Transcript: Superspreaders: The Key to Covid-19? | Oct 23, 2020

Nam sits in the studio. She's in her early forties, with shoulder length curly brown hair. She's wearing glasses and a black blazer over an indigo shirt.

A caption on screen reads "Superspreaders: The key to COVID-19? Nam Kiwanuka, @namshine, @theagenda."

Nam says A SPIN CLASS IN HAMILTON. A WEDDING IN OTTAWA. HARMLESS IN NORMAL TIMES. BUT IN THESE COVID TIMES, THEY'RE EVENTS THAT LED TO DOZENS AND DOZENS OF INFECTIONS. WHAT ARE "SUPERSPREADERS"? WITH US TO EXPLAIN: IN THE NATION'S CAPITAL: RAYWAT DEONANDAN, PROFESSOR IN THE FACULTY OF HEALTH SCIENCES, AT THE UNIVERSITY OF OTTAWA...

Raywat is in his forties, clean-shaven, with short brown hair. He's wearing a blue shirt and tie.

Nam continues AND IN THE EAST END OF TORONTO: ASHLEY TUITE, EPIDEMIOLOGIST AT THE UNIVERSITY OF TORONTO'S DALLA LANA SCHOOL OF PUBLIC HEALTH...

Ashley is in her thirties, with shoulder-length curly brown hair. She's wearing a black sweater.

Nam continues WELCOME TO YOU BOTH. ASHLEIGH, I HAVE TO SAY I LIKE YOU ALREADY, BECAUSE IN THE OFFICE WE HAVE THIS EAST VERSUS WEST, AND ANYONE WHO IS EAST IS THE BEST. IT'S NICE TO HAVE YOU ON THE SHOW.

[LAUGHTER]

Nam says TO GET INTO THE CONVERSATION, I JUST WANTED US TO LOOK AT SOME NUMBERS. SHELDON, IF YOU COULD, PLEASE? IN A CONTACT TRACING EFFORT INVOLVING OVER 3 MILLION PEOPLE IN INDIA...

A slate appears on screen, with the title "Superspreaders do all the work."

Nam reads data from the slate and says
8 percent OF PATIENTS ACCOUNTED FOR 60 percent OF INFECTIONS WHILE 70 percent OF THE PATIENTS INFECTED NO ONE. A STUDY IN HONG KONG FOUND ABOUT 19 percent OF CASES WERE RESPONSIBLE FOR 80 percent OF INFECTIONS WHILE 69 percent OF CASES DID NOT INFECT ANOTHER PERSON. AND ONE PATIENT, KNOWN AS PATIENT 31, IN SOUTH KOREA, INFECTED... GET THIS... MORE THAN 5,000 PEOPLE. RAYWAT, THAT IS ASTOUNDING. WE ARE NINE MONTHS INTO THE PANDEMIC. WHAT HAVE WE LEARNED SO FAR ABOUT HOW THIS DISEASE SPREADS?

The caption changes to "Raywat Deonandan. University of Ottawa."
Then, it changes again to "Clusters of infection."

Raywat says THERE'S SOMETHING IN THE SOCIAL SCIENCES CALLED THE PAREDO PRINCIPLE. THAT'S WHEN A MAJORITY OF CASES ARE CAUSED BY A MINORITY OF CASES. THIS ISN'T SEEPING HOMOGENOUSLY ACROSS THE POPULATION. I THINK IT WAS A BRECK COMMERCIAL, SHAMPOO COMMERCIAL, I TOLD TWO FRIENDS AND THEY TOLD TWO FRIENDS AND SO ON AND SO ON, IF YOU'RE OLD ENOUGH TO REMEMBER THAT COMMERCIAL? THIS IS LIKE I TOLD TWO FRIENDS, ONE FRIEND DIDN'T TELL ANYBODY, BUT THE OTHER FRIEND TOLD FIVE PEOPLE, AND OF THOSE FIVE, FOUR DIDN'T TELL ANYBODY. IT'S EXPLODING IN A PUNCTUATED FASHION AND WE CALL THIS THE SUPER SPREADER PHENOMENON. THAT'S WHAT WE'RE LEARNING HERE. IT'S UNLIKE ANOTHER EXPONENTIAL INCREASES IN THAT WAY.

Nam says ASHLEIGH, WHY IS IT IMPORTANT TO KNOW THIS?

The caption changes to "Ashleigh Tuite. University of Toronto. Dalla Lana School of Public Health."

Ashleigh says I THINK RAYWAT EXPLAINED THAT WELL. WHEN WE INITIALLY REALIZED WHAT COVID WAS AND WE WERE TRYING TO CHARACTERIZE IT, ONE OF THE FIRST THINGS THAT SCIENTISTS TALKED ABOUT WAS SOMETHING CALLED THE REPRODUCTION NUMBER. AND THAT'S THE AVERAGE NUMBER OF NEW CASES EACH OLD CASE CAUSES. FOR COVID-19 WE THINK IT'S BETWEEN TWO AND THREE. BUT WE'VE LEARNED THAT IT'S REALLY, VARIABLE. AND SO SOME PEOPLE WILL INFECT A LOT OF PEOPLE AND A LOT OF CASES WILL GO ON TO TRANSMIT TO NOBODY OR ONE OR TWO OTHER PEOPLE. AND THAT VARIABILITY AND UNDERSTANDING IT IS REALLY IMPORTANT BECAUSE IT ALLOWS US TO THINK ABOUT, HOW DO WE CONTROL IT AND HOW DO WE INTERVENE IN A WAY THAT CAPTURES THE FACT THAT A LOT OF CASES ARE NOT GOING TO TRANSMIT TO A LOT OF PEOPLE AND THAT, YOU KNOW, IF WE CAN UNDERSTAND THIS CLUSTERING OF CASES AND HOW IT TRANSMITS, WE CAN POTENTIALLY CONTROL THIS IN A WAY THAT DOESN'T REQUIRE THESE BROAD LOCKDOWNS AND VERY SORT OF POPULATION-WIDE INTERVENTIONS THAT COULD BE INCREDIBLY DISRUPTIVE.

Nam says SINCE THE PANDEMIC BEGAN, WE'VE BEEN LOOKING AT THE MEASURE OF HOW CONTAGIOUS THIS DISEASE IS ON AVERAGE, KNOWN AS THE RNOT. DOES THAT MEASURE TELL THE FULL STORY OF HOW THIS DISEASE SPREADS, ASHLEIGH?

Ashleigh says NO. THAT'S WHEN DISPERSION COMES IN. WHAT THAT MEANS IS IT'S A MEASURE OF SORT OF THAT HETEROGENEITY. SO IT'S A MEASURE OF THE FACT THAT MOST PEOPLE ARE NOT GOING TO TRANSMIT TO A LOT OF PEOPLE, AND FOR THE CASE OF COVID-19, WE KNOW THAT THIS OVERDISPERSION IS THE NUMBER... THE NUMBER FOR OVERDISPERSION IS LOW. WHAT THAT MEANS IS THAT A SMALL NUMBER OF PEOPLE ARE RESPONSIBLE FOR LARGE AMOUNTS OF TRANSMISSION. AND SO WHEN WE TALK ABOUT AVERAGES, WHICH IS WHAT THAT BASIC REPRODUCTION NUMBER IS, IT DOESN'T CAPTURE THAT HETEROGENEITY. AGAIN, THAT'S AN IMPORTANT FEATURE OF THE DISEASE AND IT'S SOMETHING THAT'S QUITE DIFFERENT FROM FLU. SO FLU IS A DISEASE THAT HAS A REPRODUCTION NUMBER OF, AGAIN, BETWEEN PROBABLY 1.5 AND 2. BUT IT LOOKS DIFFERENT THAN COVID-19 BECAUSE MOST PEOPLE TRANSMIT TO ONE OR TWO PEOPLE AND WE DON'T HAVE THESE SUPER SPREADER TYPES OF EVENTS.

Nam says HOW IMPORTANT IS THAT TO KNOW? WE'VE BEEN HEARING A LOT ABOUT A POTENTIAL TWINDEMIC WITH COVID-19 AND THE SEASONAL FLU. HOW IMPORTANT IS THAT NOW?

The caption changes to "Watch us anytime: tvo.org, Twitter: @theagenda, Facebook Live, YouTube."

Ashleigh says I THINK THE IMPORTANT THING IS REALLY WHEN WE TALK ABOUT INTERVENTIONS AND WE THINK ABOUT HOW WE CONTROL THIS, THE WAY THAT WE RESPONDED IN THE SPRING WAS REALLY BASED ON THE ASSUMPTION THAT WHEN WE HAD A PANDEMIC DISEASE, IT WAS GOING TO LOOK A LOT LIKE THE FLU. SO ALL OUR PANDEMIC PLANS WERE BASED ON THAT. AND WE'VE LEARNED OVER THE COURSE OF THE PAST SEVERAL MONTHS, THAT THIS ISN'T THE FLU. WE CAN BASICALLY LEVERAGE THIS PATCHINESS AND CLUSTERING AND WE CAN USE THAT INFORMATION TO BETTER CONTROL THIS AND TO THINK ABOUT INTERVENTIONS THAT ADDRESS THIS CLUSTERING AND THIS PATCHINESS AND, AGAIN, YOU KNOW, WE HAVE TO THINK A LITTLE BIT DIFFERENTLY. WE CAN'T JUST TREAT THIS THE SAME AS THE FLU.

Nam says RAYWAT, HAS THIS UNDERSTANDING OF SUPERSPREADERS WORKED ITS WAY INTO HOW WE UNDERSTAND COVID-19?

The caption changes to "Raywat Deonandan, @deonandan."

Raywat says IN A SENSE. WHAT DO WE KNOW NOW THAT WE DIDN'T KNOW BACK IN THE SPRING? WE KNOW SOME THINGS CLINICALLY. I'M NOT A CLINICIAN, BUT I'VE BEEN TOLD BY MY CLINICIAN FRIENDS HOW TO TREAT IT BETTER. WE UNDERSTAND IT'S A SUPER SPREADING KIND OF THING. AS ASHLEIGH ELOQUENTLY PUT IT, NOW WE KNOW WHAT LEVERS TO PULL AT A POLICY OR PUBLIC HEALTH LEVEL. THAT'S CRITICAL. THAT MEANS WE HAVE A PATH FORWARD TOWARDS SOMETHING RESEMBLING NORMALITY, ABSENT A DISEASE OR A THERAPY.

Nam says I WANT TO READ AN EXCERPT ON HOW JAPAN APPROACHED COVID-19 AND THIS WAS IN THE ATLANTIC MAGAZINE, AND THEY WRITE...

A quote appears on screen, under the title "Individual infections versus clusters of infections." The quote reads "Hitoshi Oshitani, a member of the National COVID-19 Cluster Taskforce likens his country's approach to looking at a forest and trying to find the clusters, not the trees. Meanwhile, he believes, the Western world was getting distracted by the trees, and got lost among them."
Quoted Zeynep Tufecki, The Atlantic. September 30, 2020.

Nam says RAYWAT, HAVE WE HERE IN CANADA BEEN TOO FOCUSED ON INDIVIDUAL INFECTIONS VERSUS CLUSTERS OF INFECTIONS?

The caption changes to "Seeing the clusters among the trees."

Raywat says ABSOLUTELY, YES. SOUTH KOREA IS A GREAT EXAMPLE OF THIS. THEY HAVE A FANTASTIC SYSTEM. I MEAN, IT'S A REALLY ROBUST, COMPLICATED, COMPREHENSIVE SYSTEM USING ALL KINDS OF TOOLS FOR CONTACT TRACING, INCLUDING TRACKING CREDIT CARD USAGE TO UNDERSTAND WHERE PEOPLE HAVE BEEN RECENTLY, USING CELL PHONE DATA TO TRACK MOBILITY AND SO FORGOT. THEY HAVE A QR SYSTEM, IF YOU GO INTO A BUSINESS OR NIGHTCLUB OR BAR OR SOMETHING, YOU HAVE TO SCAN THE QR CODE AND THAT CREATES AN ELECTRONIC LOG THAT YOU HAVE BEEN THERE. THAT'S KEPT FOR FOUR WEEKS SO IN CASE THERE'S AN OUTBREAK, WE CAN FIGURE OUT ALL THE PEOPLE WHO ARE LIKELY PART OF THAT CLUSTERING EVENT. HERE IN THE WEST, WE DO FORWARD CONTACT TRACING. THAT'S WHERE YOU IDENTIFY SOMEONE WHO IS INFECTED AND FIGURE OUT WHO THEY THEN CAME INTO CONTACT WITH AFTER THEY BECAME INFECTED. AND YOU GET A FAIR NUMBER OF CASES THAT WAY. BUT IF YOU CAN GO BACKWARDS AND FIGURE OUT WHERE THAT FIRST PERSON GOT INFECTED IN THE FIRST PLACE, THEY WERE PROBABLY PART OF A CLUSTER. SO WE IDENTIFY THAT CLUSTER AND THEN SEE OTHER PEOPLE IN THAT CLUSTER AND FOLLOW THEM. SO THERE WAS A FAIRLY IMPORTANT PAPER BY ENDO, I THINK IT WAS, THAT SUGGESTED USING FORWARD CONTACT TRACING, MORE ROBUSTLY AND JUST IDENTIFYING MORE CONTACTS, YOU CAN INCREASE YOUR CASE COUNT BY 15 percent, THE NUMBER OF PEOPLE THAT YOU CATCH. BUT BACKWARD CONTACT TRACING, GOING BACKWARDS AND FINDING THE ORIGINAL CLUSTER, YOU CAN INCREASE THE NUMBER OF INFECTIOUS CASES YOU IDENTIFY BY TWO OR THREE TIMES. THAT'S HUGE. AND THAT'S AN ENORMOUS POLICY LEVER AND PROBABLY WHY SOME ASIAN COUNTRIES WHO DO THIS ARE ABLE TO, AGAIN, HAVE A KIND OF PSEUDO NORMALITY THAT WE HAVE YET TO ACQUIRE. THERE ARE PRIVACY ISSUES. YOU HAVE TO HAVE A COMPLIANT POPULATION THAT PARTICIPATES IN THIS ENDEAVOUR. WE HAVE TO AGREE TO USE QR CODES, WE HAVE TO AGREE TO BE TRACKED, AND ALSO YOU NEED A REALLY GOOD TESTING SYSTEM BECAUSE YOU HAVE TO TEST THESE PEOPLE ONCE YOU FIND THEM QUICKLY ENOUGH FROM IT NOT SPREADING FURTHER AND A STRONG ISOLATION PROCEDURE AS WELL. IT REQUIRES A RETHINKING OF OUR INFRASTRUCTURE OVERALL.

The caption changes to "Subscribe to The Agenda Podcast: tvo.org/theagenda."

Nam says JUST TO GO ON WHAT YOU WERE TALKING ABOUT WITH A BACKWARDS CONTACT TRACING, ASHLEIGH, CAN YOU GIVE US A DEFINITION? WHAT IS BACKWARD CONTACT TRACING TRACING?

The caption changes to "Cluster busting."

Ashleigh says SO IT'S TURNING CONTACT TRACING A LITTLE BIT ON ITS HEAD. THE WAY WE TYPICALLY DO CONTACT TRACING IS, AGAIN, EXACTLY AS RAYWAT DESCRIBED, IS YOU START WITH YOUR INITIAL CASE THAT YOU FIND VIA TESTING AND YOU ASK THEM WHO THEY HAVE BEEN IN TOUCH WITH UP TO TWO DAYS BEFORE THEY HAD SYMPTOMS AND OVER THE TIME WHICH THEY WERE INFECTIOUS, AND YOU FIND THOSE PEOPLE WHO ARE CONTACTS AND YOU ISOLATE THEM AND YOU GET THEM TESTED AND BASICALLY WHAT YOU'RE TRYING TO DO IS INTERRUPT THESE CHAINS OF TRANSMISSION. WITH BACKWARD TRACING, WHAT WE'RE SAYING IS, WHEN WE HAVE THAT INITIAL INDEX CASE, WE WANT TO KNOW, WAS THAT PERSON THE CONTACT OF THE CASE THAT WE'VE ALREADY IDENTIFIED, AND IF NOT, HOW DID THAT PERSON GET INFECTED? WHAT WE DO IS WE LOOK BACKWARDS FOR A LONGER PERIOD OF TIME AND WE TRY TO IDENTIFY WHERE THAT PERSON WAS, WHAT WAS THE MOST LIKELY PLACE THAT THEY WERE EXPOSED AT, AND THEN ONCE WE FIND THAT POTENTIAL EXPOSURE EVENT, WE SORT OF IDENTIFY PEOPLE WHO WERE ALSO AT THAT VENUE OR ASSOCIATED WITH A PARTICULAR ACTIVITY, AND WE DO FORWARD TRACING. SO YOU BASICALLY ARE DOING THE BACKWARDS AND FORWARDS DANCE, BUT THE IDEA IS REALLY TO LOOK BACKWARDS IN TIME TO FIND THOSE RISKY ACTIVITIES, RISKY VENUES, SO THAT YOU FIND MORE CASES. AND THE IDEA IS THAT YOU JUST GET A HIGHER YIELD BECAUSE THIS DISEASE CLUSTERS SO MUCH, ONCE YOU HAVE AN INITIAL CASE, IT'S HIGHLY LIKELY THAT THEY'RE ASSOCIATED WITH A LARGER CLUSTER. AND IF YOU'RE ABLE TO LOOK BACK IN TIME AND DO THIS BACKWARDS CONTACT TRACING, YOU CAN POTENTIALLY FIND MORE CASES AND INTERRUPT TRANSMISSION.

Nam says SO I WANT TO ASK YOU BOTH. DO WE NEED TO CHANGE HOW WE DO CONTACT TRACING IN THIS PROVINCE? RAYWAT, I'LL GO TO YOU FIRST.

Raywat says YES. ABSOLUTELY. IF A VACCINE IS MONTHS AWAY, IF NOT YEARS AWAY, AND WE HAVEN'T GOT A TREATMENT YET AND WE WANT TO AVOID ECONOMIC CLOSURES, I THINK THERE ARE LESSONS TO BE LEARNED FROM ASIAN COUNTRIES WHO SEEM TO HAVE HANDLE THIS BETTER THAN WE DO. OF COURSE THEY HAVE OTHER CULTURAL DIFFERENCES THAT MAKE IT POSSIBLE FOR THEM TO DO THIS. BUT, YEAH, I THINK IF WE REALLY STRENGTHEN OUR TESTING, TRACING, AND ISOLATION REGIME, WE HAVE A REALLY GOOD CHANCE OF HAVING A BETTER HANDLE ON THIS. THAT MEANS BACKWARD CONTACT TRACING, HIRING MORE CONTACT TRACERS, USING ELECTRONIC DATA FOR TRACKING AND SO FORTH, MAYBE EVEN SOCIAL MEDIA CRAWLING, AND IT MEANS INVESTING IN MORE TESTING CAPACITY FOR THAT FASTER TURN-AROUND ONCE YOU FIND CASES. YES, I THINK THIS IS HOW WE HAVE TO DO IT GOING FORWARD.

Nam says ASHLEIGH?

Ashleigh says I AGREE 100 PERCENT. BACKWARD CONTACT TRACING IS EFFECTIVE WHEN YOU DON'T HAVE A LARGE NUMBER OF CASES. IT'S MOST EFFECTIVE EARLY ON IN THE EPIDEMIC WHEN IT'S STARTING TO GROW AND TOWARDS THE TAIL OF AN EPIDEMIC CURVE WHEN CASE COUNTS ARE LOW AGAIN. WHEN YOU'RE IN THE MIDST OF HIGH CASES WHERE WE ARE IN ONTARIO RIGHT NOW AND WE'RE STRUGGLING TO KEEP UP WITH BASIC CONTACT TRACING, THE EFFECTIVENESS IS GOING TO BE HARDER. I HAVE A LOT OF RESPECT FOR PEOPLE DOING CONTACT TRACING RIGHT NOW BECAUSE THEIR JOBS ARE INCREDIBLY DIFFICULT. SO I DO THINK THAT THERE'S HUGE VALUE IN DOING BACKWARD CONTACT TRACING, BUT WE ALSO NEED TO BE COGNIZANT OF THE WORKLOAD THAT'S INVOLVED AND AGAIN PROVIDE I THINK INNOVATIONS IN TERMS OF, HOW DO WE DO THIS, HOW DO WE SUPPORT THE PEOPLE DOING CONTACT TRACING, AND I THINK THE OTHER COMPONENT OF TEST, TRACE, ISOLATE, IS SUPPORT. I DON'T THINK WE HAVE ENOUGH CONVERSATIONS ABOUT THIS IN TERMS OF WHEN PEOPLE ARE IDENTIFIED AS CASES OR WHEN THEY'RE IDENTIFIED AS CONTACTS, WE NEED TO MAKE SURE THAT THEY HAVE THE SUPPORTS THAT THEY NEED TO BE ABLE TO SELF-ISOLATE AND TO BE ABLE TO ADHERE TO ALL THE RECOMMENDATIONS THAT WE'RE SUGGESTING.

Nam says KIND OF LIKE HAVING A PLACE TO STAY FOR QUARANTINE, ET CETERA?

Ashleigh says EXACTLY.

Nam says I KNOW SOME PEOPLE LISTENING TO THIS AND THERE'S A LOT OF FRUSTRATION ALL AROUND BECAUSE WE DO KNOW THAT RIGHT NOW WE'RE USING A CONTACT EXPOSURE TRACING APP AND IN THE PAST FEW DAYS, WE KNOW THAT NOT MANY PEOPLE ARE USING IT. SO DO YOU SEE... YOU KNOW, IF WE ARE TO TAKE ON THE BACKWARDS CONTACT TRACING, DO YOU WORRY THAT THAT'S GOING TO ADD ANOTHER LAYER OF CONFUSION AROUND THIS WHOLE COVID-19 SITUATION? RAYWAT?

Raywat says IT'S POSSIBLE. ABSOLUTELY. AND MESSAGING AROUND THIS PANDEMIC HAS BEEN A PROBLEM FROM THE START. GETTING BUY-IN FROM THE PUBLIC HAS BEEN AN ISSUE. GETTING CLARITY ON WHAT WE EXPECT FROM PEOPLE HAS BEEN AN ISSUE AS WELL. BUT THIS IS THE NATURE OF OUR GAME. WE'RE IN CHAOTIC AND UNPRECEDENTED TIMES. AGAIN FROM WHAT WE SEE FROM PLACES LIKE SOUTH KOREA AND JAPAN IS THE QR SYSTEM SEEMS TO BE EASIER FOR PEOPLE TO HANDLE AS THEY TAKE OUT THEIR PHONES AND SCAN THE QR CODE AT THE ENTRANCE OF A PLACE AND THEY'RE DONE. THAT REQUIRES PEOPLE TO HAVE A PHONE WITH THE REQUIRED TECHNOLOGY ATTACHED TO IT AND PEOPLE DOING WHAT WE ASK OF THEM. PUBLIC COMPLIANCE IS VERY IMPORTANT. I HOPE GOING FORWARD IS WE MAKE INVESTMENTS IN ASSUAGING PEOPLE'S CONCERNS AND GETTING CITIZENS ON BOARD AS PARTNERS IN THIS ENDEAVOUR. THIS CAN'T BE DONE FROM A TOP-DOWN PROCESS ALONE. IT NEEDS BUY-IN FROM THE PEOPLE AND LEADERSHIP FROM THE PEOPLE AS WELL. THIS IS A DEMOCRATIC PROCESS. PANDEMIC CONTROL IS A DEMOCRATIC PROCESS.

Nam says WHEN WE TALK ABOUT SUPERSPREADERS, DO WE KNOW HOW THAT HAPPENS, RAYWAT?

Raywat says WOW, THAT'S A GOOD QUESTION. I THINK ABOUT THE SWISS CHEESE MODEL, YOU KNOW? DIFFERENT SLICES OF CHEESE HAVE DIFFERENT HOLES IN THEM, AND YOU NEED ALL THE SLICES TO LINE UP JUST RIGHT TO GET A HOLE RIGHT THROUGH. SO YOU NEED SEVERAL THINGS TO LINE UP JUST RIGHT FOR A SUPER SPREADING EVENT TO OCCUR, AND THESE INCLUDE CHARACTERISTICS OF THE VIRUS, CHARACTERISTICS OF THE VIRUS INTERACTING WITH THE INFECTED INDIVIDUAL, AND MOST IMPORTANTLY, IN MY OPINION, CHARACTERISTICS OF THE ENVIRONMENT. SO IS THE INFECTION UPPER RESPIRATORY OR LOWER? HOW FAR ALONG THE INFECTION DISEASE CYCLE IS THE INDIVIDUAL? ARE THEY SYMPTOMATIC OR NON-SYMPTOMATIC? ARE PEOPLE AROUND THEM RESILIENT, OLDER OR YOUNGER? OR THE ENVIRONMENT, IS IT CROWDED, IS THERE ALCOHOL INVOLVED TO REDUCE THE ABILITY OF PEOPLE TO MAKE RATIONAL CHOICES. IS THERE GOOD VENTILATION? ALL THESE THINGS MATTER BUT THEY'RE HAPPENING SO FREQUENTLY THAT BY CHANCE ALONE, THE CHEESE SLICES LINE UP MORE FREQUENTLY THAN YOU THINK AND THAT'S HOW WE GET THE SUPER SPREADING EVENTS. WE NEVER KNOW WHICH EVENT IS GOING TO BE A SUPER SPREADING EVENT. BUT WE HAVE A GOOD IDEA OF THE ENVIRONMENTS THAT ARE AMENABLE TO SUPER SPREADING OCCASIONS AND THAT'S A GOOD THING. IT MEANS WE CAN IDENTIFY THOSE LIKELY SCENARIOS AND TAKE THEM OFF THE TABLE IN TIMES OF CASELOAD INCREASE, AS WE'VE DONE IN ONTARIO RECENTLY. I THINK CLOSING SOME BUSINESSES WAS A WISE THING TO DO BECAUSE THOSE ARE LIKELY SUPER SPREADING OPPORTUNITIES.

The caption changes to "Super emitters of the virus?"

Nam says AND ASHLEIGH, ARE SOME INDIVIDUALS SUPER EMITTERS OF THE VIRUS?

Ashleigh says YEAH. SO, AGAIN, YOU KNOW, IT'S A COMPLICATED QUESTION. I HAVE A COLLEAGUE, DAVID, WHO REFERS TO SUPERSPREADERS EVENTS AS THE LEMONY SNICKET SERIES OF EVENTS THAT LEAD TO A SUPER SPREADER EVENT. SO IT'S A COMBINATION OF THE INDIVIDUAL... YOU KNOW, OVER THE COURSE OF AN INFECTION, PEOPLE HAVE DIFFERENT LEVELS OF VIRUS. SO PEOPLE TEND TO BE MOST INFECTIOUS AROUND THE TIME THEY DEVELOP SYMPTOMS. SO IF YOU HAPPEN TO BE OUT AT THAT PARTICULAR TIME, YOU'RE MORE LIKELY TO TRANSMIT THAN IN ANOTHER STAGE OF YOUR INFECTION. SIMILARLY, DIFFERENT PEOPLE HAVE DIFFERENT VIRAL LOADS. SO SOME PEOPLE ARE MORE INFECTIOUS THAN OTHERS. BUT AGAIN, YOU KNOW, THE OTHER SORT OF PIECE THAT GOES INTO THIS IS THE ENVIRONMENT. SO WHERE ARE YOU? IF YOU'RE STAYING HOME, EVEN IF YOU'RE GENERATING LARGE AMOUNTS OF VIRUSES, IF YOU'RE NOT SEEING OTHER PEOPLE, YOU CAN'T REALLY HAVE A SUPER SPREADER EVENT. SO AGAIN IT'S JUST REALLY THIS CONFLUENCE OF VARIOUS FACTORS THAT'S REALLY IMPORTANT FOR GENERATING SUPER SPREADER EVENTS.

Nam says AND OBVIOUSLY, NOT TO MAKE LIGHT OF IT, BUT LIKE A SERIES OF UNFORTUNATE EVENTS, IN A WAY?

Ashleigh says EXACTLY, EXACTLY. YOU SORT OF HAVE TO BE AT YOUR PEAK OF INFECTIOUSNESS AND YOU HAVE TO BE OUT AT A RESTAURANT THAT HAS POOR VENTILATION AND YOU HAPPEN TO BE IN CLOSE CONTACT WITH A LOT OF PEOPLE OR THE AIR-CONDITIONING IS BLOWING IN A WAY THAT YOU COUGH AND YOUR VIRUS PARTICLES ARE SPREADING INTO A BUNCH OF OTHER PEOPLE. IT'S REALLY THESE SERIES OF CIRCUMSTANCES, SOME OF WHICH WE CAN CONTROL BUT THINGS WE CAN'T NECESSARILY PREDICT AHEAD OF TIME.

The caption changes to "Watch us anytime: tvo.org, Twitter: @theagenda, Facebook Live, YouTube."

Nam says WHAT ABOUT KIDS? ARE KIDS SUPERSPREADERS OF THE VIRUS?

Raywat says THAT IS A CONTROVERSIAL QUESTION THAT WILL GET BOTH OF US INTO TROUBLE DEPENDING WHO IS LISTENING TO THIS. SOME PEOPLE SAY NO. I SAY YES, WE ARE. ASHLEIGH TWEETED A STUDY RECENTLY FROM SFU THAT FOUND THAT MOST KIDS, WHEN THEY'RE INFECTIOUS, DO NOT CAUSE CLUSTERS. BUT SOME DO. AND THE PROBLEM WITH THOSE THAT DO IS KIDS ARE MORE LIKELY TO BE ASYMPTOMATIC. SO THEY'RE STEALTH INFECTORS. AND THESE STEALTH INFECTION EVENTS CAN CAUSE CLUSTERS THAT ARE MORE DIFFICULT TO DETECT. YOU STARTED OUT THE SHOW BY CITING THIS INDIA STUDY THAT LOOKED AT 3 MILLION PEOPLE AND THEY FOUND THAT CHILDREN WHO ARE INFECTED HAVE JUST AS MANY FIRST ORDER INFECTED CONTACTS AS ADULTS. SO KIDS AND ADULTS HAVE EQUAL PROPORTIONS OF INFECTIVITY, EQUAL LIKELIHOOD OF INFECTING OTHERS, AND NOW WE HAVE KIDS IN SCHOOLS ALL OVER THE WORLD. NOW, THE GOOD NEWS IS THAT THE NUMBER OF SCHOOL OUTBREAKS IS PROBABLY LESS THAN SOME PEOPLE EXPECT. IT'S NOT THE APOCALYPTIC EVENT THAT SOME HAD PROJECTED. HOWEVER, SCHOOL OUTBREAKS ARE HAPPENING. IN THE U.K. THEY'VE HAD SCORES OF SCHOOL OUTBREAKS. FRANCE, THERE ARE MORE OUTBREAKS IN EDUCATIONAL SETTINGS THAN THERE ARE IN WORKPLACE SETTINGS. SO THE ANSWER IS YES. KIDS CAN BE SUPERSPREADERS, IN MY OPINION.

Nam says I'M SORRY, I DIDN'T MEAN FOR IT TO BE A CONTROVERSIAL QUESTION BECAUSE, YOU KNOW, KIDS HAVEN'T BEEN IN SCHOOL FOR A VERY LONG TIME AND KIDS ARE GOING TO SCHOOL, SO I'M SURPRISED IT IS A CONTROVERSIAL. SO, ASHLEIGH, ARE KIDS SUPERSPREADERS?

The caption changes to "Ashleigh Tuite, @AshTuite."

Ashleigh says I'M GOING TO HEDGE THIS A BIT AND SAY I'M NOT REALLY COMFORTABLE WITH CALLING CHILDREN SUPERSPREADERS. I WOULD SAY CHILDREN ARE ASSOCIATED WITH SUPER SPREADER TYPE EVENTS. WE KNOW THAT CHILDREN CAN GET INFECTED. WE KNOW THAT CHILDREN CAN TRANSMIT THE VIRUS. AND WE HAVE GROWING EVIDENCE OF SUPER SPREADER EVENTS HAPPENING IN SCHOOLS. BUT AGAIN, YOU KNOW, IT'S THAT COMBINATION OF CHILDREN ARE INFECTIOUS, THEY CAN BE INFECTED WITH THE VIRUS. THEY CAN BE INFECTED AND ASYMPTOMATIC. SO WE DON'T NECESSARILY KNOW IT. AGAIN, SCHOOLS ARE AN EXAMPLE OF A REALLY GOOD ENVIRONMENT FOR SPREADING COVID-19. WE HAVE CLOSED SPACES WITH POOR VENTILATION. YOU HAVE LOTS OF PEOPLE TOGETHER IN A CROWDED SPACE. IN THE ABSENCE OF MASKS AND IN THE ABSENCE OF PHYSICAL DISTANCING, WE HAVE A LOT OF PEOPLE WHO ARE TALKING, THEY'RE OFTEN VERY CLOSE TO EACH OTHER. SO AGAIN, YOU KNOW, I THINK SCHOOLS ARE ABSOLUTELY SHOWING TO BE ENVIRONMENTS WHERE THERE CAN BE A SUPER SPREADING EVENT... SO, YEAH, A SUPER SPREADER EVENT CAN HAPPEN. I HESITATE TO CALL CHILDREN SUPERSPREADERS BECAUSE I DON'T THINK THERE'S SOMETHING UNIQUE ABOUT CHILDREN THAT MAKE THEM TRANSMIT THE VIRUS THAN OTHER PEOPLE.

Nam says SO IT'S THE ENVIRONMENT. I THINK, AGAIN, WE'VE TALKED ABOUT MESSAGING AND, YOU KNOW, PEOPLE... WE'VE TALKED ABOUT WHAT'S HAPPENING IN ONTARIO, ABOUT THE CLASS SIZES BEING BIGGER THAN WHAT SCIENTISTS HAVE SUGGESTED. BUT WE'VE HAD THAT CONVERSATION ALREADY. ASHLEIGH, FOR THE AVERAGE PERSON TRYING TO GO ABOUT THEIR DAY, HEADING TO THE GROCERY STORE, MAYBE EVEN CONSIDERING GOING TO THE MALL, USING PUBLIC TRANSIT, WHAT DOES OUR UNDERSTANDING OF SUPER SPREADING MEAN FOR THE LEVEL OF RISK THAT THEY SHOULD FEEL?

The caption changes to "Does the level of risk change?"

Ashleigh says SO I THINK ONE OF THE CHALLENGES WITH THE IDEA OF SUPER SPREADING EVENTS IS ON THE ONE HAND IT'S A LITTLE BIT REASSURING. YOU HEAR THIS AND YOU SAY MOST PEOPLE ARE NOT GOING TO INFECT ANYBODY OR THEY'RE NOT GOING TO INFECT A LOT OF PEOPLE. BUT THE CHALLENGE IS WE DON'T KNOW AHEAD OF TIME WHO THOSE PEOPLE ARE AND WHAT THE CIRCUMSTANCES ARE. SO I DON'T THINK THAT WE SHOULD GO ABOUT OUR LIVES NECESSARILY FEELING MORE COMFORTED. I THINK, THOUGH, GIVEN WHAT WE KNOW ABOUT THE SORTS OF ACTIVITIES AND ENVIRONMENTS THAT FACILITATE SUPER SPREADING, I THINK WE CAN USE THAT TO GUIDE OUR DAY-TO-DAY ACTIVITIES. SO THE JAPANESE HAVE WHAT THEY CALL THE THREE CS, SO CLOSED SPACES, INDOORS, CROWDED SPACES, AND CLOSE CONTACT SETTINGS, SO PLACES WHERE PEOPLE ARE CLOSE TOGETHER TALKING AND SINGING. I THINK THAT CAN REALLY HELP YOU GUIDE YOUR DAY-TO-DAY ACTIVITY. SO IF YOU'RE GOING OUT TO A GROCERY STORE, YOU'RE WEARING A MASK, YOU'RE KEEPING OUR DISTANCE FROM OTHER PEOPLE, YOU'RE NOT SPENDING A LOT OF TIME INDOORS. THAT'S NOT A HIGH-RISK INTERACTION. BY CONTRAST, YOU KNOW, HAVING TEN OF YOUR CLOSEST FRIENDS OVER TO YOUR HOUSE AND, YOU KNOW, DOING KARAOKE IS A HIGH RISK BECAUSE YOU HAVE LOTS OF PEOPLE INDOORS, YOU'RE SINGING, AND SO, YOU KNOW, THINKING ABOUT THOSE DIFFERENT FACTORS AND UNDERSTANDING THAT THOSE THREE CS CAN REALLY SORT OF HELP US PREDICT THE SORTS OF ENVIRONMENTS THAT ARE HIGHER RISK, I THINK THAT CAN HELP US SORT OF NAVIGATE OUR LIVES, RECOGNIZING THAT WE CAN'T ALL STAY INDOORS FOREVER. WE NEED TO GO OUTSIDE FOR SOME OF OUR LIVES.

Nam says RAYWAT, I'LL ASK YOU THE SAME QUESTION.

Raywat says YEAH, IT DOESN'T CHANGE WHAT INDIVIDUALS HAVE TO DO. WE HAVE TO KEEP OUR DISTANCE FROM PEOPLE, WEAR OUR MASKS WHEN WE CAN'T KEEP OUR DISTANCE FROM PEOPLE, WHEN WE'RE INDOORS, AND AVOID SOCIAL GATHERINGS WE DON'T NEED TO GO TO. NOW, INDIVIDUALS MAY BE CALLED UPON IN THE FUTURE TO PARTICIPATE IN THESE BACKWARD TRACING ENDEAVOURS, USING QR CODES AND SO FORTH. THAT'S WHERE CITIZENS CAN DO THEIR PART. BUT THE SUPER SPREADING THING I THINK HAS MORE RELEVANCE FOR MANAGERS AT THE PUBLIC HEALTH LEVEL TO ALLOW US TO FIGURE OUT WHICH OPPORTUNITIES TO TAKE OFF OF THE TABLE AT A SOCIETAL LEVEL. SO FOR PEOPLE, THE AVERAGE CITIZEN, JUST KEEP YOUR DISTANCE AND AVOID SOCIAL GATHERINGS.

Nam says AND I WANT TO GO BACK TO WHEN WE WERE TALKING ABOUT CLUSTERS, WE KNOW THAT THERE'S BEEN A LOT OF CASES IN CONGREGATE SETTINGS. WE'RE TALKING ABOUT SCHOOLS, WE'RE TALKING ABOUT LONG-TERM CARE HOMES. ASHLEIGH, COULD WE TEST WASTEWATER TO HELP DETECT CLUSTERS OF INFECTIONS?

Ashleigh says YEAH, I THINK THAT THE WASTEWATER STUFF IS TURNING OUT TO BE A REALLY EFFECTIVE TOOL RIGHT NOW. SO OTTAWA HAS STARTED USING IT. I THINK OTHER PARTS OF THE PROVINCE ARE STARTING TO USE IT. AND IT SHOWS THAT IT DOES TRACK WHAT'S HAPPENING IN THE COMMUNITY. SO I DO THINK, YOU KNOW, PARTICULARLY IN CONGREGATE SETTINGS LIKE LONG-TERM CARE HOMES, THERE'S HUGE POTENTIAL TO BASICALLY GET A HANDLE ON WHAT'S HAPPENING RATHER THAN SIMPLY RELYING ON REPORTED CASES, WHICH, YOU KNOW, HAVE BECOME CLEAR ARE REALLY, REALLY CHALLENGING TO INTERPRET AS WE START CHANGING OUR TESTING POLICIES. SO I DO THINK IT'S A REALLY IMPORTANT STREAM OF DATA. HAVING SAID THAT, I THINK WE'RE STILL TRYING TO FIGURE OUT EXACTLY HOW TO INTERPRET IT AND WHAT SOME OF THE NUANCES ARE IN TERMS OF, YOU KNOW, HOW TO ACT ON THAT INFORMATION. BUT I DO THINK THERE'S A LOT OF EMERGING EVIDENCE THAT IT IS AN EFFECTIVE TOOL.

Nam says RAYWAT, I'M GOING TO END WITH A BIG QUESTION. WE ONLY HAVE ABOUT 30 SECONDS. BUT TO WHAT EXTENT IS COVID-19 STILL A BIT OF A MYSTERY TO US?

Raywat says OH. WELL, IT'S A HUGE MYSTERY. WE DON'T KNOW WHERE IT CAME FROM, REALLY, TO SOME EXTENT. I MEAN, RUMOURS THAT THERE'S EVIDENCE IT MAY HAVE BEEN WITH US LONGER THAN WE THOUGHT, FIVE WEEKS OR A MONTH. WE DON'T KNOW ITS EFFECTS PHYSIOLOGICALLY AS WELL AS WE COULD OR SHOULD AND WE DON'T KNOW ABOUT IMMUNITY. THAT'S RELEVANT FOR DEVELOPING A VACCINE. BUT EPIDEMIOLOGICALLY, WE'RE GETTING A HANDLE ON TRANSMISSION DYNAMICS, WHICH IS REALLY GOOD.

The caption changes to "Producer: Eric Bombicino, @ebombicino."

Nam says ASHLEIGH AND RAYWAT, THAT'S ALL THE TIME. RAYWAT, YOU HAVE BEEN ON THE SHOW BEFORE. ASHLEIGH, I WANT TO SAY, YOU WERE TERRIFIC. HOPEFULLY YOU'LL COME BACK ON THE SHOW.

Ashleigh says THANK YOU SO MUCH.

Watch: Superspreaders: The Key to Covid-19?