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Zitat von TPZ

Hier hat man dann auf/ab S. 16 die wissenschaftliche Begründung der STIKO.

Auf den ersten kurzen Blick darauf interessant:
Auch wenn derzeit noch keine Ergebnisse zur Wirksamkeit der Impfstoff-induzierten T-Zellimmunität gegenüber der Omikron-Mutante vorliegen, deuten die Antikörperdaten auf einen verringerten Impfschutz nach abgeschlossener Grundimmunisierung hin.
Laborstudien zeigen außerdem, dass die Neutralisationsfähigkeit von Seren geimpfter Personen gegenüber der Omikron-Variante durch eine Auffrischimpfung zumindest teilweise wiederhergestellt werden kann.

Ich hoffe mal, dass sie schnell zu Daten in Punkto T-Zell-Immunität kommen (wobei es die eigentlich bereits geben müsste )...

Bei 23 Personen, die an dieser - zweiseitigen - wissenschaftlichen Begründung gearbeitet haben, erwarte ich eine deutlich umfassendere und gründlichere Auseinandersetzung mit der Studien- und Datenlage.
Da kann man nur froh sein, dass es SARS-CoV2 und nicht irgendein noch gefährlicheres Virus ist mit dem wir es zu tun haben.

Nicht berücksichtigt wurden u.a.
Janssen/Omikron
https://www.medrxiv.org/content/10.1....26.21268380v1
"Despite extensive neutralization escape against Omicron, 70-80% of the T cell response is preserved. The limited effect of Omicron’s mutations on the T cell response suggests that vaccination or prior infection may still provide substantial protection from severe disease."

Janssen/BNT/Delta
https://www.biorxiv.org/content/10.1...707v1.full.pdf
"As compared to the neutralizing activity in Ad26.COV2.S elicited immune sera against the B.1 virus, neutralizing activity is more strongly reduced against the Beta (B.1.351) and Gamma (P.1) variants than against the rapidly spreading Delta (B.1.617.2) variant. These results are in line with recently published studies in which sera from subjects who received the Moderna, Pfizer‐BioNTech, or Oxford‐AstraZeneca COVID‐19 vaccines were tested for neutralizing activity against VOCs 7, 8. For all the vaccines, the reduction in neutralization titer was greater for the Beta (B.1.351) than observed for the Delta (B.1.617.2) variant."

Janssen/BNT/Omikron
https://www.medrxiv.org/content/10.1...634v1.full.pdf
"Ad26.COV2.S vaccination, there were substantially initial lower WA1/2020-specific NAb
responses at month 1, but these responses were more durable and persisted at month 8. However, minimal cross-reactive Omicron-specific NAbs were observed for both vaccines
(Fig. 1a), consistent with recent data in the absence of additional boosting...
Our data demonstrate that Ad26.COV2.S and BNT162b2 elicit broadly cross-reactive
cellular immunity against SARS-CoV-2 variants including Omicron. The consistency of these
observations across two different vaccine platform technologies (viral vector and mRNA)
suggests the generalizability of these findings. The extensive cross-reactivity of Omicron specific CD8+ and CD4+ T cell responses contrasts sharply with the markedly reduced Omicron-specific neutralizing and binding antibody responses."

Omikron-Daten aus den USA inkl. Booster (3x BNT oder 2x BNT + Janssen)
https://www.medrxiv.org/content/10.1...198v2.full.pdf
"Both heterologous “mix-and-match” Ad26.COV2.S boosting and homologous
BNT162b2 boosting increased Omicron-specific humoral and cellular immune responses in
individuals who were vaccinated at least 6 months previously with BNT162b2, although these
boosting strategies showed different immune kinetics"

https://www.mdpi.com/1999-4915/14/1/79/htm
"Overall, given that most of the experimental T cell epitopes known to be targeted in vaccinated and/or previously infected individuals (collectively, accounting for ~60% of the global population as of 25 December 2021 [22]) are unaffected by Omicron mutations, our preliminary analysis suggests that the effectiveness of pre-existing T cell immunity will remain intact. T cell responses alone, however, do not block infection and therefore do not prevent transmission. Thus, while the number of infections may rise considerably as a consequence of Omicron’s ability to evade antibodies"

Etwas zu neu (14.1.2022)
https://media.nature.com/original/ma...22-00017-z.pdf
"We report here that SARS-CoV-2 spike-specific CD4+ and CD8+ T cells induced by prior infection or BNT162b2 vaccination provide extensive immune coverage against B.1.1.529."

usw. usf. alles unberücksichtigt.

Letztlich bestätigen diese ganze Studien auch nur, was man aus den Daten zu Impfungen, Infektionen und Hospitalisierungen in div. Ländern ablesen/berechnen kann:
Schutz vor Infektionen sinkt und/oder ist gegen Omikron kaum vorhanden bzw. kann mit Boostern (kurzfristig) wieder auf Münzwurf-Niveau [1] erhöht werden, aber der Schutz vor schweren Verläufen ist stabil hoch (auch ohne Booster).

[1] https://www.medrxiv.org/content/10.1...966v2.full.pdf Studie aus Dänemark
"However, the VE is significantly lower than that against Delta infection and declines rapidly over just a few months. The VE is re-established upon revaccination with the BNT162b2 vaccine (54.6%, 95% CI: 30.4 to 70.4%)."