In Israel, real-world evidence on VOCs and vaccine protection: Mainly, B.1.351 enriched in infected vaccinated individuals, but this is offset by lack of ability of this variant to spread.
https://www.medrxiv.org/content/10.1101/2021.04.06.21254882v1
@taliakustin @noamharel8 @ranbalicer @TelAvivUni
More details:

1. We wanted to test what type of variant infects the very few vaccinated individuals who go on to become infected with SARS-CoV-2. To this end, we generated a case-control cohort: every vaccinee was matched with a non-vaccinated individual infected with the virus

2. Two categories interested us: (i) those fully immunized, 7+ days post the second dose of the Pfizer/BioNtech vaccine, (ii) those partially immunized, between 14+ days after the first dose and before 7 days after the second dose.

3. All in all – most infections in both categories were from the “British” variant B.1.1.7. However, we noted 8 cases of infection with the “S.A” variant B.1.351 in fully immunized individuals, as compared to only 1 infection in the control (non-immunized).

4. Furthermore, focusing on the partially immunized, we noted more breakthrough by the “British” variant”. We think this might explain why during the early stages of the vaccination rollout in Israel, it took a while till vaccination effects were noted and cases began to drop

5. To summarize: we see evidence for reduced vaccine effectiveness against the British variant, but after two doses – extremely high effectiveness kicks in. We see evidence for reduced vaccine effectiveness against the S.A. variant, but it does not spread in Israel.

6. We think that this reduced effectiveness occurs only in a short window of time (no B.1.351 cases 14+ days post 2nd dose), and that the S.A. variant does not spread efficiently. Thus, even more of a reason to get vaccinated and drive down cases to zero!