Is there any chance that the pfizer or moderna vaccine could cause health issues down the line? (after more than one year)such as blood clots, heart issues etc how can we be confident when no long term studies have been done?

You're correct in that we don't have real long term studies yet, but after some months, at least anecdotally, many of us haven't heard of adverse reactions after over 7 months amongst our or our colleagues' patients and relatives who received both shots. I strongly advocate getting vaccination with the rna vaccines,at least. I feel people under 40 or pregnant should avoid the AstraZeneca vaccine.