09/08/2021
Thank you virologist, Dale Harrison! All of your work/explanations are so clear and informative.
IMMUNE PROTECTION FROM VACCINATION VS NATURAL INFECTION
A critical question regarding vaccination is how does it compare to immune protection after natural infection.
There are two general aspects to this question:
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1. How effective is the immune response?
2. How long does that immune response last?
Here, we're going to focus on just the 1st question. How good is the overall protection from vaccination vs natural infection?
A NEW STUDY
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A new study has just been published by a large Dutch research group that provides the best answers to date on the relative effectiveness of the strength of the immune response after vaccination vs. natural infection.
I've been closely following the research around this question and most of the work so far has been of poor quality with significant flaws in design or data analysis or significant confounding factors not addressed.
This paper is absolutely in a class by itself in terms of the thoroughness of the approach and the quality of the results. At least at this point...this paper is the Gold Standard on this question!
The paper is peer-reviewed and was just published Friday, September 2nd in the Journal Science...one of the most prestigious scientific journals in the world.
What the Dutch Study got right:
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What makes the Dutch study different is that it attempts to address almost ALL of the weaknesses generally seen in these sorts of molecular studies.
The key aspect is that they're looking at the neutralization of actual viruses. Specifically, looking at how well does that full range of antibodies produced after either natural infection or vaccination work against actual attacking active viruses.
Again, you might have a high level of antibodies, but they're incapable of binding to the virus, then they confer NO immune protection.
These are difficult experiments and require access to at least a BLS-3 high-level bio-containment facility to carry out all the validation studies.
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The other issue that's been long suspected is that the level of effective neutralizing antibodies produced after natural infection is strongly tied to the severity of the infection.
There have been indications that mild or asymptomatic versions of Covid produce little or no persistent immune response and no effective durable immunity.
This is fairly typical behavior seen during mild infections of similar upper respiratory viruses. So no real surprise that SarsCoV2 would be the same.
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To look at this effect, the Dutch study separated patients into three categories:
1. Those recovered from severe illness that required full hospitalization.
2. Those will less severe illness requiring medical care, but who were able to recover at home.
3. Those who had never been infected and received the full 2-dose round of the Pfizer vaccine.
All patients in the study were sampled 6-weeks after full vaccination or full recovery from infection. This is when antibody levels would be at the absolute peak.
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The researchers used a metric called ED50 that measures the median effective dosage of recovered antibodies needed to completely neutralize active viruses.
In addition, they looked at how the full range of antibodies produced by each patient neutralized not just the original Wuhan variant, but three other variants:
• B.1.1.7 (the UK variant)
• B.1.351 (the South African variant)
• P.1 (the Manaus variant from Brazil)
STUDY FINDINGS:
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The findings were quite interesting!
• The highest level of effective neutralizing antibodies was found in those who experience the most severe levels of illness and had required full hospitalization.
• Those who had less severe "at-home Covid" produced the lowest levels of effective antibodies (20% of which had NO effective immune protection after recovery).
• Those who were vaccinated produced high levels of effective antibodies - generally 10x to 100x greater than those recovered from "at-home Covid"
On average, vaccine-induced immune protection was comparable to immune protection after severe hospitalization.
And significantly higher than that seen after mild to moderate illness following recovery at home from natural infection.
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In addition, these differences were magnified when looking at effectiveness at neutralizing more recent variants!
All patients experienced a drop in effectiveness against newer variants, but those who recovered from mild to moderate "at-home" illness had significantly reduced immune protection.
So the virus is learning to escape NOT JUST vaccine-induced immune protection but is even MORE effective at escaping immunity after prior natural infection.
Again, NO surprise!
DELTA VARIANT
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The study was completed before the Delta variant was widespread, although the South African variant (B.1.351) included in the study is closest to the Delta.
The study shows that vaccine effectiveness held up quite well against the B.1.1.7 variant seen through the Spring and early Summer. Although, natural immunity after at-home Covid dropped significantly against the B.1.1.7.
This would indicate that the increased rate of infections and hospitalizations seen in vaccinated individuals with Delta is at least partially driven by reduced antibody neutralization against the new variant and NOT just by waning antibody levels.
Meaning that you've got fewer antibodies to fight Delta...AND those antibodies left are less effective at fighting the variant.
A double whammy!!!
But those with natural immunity (specifically after at-home Covid) are likely seeing an even more dramatic drop in antibody effectiveness based on what was seen in the study against the B.1.351 South African variant.
CONCLUSION
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• Vaccine immune protection has uniformly high levels of effectiveness against neutralizing actual virus.
• Natural infection has comparable levels of effectiveness, but ONLY if you had severe illness requiring full hospitalization
• Immune protection after natural infection is chaotic and ranges from non-existent to mildly effective at best.
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• Those who were vaccinated and showed the LOWEST level of immune protection had BETTER immune protection than the BEST protected patients after recovering at-home Covid!
• Natural immune protection after at-home Covid has dramatically reduced effectiveness against new emergent variants.
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So if you want to be as well protected as possible from Covid, either get vaccinated or spend a couple of weeks in the ICU on a ventilator...both will confer similar levels of protection!
Every single person will catch Covid repeatedly whether vaccinated or previously infected.
The difference being that vaccination and boosters have a FAR higher guarantee of giving you a fighting chance against the virus.
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Antibodies of convalescent COVID-19 patients and vaccine recipients show reduced recognition of SARS-CoV-2 variants of concern.
