Fig 3. Correlation of anti-SARS-CoV-2 IgG levels and age of participants without evidence of prior infection who had received at least one dose of a vaccine.

Correlation between IgG levels and the age of participants in three age groups namely 18–45 years (A), 46–65 years (B), and > 66years (C) was performed with Spearman’s r-test. Dotted lines: positive cut-off values.