Covid virions on infection, replicate exponentially and once the body's defense system starts attacking it then it also seems to decrease exponentially.
The time period when the PCR test is positive is 14 days, let it be $t$. In the above graph it is from 4th day to 17th day.
Let the peak count be $k$, which is around $10^9$ to $10^{11}$. Source
The lifespan of a single covid cell seems to be around a single day.
How do we model this?
What would be the total number of Covid virons that existed during the entire period of infection, from day 0 to day 25?