Mon 2021-Jul-19

COVID-19 Vaccination is Better Than Natural Immunity

Tagged: COVID / JournalClub / MathInTheNews / PharmaAndBiotech / Politics / Statistics

Periodically I meet people who think “natural” immunity from having had COVID-19 is somehow better than being vaccinated. A new Israeli study plumbs the depths of just how wrong that is.

“Natural” immunity

People just get hypnotized by the word “natural”, as though it were synonymous with “good”. As we’ve explored before on this crummy little blog that nobody reads, natural immunity is generally inferior to vaccination:

  • First you have to go through the harrowing experience of having COVID-19, avoid long-term damage to organs (including brain damage!), and not be long-term disabled. You also might use up hospital beds, ICU beds, and ventilators in the meantime, meaning someone else will die from the lack thereof.
  • Then, you get immunity of approximately 83% efficacy, whereas an mRNA vaccine will get you something around 95% with way less trouble. (Both figures are for the “classic” SARS-CoV2 virus; a bit lower for the new Delta variant).

So the vaccine gets you better immunity, faster immunity, and safer immunity than the “natural” immunity. You really have to be hypnotized to choose “natural” here.

What about antibody levels?

Israeli study: antibody levels from vaccination better than convalescent A recent Israeli study by Shapira, et al. [1] on the medRχiv preprint server (not yet peer reviewed) tells us about the difference in antibody levels between convalescent patients who have suffered through COVID-19 vs those who have received the Pfizer/BioNTech mRNA vaccine.

And it’s not just a little study: because nations like Israel have absolutely universal health care systems with uniform databases (unlike the rather backward American system), they can do all sorts of good stuff. Here, for example, the study authors compared blood samples from $N = 26{\small,}170$ patients. Of those:

  • 13.4% had gotten the Pfizer vaccine,
  • 6.3% were recovering from symptomatic, PCR-verified COVID-19, and
  • 80.5% were asymptomatic but found in routine checkups.

Their age ranges were quite wide, from infants to the 80s-90s.

Israeli study: Violin plot of distribution of antibody levels in convalescent vs vaccinated patients Israeli study: Antibody levels by age, comparing natural vs vaccinated patients The key result is Figure 1: a violin plot of antibody levels in asymptomatic unvaccinated (orange), recovering symptomatic (light blue), and vaccinated patients (dark blue). If you’ve never seen a violin plot before, here’s the trick: the antibody level is on the vertical axis, the horizontal black line in each “violin” is the median, and the width gives you an idea of the probability distribution of the antibody level.

The brute-force conclusion: Vaccinated patients have a median antibody level of about 4 times that of the poor souls trying to make do with “natural” immunity. Vaccination is better!

Figure 3 is also interesting: it shows the antibody levels as a function of age, for the 2 “natural” groups and the vaccinated group.

  • Especially for the young, vaccinated immunity is dramatically better.
  • But since for the old, COVID-19 is a life-threatening event and vaccination is not: it’s important to note that we oldsters can still get immunity better than from “natural” recovery with just a shot and no life threatening illness. It’s more like 1.5x better instead of the 4x better that the youngs get, but still it comes wihtout risk to ones life.

The other brute-force conclusion: Vaccinated patients, across all age groups, are better off than the “natrual” immunity of convalescent patients.

The Weekend Conclusion

Look, just get vaccinated, ok?

You know it’s the right thing to do. Do it for yourself, for your family, for your neighbors, for your country, for humanity, and for not breeding more variants! It really couldn’t be more clear.

Notes & References

1: G Shapira, et al., “Antibody response to SARS-CoV-2 infection and BNT162b2 vaccine in Israel”, medRχiv, 2021-Jul-07.

Published Mon 2021-Jul-19

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