Thread by @c0nc0rdance

In light of ongoing comments from @BretWeinstein partisans, I'd like to talk about "perfect vaccines" & emergence of vaccine resistance. (THREAD)

I've put together a spreadsheet of existing vaccines with efficacy, coverage, year of 1st use & subunit vs. whole pathogen, notes.

8 points to make:

1. Out of 23 approved vaccines, vax resistance emerged in only 2 since 1853.

Pertussis vaccine resistance (pertactin negative) emerged 76 years after it was 1st used.

Hepatitis B vaccine escape emerged about 8 years after 1st use: I'll talk about it later.

2. No vaccine has ever been discontinued for vax resistance.

Both of those vaccines are still in use because they still prevent disease. Pertussis is likely acquiring resistance against 1 of 4 immunogens (pertactin) in the vax, but no resistance found in the other 3.

HepB escape mutants are still incapable of causing disease in vaccinated individuals, so they have no clinical significance & low potential for spread at present, *40 years* after escape mutants were first detected.

3. Vaccine escape mutants are also *immune escape* mutants.

Vaccination mimics optimal adaptive immunity, so selection pressure is already acting on epitopes (bits of the pathogen's proteins) that generate neutralizing antibodies.

Hep B vaccine escape mutants found in *unvaccinated* Hep B patients. Enrichment of vaccine escape in Hep B greatly enhanced when recombinant vaccine is supplemented with anti-serum/HBIG & anti-viral nucleosides mutagens, both of which are standard in pre-exposure protocols.

4. None of the known escape mutants are more virulent, just resistant to the full efficacy of existing vaccines.

5. Out of 23 vaccines, 16 have whole pathogen version; 14 have a subunit/protein/carbohydrate isolate as active immunogen.

Stop wringing your hands about single protein targets: HiB vax is 84% effective, has 70% global coverage, has been in use since 1977 w no resistance. (and it works beautifully)

6. Out of 23 vaccines, 14 have global coverage <80% and 12 have efficacy of <90%.

We'll approach numbers well above that for coverage and average efficacy before long, making SARS-CoV-2 better than most over the last century.

A "perfect vaccine" doesn't exist. All SARS-CoV-2 commercial vaccines have properties that put them in the same range as vaccines that have been in use for over a hundred years.

7. There are already 11 knowns SARS-CoV-2 variants of varying virulence without vaccine selection. Stopping their further mutation or the emergence of entirely new variants is what public health professionals are concerned about.

8. The solution, near term, is to reduce the reservoir of generated mutants by increasing vaccination & NPI barrier methods.

The solution long-term is to develop multivalent vaccines that increase the hurdles that must be overcome to escape.

In conclusion, vaccine escape events are extremely rare, occur after decades & best way to combat them is reducing global viral load.

There's nothing about any of the current SARS-CoV-2 vaccines that makes them higher risk or exceptional from an immunological perspective.