Tufts doctor explains what results of Boston antibody test may mean

Dr. Shira Doron, hospital epidemiologist at Tufts Medical Center, answers the latest questions about COVID-19, possible treatment and vaccines.

EVERY NIGHT WE GO STRAIGHT TO, THE MEDICAL EXPERTS IN BOSTONFOR THE LATEST ON THECORONAVIRUS PANDEMIC.TONIGHT, WE’RE JOINED BY DR.SHIRA DORON, HOSPITALEPIDEMIOLOGIST AT TUFTS MEDICALCENTER.THANKS FOR BEING HERE.WE WANT TO TALK ABOUT BOSTON’SMAYOR TODAY SAYING THE CITY’SPUBLIC HEALTH EMERGENCY WILLSTAY IN EFFECT, PARTLY DUE TOTHE RESULTS OF A SMALL ANTIBODYSTUDY.750 CITY RESIDENTS.IT FOUND 90% HAD NOT BEENEXPOSED TO COVID-19.1 IN 40 WERE POSITIVE FOR THEVIRUS, BUT ASYMPTOMATIC.WHAT DO THESE RESULTS TELL US?DR. DORON: YEAH, SO THIS ISPRETTY IMPORTANT INFORMATION.9.9% WERE THE NUMBER OFBOSTONIANS IN THE STUDY THATWERE POSITIVE FOR ANTIBODY, SOTHAT MEANS 90% OF THE PEOPLE INTHIS SAMPLE AND IF YOUEXTRAPOLATE THAT TO REFLECT ALLBOSTONIANS, WHICH IT MAY NOT, ITMEANS 90% ARE STILL SUSCEPTIBLETO THE INFECTION.THAT MEANS THAT AS WE OPENTHINGS UP, WE COULD STILL HAVE ALOT OF PEOPLE GETTING SICK,ENDING UP IN THE ICU AND DYING.ALL OF THESE PEOPLE DID NOT HAVESYMPTOMS.2.2 WERE ACTUALLY POSITIVE FORACTIVE INFECTION.THAT TELLS YOU WHAT THEPERCENTAGE OF THE POPULATION ISPOTENTIALLY WALKING OUT THERENOT KNOWING THAT THEY ARETRANSMITTING THE DISEASE.IT’S REALLY IMPORTANT TO KNOWWHAT PROPORTION OF PEOPLE COULDBE INFECTING OTHERS AND ITREALLY REFLECTS HOW IMPORTANT ITIS TO SCALE UP TESTING TO APOINT WHERE WE COULD BE TESTINGPEOPLE WITHOUT SYMPTOMS.EMIL IT IS SUCH AN IMPORTANTPOINT.LET’S SHIFT GEARS AND TALK ABOUTTHE VACCINE.PRESIDENT TRUMP SAYS HE EXPECTSA VACCINE ON THE MARKET, READYTO DISTRIBUTE BY THE END OF THEYEAR.IS THERE A DIFFERENCE BETWEENHAVING DOSES DELIVERED, READY TOGO AND BEING ABLE TO GIVE THEMTO THE PUBLIC?DR. DORO YEAH, THERE IS ADIFFERENCE.THERE ARE MANY LOGISTICALCONSIDERATIONS ABOUT GETTINGTHAT TO THE PUBLIC.THE THING WE ARE MOST CONCERNEDABOUT IS HOW REALISTIC I IT TOHAVE THE VACCINE READY TO GO INSUCH A SHORT TIME.WE HAVE NEVER PRODUCED A VACCINEIN THAT SHORT A TIME.IT TYPICALLY TAKES 10 YEARS.THERE IS AN ULTIMATE OF TIMETHAT IS ESSENTIAL.YOU DO HAVE TO WAIT SOMETIMES TOSEE IF THEIR LONG-TERM SIDEEFFECTS.WE JUST NEED TO BECAUSE SHOWS.-- BE CAUTIOUS.EMIL IT’S SUCH AN IMPORTANTDISTINCTION.SOME EXPERTS WE ARE HEARING SAYIT MAY NOT BE A SINGLE DRUG, BUTA COCKTAIL OF DRUGS, THE WAYTHAT WE TREAT HIV ORTUBERCULOSIS.WHAT DO THINK ABOUT THAT?WHY MIGHT IT TAKE A COCKTAIL TOTREAT?DR. DORO HIV AND TUBERCULOSISARE UNIQUE IN THAT THEY DEVELOPSO QUICKLY.THAT’S NOT NECESSARILY THE CASEWITH COVID.THERE ARE CLINICAL TRIALS WITHONE DRUG CLINICAL TRIALS WITHCOCKTAILS OF DRUGS.I THINK THE ISSUE WITH COCKTAILSIS IF YOU HAVE SUCCESSFULCLINICAL TRIAL YOU DON’T KNOWWHICH DRUG WAS THE SUCCESSFULONE.OR DOES IT REQUIRE ALL OF THEM?EMIL RIGHT.ONE MORE QUESTION.WE ARE GETTING A LOT OFQUESTIONS ABOUT THE DIFFERENTKINDS OF TESTS.CAN YOU EXPLAIN THE DIFFERENCEBETWEEN THE TWO PRIMARY TEST WEHAVE RIGHT NOW.WE HAVE THEPCR IN THE ANTIBODYTESTS.DR. DORON: RIGHT.THE PCR IS THE NASAL SWAB ANDTHE NEW ONE COMING ONTO THEMARKET IS THE SALIVA TESTING ATTHEY TELL YOU IF YOU AREACTIVELY INFECTED RIGHT NOW.YOU MAY BE EFFECTED WITHSYMPTOMS.YOU MAY BE AFFECTED WITHOUTSYMPTOMS.IT COULD MEAN YOU HAVE THEDISEASE A FEW WEEKS AGO IF YOUGET THE ANTIBODY TEST.IT DOES NOT NECESSARILY MEANYOU’RE STILL CONTAGIOUS.THE SEROLOGY TEST OR THEANTIBODY TEST TELLS YOU IF YOUEVER HAVE THE INFECTION AND THATIS MORE IMPORTANT FOREPIDEMIOLOGIC STUDIES.THERE’S A FAIR AMOUNT OF FALSEPOSITIVES IN THE SEROLOGY TEST,WHERE THERE AREN’T IN THE PCR.YOU WOULD NOT WANT TO OVERLYINTERPRET THE ANTIBODY TESTSAYING, I HAVE HAD IT, I AMSAFE, BECAUSE THAT’S NOTNECESSARILY TRUE.