We’ve heard a lot about how those who have some immune deficiency, or take some medication which impairs immune function, are more likely to have a diminished response to the SARS-Cov-2 vaccine. In fact, those on anti-rejection immune suppressing drugs may only have a 30% response after 2 doses, rising to 50% after the third dose. We even tell patients who are getting vaccinated to avoid NSAIDS like motrin and aleve before and after vaccination to give the vaccine the best chance at a full immune response.
It appears that those same conditions can impair your body’s ability to clear the virus if you get sick.
The standard advice is that if you get Covid-19, you should quarantine for 10 days after symptom onset or a positive test.
Since the start of the pandemic, we have also known that if you had Covid-19, you could continue to have a positive genetic test for weeks, even months afterwards because of how the test works. The PCR (polymerase chain reaction) test amplifies genetic material. Each amplification round is called a “cycle” and increases the amount of genetic material there is in order to increase sensitivity. Even after the virus is long dead, pieces of its genetic code can continue to hang around and make the test positive. Genetic material can even be measured in poop months afterwards. In fact, analysing bathroom effluent from dormitories at schools is how some schools are monitoring for Covid outbreaks. If they come up positive, they then test all the kids living there.
If your immune system is weakened, it may not clear the virus as fast as in someone who has a healthier immune system. For example, someone who recently had chemotherapy for cancer or takes a biologic drug for an autoimmune condition can continue to shed live virus for much longer than the typical 10 days, even 3-4 weeks. An infectious disease specialist I spoke with recently told me that she had a very ill patient who continued to shed virus for almost a year before the patient passed away.
Add to that the fact that the Delta variant replicates 1000x more in the nose and spreads more easily than the original Wuhan virus.
How can you tell who just has dead virus but remnant material from those who are still infected? One way is to look at patient secretions under an electron microscope looking for the virus. Not practical for the general population. The way which is used now is to look at how many cycles of amplification of the PCR test it takes to detect viral material. If it only takes a few cycles, then you have a very high load and the assumption is that you are still infected and more importantly, infectious to others. If it takes more than 30 cycles, the present cut off used by some institutions like PENN, then you are likely dealing with a non-infectious patient. This is not a standard test and is only done at hospitals.
So what does that mean practically for most people? Well, it reinforces the important fact that YOU DO NOT WANT TO CATCH THIS VIRUS. More importantly, YOU DO NOT WANT TO TRANSMIT THIS VIRUS TO SOMEONE ELSE. Breaking the reproductive cycle of this virus by preventing it’s spread is the only way past this. Vaccination is the single most important tool we have to combat and deal with this pandemic.
For the majority of people, even with 1 or 2 chronic diseases (which is most Americans), the 10 day quarantine is adequate. As far as how long to quarantine if you have some kind of immunocompromising condition? Well that depends on how immunosuppressed you really are? Don’t make medical decisions by speaking with Dr. Google. Talk with your doctor, be it a primary care, oncologist, rheumatologist or whatever specialist who may be treating you. They may not have the exact answer since our knowledge about how to manage this virus and treat it evolves in the same way the virus itself evolves. They may need to consult with an infectious diseases specialist who is usually on top of the latest Covid-related information.
Stay safe and be well.
AC