Current guidelines recommend that adolescents receive two doses of human papillomavirus (HPV) vaccine while young adults and immunocompromised persons should receive three doses. The authors looked at the secondary responses of vaccine-elicited memory B cells (Bmem) in naive women who received three doses of the quadrivalent HPV vaccine. They found that there was actually a lower Bmem response rate and magnitude of Bmem responses to the third dose than to a booster dose administered at month 24. In addition, high titres of antigen-specific serum antibody at vaccination inversely correlated with Bmem responses. The intended purpose of additional doses/boosters is to stimulate Bmem to rapidly boost antibody levels and therefore these results suggest that the timing of the third dose is suboptimal and therefore a two-dose HPV vaccine should be considered also for young adults. Additionally, multidose vaccine schedules should be rationally determined on the basis of studies demonstrating Bmem responses.
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