Recently Released British Study - Vaccine vs Natural Immunity with Delta Variant

Windy City Ag

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12:41p, 8/31/21

AG

Saw this from the twitter feed of Shane Crotty at the LaJolla Institute. The Limeys just released a pretty thorough study regarding the effectiveness of vaccines and natural immunity against Delta.

Takeaways are partly what we have already heard . . .Delta reduces the efficacy of both vaccines and natural immunity. Breakthrough cases exhibit the same peak viral load between vaccinated and unvaccinated but the vaccinated tend to recovery very quickly after a 5 day or so period whereas the unvaxxed do not.

The different takeaway was that there was not difference between prior infection natural immunity and MRNA vaccine induced immunity. That contradicts the line out of Israel that has made headlines.

They also note the combo of prior natural immunity plus vaccine booster produces the best line of defense.

https://www.medrxiv.org/content/10.1101/2021.08.18.21262237v1

Quote:
A single dose of the mRNA-1273 vaccine had similar or greater effectiveness compared to a single dose of BNT162b2 or ChAdOx1. Effectiveness of two doses remains at least as great as protection afforded by prior natural infection. The dynamics of immunity following second doses differed significantly between BNT162b2 and ChAdOx1, with greater initial effectiveness against new PCR-positives but faster declines in protection against high viral burden and symptomatic infection with BNT162b2. There was no evidence that effectiveness varied by dosing interval, but protection was higher among those vaccinated following a prior infection and younger adults.

With Delta, infections occurring following two vaccinations had similar peak viral burden to those in unvaccinated individuals. SARS-CoV-2 vaccination still reduces new infections, but effectiveness and attenuation of peak viral burden are reduced with Delta.

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NASAg03

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1:31p, 8/31/21

They define natural immunity as a positive PCR test or anti-body test > 90 days. They are comparing that to full (two dose) vaccine immunity > 14 and 21 days. Not an even comparison IMO. Regardless, the data shows natural immunity to delta is better than alpha, and on par with the full vaccination for either of their vaccines.

This reaffirms that vaccines shouldn't be pushed on those with naturally immunity, and those people shouldn't be treated as second-class citizens.

If someone wants even more protection, that should be their choice.

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Zobel

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In reply to NASAg03 • 1:55p, 8/31/21

AG

They broke positive episodes into 90 day periods, so they excluded people within the 90 day window from being double counted as a current episode and previously infected. Prior positivity was either previous PCR or positive S antibody >90 days, or two consecutive N positive antibody measurements >42 days.

The paper says -

Quote:
Only the first test-positive visit in each new PCR-positive infection episode starting after 1 December 2020 was used, dropping all subsequent visits in the same infection episode and all negative visits before the first time a participant could be considered "at risk" for a subsequent new positive episode (as defined above), to avoid misattributing ongoing PCR-positivity to visit characteristics and immortal time bias respectively. Primary analysis included all new PCR-positive episodes.

I'm not sure I understand your objection?

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Kyle Field Shade Chaser

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In reply to NASAg03 • 2:17p, 8/31/21

AG

I ended up getting the "extra line of protection" even though I had natural immunity. I definitely feel like unvaxxed naturally immune are treated in the same category as unvaxxed no immunity. I think it is wrong. The evidence is becoming more clear though it would be nice to have more....

That said, I decided to get the pfizer for the additional benefits on top of natural immunity. I have had side effects from the flu vaccine, so I'm a little nervous. So far not side effects other than a sore shoulder.

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NASAg03

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In reply to Zobel • 3:11p, 8/31/21

It's good data and they present it well. My only objection is that the infection windows are greatly different. The paper shows that immunity wanes over time, regardless of type.

But they aren't comparing the same time windows / response since immunity. You could theoretically be comparing immune response between someone that has covid 1 year ago with someone who's been vaxxed 15 days ago. Way to many variables in there.

This is a good start, but a better study will better exclude variables.

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Zobel

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In reply to NASAg03 • 3:32p, 8/31/21

AG

Ah yes, I agree. The main limitation is they're not tracking anything with respect to time. The Israeli study that found such a big difference between vaccine and prior infection had a similar problem but not so apparent - their prevalence rates in the prior infection group changed a lot within the study.

I think this is a really difficult question to answer, and even when we do start to figure it out the answer is probably going to be a lot more complicated than this one or that one is superior.