Dear All,
Apologies for my prolonged absence on the blog front but wanted to report out on some new information from the past few weeks and will try to get something out on a more regular basis as COVID rates unfortunately increase across the country. I am also getting more frequent calls / questions from friends/family/acquaintances on folks getting infected, being exposed, which is probably not a coincidence given the rising case counts and hospitalization rates being reported nationally. To those who do reach out to me w/ questions, feel free to keep doing so, I’m happy to help and it gives me an idea of the key issues to discuss in the blog.
Certainly, some things have changed since our last blog post in August, but in some respects, there hasn’t been as much change in my opinion than the daily news would indicate. We are still awaiting vaccine trial data, we do not have a silver bullet therapeutic, and masks remain our best defense against the virus. There are several promising things under development, and I anticipate more breakthroughs over the coming months but the fundamentals have not changed significantly since August.
One area that has seen some recent new evidence and is worth discussing is around the possibility of re-infection. Specifically, whether it is possible to contract COVID-19 a second time after clearing an initial infection.
We know that antibody levels wane over time and are generally undetectable 3-9 months after infection. There are outliers but this is a reasonable range that will apply to many people. On a personal side note, many of you know that I contracted COVID-19 back in March of 2020. I participate in a research trial where my antibody levels have been checked monthly since my infection. I was notified in August (~5 months later) that my antibodies became undetectable. This is not surprising but confirms that most of us who have had an infection will lose our detectable antibodies at some point.
What we don’t know is whether the immune system generates memory B-cells and T-cells that could stay around in the body and potentially confer some amount of protection if you are re-exposed to the virus. The jury is still out on this question, but what we did learn this week is that it is possible to be re-infected a second time with clinically significant virus.
Last week, The Lancet published a case study of a 25 year old man in Nevada with no known medical problems or immune deficiencies that has now tested positive for a 2nd time with a new COVID-19 infection.
The quick back story is he tested positive back in April 2020 and subsequently had 2 negative PCR tests following his initial positive test after recovering. 48 days after the initial positive test he again tested positive for COVID-19. Scientists analyzed his initial specimen and 2nd infection and found significant genetic differences in the strands of virus indicating he was likely re-infected as opposed to this being persistence of his initial illness. Notably, his clinical symptoms were worse in his second bout where he required oxygen support and hospitalization before recovering.
Now before you hit the panic button, recognize this is a case study of one person in the United States when we’ve had over 8 million confirmed cases. It is reassuring that cases such as the one described above seem to be infrequent and we haven’t read about thousands of repeat infections with more significant symptoms in the 2nd infections. Conversely, since testing has been limited since the start of the pandemic and we’re only ~7 months in, it is impossible to know the true rate of reinfection. Reports of re-infection have been published from other countries some of which are showing milder disease the second time around and some showing worsening disease. The point is not to over-index on one case, but the case study does bring out some new conclusions that had been more uncertain to date:
1) It is possible to be re-infected a second time. This is more or less indisputable but the frequency of re-infection and the frequency that re-infection leads to a worse disease course the second time around remains unknown.
2) Herd immunity will not work from natural infections alone. This is probably not surprising to most but just in case your plan was to rely on enough people becoming naturally infected to promote long-term immunity is a doomed (and deadly) strategy. Herd immunity will require vaccines which will hopefully be available soon. Sadly, I continue to see articles and opinions in mainstream publications suggesting a herd immunity approach and am disappointed that these theories continue to get widespread attention.
3) Those who have already had COVID-19 should continue taking reasonable precautions to prevent the risk of re-infection and prevent the risk of asymptomatically transmitting to the virus to others. While it is possible the risk of re-infection may be lower as compared to someone who has yet to be exposed, you should not feel invincible post-infection.
In our next blog, I will review the latest in treatment updates including what we know about steroids, remdesivir, and monoclonal antibodies, all of which, have gotten some degree of attention over the past few months.
In the meantime, be well and stay safe,
Harry
Click here to subscribe to future posts