Should there be three dots instead of four?

I think it is a matter of "writer's discretion". Personally, I would have used one.

That's a question of style. I would use three, with spaces between them, but there is no rule here.

Thanks, Ponderer and Setanta.

Four dots are correct here. One is a period and should be separated from the other dots. In fact there should be spaces between each of the dots.

“AIDS is still a massive problem. . . . It is a pressing issue

Thanks.

Three dots for an ellipsis is to indicate that the remainder of the sentence is a continuation of the sentence prior to the ellipsis.

Four dots ellipsis means that the sentence is longer than what's written here but the person doesn't want or need to completely write it out fully. The fourth dot indicates that the sentence has come to a full dead stop. The capitalization of "It" means a new sentence has started (and is completely separated from the previous sentence in the quote).

At least this is how the Chicago style Manual defines the process of the four dot ellipsis. For me? It's the correct way.

According to the Chicago Manual of Style, there aren't supposed to be spaces between the periods.

Which takes us back to the original point, which is that it is a matter of style.

Three dots is called "ellipsis" which is a figure of speech where something is omitted. I am not aware of any rule specifying the number of dots.