After 6 months of first jab and in front of Indian Delta-stamm's storm here, I voluntary went to clinic today and got revaccination booster by Sputnik V again.

I did it because S-spike antibody test week ago shows what my antibody level is just 25% above of minimal level needed for protection. Here everyone who wants to get boost may do it 6 months after first jab of first vaccination or recovery from COVID illness.