their specific itineraries. For the most up-to-date information, health care practitioners can visit the Centers for Disease Control and Prevention (CDC) Travelers' Health website (http://wwwnc.cdc.gov/travel) or review CDC's Yellow Book online (http://wwwnc.cdc.gov/travel/page/yellowbook-home-2014).

London 2012 Olympic and Paralympic Games: public health surveillance and epidemiology

Mass gatherings are regarded as potential risks for transmission of infectious diseases, and might compromise the health system of countries in which they are hosted. The evidence for increased transmission of infectious diseases at international sporting mass gatherings that attract many visitors from all over the world is not clear, and the evidence base for public health surveillance, epidemiology, and response at events such as the Olympics is small. However, infectious diseases are a recognised risk, and public health planning is, and should remain, a crucial part of the overall planning of sporting events. In this Series paper, we set out the planning and the surveillance systems that were used to monitor public health risks during the London 2012 Olympic and Paralympic Games in the summer of 2012, and draw attention to the public health issues-infectious diseases and chemical, radiation, and environmental hazards-that arose. Although the absolute risk of health-protection problems, including infectious diseases, at sporting mass gatherings is small, the need for reassurance of the absence of problems is higher than has previously been considered; this could challenge conventional public health surveillance systems. Recognition of the limitations of health-surveillance systems needs to be part of the planning for future sporting events.

Impact of the London 2012 Olympic and Paralympic Games on demand for microbiology gastrointestinal diagnostic services at the Public Health Laboratory London

Planning for the London 2012 Olympic and Paralympic Games at the Public Health Laboratory London was based on the requirement to meet potential increased demand with scalable capacity. The aim of this study was to determine the impact on demand for microbiology gastrointestinal diagnostic services during the Games period. Retrospective cross-sectional time-series data analysis was used to assess the number of gastrointestinal specimens received in the laboratory and the number of positive results. There was no increase in the number of gastrointestinal specimens received during the Games period, thus the Games had no impact on demand for microbiology gastrointestinal diagnostic services at the laboratory. There was a decrease in the number of public health specimens received for culture [incidence rate ratio = 0.34, 95% confidence interval (CI) = 0.13-0.86, P = 0.02] and a decrease in the number of culture positive community specimens (odds ratio = 0.59, 95 % CI = 0.40-0.85, P = 0.005), suggesting a decrease in gastrointestinal illness during the Games period. As previous planning assumptions were not based on actual specimen activity, the results of this study may modify the extent of additional planning for microbiological services required for mass gatherings.

Illness in travelers returned from Brazil: the GeoSentinel experience and implications for the 2014 FIFA World Cup and the 2016 Summer Olympics

BACKGROUND

Brazil will host the 2014 FIFA World Cup and the 2016 Olympic and Paralympic Games, events that are expected to attract hundreds of thousands of international travelers. Travelers to Brazil will encounter locally endemic infections as well as mass event-specific risks.

METHODS

We describe 1586 ill returned travelers who had visited Brazil and were seen at a GeoSentinel Clinic from July 1997 through May 2013.

RESULTS

The most common travel-related illnesses were dermatologic conditions (40%), diarrheal syndromes (25%), and febrile systemic illness (19%). The most common specific dermatologic diagnoses were cutaneous larva migrans, myiasis, and tungiasis. Dengue and malaria, predominantly Plasmodium vivax, were the most frequently identified specific causes of fever and the most common reasons for hospitalization after travel. Dengue fever diagnoses displayed marked seasonality, although cases were seen throughout the year. Among the 28 ill returned travelers with human immunodeficiency virus (HIV) infection, 11 had newly diagnosed asymptomatic infection and 9 had acute symptomatic HIV.

CONCLUSIONS

Our analysis primarily identified infectious diseases among travelers to Brazil. Knowledge of illness in travelers returning from Brazil can assist clinicians to advise prospective travelers and guide pretravel preparation, including itinerary-tailored advice, vaccines, and chemoprophylaxis; it can also help to focus posttravel evaluation of ill returned travelers. Travelers planning to attend mass events will encounter other risks that are not captured in our surveillance network.

An outbreak of influenza B in an isolated nomadic community in Jammu & Kashmir, India

BACKGROUND & OBJECTIVES

Community outbreaks of disease amongst nomadic populations generally remain undocumented. Following a reported increase in acute respiratory tract infections (ARI) in May 2011 in a nomadic population of Sangerwini in Jammu & Kashmir, India, we examined the patients with ARI symptoms and their nasal swabs were tested for influenza virus.

METHODS

Patients with ARI (n=526) were screened from May 14 to 23, 2011 and nasopharyngeal swabs collected from 84 with Influenza like illness (ILI) for bacterial cultures and influenza virus testing. Samples were tested for influenza A and influenza B by real time (RT)-PCR.

RESULTS

Twelve (14.3%) of the 84 patients tested positive for influenza B, compared to only one (0.9%) of 108 patients with ILI in a parallel survey performed in Srinagar during the same period, suggesting a localized outbreak in the isolated nomadic community. All presented with respiratory symptoms of less than seven days. Familial clustering was seen in 40 per cent (25% of influenza B positives). Average daytime temperatures ranged from 15-16 ° C compared to 22 ° C in Srinagar. Four patients developed pneumonia whereas others ran a mild course with a total recovery with oseltamivir and symptomatic therapy.

INTERPRETATION & CONCLUSION

Our report of confirmed influenza B in this underprivileged nomadic population argues for routine surveillance with efforts to improve vaccination and infection control practices.

International infectious disease surveillance during the London Olympic and Paralympic Games 2012: process and outcomes

Surveillance for possible international infectious disease threats to the Olympic and Paralympic Games in London, United Kingdom, was conducted from 2 July to 12 September 2012 by a collaborative team comprising representatives from the Health Protection Agency (Public Health England since April 2013), the European Centre for Disease Prevention and Control and the National Travel Health Network and Centre. Team members enhanced their usual international surveillance activities and undertook joint risk assessments of incidents identified as relevant through an agreed set of criteria designed for the Games and using tools developed for this purpose. Although team members responded to a range of international disease incidents as part of their routine roles during this period, no incident was identified that represented a threat to the Games. Six incidents were highlighted by the team that were likely to attract media attention and hence could generate political and public concern. Responding to such concern is an important aspect of the overall public health management of mass gathering events. The lessons learned about the process and outcomes of the enhanced international surveillance will help inform planning by future hosts of similar events.

Reducing the risk of public health emergencies for the world's largest mass gathering: 2010 World Exposition, Shanghai China

Mass Gatherings and Public Health

 

Mass gatherings are highly visible events with the potential for serious health and political consequences if not managed carefully and effectively.^1-4 Mass gatherings have been reported to have significant impact upon public health systems throughout the world.^5-10 International mass gathering events, such as those associated with the Olympic Games, often carry high political significance and have a historical risk for terrorist attacks.² Mass gatherings ranging from the subnational level to international the level have also been associated with outbreaks and subsequent spread of communicable diseases. These events have included outbreaks of foodborne shigellosis occurring at an outdoor music festival in the United States.^5,6 The annual Hajj pilgrimage in Saudi Arabia has been plagued by public health threats such as fires, stampedes and an outbreak of meningitis.^7,9 Influenza outbreaks were also reported during the 2008 World Youth Day mass gathering in Australia.¹⁰ Local, provincial and national public health and medical agencies are frequently involved before, during and after a major event. Therefore, disaster risk reduction is a key element for the effective management of mass gatherings.

Disaster Risk Reduction

Throughout the world, the overall approach to emergencies and disasters has recently shifted from post-impact activities (i.e., ad hoc relief and reconstruction) to a more systematic and comprehensive process of risk management.¹¹ Disaster risk management includes pre-impact disaster risk reduction (i.e., prevention, preparedness and mitigation) as well as post-impact response and recovery).¹² While planners may not always have the ability to prevent health hazards from occurring at mass gathering events, the health sector can play an important role in preventing the public health impact of such hazards. This manuscript describes a comprehensive approach for disaster risk reduction as implemented by those entities responsible for health security associated with the 2010 Shanghai World Exposition (Shanghai Expo).

Modeling rapidly disseminating infectious disease during mass gatherings

We discuss models for rapidly disseminating infectious diseases during mass gatherings (MGs), using influenza as a case study. Recent innovations in modeling and forecasting influenza transmission dynamics at local, regional, and global scales have made influenza a particularly attractive model scenario for MG. We discuss the behavioral, medical, and population factors for modeling MG disease transmission, review existing model formulations, and highlight key data and modeling gaps related to modeling MG disease transmission. We argue that the proposed improvements will help integrate infectious-disease models in MG health contingency plans in the near future, echoing modeling efforts that have helped shape influenza pandemic preparedness plans in recent years.

Analysis of Presentations to On-site Medical Units During World Youth Day 2008

World Youth Day 2008 was held in Sydney, Australia in July 2008. New South Wales (NSW) Health, the government health provider in Australia's most populous state, worked with partner agencies to provide medical services via on-site medical units at key event venues.

A post-event review of medical records from the on-site medical units indicated 465 patient presentations, comprised largely of infectious respiratory symptoms and general health concerns of a primary care nature. Providing on-site health services is considered an important risk-mitigation action for many mass gatherings, especially those that generate a substantial temporary population of participants and take place over a number of days.

TynerSE,HennessyL,CoombsLJ,FizzellJ.Analysis of presentations to on-site medical units during World Youth Day 2008.Prehosp Disaster Med.2012;27(6):1-6.

Public Health Preparedness for the World's Largest Mass Gathering: 2010 World Exposition in Shanghai, China

The 2010 World Exposition in Shanghai China (Expo) was the largest mass gathering in world history, attracting a record 72 million visitors. More than 190 countries participated in the Expo, along with more than 50 international organizations. The 2010 Expo was six months in duration (May 1 through October 30, 2010), and the size of the venue site comprised 5.28 square kilometers. Great challenges were imposed on the public health system in Shanghai due to the high number and density of visitors, long duration of the event, and other risk factors such as high temperatures, typhoon, etc.

As the major metropolitan public health agency in Shanghai, the Shanghai Municipal Center for Disease Control and Prevention (SCDC) implemented a series of actions in preparing for, and responding to, the potential health impact of the world's largest mass gathering to date, which included partnerships for capacity building, enhancement of internal organizational structure, risk assessment, strengthened surveillance, disaster planning and exercises, laboratory management, vaccination campaign, health education, health intervention, risk communication and mass media surveillance, and technical support for health inspection. The clear-cut organizational structures and job responsibilities, as well as comprehensive operational and scientific preparations, were key elements to ensure the success of the 2010 World Exposition.

YiH, Zheng'anY, FanW, XiangG, ChenD, YongchaoH, XiaodongS, HaoP, MahanyM, KeimM. Public health preparedness for the world's largest mass gathering: 2010 World Exposition in Shanghai, China. Prehosp Disaster Med. 2012;27(6):1-6.

Microbiological aspects of public health planning and preparedness for the 2012 Olympic Games

Although communicable diseases have hitherto played a small part in illness associated with Olympic Games, an outbreak of infection in a national team, Games venue or visiting spectators has the potential to disrupt a global sporting event and distract from the international celebration of athletic excellence. Preparation for hosting the Olympic Games includes implementation of early warning systems for detecting emerging infection problems. Ensuring capability for rapid microbiological diagnoses to inform situational risk assessments underpins the ability to dispel rumours. These are a prelude to control measures to minimize impact of any outbreak of infectious disease at a time of intense public scrutiny. Complex multidisciplinary teamwork combined with laboratory technical innovation and efficient information flows underlie the Health Protection Agency's preparation for the London 2012 Olympic and Paralympic Games. These will deliver durable legacies for clinical and public health microbiology, outbreak investigation and control in the coming years.

Global perspectives for prevention of infectious diseases associated with mass gatherings

We assess risks of communicable diseases that are associated with mass gatherings (MGs), outline approaches to risk assessment and mitigation, and draw attention to some key challenges encountered by organisers and participants. Crowding and lack of sanitation at MGs can lead to the emergence of infectious diseases, and rapid population movement can spread them across the world. Many infections pose huge challenges to planners of MGs; however, these events also provide an opportunity to engage in public health action that will benefit host communities and the countries from which participants originate.

Infectious disease surveillance and modelling across geographic frontiers and scientific specialties

Infectious disease surveillance for mass gatherings (MGs) can be directed locally and globally; however, epidemic intelligence from these two levels is not well integrated. Modelling activities related to MGs have historically focused on crowd behaviours around MG focal points and their relation to the safety of attendees. The integration of developments in internet-based global infectious disease surveillance, transportation modelling of populations travelling to and from MGs, mobile phone technology for surveillance during MGs, metapopulation epidemic modelling, and crowd behaviour modelling is important for progress in MG health. Integration of surveillance across geographic frontiers and modelling across scientific specialties could produce the first real-time risk monitoring and assessment platform that could strengthen awareness of global infectious disease threats before, during, and immediately after MGs. An integrated platform of this kind could help identify infectious disease threats of international concern at the earliest stages possible; provide insights into which diseases are most likely to spread into the MG; help with anticipatory surveillance at the MG; enable mathematical modelling to predict the spread of infectious diseases to and from MGs; simulate the effect of public health interventions aimed at different local and global levels; serve as a foundation for scientific research and innovation in MG health; and strengthen engagement between the scientific community and stakeholders at local, national, and global levels.

Could influenza transmission be reduced by restricting mass gatherings? Towards an evidence-based policy framework

Introduction: Mass gatherings (MG) may provide ideal conditions for influenza transmission. The evidence for an association between MG and influenza transmission is reviewed to assess whether restricting MG may reduce transmission.

Methods: Major databases were searched (Pubmed, EMBASE, Scopus, CINAHL), producing 1706 articles that were sifted by title, abstract, and full-text. A narrative approach was adopted for data synthesis.

Results: Twenty-four papers met the inclusion criteria, covering MG of varying sizes and settings, and including 9 observational studies, 10 outbreak reports, 4 event reports, and a quasi-experimental study. There is some evidence that certain types of MG may be associated with increased risk of influenza transmission. MG may also “seed” new strains into an area, and may instigate community transmission in a pandemic. Restricting MGs, in combination with other social distancing interventions, may help reduce transmission, but it was not possible to identify conclusive evidence on the individual effect of MG restriction alone. Evidence suggests that event duration and crowdedness may be the key factors that determine the risk of influenza transmission, and possibly the type of venue (indoor/outdoor).

Conclusion: These factors potentially represent a basis for a policy-making framework for MG restrictions in the event of a severe pandemic.