“The general consensus among health experts and government agencies is that the elderly and those with underlying health conditions, who are at a greater risk of severe illness and death from COVID-19, should get immunized first.“
Source: https://globalnews.ca/news/7468036/canada-coronavirus-vaccine-rollout/amp/
If the public health officials follow through on vaccinating the most vulnerable first, followed by the health-care workers etc, and if the vaccines work as hoped (that is, prime the recipient’s own immune system to be able to recognize the SARS-CoV-2 virus and thus ward off illness and severe illness if later exposed to the actual virus) a visit to a vaccinated grandparent should be safe, eventually.
We certainly hope that is eventually the case, because until then we all need to continue to rigorously follow the public health measures that are meant to reduce transmission (physical distancing from everyone outside your household/bubble, hand washing after touching surfaces, masking to limit droplet spread, minimizing exposure/transmission as much as possible by staying home if feeling unwell, and limiting in-person shopping to essential items.)
If/when there is an effective vaccine, your tactics can change to protecting yourself by getting your vaccination. It won’t matter if someone you know chooses not to get vaccinated as they can’t harm you after you are vaccinated, nor can they harm a vaccinated senior by their own personal choice to reject an available vaccine.