1:1 texture application

I have a texture with a font in it (sort of glfont system), I would like to use it as is, same size as in the texture, so no mipmapping needed. The problem is that even if I use a GL_NEAREST, using 2D coordinates, and with a simple

#version 330 core
layout (location = 0) in vec3 aPos; // the position variable has attribute position 0
out vec4 vertexColor; // specify a color output to the fragment shader

void main()
    gl_Position = vec4(aPos, 1.0); // see how we directly give a vec3 to vec4's constructor
    vertexColor = vec4(0.5, 0.0, 0.0, 1.0); // set the output variable to a dark-red color

with the buffer sent to “aPos” calculated with ( (vx - screen_width/2)/(screen_width/2) , (vy - screen_height/2)/(screen_height/2) ,0.0f)

the texture is still filtered, not “aliased” like in the original texture, so the text is not as readable as before

Could someone help me on this, please?