Dear Dr.

Ive tried to find the answer to this question on this site and others but have had no joy. When a regimen is started and it takes weeks to months for the viral load to reach undetectable, during this time how is the virus still making copies of its self.I thought that the drugs either worked or didnt. I ask this because i see posts where people are having blips with the ensuing resistance worries and i wonder how having a load far greater than a blip level for possibly months doesnt cause resistance.

Thanks Steve

Since the virus is replicating in many kinds of cells and different organs, it takes time for the drugs to achieve effective concentrations and then kill off a sufficient number infected cells to lower the total body viral burden.