The following vaccines (including mix-and-match vaccines) are recognised: BioNtech/Pfizer, AstraZeneca, Johnson & Johnson, Moderna, and Sinopharm. (Please be aware that this only applies to entering the country. Sinopharm is not valid for entering hotels, restaurants etc. within Austria.) You are considered "vaccinated" starting on the 22nd day after your first dose, lasting for 3 months from the vaccination date. After the second dose, the validity extends for another 6 months (i.e. the vaccination is then valid for 9 months total from the first vaccination date). Vaccines that only require one dose are valid from the 22nd day after that dose and for 9 months from the vaccination date. This also applies to people who have had COVID before and received only one dose of any vaccine.
Ds and I fly into Vienna enroute to Prague in December. The above is what I found on the 9 month vaccine requirement. I received my second dose last week and ds receives his on Sunday, so we should both be okay. However I see that Prague isn't on the list of countries permitted to enter Vienna without quarantining -- hopefully this will change. I don't suppose it matters currently as we fly from Canada, which isn't currently on Vienna's permitted list of countries either (I expect this to change soon). I am really looking forward to our Christmas Market European tour, so I hope it happens.