10 of the Worst Covid-19 Super Spreader Events So Far

What is a super spreader event?

There’s a reason public health officials are urging people to maintain social distancing and wear a face mask to prevent the spread of Covid-19: Being in close quarters can spread the virus rapidly, especially if there’s a person in the crowd who’s highly contagious.

These so-called super spreader events have no easy definition, says William Schaffner, MD, an infectious diseases specialist at Vanderbilt University Medical Center in Nashville. Although he adds, they do seem to involve a combination of one or more highly infectious individuals in a crowded setting.

There have been dozens of these events in the United States alone, including one at the White House Rose Garden that was linked to at least 35 infections (more on that later).

With winter coming, and still no sign of the pandemic slowing, we’re likely to see more of these as people spend more time indoors, says Dr. Schaffner.

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Verifying super spreader events

While there are no specific numbers suggesting how many people need to be infected for an event to be considered a “super spreader” event, public health officials perform as much contact tracing as they can—sort of “gumshoe detective” work, says S. Wesley Long, MD, associate professor of pathology and genomic medicine at Houston Methodist Hospital—to verify these outbreaks.

This is a list of only some—not all—of the gatherings that have been linked to multiple cases of Covid-19, and in some cases, deaths.

In addition to these events, super spreader events have occurred at a wedding in Maine linked to at least 170 cases and seven deaths, and a funeral in Chicago linked to 16 cases, including three deaths.

Here are a few of the most high profile or biggest super spreader events officials have identified since February.

Soccer game in Madrid, Spain, Feb. 19

The Champions League match against Valencia (Spain) was the largest soccer game ever for Atalanta soccer club based in Bergamo, Italy. A crowd of 45,792 people arrived at the Madrid stadium in cars, trains, and buses.

They thronged to the stadium and stood or sat centimeters apart. They waved, whooped, and cheered as Atalanta won 4-1, then they headed to local bars or loaded back into those cars, trains, and buses and dispersed.

Now experts are calling it “Game Zero” because so many cases of Covid-19 were traced to the event, which occurred two days before Italy had its first confirmed case of the virus.

More than a third of the Valencia team tested positive. While singing may spread Covid-19 more than loud talking, yelling may be even worse: Japan has banned singing and chanting at sports events.

Number of infected: As many as 7,000
Serious cases: Unclear
Deaths: Unclear

Learn why some people are more likely to spread Covid-19 than others.

Conference in Boston, Feb. 26-27

Not long after the soccer competition, biotechnology company Biogen held a meeting of 175 corporate bigwigs from all over the world. Executives gathered for buffets, cocktails, and networking at Boston’s Marriott Long Wharf hotel overlooking the famed harbor.

Public health officials had not yet imposed any restrictions and colleagues didn’t think to wear masks, forego handshakes, or social distance. The attendees then swept back across the globe, taking the virus to six states, the District of Columbia, and three countries.

Number of infected: 99 conference attendees and potentially 2,000 more. An August study published in medRvix, which has yet to be peer-reviewed or evaluated, suggests the tally of infected patients may have been significantly higher.
Serious cases: 219 hospitalized
Deaths: 25

Prayer meeting in Mulhouse, France, February

One of Europe’s largest clusters seems to have started at a five-day prayer meeting at a church in Mulhouse, France, attended by 2,500 people. At the time, only 12 people in France had confirmed Covid-19 cases and all were in other provinces. Afterwards, cases were seen throughout France, Europe, and even Africa.

A woman whose children had been at the church tested positive, as did a man in a city almost 400 miles away who had himself been at the prayer meeting, then a nurse who infected about 250 people in a distant city.

In Corsica, 263 cases and 21 deaths were traced to attendees who had flown home after the prayer event; a pastor and his wife became the first two cases in Burkina Faso. Cases were also seen in Guyana and Switzerland.

Number of infected: 2,500
Serious cases: Unclear
Deaths: At least 21

Nursing home in Washington State, February-March

Like universities, nursing homes are more of a Covid-19 super spreader “situation” than an event. However, one clear outbreak at a nursing home in Kirkland, Washington, does look like a super spreader.

On Feb. 27, officials identified a 73-year-old woman who they believe was patient zero. She was a resident of the facility who had diabetes, coronary artery disease, and heart failure, all risk factors for severe Covid-19. She developed what is now known as the classic symptoms of Covid-19— cough, fever, and trouble breathing—and ended up on a ventilator at the hospital.

While she may have been the first, the spread was likely facilitated by infected staff members not taking proper precautions and staff who went back and forth between facilities.

Number of infected: 129 at the facility, including 81 residents, 34 staff members, and 14 visitors
Serious cases: Unclear
Deaths: 23

Birthday party in Westport, Connecticut, March

A Westport, Connecticut socialite celebrated her 40th birthday on March 5 with more than 50 guests from around the world who mingled at a buffet.

The first to fall ill was a 43-year-old businessman from South Africa who developed symptoms on a flight back to Johannesburg. He soon tested positive for Covid-19.

Other guests went about their daily lives with one attending an event with 420 other people, making contact tracing that much more difficult. Connecticut, New York, and New Jersey soon became Covid-19 hotspots.

Number of infected: 20 party guests, not including secondary transmissions
Serious cases: At least one hospitalized
Deaths: Unclear

Choir practice in Washington State, May 10

Sixty-one members of the choir at Mount Vernon Presbyterian Church in Washington State arrived just as they did every Tuesday night. They parked their cars outside then entered the building, which sits atop a small hill.

It was March 10 and Covid-19 was just a budding reality in the U.S. The choir members, most of them elderly, refrained from hugging or shaking hands but otherwise interacted normally.

They set up chairs 6-10 inches apart, first rehearsing as a group, then in smaller groups even closer together. They ate cookies and oranges together during a break, then practiced again and tidied up after.

They spent a total of 2 1/2 hours together. A few days later, one of the singers tested positive for Covid-19. This was one of the first documented super spreader events in the U.S. Not only were the singers in close proximity, but they were also singing which, says Dr. Long, “has a propensity to dispense more droplets.”

Number of infected: 32 confirmed, 20 probable
Serious cases: 3 hospitalized
Deaths: 2

Night clubs in Seoul, South Korea, May

In early May, South Korean officials were rattled by a cluster of new Covid-19 cases in Seoul that they feared would spread nationwide. The outbreak was linked to one 29-year-old man who tested positive a few days after going to five clubs in Seoul’s Itaewon district on the night of May 1 into the early hours of May 2.

Officials believe as many as 5,500 people had been in those venues at the same time. Contact tracers tracked down many of these people but not others.  (Here are the public places doctors avoid.)

Number of infected: 54
Serious cases: Unclear
Deaths: Unclear

Vegetable market in Chennai, India, May

Officials believe it may have started with a 54-year-old vegetable vendor at Koyambedu market in Chennai, India. Covering almost 300 acres, Koyambedu is one of the largest markets in Asia, with massive displays of fruits, flowers, and vegetables.

Contact tracing led to 45 more cases, four of them in the market, another to a barber just outside the market then to some of his customers, and on to truck drivers, day laborers, and other vendors all of whom traveled back and forth from towns and villages to the market.

Cases connected to the market may have accounted for more than a third of all cases in Tamil Nadu State. (Read more about traveling during Covid-19.)

Number of infected: 2,760
Serious cases: Unclear
Deaths: Unclear

University in Harrisonburg, Virginia, September

It was the start of the fall semester and excited students attended group and club meetings, stood in line in the dining hall, and jammed into Ubers to go to parties.

In one class at James Madison University (JMU), a class called Problem Solving Approaches in Science and Technology, held in a ballroom, was standing room only.

The university, located in Harrisonburg, experienced one of the largest Covid-19 outbreaks at a university or college. JMU had started in-person classes without requiring testing for any of its 20,000 undergraduates. They soon sent students home. (Here’s how Covid-19 experts protect their kids.)

Number of infected: 772 students and faculty
Serious cases: Unclear
Deaths: Unclear

White House in Washington, D.C., September 26

On a clear autumn day in late September, about 200 dignitaries sat side by side in the White House Rose Garden to celebrate the Supreme Court nomination of Judge Amy Coney Barrett.

Photos showed few people wearing masks and little social distancing either at the outside event or the inside reception after.

“I don’t know how good the ventilation is in the White House but no one was wearing masks, nobody was distancing,” says Dr. Long. Although information about contact tracing has been spotty, it appears that SARS-CoV-2, the virus that causes Covid-19, not only infected attendees but also journalists and White House staff members. Debate preparation sessions also might have contributed.

Number of infected: At least 35 including President Donald Trump and 11 other Rose Garden attendees
Serious cases: Unclear, though both President Trump and Governor Chris Christie of New Jersey were hospitalized
Deaths: None so far

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