Measles: Understanding the most contagious preventable disease | About That

>> Andrew: SO YOU’VE BEEN WATCHING THE COVERAGE OF MEASLES ON THE NEWS, AND IT SOUNDS A LOT LIKE THIS: >> URGENT NEW WARNINGS ABOUT THE SPREAD OF MEASLES. >> HIGHLY CONTAGIOUS AND POTENTIALLY DANGEROUS ILLNESS. >> THE NUMBER OF OUTBREAKS. >> ARE RISING IN SOME PARTS OF

THE WORLD. >> Andrew: AND IT OCCURRED TO ME A LOT OF US, MYSELF INCLUDED, HAVE NEVER ACTUALLY SEEN A MEASLES CASE IN PERSON BEFORE BECAUSE CANADA WIPED IT OUT MORE THAN 25 YEARS AGO, SO EITHER THIS IS AN UNFAMILIAR FOE TO YOU

OR, IF YOU’RE OLDER, MAYBE EVEN HAD THE MEASLES WHEN YOU WERE A KID, THIS IS LIKE A BAD DREAM TAKING YOU WAY BACK IN TIME. SO LET’S CUT THROUGH IT ALL. ? MEASLES IS AN AIRBORNE VIRUS. IT GETS YOU SICK WHEN YOU BREATHE IT IN, SO YOUR MOUTH,

YOUR NOSE, BUT EVEN YOUR EYES CAN BE AN ENTRY POINT, AND IT CAN OVERRUN YOUR LUNGS. ONE BY ONE, MEASLES TURNS YOUR CELLS INTO LITTLE MEASLES-MAKING FACTORIES, AND EVENTUALLY IT USES YOUR IMMUNE SYSTEM AGAINST YOU, INFECTING THE VERY MESSENGERS THAT COORDINATE YOUR IMMUNE RESPONSE, PIGGYBACKING

THEIR WAY THROUGH YOUR ENTIRE BODY. >> THE VIRUS ACTUALLY SPREADS THROUGHOUT THE ENTIRE BODY. IT CAN RANGE FROM BEING A FEVER OR RASH ILLNESS ALL THE WAY THROUGH TO YOU REQUIRE HOSPITALIZATION VERY, VERY ILL PROBLEM. >> Andrew: THAT’S WHY A FULL

BODY RASH IS ONE OF THE MOST TELLTALE SIGNS THAT YOU’VE GOT MEASLES. THE PROBLEM IS, IT DOESN’T STOP THERE. IT DOESN’T EVEN ACTUALLY START THERE. THE EARLIER SYMPTOMS OF MEASLES ARE WHAT DOCTORS CALL THE THREE Cs. SO YOU HAVE COUGH. MEASLES INFECT YOUR RESPIRATORY

TRACTS, AFTER ALL. YOU HAVE CONJUNCTIVITIS, WHICH IS BASICALLY A FANCY WORD FOR PINK EYE. SO YOUR EYES MIGHT GET SWOLLEN AND START LEAKING A LITTLE. THE LAST C IS CORIZA. GET THAT “O” NICE AND PRETTY. THAT’S SWELLING RIGHT HERE. BASICALLY YOU GET A STUFFY NOSE,

WHICH A LOT OF PEOPLE MISTAKENLY THINK HAS TO DO WITH HAVING TOO MUCH MUCOUS UP THERE CLOGGING THE PIPES, BUT A STUFFY NOSE IS ACTUALLY KIND OF THE REVERSE OF THAT. YOU GET STUFFED UP BECAUSE THE PIPES GET NARROWER BECAUSE YOUR NASAL TISSUE IS SWELLING UP.

BOTTOM LINE IT’S DURING THESE EARLY SYMPTOMS WHERE YOU’RE MOST LIKELY TO GET OTHER PEOPLE SICK. >> FOUR DAYS BEFORE THAT RASH IS SUPPOSED TO BREAK OUT, AND THEN FOUR DAYS AFTER THE RASH BREAKS OUT. SO WE THINK ABOUT THAT NEARLY EIGHT DAYS WHERE PEOPLE ARE

REALLY INFECTIOUS TO OTHERS, AND THE SCARY PART OF THIS DISEASE IS THAT AT LEAST FOUR OF THOSE DAYS ARE WITHOUT THE RASH. >> Andrew: AND WE SHOULD SAY YOU CAN STILL SPREAD THE DISEASE EVEN BEFORE YOU START SHOWING ANY SYMPTOMS AT ALL. IF YOU’RE INFECTED, JUST

BREATHING CAN BE ENOUGH TO DO IT. DIFFERENT DISEASES SPREAD DIFFERENTLY IN DIFFERENT POPULATIONS, BUT MEASLES IS LIKE WILDFIRE ANYWHERE. >> MEASLES IS ONE OF THE MOST TRANSMISSIBLE DISEASES ON EARTH. >> Andrew: WE’VE TALKED ABOUT HOW MEASLES IS AN AIRBORNE VIRUS, MEANING YOU CAN SPREAD IT

BY COUGHING, SNEEZING, TALKING, EVEN BREATHING, BUT WE HAVEN’T MENTIONED HOW LONG IT SURVIVES ONCE YOU COUGH OR BREATHE IT OUT. UP TO TWO HOURS IN THE AIR ON A SURFACE. >> FOR MEASLES, PUBLIC HEALTH RECOMMENDATIONS ARE WITHIN TWO HOURS OF BEING IN THE SAME ROOM,

MEANING IF I LEFT THE ROOM AND SOMEONE COMES INTO THAT ROOM WITHIN THE NEXT TWO HOURS, THEY ARE STILL CONSIDERED EXPOSED. >> Andrew: THAT FACT THAT MEASLES IS SO ENVIRONMENTALLY STABLE, ABLE TO LINGER IN THE AIR, WE’VE SEEN THAT HAPPEN ON A PRETTY EXTRAORDINARY SCALE.

>> I’LL MENTION ONE, AND IT’S SPECIAL OLYMPICS IN THE UNITED STATES WHERE SOMEONE THAT WAS ESSENTIALLY AT THE OPENING CEREMONIES, YOU KNOW, ON THE TRACK, INFECTED SOMEONE THAT WAS SITTING IN THE UPPER DECK. THAT REALLY JUST SUGGESTS HOW FAR AND HOW LONG AND HOW STABLE

THIS VIRUS CAN BE AT SIGNIFICANT DISTANCES. >> Andrew: SO YEAH, WE LOOKED INTO THAT. HE’S TALKING ABOUT THE INTERNATIONAL SPECIAL OLYMPICS IN 1991. MINNEAPOLIS OPENING CEREMONY. THIS IS A STUDY LOOKING INTO WHAT HAPPENED. A TRACK ATHLETE FROM ARGENTINA WAS APPARENTLY SICK. TWO SPECTATORS WHO GOT INFECTED

WERE SITTING MORE THAN 30 METRES ABOVE THE ATHLETES’ ENTRANCE IN THE UPPER DECK OF THE STANDS. THAT’S AN ENORMOUS DISTANCE FOR A VIRUS TO TRAVEL. INVESTIGATORS RULED OUT ANY OTHER POSSIBLE EXPOSURE, AND IT’S OBSERVATIONS LIKE THESE THAT CONTRIBUTE TO WHAT EPIDEMIOLOGISTS CALL THE R NOT

VALUE OF A DISEASE. BASICALLY WHEN SOMEONE IS INFECTED, HOW MANY OTHER PEOPLE ARE THEY LIKELY TO GET SICK? >> R NOT, YOU KNOW, REPRODUCTIVE RATE OR REPRODUCTIVE NUMBER REALLY REFERS TO, YOU KNOW, IN GENERAL TERMS HOW MANY PEOPLE ARE SECONDARILY INFECTED OUT OF

AN INDIVIDUAL BEING INFECTED. SO IF I’M INFECTIOUS TODAY, HOW MANY PEOPLE WILL ACQUIRE MEASLES FROM MY INFECTION FROM TYPICAL EXPOSURE. >> Andrew: AND THIS IS HELPFUL TO KNOW BECAUSE WE CAN ESSENTIALLY BOIL DOWN EVERY INFECTIOUS DISEASE TO A SINGLE

NUMBER, AND I’M GOING TO SHOW YOU A FEW, BUT JUST KNOW THAT THE VALUES YOU’LL SEE ARE APPROXIMATIONS, RANGES, COBBLED TOGETHER FROM A BUNCH OF SOURCES, BUT PAY ATTENTION TO HOW EACH DISEASE COMPARES TO THE OTHERS. SO SOMEONE INFECTED WITH EBOLLA, DESPITE BEING ONE OF THE

DEADLIEST DISEASES ON EARTH, MIGHT ONLY, ON AVERAGE, GET A COUPLE OF OTHER PEOPLE SICK. EBOLA ISN’T AIRBORNE, BUT DISEASES LIKE THE FLU AND MUMPS ARE. THEY SPREAD MORE EASILY. SOME DISEASES, LIKE H.I.V., CAN SPREAD FAR AND WIDE IN PART BECAUSE PEOPLE AREN’T ALWAYS

AWARE THAT THEY ARE INFECTED. THAT CAN GO ON FOR MONTHS OR EVEN YEARS. THEN ALL THE WAY AT THE EXTREME END OF THE SPECTRUM YOU HAVE MEASLES. AND IF YOU TAKE THAT REPRODUCTION NUMBER AT FACE VALUE, SOMEWHERE BETWEEN 12 AND

18, LET’S JUST CALL IT 15 ON AVERAGE, SO YOU HAVE YOUR ONE PERSON WHO IS YOUR SOURCE INFECTION, THEY, YOU WOULD EXPECT, TO INFECT 15 PEOPLE. EACH OF THOSE 15 PEOPLE GOES ON TO INFECT 15 OTHER PEOPLE, SO YOU END UP WITH 225 PEOPLE.

EACH OF THOSE PEOPLE GOES ON TO INFECT 15 OTHER PEOPLE, AND SO ON AND SO FORTH. IT JUST KEEPS GOING, AND YOU CAN SEE JUST HOW WITHIN A FEW GENERATIONS OF SPREAD YOU QUICKLY GET THOUSANDS OF CASES. BUT A FEW THINGS TO BRING US BACK DOWN TO REALITY.

ONE, THE RATE OF SPREAD REALLY DOES DEPEND ON EACH CASE. SO HOW MUCH CONTACTS DOES THE PERSON HAVE WITH OTHERS? DO THEY LIVE IN A BIG CITY OR IN A SMALL TOWN? WHAT KIND OF PUBLIC HEALTH RESOURCES ARE IN PLACE? BUT MOST IMPORTANTLY, WE HAVE VACCINES.

THIS IS A DISEASE THAT WE UNDERSTAND, AND MEDICALLY, AT LEAST, HAVE SOLVED, WHICH IS WHY IN CANADA, FOR EXAMPLE, AT THE TIME I’M RECORDING THIS THE MOST RECENT OUTBREAKS HAVE LED TO ONLY 17 CONFIRMED CASES IN THE ENTIRE COUNTRY. ? WE’VE HAD AN EFFECTIVE VACCINE

AGAINST MEASLES SINCE THE 1960s. BY THE ’70s WE HAD THE MODERN MMR VACCINE WHICH PROTECTS AGAINST MEASLES, MUMPS AND RUBELLA. BY 1998, MEASLES WAS WIPED OUT IN CANADA. >> CANADA WAS ACTUALLY DECLARED FREE OF MEASLES, AND THE ONLY CASES THAT WE HAVE HAD SINCE

THEN HAVE BEEN RELATED TO IMPORTATION OF CASES. >> WE REALLY DON’T SEE LOCAL TRANSMISSION OF MEASLES IN SOME COUNTRIES BECAUSE VACCINE RATES ARE SO HIGH, DESPITE IT BEING SUCH AN INFECTIOUS ORGANISM. >> Andrew: THE VACCINE IS NEARLY 100% EFFECTIVE, BUT MEASLES IS

SO CONTAGIOUS ALMOST EVERYBODY NEEDS TO BE VACCINATED IN ORDER FOR A POPULATION TO HAVE HERD IMMUNITY. THE PROBLEM IS, WE’RE NOT QUITE THERE. NORMALLY A KID WHO TURNS SEVEN SHOULD HAVE HAD BOTH DOSES OF THE MMR VACCINE, BUT IN THE LAST FEW YEARS THE VACCINATION RATE

AMONG 7-YEAR-OLDS REALLY STARTED SLIDING, DROPPING BELOW 80%. WITH THE PANDEMIC, WE SAW THIS RESURGENCE OF MISINFORMATION ABOUT HOW THE MMR VACCINE CAUSES AUTISM. THOROUGHLY DEBUNKED, BUT BELIEVED ANYWAY. AND JUST THIS WEEK, TO GIVE YOU AN EXAMPLE, MONTREAL PUBLIC HEALTH SAID AT SOME OF ITS

SCHOOLS THE VACCINATION RATE AGAINST MEASLES WAS ONLY 30%. >> IT’S EASILY PREVENTABLE IF EVERYONE IS ON BOARD, AND THAT’S I THINK MORE THE WEAK LINKS RIGHT NOW, IS THAT VACCINATION HAS TAILED OFF FOR A NUMBER OF REASONS, AND THAT’S WHY WE’RE SEEING A GLOBAL RESURGENCE OF

THIS DISEASE. >> Andrew: THERE IS, APPARENTLY, NO BENEFITS TO GETTING THE MEASLES. IT DOESN’T STRENGTHEN YOUR IMMUNE SYSTEM. IT DOESN’T DO ANYTHING THAT VACCINES CAN’T ALREADY DO, WHICH IS TO GIVE YOU IMMUNITY TO MEASLES. AND THERE’S ABSOLUTELY ADDED RISK. YOU KNOW, MOST CASES OF MEASLES ARE MILD.

YOU GET COLD SYMPTOMS, FEVER, FATIGUE. YOU GET THE BLOTCHY SKIN, AND A FEW WEEKS LATER YOU COME OUT THE OTHER SIDE. BUT RARELY MEASLES GETS WAY WORSE. >> THE MEASLES VIRUS CAN ACTUALLY BECOME LA TENT IN THE BRAIN FOR SOME TIME AND PEOPLE

CAN GET A COMPLICATION DECADES LATER THAT CAN LEAD TO BRAIN DAMAGE. >> Andrew: AND ONE OF THE MOST INSIDIOUS THINGS ABOUT THIS DISEASE IS HOW GETTING SICK WITH MEASLES CAN ACTUALLY LEAD YOU TO GET SICK WITH OTHER THINGS. >> THE UNIQUE PART OF THIS VIRUS

IS THAT, YOU KNOW, YOU GET AMNESIA TO OTHER INFECTIONS THAT YOU’VE BEEN EXPOSED TO IN THE PAST, AND CERTAINLY SOME OF THOSE INFECTIONS MAY SHOW UP IN THE RECOVERY PHASE AND LEAD TO THEIR OWN COMPLICATIONS. EVEN IN HEALTHY INDIVIDUALS WE DO SEE COMPLICATIONS OF MEASLES

THAT LANDS PEOPLE IN HOSPITAL, AND YOU KNOW, IN THE GLOBAL CONTEXT OF THE SPREAD THAT’S BEEN OCCURRING OVER THE LAST DECADE, WE’VE SEEN COMPLICATIONS OF MEASLES LEADING TO ADULTS TO DIE IN WESTERN COUNTRIES WITH ADEQUATE HEALTH CARE SYSTEMS. >> Andrew: ACCORDING TO THE U.S.

CENTERS FOR DISEASE CONTROL, MOST OF THE WORLD HAS AT LEAST ONE DOSE OF THE VACCINE, BUT WITH MEASLES, MOST ISN’T ENOUGH. ? ?

There are early signals that measles — one of the world’s most contagious but preventable diseases — may be spreading in parts of Canada. Andrew Chang breaks down the way the virus attacks the body and what makes it so contagious.

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