There are unlimited opportunities for COVID-related questions. You can come up with them by yourself.
Just take a matrix of industry (pharma, public sector, etc.) and function (strategy, operations, etc.) and you can create your own cases very quickly. To illustrate, pick pharma and operations and you already got yourself a case:
'The client is a global vaccine producer and needs to distribute the new COVID vaccine to countries in Africa - how would you go about that?'
You need a bit of creativity but can come up with 100s of different cases in such a manner. You can also look at newspaper articles and reframe the headline into a case question.
I have created a few COVID-related McKinsey-like cases myself that I use with my coaching candidates these days.
However, that being said, I always recommend staying away from pre-learning solutions for specific cases or even industry frameworks. McKinsey has been aware of the industry and functional frameworks for years and the cases you will get have very little to with such frameworks and at best, hamper your creativity to come up with insightful solutions and recommendations.
Try to learn an approach that works regardless of case or context. I can help you with that.