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The irony — and ignominy — of medical conferences as superspreader events

The irony — and ignominy — of medical conferences as superspreader events

Emergency physicians like us have seen the worst of Covid-19, from children gasping for breath to death on an unimaginable scale. So you might expect us to be cautious about attending large public gatherings and set a standard by establishing careful guidelines for organizing them.

You’d be wrong.

During the second week in May, the Society for Academic Emergency Medicine (SAEM), a large medical organization, held its annual meeting in person in New Orleans after canceling the event in 2020 and holding it virtually in 2021. The meeting brought together emergency physicians, residents, fellows, medical students, clinical researchers, and corporate exhibitors from across the U.S. at a time when the country was enduring yet another Covid-19 surge, this time from the Omicron BA.12.1 subvariant.


Organizers of the conference reported expecting more than 3,000 attendees, one of the largest events the society had ever hosted, and social media images from conference events showed large, closely packed indoor crowds in close contact and without masks on.

With cases and hospitalizations rising in many parts of the country, including New Orleans, and a community vaccination rate of around 50% for the host city, attending a large, multi-day, indoor meeting with after-hours socializing in the community posed numerous safety risks. In fact, a computing conference held in New Orleans the prior week was under scrutiny as a high transmission event. Yet the SAEM’s Covid policy was not modified to reflect contemporaneous public health data. Nor did the organizers implement a vaccine verification system, require boosters, or incorporate a Covid-19 testing strategy. Masks were “welcome” but optional. No information was provided about ventilation and there were no efforts to minimize indoor crowding. No standards were suggested about minimizing spread in social gatherings.


The three of us did not attend the conference in person, and are grateful for making that decision.

The week after the conference, news of Covid-19 cases began circulating among our colleagues. Some shared stories of becoming ill, others described how they were pulled in to cover the shifts of others who were struck by Covid.

To come up with a back-of-the-envelope estimate, we reached out informally to 15 emergency medicine programs across the country to see how many of their attending physicians, fellows, residents, and research staff attended the conference and how many cases were thought to have resulted from the conference. Among the 11 programs that responded, the number of attendees ranged from five to more than 50, and Covid-19 case rates ranged from 18% to 67%. While there are many caveats to the data (it’s a nonrandom, convenience sample, the data are self-reported estimates), they suggest that this single academic event was responsible for many hundreds of cases.

Do these cases matter? We believe they do, as there is the continued risk of severe disease, long Covid, and significant impact on training and careers, increased burden on already-strained health systems, and the exposure of untold numbers of other travelers in planes that no longer have mask-wearing rules, family members, patients, and others, some with increased vulnerability to severe disease due to underlying illnesses.

This certainly isn’t news. Conferences have been shown to have massive potential as superspreader events over the last two years. In February 2020, Biogen held a conference in Boston where 175 executives in attendance were infected, subsequently traveling home and carrying a specific genome of Covid-19 to tens of thousands of individuals in Australia, Singapore, and the United States, including some people in Boston’s homeless shelters. An estimated 20,000 cases resulted from this single event.

Just weeks after SAEM’s event, the American Society of Clinical Oncology (ASCO) hosted its annual meeting in Chicago with additional mitigation strategies including daily rapid antigen testing. Despite this, there are reports that a significant number of attendees contracted Covid-19.

SAEM’s Covid policy did require attendees to be vaccinated (unless medically exempt), but no reliable vaccination verification system was employed and the policy did not specify whether boosters were included in the definition of vaccinated. Despite rising case levels in Orleans Parish, where New Orleans is located, wearing masks was not recommended for the indoor conference events. The Centers for Disease Control and Prevention currently encourages the use of masks indoors in areas with high hospitalization rates, but some consider this akin to shutting the barn door after the horse is out. The meeting did not employ screening efforts using rapid tests. In essence, bare minimum Covid-19 mitigation strategies were in place.

But with surging cases nationwide and in New Orleans, meeting planners and attendees could have embraced a higher level of safety precautions to mitigate potential spread of Covid-19, particularly when the organizers advertised that “the health and safety of our attendees, exhibitors, and speakers remains priority number one.”

With such a high concentration of the U.S. emergency health care workforce gathered in one place, people with vast collective expertise on how to protect themselves and two-plus years of closely following rigorous safety protocols in their clinical environments, we have to ask: Why did so many eschew restrictions in the face of surging Covid? And if medical professionals don’t gather safely, how can other professionals, not to mention the general public, be expected to do that?

The argument for individual responsibility has been increasingly present over the past few months: Informed individuals can decide to add layers of protection as they see fit. It’s hard to argue that a group of academic emergency physicians isn’t well informed about the dangers of Covid, as well as about the best measures to mitigate risk. Yet the majority of attendees did not layer in mitigation strategies, ask the conference organizers to consider changing their policies, or cancel their trips to the conference after witnessing the minimal protections in place.

It is easy to blame individuals for taking high risks. But most people have personally witnessed how easy it is to fall in step with the lowest level of mitigation — even when they know better. Instead of blaming individuals, the focus should be on the systems in place that encouraged “throw caution to the wind” decision-making at events. Organizations should work to protect their members by requiring mitigation strategies, providing the appropriate technological and material resources, and making safety the norm. It is much harder for the individual to make the right choice when it entails increased effort and there is no incentive to be responsible.

No set of measures can completely eradicate the risk of contracting or spreading Covid-19. That said, public health experts agree that risk can be maximally mitigated by embracing good policies, and for conferences and meetings we further recommend:

  • Ensuring that everyone is vaccinated and boosted (no exceptions)
  • Reviewing the local prevalence of Covid-19, as well as whether the number of cases is rising or falling, and informing attendees about this information
  • Requiring a negative Covid-19 test within 24 hours of attendance, or daily testing if there are settings where masks are not worn
  • Mandating the use of high-quality medical-grade masks in indoor settings
  • Ensuring proper building ventilation and using outdoor spaces whenever possible
  • Reducing the number of attendees at sessions and the duration of sessions
  • Providing suggestions for the safest places to hold events, including outdoor venues
  • Engaging those with expertise in infection control and those who are immunocompromised or otherwise at high risk for infection and severe disease in planning the event

Live medical conferences play an important role in academic development, advancing ideas, research collaboration, and professional development. Each of us has benefited in our careers from these assemblies. However, the organizations planning them bear a responsibility to protect their members and, in terms of medical conferences, a responsibility to the public to protect the health care workforce.

To avoid past mistakes, conference planning committees should have groups dedicated to creating safe environments during this pandemic and future ones. Embracing the measures outlined above is a start, but these organizations must be agile in order to shift policies based on an ever-changing situation. Further, failures to keep attendees safe from infection should be acknowledged directly and a subject of open discussion to give the organization the best chance of making a feasible and adequate plan in future years’ events.

Anand Swaminathan is an assistant professor of emergency medicine in New Jersey. Jessica Smith is a professor of emergency medicine and clinician educator in Rhode Island. Esther Choo is a professor of emergency medicine at Oregon Health & Science University and co-founder of Equity Quotient. All three are emergency medicine physicians.

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COVID-19 superspreader events typically originate from few carriers

Study: Analysis of overdispersion in airborne transmission of COVID-19. Image Credit: oxinoxi / Shutterstock

A recent research paper published in the journal Physics of Fluids analyzed the overdispersion in the coronavirus disease 2019 (COVID-19) airborne transmission.

Study: Analysis of overdispersion in airborne transmission of COVID-19. Image Credit: oxinoxi / ShutterstockStudy: Analysis of overdispersion in airborne transmission of COVID-19. ​​​​​​​Image Credit: oxinoxi / Shutterstock


The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been characterized by overdispersion and superspreading events comparable to SARS and other respiratory virus outbreaks. Any incident that results in more than the typical number of secondary transmissions is referred to as superspreading.

Overdispersion is a non-random trend of grouping in the context of contagious diseases, which frequently involves a large proportion of zero cases and a limited percentage of large outbreaks.

Nevertheless, the specific functions and influences of established physical and viral factors correlated to transmission processes on overdispersion are still unknown. Moreover, the characteristics and nature of superspreading episodes are instrumental in explaining the spread of SARS-CoV-2. To date, mechanistic simulations depicting airborne transmission have not been combined with real-world occupancy and distribution data to better explain large-scale characteristics of disease dynamics, such as transmissibility overdispersion.

About the study

In the present study, the authors used real-world occupancy information from over 100,000 social contact contexts in 10 United States (US) metropolises to undertake mechanistic modeling of COVID-19 point-source transmission via infectious aerosols. The primary purpose of this study was to use the molecular basis of airborne disease transmission to investigate event-level SARS-CoV-2 spread overdispersion utilizing real-world data from a significant number of social engagements.

The team tried to establish an algorithm centered on aerosol dispersion with randomized data and obtainable occupancy information to derive the distribution of the number of secondary infections for every infectious case. They investigated whether observed trends of overdispersion in secondary transmissions could be replicated through simulations utilizing the above algorithm.

Further, the scientists aimed to develop an analytical function (rather than a fit) that may explain the probability density function of the number of secondary infections arising from the dynamics of the problem. Furthermore, they attempted to determine the dominant factors that cause overdispersion and the consequences for mitigation strategies.

To achieve this, the scientists used 100,000 random social-contact conditions to solve an aerosol dispersal model by combining real-world area and occupancy data with practical ventilation and viral load rate to attain the probability distributions for the number of secondary infections for each infectious case in those situations.

Results and discussions

According to the simulated results, the aerosol transmission pathway was compatible with overdispersed individual COVID-19 infectivity. In addition, with exposure time, ventilation rate, and speaking time, SARS-CoV-2 load fluctuation was the most substantial factor controlling secondary attack rates. According to the authors, they, for the first time, generated analytical equations that precisely characterized the modeled probability density functions of secondary attack and infection rates. Besides, the generated analytical expressions revealed how the quantitative link among personal-level viral load variance and event-level occupancy governs overdispersion simultaneously.

These findings reveal that even in the case of airborne transmission, about 4% of index cases in indoor contexts were responsible for 80% of secondary cases, underlining the need for identifying and concentrating mitigation efforts on superspreading event causes. The results emphasize the significance of interventions, including isolation through rapid testing to identify intense viral shedding periods, for reducing exposures during stages of heightened viral shedding, improved ventilation, and the higher likelihood of outbreaks with SARS-CoV-2 variants of concern (VOCs) correlated with superior viral loads. Ultimately, considering viral burden and occupancy over indoor environments, the present analytical function may predict the spatially specified likelihood of outbreaks and outbreak magnitude via point-source transmission events.


Overall, the study findings demonstrated that around 4% of COVID-19 index cases possibly caused 80% of secondary SARS-CoV-2 infections, resulting in an extended tail probability distribution function of secondary infections per infectious event. Overdispersion appears to be notably driven by personal-level heterogeneity in SARS-CoV-2 load, with occupancy coming in second. The team then developed an analytical function that mimics the modeled SARS-CoV-2 overdispersion. Further, they illustrated the efficacy of potential COVID-19 mitigation techniques using this analytical function.

The present analysis adds a relevant dimension to the growing body of proof regarding SARS-CoV-2 airborne transmission by linking the mechanistic insights of COVID-19 aerosol spread with reported large-scale epidemiological features of outbreaks and thus unfolds as a potent tool for evaluating the likelihood of epidemics and the possible effects of mitigation actions on extensive disease dynamics. The simulation in this article covers overdispersion in the number of secondary cases rendered by each infectious case over an hour in such 100000 instances, assuming one index case at each site. The team mentioned that when combined with appropriate data, the current analytical expressions created and confirmed using simulations could explain overdispersion through drastically broader timeframes and contact vicinities.

Journal reference:

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Superspreader events blamed for monkeypox surge – follow live

Superspreader events blamed for monkeypox surge - follow live

UK Government is cautious but not ‘concerned’ about Monkeypox outbreak

A British minister has insisted monkeypox is not a “repeat of Covid” as he attempted to quell fears.

Simon Clarke, the chief secretary to the Treasury, said the virus “certainly does not appear to be anywhere near the same platform of seriousness” as the Covid-19 pandemic.

He also mentioned the fact there was already a vaccine available that works for monkeypox as he spoke to media on Monday morning.

It comes as the UK braces for more cases to be announced on top of the current tally of 20.

Meanwhile, the World Health Organisation has confirmed 92 confirmed cases of monkeypox around the world – including Europe and the US – and another 28 suspected infections.

This tally does not include cases in Israel, Switzerland and Austria that were announced later.

Monkeypox – which belongs to the same virus family as smallpox but gives milder symptoms – is rarely identified outside of Africa.


Superspreader events likely behind global surge in cases, expert says

An infectious diseases expert has said superspreader events are likely behind the global surge in monkeypox cases.

Sir Jeremy Farrar, the director of Wellcome, said there have been small outbreaks in the past with cases in the UK – but “something has changed” with this one.

“The virus may have changed, but I think that’s unlikely,” he told BBC Radio 4’sToday programme.

“More likely is, I think, that the niche that this virus now finds itself in has allowed for some superspreader events and those individuals involved in that have then travelled to other parts of the world and taken the infection with them.”

He said the fact the virus has “spread across borders so quickly” is different from what has happened before.

Additional reporting by PA

Zoe Tidman23 May 2022 10:47


Opinion: The public health threat of a ‘toxic relationship’ with animals

“When will we learn?” Julia Baines from Peta UK asks.

“Now that monkeypox has been detected in Canada, Portugal, Spain, the UK, and the US, we should accept that our toxic relationship with animals is sleepwalking us into disaster.”

Read her take on the spread of monkeypox here:

Zoe Tidman23 May 2022 10:12


What has been the trajectory in the England?

7 May: One case confirmed in England. Patients had recently travelled to Nigeria where they were believed to have picked the virus up.

14 May: Two people who live together in London confirmed as having monkeypox.

16 May: Four more cases confirmed: three in London and one in the North East.

18 May: Two more cases confirmed: one in London, the other in the South East.

20 May: Eleven more cases in England confirmed.

Another announcement on monkeypox cases expected later today. Stay tuned for more.

Zoe Tidman23 May 2022 09:43


ICYMI: Scientists ‘stunned’ by global spread

Experts who have monitored previous outbreaks of monkeypox have said they are “stunned” by the recent spread of the virus in Europe and North America.

Zoe Tidman23 May 2022 09:24


Watch: UK minister denies Covid comparison

Simon Clarke, the chief secretary to the Treasury, has said monkeypox is not a “repeat” of the Covid pandemic.

Watch his make the comments here:

UK Government is cautious but not ‘concerned’ about Monkeypox outbreak

Zoe Tidman23 May 2022 09:04


UK tally expected to increase today

The UK is expected to announce an increase on its 20 confirmed cases of monkeypox later today.

It comes after a senior doctor warned new cases were being reported every day.

Furvah Shah reports on the situation in the UK:

Zoe Tidman23 May 2022 08:49


UK minister says Monkeypox not ‘some repeat of Covid’

Monkeypox is not a “repeat of” Covid-19, a UK government minister has assured.

“As with any new disease, and obviously after the Covid pandemic doubly so, we continue to monitor this very closely,” Simon Clarke, the chief secretary to the Treasury, told Sky News.

“I would say I am cautious but I am certainly not concerned about our ability to handle the situation.

“There is a vaccine which is available and works for monkeypox, and all the evidence is that it is spread by physical contact.

Mr Clarke added: “What I would say is we are cautious but we are certainly not in a position where I would in anyway worry the public that this is some repeat of Covid, because it certainly does not appear to be anywhere near the same platform of seriousness.”

Zoe Tidman23 May 2022 08:06


Joe Biden says US stockpiles are ‘enough’

Joe Biden has also said the smallpox vaccine works for monkeypox.

Asked whether the US has enough stockpiles of that vaccine to handle the monkeypox spread, the US president said: “I think we do have enough to deal with the likelihood of a problem.”

Joe Biden says the US stockpiles are ‘enough’ to deal with monkeypox threat

(AFP via Getty Images)

Zoe Tidman23 May 2022 08:00


Joe Biden seeks to calm monkeypox concerns

The US president has sought to calm concerns about recent cases of monkeypox around the globe.

Joe Biden said at the weekend the virus was something “to be concerned about”.

He has now clarified: “I just don’t think it rises to the level of the kind of concern that existed with Covid-19.”

Zoe Tidman23 May 2022 07:46


Monkeypox explained

Here is a quick reminder about what we know about monkeypox so far:

Zoe Tidman23 May 2022 07:33

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Some students upset by another potential ‘superspreader’ event

James Hight building at the University of Canterbury

By Tessa Guest

During the day, the University of Canterbury’s campus is almost deserted.

James Hight building at the University of Canterbury

The University of Canterbury’s Ilam campus.
Photo: Wikimedia Commons

Staff and students are isolating with Covid-19, or participating in courses online. Only a few classes remain in-person.

But on Saturday night, a field near the campus was filled with noise and people.

University-owned Ilam Fields has become home to uncontrolled parties taking place instead of traditional Orientation Week events, which were canned due to Covid-19 restrictions.

Hundreds of students gathered for a makeshift toga party two weeks ago, and more returned for another large gathering last weekend.

Mattresses were thrown around, people urinated in bushes, and the field was left strewn with rubbish and broken glass.

First-year hall resident Molly said the organisers and attendees were largely other student residents, and that the hall’s strict alcohol bans pushed people to drink in public spaces.

With community cases surging, she said the gatherings made some residents feel more anxious about getting Covid-19.

“I was definitely keeping my distance because I didn’t want to catch it, and it was definitely a superspreader,” she said.

Third-year geography student Natalie O’Connell was one of the few students choosing to work from the campus this week, and said it was clear the party-goers didn’t care about the effect their actions were having.

“People are going out of their way to get mass gatherings of definitely more than 100, no one’s checking vaccine passes, no one’s on security, so it’s all round pretty irresponsible, and they know it,” she said.

‘Tough time for students’

University of Canterbury Student Association president Pierce Crowley was sympathetic to those who attended, citing the lack of Orientation Week events as the driver of alternative gatherings.

Pierce Crowley, UCSA president

Pierce Crowley
Photo: Supplied

“It’s a really tough time for students. For many of them, this is their second or third year of disrupted learning,” he said.

“This [the partying] hasn’t happened in the past, and that’s because we’ve been able to host events that have got it out of people’s systems in a big burst at the beginning of the semester.”

He said the association was focused on educating students on the legal requirements of gatherings in the red traffic light setting.

Co-editor of the university’s student magazine, Ella Gibson, thought more could be done now to give students safe partying options.

“There’s definitely a gap in the fun infamous night-time drinking events,” she said.

She thought the party-goers were on the right track in using Ilam Fields, and that the area could be used for controlled night-time events within the current Covid-19 guidelines.

Crowley said the restrictions made it too difficult to host any large events safely now, but a priority for the association was hosting replacements to Orientation Week events as soon as it was possible.

“We’re really keen, once we have the ability to do so again, to host these events and get it in a supervised environment where students can party safely and stay out of the community’s hair.”