There are lots of factors that determine your level of protection from Delta Variant.
Are you vaccinated?
If so, which one?
Have you had COVID already?
Did you have COVID and the vaccine?
Are you immunocompromised?
Will the booster shot give you more protection?
Since the Delta COVID Variant is still fairly new, there are still many questions.
After having a COVID infection, whether a mild or severe illness, most people appear to have some protection against SARS CoV 2 for about a year; this is based on a study published in Nature that looked at recovered patients. There’s also other research showing that vaccinating these people significantly substantially enhanced their immune response to the virus and gave them strong protection against variants of concern, such as the (B.1.617.2) delta variant. For example, researchers looked at immunity in a group of recovered adult patients 1 month and 6 months after their infection, and some of them even had a 12 months follow-up blood draw.
The first study had 149 participants who were considered to have recovered from COVID. About 10% were hospitalized with COVID. People were excluded from the study if they had long COVID. For example, they had ongoing or persistent shortness of breath, chest pain, fatigue, fever, or loss of taste or smell. Of the 149 people, 87 returned for the 6-month follow-up, and 63 returned for the 12-month follow-up. 41% ended up getting at least 1 dose of an mRNA vaccine an average of 40 days before the 12-month follow-up visit.
So what were the main takeaways from the study?
Compared with 6 months prior, those who were not vaccinated maintained most of their plasma antibodies against the virus’s receptor-binding domain (RBD). Also, their plasma, which contains antibodies, had similar neutralizing activity against a nonreplicating virus engineered with the SARS CoV 2 spike protein. Their memory B cells that produce anti-RBD antibodies were slightly lower than at the previous visit and evolved to produce a broader and more potent range of antibodies.
However, their plasma had less neutralizing activity against the variants B.1.1.7 (Alpha), B.1.351 (Beta), B.1.526 (Iota), and P.1 (Gamma), with the greatest loss of activity against the beta variant first detected in South Africa. Compared with unvaccinated participants, those who had received at least 1 dose of the mRNA vaccine had higher plasma anti-RBD antibodies and a nearly 50-fold increase in neutralizing activity.
So what’s going on here?
For those who’ve had COVID, vaccination boosts the memory antibodies that develop after infection, causing a more robust response.
We are still learning about the Delta Variant, with new studies coming out.
A recent study in France looked at recovered patients’ immunity against the delta variant. Specifically, they looked at unvaccinated health care workers. They appeared to have less protection against the delta and beta variants than alpha, about a year after they recovered from mild COVID. In this group, 88% had neutralizing antibodies against alpha, compared to 47% against delta variant.
But, for the recovered health care workers who had received 1 dose of either the AstraZeneca, Pfizer, or Moderna vaccines, they had a huge increase in protective antibodies against the Delta, Beta, and Alpha variants.
So the big takeaway here is that vaccinating person who had previous COVID will likely give them much higher protection against delta and other variants.
Weren’t they supposed to tweak the booster shot to accommodate the new variants?
As of right now, the booster shot will be the same as the 1st doses and not genetically tweaked to accommodate new strains such as the delta variant.
The booster’s job will probably be to simply boost the current immune system to get maximum protection against these covid variants. Until you have a variant escaping the vaccines, meaning lots of breakthrough infections that result in many hospitalizations and deaths, there likely isn’t a need to genetically tweak the current vaccine.
But of course, this can change with time if a new variant proves to escape the current vaccines.
Doctor Mike Hansen, MD
Internal Medicine | Pulmonary Disease | Critical Care Medicine
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