Updated: 17/07/2021, 4:01 pm We answer your questions about the Covid testing system and how it works. Do Covid tests only work if you have symptoms of the virus – and are the results reliable? We answer your questions on PCR and lateral flow testing. It is hard to avoid conversation and comments about coronavirus online – with many people sharing their takes and opinions on the topic. We’ve gone to the experts to put minds at ease and answer some of your questions. Q: “Do Covid tests only work if you’re showing symptoms?” Concerns about asymptomatic Covid have emerged following widely-circulated claims by Dr Mike Yeadon, a former vice-president of Pfizer.