High human papillomavirus (HPV) prevalence in South African adolescents and young women encourages expanded HPV vaccination campaigns

Abstract

The objectives of the study were to investigate prevalence of cervical human papillomavirus (HPV) genotypes to inform HPV vaccination strategy in South Africa and to study factors associated with HPV prevalence. Sexually active, HIV-negative women, aged 16-22 years recruited from Soweto (n = 143) and Cape Town (n = 148) were tested for cervical HPV and other genital infections. Overall HPV prevalence was 66.7% (194/291) in young women. Cape Town women were more likely to have multiple HPV infections than the Soweto women (48.0%, 71/148 versus 35.0%, 50/143 respectively, p = 0.033) and probable HR-HPV types (34.5%, 51/148 versus 21.7%, 31/143 respectively, p = 0.022). The most frequently detected HPV types were HPV-16 (11.7%), HPV-58 (10.3%), HPV-51 (8.9%), HPV-66 (8.6%), HPV-18 and HPV-81 (7.6% each). HPV types targeted by the bivalent HPV vaccine (HPV-16/18) were detected in 18.6% (54/291) of women, while those in the quadrivalent vaccine (HPV-6/11/16/18) were detected in 24.7% (72/291) of women; and those in the nonavalent vaccine (HPV-6/11/16/18/31/33/45/52/58) were detected in 38.5% (112/291) of women. In a multivariable analysis, bacterial vaginosis remained significantly associated with HPV infection (OR: 4.0, 95% CI: 1.4-12.6). Women were more likely to be HPV positive if they had received treatment for STI during the past 6-months (OR: 3.4, 95% CI: 1.1-12.4) or if they had ever been pregnant (OR: 2.3, 95% CI: 1.1-5.5). Compared to women who reported only one sexual partner, those with increased number of lifetime sex partners were more likely to have HPV (4-10 partners: OR: 2.9, 95% CI: 1.1-8.0). The high prevalence of HPV types targeted by the nonavalent HPV vaccine encourages the introduction of this vaccine and catch-up HPV vaccination campaigns in South Africa. The high burden of BV and concurrent STIs also highlights the need to improve the prevention and appropriate management of sexually-acquired and other genital tract infections in South African youth.

Fig 1. The prevalence of human papillomavirus genotypes according to study site in adolescents and young adults.

HR-HPV types included HPV-16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58 and -59; probably or possible HR-HPV types included HPV-26, -53, -66, -67, -68, -70, -73 and -82; and low-risk (LR) HPV types HPV-6, -11, -40, 42, -54, -55, -61, -62, -64, -69, -71, -72, -81, -83, -84, -89 (HPV-CP6108) and–IS39 [22].

Fig 2. Prevalence of human papillomavirus (HPV) types targeted by current vaccines and non-vaccine types.

Bivalent types: one or both HPV types targeted by the Cervarix HPV vaccine (HPV16/18); Quadrivalent types: one or more HPV types targeted by the Gardasil HPV vaccine (HPV6/11/16/18); Nonavalent types: one or more HPV types targeted by the Gardasil-9 HPV vaccine (HPV6/11/16/18/31/33/45/52/58); HR-HPV excluding vaccine & cross protective types (HPV-35/39/56/59).

Fig 3

Pattern of sexual transmitted infection among South African adolescents and young women (A) Pattern of single infection (HPV or CT or NG or TV or MG or HSV-2), co-infection with more than one of the six STIs; (B) Pattern of infection among women with one of the six investigated STIs; (C) Prevalence of co-infections^a among South African adolescents and young women with one or more sexual transmitted infections. ^a among 194 women that were HPV positive, 56% were positive for HPV only (Solo infection); 34% were co- infected with CT or NG or TV or MG or HSV-2 and 10% were infected with ≥2 other STI; (D) Prevalence of co-infections^b among South African adolescents and young women with one or more sexual transmitted infections. ^b among 97 women that were HPV negative, 70% were negative for all tested STIs, 20% were infected with CT or NG or TV or MG or HSV-2 and 10% were infected with ≥2 other STI. HPV: Human papillomavirus. CT: Chamydia trachomatis. NG: Neisseria gonorrhoeae. TV: Trichomanas vaginalis. MG: Mycoplasma genitalium. HSV-2: Herpes simplex virus-2.