Acquisition of HIV by Kenyan Sex Workers Prevented by Genital IgA and Systemic T Cell Proliferation. Obviously, there are many problems to solve in attempting mucosal immunization. One approach is to mix routes of administration, for example priming with oral vaccination and following with parenteral boost. Moreover, it is not impossible to consider mixed intranasal and intrarectal administration to immunize both the genital and gastrointestinal tract. Aerosol administration of HPV vaccine has been reported to induce IgA secreting cells in the genital tract , and there is recent work suggesting that sublingual administration of antigens may be a way around compartmentalization of mucosal immunity  (see table 7).
Plotkin Journal of the International AIDS Society 2009 12:2 doi:10.1186/1758-2652-12-2