Some Adventist Vegetarian Diabetics™ have asked if the COVID-19 vaccines affect blood sugar. According to the resources I consulted (both online and with a Kaiser physician), the vaccine itself does not raise blood glucose.
However, if you experience mild to moderate side effects, the stress of that could potentially raise blood glucose. The advice is to closely monitor your blood glucose for the first 48 hours after getting the injection. Yes, this means sticking your finger more often! And stay hydrated.
Since information about COVID changes so rapidly, we are leaving it up to you, the reader, to do your own research of legitimate sources. However, here is the link to the CDC (Center for Disease Control).