Social isolation is where you do not interact socially with others; whereas loneliness is an emotional state that arises from not having the desired sufficient meaningful connections with others. During COVID-19 lockdown, the Social Wellbeing Agency published an excellent short report on the difference between loneliness and social isolation.
Using responses to the General Social Survey 2018, they prepared a visualisation of loneliness versus social isolation to show which demographic groups are more likely to be social isolated and/or lonely (see Figure 1 below). Seniors are not shown in the Figure but are off the chart in the top left quadrant.
Published with permission of the Social Wellbeing Agency