Question: is this a 2) strong advice, 1) weak advice 0) no advice?

This result is lower than those obtained in 2 recent Italian studies that showed a proportion of seroprotected subjects vaccinated in infancy and adolescence of nearly 77% and 88% respectively, after similar period since HBV vaccination.10,20 However, previous studies have reported that 40–60% of subjects vaccinated in infancy had a seroprotective ant-HBs level after 15–20 y since vaccination, meanwhile the prevalence rise to 85–90% in those vaccinated in adolescence after 10 y since vaccination.21,22 The immune response in subjects vaccinated during infancy showed a physiological decline in terms of anti-HBsAg antibody concentrations, a well known phenomenon already reported.18 The antibody concentations decline observed in our study didn't impact on the protection of vaccinees against HBV, thanks to the immunological memory acquiered with the infant immunization course. 
user
This is no advice
assistant