Pandemic H1N1 IgG levels in healthcare workers

Editor, the recent report on pandemic H1N1 IgG levels in healthcare workers is interesting (1). Çifci et al. found that “the IgG antibody level was higher in the vaccinated healthcare workers than among the unvaccinated healthcare workers (1).” The implication of this important finding should be discussed. Whether this finding shows the effectiveness and usefulness of vaccination among healthcare workers or not should be further considered. First, IgG antibody might be due to natural infection or vaccination.