ИМХО, на все такие вопросы по всему ЕС пока ответ один: лучше лететь через Грецию/Венгрию или уметь аргументированно объяснить свою позицию авиакомпании.
В случае с Бельгией объяснить свою позицию просто. У них явно указано:
Published 12.01.2022
1. Passengers are not allowed to enter.
This does not apply to:
- ...
- passengers with a COVID-19 vaccination certificate showing that they were fully vaccinated at least two weeks before departure. Vaccines accepted are AstraZeneca (Vaxzevria), Covishield, Janssen, Moderna (Spikevax) and Pfizer-BioNTech (Comirnaty);
- unvaccinated passengers younger than 12 years if accompanied by a parent with a COVID-19 vaccination certificate showing that the parent was fully vaccinated at least two weeks before departure. Vaccines accepted are AstraZeneca (Vaxzevria), Covishield, Janssen, Moderna (Spikevax) and Pfizer-BioNTech (Comirnaty);"
Аргументы тут:
https://www.iatatravelcentre.com/world.php