When the individual gB genotypes were analysed separately the 1st phase decline in gB1, gB2 and gB4 infections was significantly correlated with the log decline at day 21 (r = 0.32 (p = 0.02); r = 0.45 (p = 0.04); r = 0.67 (p = 0.02) respectively) whereas the same analysis for gB3 failed to reach statistical significance (r = 0.22; p = 0.28). This evidence concerns the gene GABBR2 and infection.