With regard to risks of the covid19 vaccines, they are pretty similar to other vaccines. Here is the Australian government website listing those risks with more details.
Are COVID-19 vaccines safe?
The main risk that is > 50% of patients is a local reaction of pain and swelling at the site of the injection. May last more than a day in more severe cases.
I say to my patients that all vaccines activate your immune system which is the purpose of vaccines. And some folks (I would estimate between 10-25%) experience a mild cold-like illness for a few days after. Fever, aches, runny nose, headaches, those sorts of symptoms.
I also mention for all vaccines the very rare risk (I estimate less than 1 in a million) of severe allergic reaction. We ask folks to stay in our office for 15 minutes because if that were to happen we could treat them right away and almost all anaphylaxis occurs within that time frame.
With regard to the rare clotting risk associated with the Astra Zeneca and J&J vaccines (I estimate that to be around 1 in 250,000 but probably less) it seems to occur more in young females under the age of 50 and appears to be an autoimmune reaction and occurs within the first 3 weeks of the vaccine. In australia we only give Astra Zeneca to over 50s at the moment. Considering the risk of severe life threatening clotting with covid19 is much higher, countries with a lot of covid19 should absolutely still use the Astra Zeneca vaccine, especially if they don’t have other options. In Australia where we don’t have any covid19 at the moment, it is understandable to be more cautious.
For super rare immune reactions like Guillian Barre syndrome, there has been no data to suggest the rate of those vaccinated is any higher than the general population which is at risk of developing GBS through everyday colds and gastro infections.