I'm 65 now so should I request the extra-strength flu shot? What about pneumonia and shingles vaccines?; Would the amino acid L-lysine be effective in curing or preventing covid by inhibiting arginine which is needed for viruses to replicate?; My tap water is considered hard. What does this mean for my health? Is there any harm in drinking hard water?; Study: Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections.