Mouthwash with Carrageenan as an active ingredient

Mouthwash without Carrageenan but similar in colour, taste, and "mouthfeel" to the experimental mouthwash

15 - 20 ml of mouthwash to be gargled vigorously for 30 to 60 seconds daily (morning and night) as an adjunct to regular toothbrushing, and before and/or immediately after sexual activities.

This will be measured by the total number of participants recruited into the study. The investigators intend to recruit 40 participants. Recruitment rate will be calculated as number of participants per month.

The proportion of individuals who enrolled into the study but left before the end of the study will be documented.

This will be calculated as the proportion of participants who completed the study and complied with the mouthwash use regimen.

This will be calculated as the proportion of participants who completed the study and complied with the bi-weekly self-sampling procedure

Qualitative and quantitative assessment will be used to evaluate participants' experience with the RCT through the follow-up questionnaire and an exit question. Participants will be asked to rate their satisfaction with the study procedure on a scale of 1-10 (10 being the highest satisfaction level). This will focus on level of satisfaction of the participants with mouthwash use around sexual activities and the level of satisfaction of the participants with the biweekly self-sampling.

The mean pain score (for any pain ascribed to the mouthwash e.g., burning mouth, recurrent aphthous stomatitis e.t.c.) measured on the VAS (1-10; 10 being the worst pain) will be recorded.

Time to type-specific oral HPV infection will be recorded for participants with negative type-specific oral HPV status at baseline

Time to type-specific oral HPV clearance will be recorded for participants with positive type-specific oral HPV status at baseline