How will we have a third wave?

[lebigface]

Just wondering if someone could explain this to me. I keep seeing talk in the media of scientists warning of a possible third wave. I am wondering how this would happen with the amount of people who've now had the vaccine?
If the vaccine reduces the chance of hospitalisation and death surely we can avoid it?
Is this to do with getting both doses of the vaccine?

Appreciate everyone's answers thank you all, this has really helped me get my head around it.

@Wellbythebloodyhell
That's interesting about second doses. Why do you think that is?

@lebigface

Appreciate everyone's answers thank you all, this has really helped me get my head around it.

@Wellbythebloodyhell
That's interesting about second doses. Why do you think that is?

Most are put off by the side effects of the 1st vaccine making them ill for a few days afterwards (from both AZ and Pfizer ), there are also some that are under 40 having 2nd AZ who are holding out for a Pfizer being offered as a 2nd dose instead of AZ , who knows if that will ever be an option if there wasn't a severe hospitalisation reaction to the 1st dose?? 🤷‍♀️