The COVID-19 baseball game continues: Delta comes to the plate
I am going to make this editorial short and sweet. Last month, I wrote at some length that we appeared to be in the eighth inning of the baseball game that is COVID-19, looking longingly at the end and victory. Things were looking good — and why not? Case rates were plummeting and we as a nation were reopening.
I did say, however, “while the game is getting near the end, there is still a lot of time left to score more runs in prevention and treatment, as well as opportunities to blow the lead. We need to close this out for sure.” I never thought I would actually be so prophetic, but here we are, just 1 month later and in serious danger of not only blowing the lead but losing the game for lack of execution.
The enemy is the delta variant and it’s nasty. We are seeing a surge throughout the country and while vaccines are holding the line at preventing serious illness and hospitalization, breakthrough infection is a reality. Let me share with you a few delta facts culled from a variety of online (grey literature) and prepublication sources.
Delta has many tricks to evade our immune defenses. First, delta has the capacity to replicate far faster than the originator strains of SARS CoV-2. In fact, patients with delta have 1000 more times the viral load in their respiratory tract when compared to previous strains. As a result, the incubation phase is far shorter — at approximately 4 days (3 to 5) compared with 6 days from earlier viral strains. This means people are infected faster and have the capacity to infect more people in the preclinical phase of the disease.
Finally, what about our vaccine protection? To me, this is clearly a work in progress but there are some alarming signals. While it appears that our mRNA vaccines are protective against serious outcomes (ie, hospitalization, ICU and death) in the general population, breakthrough infections are real. While the data on this have varied, recent reports from the leading vaccine-covered country in the world (Israel) have suggested that protection from any delta infection may be less than 40% for mRNA vaccines! Finally, recent data from Ontario, Canada, has exquisitely documented that delta has increased virulence, especially for the unvaccinated. All of this is sobering and even more so for our immunocompromised patients.
In another important development, the COVID-19 Global Rheumatology Alliance has launched a new initiative to track breakthrough COVID-19 cases after vaccination. I can’t think of a more important study right now to help assess the risks our patients are experiencing. I implore all of you to register your patients for this new investigation so we can all learn together.
So, to sum up: Hold the line, vaccinate everyone and wear masks until the case rates fade asymptotically to zero. Act like our lives and the lives of our patients depend on it. Share your own impressions on where we stand at firstname.lastname@example.org or email@example.com.
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- Leonard H. Calabrese, DO, is the Chief Medical Editor, Healio Rheumatology, and Professor of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, and RJ Fasenmyer Chair of Clinical Immunology at the Cleveland Clinic.