Dawn of Delta
Greetings friends! I’ve missed you! I took a much-needed break from public posting while the pandemic slowed, but now things are picking up again.
What’s going on with Delta?
COVID-19 variants are now labeled using letters from the Greek alphabet. They are named in sequence but are categorized by “variants of interest” (identified as having significant mutations from other known strains, but NOT widely circulating) and “variants of concern” (spreading rapidly and broadly with significant mutations).
Delta has a combination of many known mutations; the effects of some mutations are still being determined. Here’s what we do know –
• Delta is 200% more transmissible than the original strain
• Delta likely causes more severe illness and death, primarily in those not vaccinated
• Vaccine efficacy for TWO DOSES of Pfizer and Moderna is still strong both also protecting against severe illness and death.
Healthcare workers are being sent to assist in Missouri. COVID-19 patients are asking for the vaccine before they are intubated – clearly too late. St. Louis is about to re-enact a mask mandate.
LA, FL, and AK are also on fire. The US experienced a 171% increase in cases over the last 14 days.
Which vaccines are working?
Vaccine efficacy is holding up well, though not for Astra Zeneca (not approved in the US) and possibly less protection provided by Janssen/J&J. There are links to several studies at the end of this post.
It is challenging to determine exact efficacy given the variables in a situation. A strong study will involve thousands of human subjects with known exposure in a natural environment. Those studies take time which is why the impact of a new variant is not immediately known. Regardless, Pfizer and Moderna work, more info will be available on J&J soon.
What about boosters?
The CDC and FDA mutually determined a booster dose is not indicated right now. An excellent recent study showed the vaccines may last even longer than initially expected mainly because of the high initial immune response. This could change if J&J shows reduced efficacy against Delta.
What should we do differently?
I recommend scaling back activities involving large gatherings, travel, or mass events. We will NOT attend the state fair. I am not traveling for work. We are traveling where we can drive for the foreseeable future. We will use masks again when instructed or we feel the need. All of this despite my family being 100% vaccinated.
If you are not vaccinated yet I strongly encourage you to read this article - https://yourlocalepidemiologist.substack.com/.../vaccine.... If you are not yet vaccinated, I frankly have no more patience for you. There are ZERO reasons to delay any longer. You are putting your family in danger and hurting our progress in this fight.
In closing, I am concerned about this most recent surge. The ability of the virus to cause another wave now with 50% of the population vaccinated means this is far from over. However, I worry much more about the fall season than the present.
I highly recommend this site run by an epidemiologist in TX for rapid fire information - https://yourlocalepidemiologist.substack.com/archive.... You can subscribe to her emails and she cites information throughout her posts.
References:
• Pfizer, Moderna and AZ efficacy by Variant
https://www.medrxiv.org/con.../10.1101/2021.06.28.21259420v1
• Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection | Nature Medicine - https://www.nature.com/articles/s41591-021-01377-8
• Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant | NEJM - https://www.nejm.org/doi/full/10.1056/NEJMoa2108891...
• Heterologous ChAdOx1 nCoV-19 and mRNA-1273 Vaccination | NEJM - https://www.nejm.org/doi/full/10.1056/NEJMc2110716...
• Good summary - Vaccine Table Update: May 20, 2021 - by Katelyn Jetelina - Your Local Epidemiologist (substack.com) - https://yourlocalepidemiologist.substack.com/.../vaccine...