we know are major culprits for community spread said dr chan who is also chief of clinical and translational epidemiology at massachusetts general hospital we have no ability to track these people at home and thats a real problemif more widely adopted the app could provide public health authorities an inexpensive tool for detecting outbreaks in cities states and even individual neighborhoods given that the loss of taste and smell appears to be an early indicator of covid19 the information the researchers said would allow health officials to prepare for a spike of infections and help guide the allocation of scarce resources like ventilators for the most seriously ill and the personal protective gear needed by medical workersas local outbreaks subside the app can also guide decisions about the easing of lockdowns and social distancing measuresthe researchers said the app did not prompt significant privacy concerns because participants are not required to provide their names and any other personal information only their zip codesjohn brownstein an epidemiologist and chief innovation officer at boston childrens hospital said the study added to the growing body of evidence that highlights the value of smartphone apps as realtime disease surveillance tools dr brownstein who was not involved in the coronavirus app study has a decade of experience using crowdsource symptom apps starting with an influenza app called flu near you and more recently covid near you an app that has already drawn more than 600000 users in the united statessurveillance apps he said can detect an outbreak well before people begin showing up at hospitals because we have such a lack of testing this kind of data is going to give us insights into symptomatology hot spots and the impact of social distancing he said without this information how are communities supposed to know were on the other side of this pandemic and whether we can reopenbut crowdsourcing apps do not provide a complete snapshot of the coronavirus pandemic because users tend to be younger they are less than ideal for charting its progression among the elderlyand they are also not a replacement for testing which is the most effective means for tracking the spread of the disease the data can also be muddled by people who report symptoms shared by other illnessesits a sort of realtime experiment done on a massive scale that couldnt have been done a couple of years ago dr spector saidthe app he helped develop piggybacks on technology that kings college london has been using to track health outcomes among 14000 twins in the united kingdom when the coronavirus outbreak temporarily idled the project dr spector realized their app could be easily repurposed to track the pandemicit was a crazy idea but four days later we launched the app and it went viral he said within three days more than a million people had downloaded the app a number that has since grown to 33 milliondr cristina menni a research fellow at kings college and another lead author of