Oxford vaccine chief ‘optimistic’ that trial results could be reached by end of 2020

If you think a negative test result means you don’t have coronavirus, you could be wrong — it can take days before a new infection shows up on a Covid-19 test. It is possible to be harboring the virus, but be testing negative and have no symptoms in the early stages of infection.
So if you want to get tested as a precaution before seeing friends or family, here’s what you need to know:
Probably not. A study in the medical journal Annals of Internal Medicine examined false-negative test results of people who actually …continued .
[Original Source: CNN]