Journal of Immunoassay and Immunochemistry, 36:622–638, 2015 Copyright © Taylor & Francis Group, LLC ISSN: 1532-1819 print/1532-4230 online DOI: 10.1080/15321819.2015.1028587

PREVALENCE OF IgG ANTIBODIES AGAINST HUMAN PAPILLOMAVIRUS (HPV) TYPE 6, 11, 16, AND 18 VIRUS-LIKE PARTICLES IN WOMEN OF CHILDBEARING AGE IN PORT HARCOURT, NIGERIA

I. O. Okonko and V. Ofoedu Medical Microbiology Unit, Department of Microbiology, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria



Most HPV prevalence studies have been carried out in high-resource countries with few studies focused on low-resource regions where highest HPV prevalence in the world occurs. This study reports on prevalence of IgG antibodies against HPVs among women of childbearing age in Port Harcourt, Nigeria. One hundred and eighty-two consented women (age-range 19–45 years) were consecutively recruited. Demographic/behavioral data and 5 mL blood samples were collected from each woman. Plasma of each sample was assayed for HPV-6/11/16/18 virus-like particles using a HPV IgG ELISA kit. The overall anti-HPV prevalence was 4.9% while 7.7% with itching/wound in the private part tested positive. Most (88.9%) of the seropositive women were sexually active. Group-specific seropositivity was low (0.0–10.0%). It also showed that all the 9(100.0%) who tested positive to the HPV responded “yes” to no information on the source of HPV information. Being younger, married, high educational level, religion, and lack of information on HPV were the main correlates of HPV positivity among these women. None was vaccinated and would have been naturally exposed to at least one of HPV-6/11/16/18. With 4.9% seropositivity and lack of information regarding HPV among these women, this study recommends a statewide enlightenment campaign and vaccination. Keywords HPV, prevalence, IgG antibodies, ELISA, seropositivity

INTRODUCTION Most prevalence studies on human papilloma virus (HPV) have been carried out in high-resource countries[1−2] with few studies focused on low-resource regions such as Central and South America,[3,4] Asia,[5,6] and Africa,[7] where the highest HPV DNA prevalence in the world occur, notably among middle-aged women.[8] HPV is the most common sexually Address correspondence to I. O. Okonko, Medical Microbiology Unit, Department of Microbiology, University of Port Harcourt, P.M.B. 5323, Choba, East-West Road, Port Harcourt, Rivers State, Nigeria. E-mail: [email protected]

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transmitted virus worldwide[9] and it is estimated that about 75% of sexually active women and men will acquire a genital HPV infection at some time.[10,11] The prevalence however in cytologically normal women varies from 1.4% in Spain to over 25% in some countries south of the Sahara. Globally, about 10% of women are infected with HPV.[9] The average duration of HPV infection is 4-20 months and the majority of infected individuals will clear the infection without any clinical consequences.[9] Human papilloma viruses are pretty heterogenic and are classified in several types that include high-risk oncogenic types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58. 59, 68) and low-risk non oncogenic types (6, 11, 42, 43, 44) in decreasing order of their association with cancerous lesions.[9,12] The several high-risk genotypes have been linked with cancers of the vulva, vagina, cervix, penis, anus, and oropharynx[13−16] with the two most common being HPV-16 and -18 which cause approximately 70% of all cervical cancers.[12] HPV 16 is the most oncogenic type and is associated with an absolute risk of high-grade cervical cancer precursors of 40% after 5 years of persistent infection.[9] Persistent infection with high-risk or oncogenic types of HPV is strongly associated with the development of preinvasive and invasive lesions of the ano-genital tract, including cancer of the cervix, anus, penis, vulva, and vagina.[9] HPV infection of the epithelium is very effective at evading the host immune surveillance system due to the absence of a viraemic phase, using non lytic replication and low expression of viral proteins until late stages of epithelial differentiation.[9] Transmission of HPV occurs most frequently with sexual intercourse but can occur following non penetrative sexual activity. Viruses in the papillomavirus family affect other species (notably rabbits and cows). The HPVs are transmitted from infected to uninfected humans by skin-to-skin contact,[17] fomites,[18] and mucosal contact through sexual intercourse and as newborns pass via the birth canal of HPV-infected mothers.[12,19] However, humans are the only natural reservoir of HPV. Genital HPV infection may be transmitted by non sexual routes, but this appears to be uncommon. Nonsexual routes of genital HPV transmission include transmission from a woman to a newborn infant at the time of birth. In utero infection also occurs. [12,19] The prevalence of HR HPV types in middle-aged women and the incidence of cervical cancer in the same age group have been strongly positively correlated.[20,21] A series of population-based HPV surveys coordinated by the International Agency for Research on Cancer (IARC) has shown a 10-fold variation between some areas in Spain[22] and North Vietnam,[23] where HPV prevalence in sexually active women aged 15–65 years was below 2%, and areas in Colombia[24] and Argentina,[25] where it was 15% or greater.[21] These observations coupled with the fact that use of HPV vaccine was recently licensed in Nigeria make investigation of HPV

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antibody prevalence in the country necessary. This study was therefore conducted among apparently healthy women in their childbearing age in Port Harcourt, Rivers State, Nigeria in order to assess their immune status in relation to current HPV vaccine antigens (low risk types 6 and 11, and high risk types 16 and 18) and hence their susceptibility to the virus. This study reports on the prevalence of IgG antibodies against the most common low- and high-risk HPVs among sexually active women of childbearing age in Port Harcourt, Nigeria. METHODS Study Area This study was carried out among females attending Eli-Johnson Specialist Hospital in Rumuibekwe, Port Harcourt. Port Harcourt is the capital of Rivers State, Nigeria[26−28] with coordinates: 4◦ 53’23”N 6◦ 54’18”E. According to the 2006 Nigerian census, Port Harcourt has a population of 1,382,59229. Port Harcourt features a tropical monsoon climate with lengthy and heavy rainy seasons and very short dry seasons. Temperatures throughout the year in the city is relatively constant, showing little variation throughout the course of the year. Average temperatures are typically between 25–28◦ C in the city.[27,28] Study Design This is a hospital-based, cross-sectional study which was approved by the Management of Eli-Johnson Specialist Hospital, Rumuibekwe, Port Harcourt, Rivers State, Nigeria. A designated physician (gynecologist) in the hospital discussed the objectives and procedures of the study with the women visiting the gynecology clinic of the hospital. One hundred and eighty-two women of childbearing age that consented to participate in the study were consecutively recruited. Each participant provided pertinent demographic/behavioral data that were obtained through intervieweradministered questionnaires. The data collected include age, educational and marital status, etc. Behavioral data of women tested for anti-HPV 6, 11, 16, and 18 antibodies were also collected. Study Population We collected blood samples and pertinent data from 182 consented women in their childbearing age (19–45 years) attending Eli-Johnson Specialist Hospital, Rumuibekwe, Port Harcourt, Rivers State, Nigeria from June, 2013–March 2014. Rumuibekwe has a relatively high socio-economic

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status and the people are predominantly Ibos and Ikwerre, with other tribes from various parts of the country and outside Nigeria. Eli-Johnson Specialist Hospital is one of the specialist hospitals in Port Harcourt, which by virtue of its location provides secondary and primary health-care services to Obio/Akpor, Eleme, Oyigbo, Okirika, and Port Harcourt Local Government Areas in Rivers State, Nigeria. Serologic Assay The sera of the participants were tested in vitro for IgG antibodies to HPV-6, -11, -16, and -18 with a commercial ELISA kit (DIA.PRO Diagnostic Bioprobes, Milano, Italy). The serologic test and interpretation of results were done according to instructions of the kit manufacturer. Optical signals generated in the microwells were read at 450 nm with an ELISA plate reader (Optic Ivymen® System, Model 2100C; Biotech SL, Madrid, Spain). The ELISA kit manufacturer provided the formula for calculating the cut-off OD450nm (OD of negative control plus 0.250) which we used as threshold for determining the reactive and non reactive serum samples. Samples with an OD450nm lower than the Cut-off value are considered not reactive for IgG specific to the HPV antigens present in the vaccine. Samples with an OD450nm higher than the Cut-Off value are considered positive for IgG specific to the HPV antigens present in the vaccine. Data Analysis The results obtained were presented with descriptive statistics using mean and percentages while binary logistic regression (BLR) was used to establish statistical association between the participants’ demographic/behavioral variables and IgG seropositivity. Data analysis was done with SPSS version 19.0 for Windows (SPSS Inc., Chicago, IL) and a P value of less than 0.05 was used as indicator of statistical significance. RESULTS Socio-Demographic and Behavioral Characteristics of Women Tested for Anti-HPV 6, 11, 16, and 18 Antibodies The age range of the 182 women that participated in the study was 19–45 years with a mean of 29.35 years. About 34.0% of them were in the 36–45 years age range and comparisons of the age-groups (Table 1) were recorded to be nonsignificantly different (P> 0.05). The women generally had high level of education (85.7% had tertiary education) with 68.7% being married (Table 1). All the women responded “no” to cigarette smoking, previous tumor/cancer diagnosis and history of cancer in the family.

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TABLE 1 Socio-demographic and Behavioral data of women tested for anti-HPV 6, 11, 16, and 18 antibodies Variables Age (years) 19-25 26-35 36-45 Educational status Primary Secondary Tertiary Marital status Others Married Religion Christians Muslims Use of oral contraceptive Yes No No response Alcohol consumption Yes No Cigarette smoking Yes No Itching/wound in private part Yes No Previous tumor/cancer diagnosis Yes No Previous STI diagnosis Yes No No response History of cancer in the family Yes No Ever heard of HPV Yes No Awareness of HPV as a sexually transmitted infection Yes No Awareness of association of HPV with tumor/cancer Yes No Source of HPV information Hospital School

Total n (%)

60 (32.0) 60 (32.0) 62 (34.0) 4 (2.2) 22 (12.1) 156 (85.7) 57 (31.3) 125 (68.7) 164 (90.1) 18 (9.9) 21 (11.5) 151 (83.0) 10 (5.5) 12 (6.6) 170 (93.4) 0 (0.0) 182 (100.0) 26 (14.3) 156 (85.7) 0 (0.0) 182 (100.0) 17 (9.3) 144 (79.1) 21 (11.6) 0 (0.0) 182 (100.0) 39 (21.4) 143 (78.6) 42 (23.1) 140 (76.9) 11 (6.0) 171 (94.0) 17 (9.3) 6 (3.3) (Continued)

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TABLE 1 (Continued) Variables

Total n (%)

Media No information HPV vaccination Yes No Use of condom during sexual intercourse Yes No Total

12 (6.6) 147 (80.8) 2 (1.1) 180 (98.9) 54 (29.7) 128 (70.3) 182 (100.0)

One hundred and eighty (98.9%) women responded no to HPV vaccination, 171 (94.0%) to awareness of association of HPV with tumor/cancer, 156 (85.7%) to itching/wound in private part, 151 (83.0%) women responded no to use of oral contraceptives, 144 (79.1%) to previous STI diagnosis, 143 (78.6%) to ever heard of HPV, 140 (76.9%) to awareness of HPV as a sexually transmitted infections (STIs), 128 (70.3%) to use of condom during sexual intercourse, while 12 (6.6%) women responded yes to alcohol consumption. However, only 6 (3.3%) ever heard of HPV from school (Table 1). Socio-Demographic Data and Seropositive Outcomes of Women Tested for Anti-HPV 6, 11, 16, and 18 Antibodies Of the 182 females investigated in this study, only 9 (4.9%) had IgG antibodies against, at least, one of the HPV VLPs. Age-Related Seropositivity Figure 1 shows prevalence of HPV IgG antibody in relation to age of women tested for anti-HPV 6, 11, 16, and 18 antibodies. Women in age group 19–25 years of age had the highest prevalence of anti-HPV IgG 6 (10.0%). This was followed by age group 26–35 years (3.3%) and ages 35–45 years had least prevalence (1.6%). In the same vein, 8 (88.9%) of the 9 seropositive women were in age group 19–35 years and the seropositivity drastically decreased with increase in age (Figure 1). Inferential statistics using BLR showed there was association between age and IgG seropositivity (Figure 1). Education-related Seropositivity Figure 2 also shows prevalence of HPV IgG antibody in relation to educational background of women tested for anti-HPV 6, 11, 16, and 18 antibodies. Women with tertiary education had higher prevalence of HPV IgG 8 (5.1%)

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FIGURE 1 Age groups (years) data and seropositive outcomes of women tested for anti-HPV 6, 11, 16, and 18 antibodies.

FIGURE 2 Educational background and seropositive outcomes of women tested for anti-HPV 6, 11, 16, and 18 antibodies.

than their other counterparts. Zero prevalence was observed among women with primary education while women with secondary education had prevalence of 4.5% (n=1). However, 8 (88.9%) of the 9 seropositive women had high educational background (Figure 2). Inferential statistics using BLR showed there was association between educational background and IgG seropositivity (Figure 2). Marital Status-Related Seropositivity Figure 3 also shows prevalence of HPV IgG antibody in relation to marital status of women tested for anti-HPV 6, 11, 16, and 18 antibodies. The prevalence of anti-HPV IgG was higher among married women 7(5.6%)

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FIGURE 3 Prevalence of anti-HPV 6, 11, 16, and 18 antibodies in relation to marital status.

than their other counterparts (3.5%). In the same vein, 7 (77.8%) of the 9 seropositive women were married (Figure 3). Inferential statistics using BLR showed there was association between marital status and IgG seropositivity (Figure 3). Religion-Related Seropositivity Figure 4 also shows prevalence of HPV IgG antibody in relation to Religion of women tested for anti-HPV 6, 11, 16, and 18 antibodies. A majority of the women used in this study were Christians 164 (90.1%) however, higher prevalence of HPV IgG was observed among the Muslims 1 (5.5%) then their Christian counterparts 8 (4.9%). Furthermore, 8 (88.9%) of

FIGURE 4 Religion and seropositive outcomes of women tested for anti-HPV 6, 11, 16, and 18 antibodies.

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the 9 seropositive women were Christians (Figure 4). Inferential statistics using BLR showed there was association between religion IgG seropositivity (Figure 4). Behavioral Characteristics and Seropositive Outcomes of Women Tested for Anti-HPV 6, 11, 16, and 18 Antibodies Figure 5 shows prevalence of HPV IgG antibody in relation to behavioral characteristics of women tested for anti-HPV 6, 11, 16, and 18 antibodies. The study showed that 2( 7.7%) of the women who responded “yes” to itching/wound in the private part tested positive to the HPV VLPs (Figure 5). It also showed that 1 (4.8%) of the women who responded “yes” to previous history of sexually transmitted infections (STIs) tested positive to the HPV VLPs, none among the 12 women who responded “yes” to alcohol consumption tested positive. One (2.4%) among the 42 women who responded “yes” to awareness of HPV as a sexually transmitted infection tested positive to the HPV VLPs, 1 (9.1%) among the 11 women who responded “yes” to awareness of association of HPV with tumor/cancer tested positive to the HPV VLPs and 1 (1.9%) among the 54 women who responded “yes” to use of condom during sexual intercourse tested positive to the HPV VLPs (Figure 5). Inferential statistics using BLR showed there was an association between any of these variables and IgG seropositivity (Figure 5).

FIGURE 5 Behavioral data and seropositive outcomes of women tested for anti-HPV 6, 11, 16, and 18 antibodies.

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FIGURE 6 Source of HPV information and seropositive outcomes of women tested for anti-HPV 6, 11, 16, and 18 antibodies.

Source of HPV Information Figure 6 shows prevalence of HPV IgG antibody in relation to sources of HPV information of women tested for anti-HPV 6, 11, 16, and 18 antibodies. It also showed that all the 9 (100.0%) who tested positive to the HPV VLPs responded “yes” to no information on the source of HPV information (Figure 6). Inferential statistics using BLR showed there was an association between sources of HPV information and IgG seropositivity (Figure 6). DISCUSSION This study assessed the prevalence of IgG antibodies against HPV types 6/11/16/18 among apparently healthy women in their childbearing age in Port Harcourt, Nigeria in order to assess their immune status in relation to current HPV vaccine antigens (low risk types 6 and 11, and high risk types 16 and 18) and hence their susceptibility to the virus. From the result obtained only 9 (4.9%) of the women tested had detectable IgG against any of the HPV VLPs. This compared favourably with the findings in previous studies in Nigeria.[12,30−32] Previous HPV surveys in sub-Saharan Africa have generally shown relatively high HPV prevalence with some variation, depending on how women were selected, and how HPV was tested for.[21] The prevalence of HPV positivity of 4.9% found in Port Harcourt, Nigeria is consistent with previous reports of the low prevalence of HPV in women in Sub-Saharan Africa. The 4.9% reported in this study is higher than

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the 3.8% reported by Ogoina et al.[11] among 26 HIV-negative participants in Zaria, Nigeria. The 4.9% prevalence reported for HPV positivity is lower than the 6.6% reported by Adekunle et al.[12] in Ilesha, Nigeria. However, the prevalence of HPV positivity of 4.9% is not consistent with previous reports of the elevated prevalence of HPV in women in Sub-Saharan Africa. The 4.9% prevalence reported for HPV positivity in this study is lower than the 26.3% overall prevalence and 24.8% among women without cervical lesions reported by Thomas et al.[21] in Ibadan, Nigeria. It is also lower than the 41.3% reported by Ogoina et al.[11] among 63 HIV-positive patients in Zaria, Nigeria. The 4.9% prevalence reported for HPV positivity in this study is lower than the 17.0% prevalence of high risk HPV types reported in rural Uganda[33] while 25% prevalence was found among HIV-negative women in Harare, Zimbabwe.[34] It is also lower than the 40% HPV prevalence in rural Mozambique;[35] the 31.0% in Harare, Zimbabwe;[36] the 18.0% in Dakar and Pikene, Senegal;[37] and the 44.0% in Nairobi, Kenya.[38] In this study, only 4.9% of the women tested had IgG antibodies against, at least, one of the HPV VLPs. Furthermore, the finding in this study of 4.9% prevalence of anti-HPV IgG antibodies among sexually active women is rather low despite having a high proportion of them with tertiary education. This is contrary to previous reports of 26.3% HPV seropositivity in Ibadan,[30] ≥ 25% seropositivity for HPV-16 and -18 in Nigeria,[31] 14.7% prevalence of HPV DNA in Ondo State, Nigeria,[32] and 6.6% for HPV-6, 11, 16, and 18 in Osun State, Nigeria.[12] The age range of the women that participated in the study was 19–45 years. This similar to the age range used in previous studies.[12] Thirtyfour percent of the women used in this study were in the 36–45 years age range and comparisons of the three age-groups were recorded to be non significantly different (P> 0.05). This deviated from what was reported by Adekunle et al.[12] The age pattern was notable, however, with a modest peak of HPV infection (mainly high risk HPV types) among women younger than 30 years and a consistently low prevalence among middle-aged and old women. In this study, women in age group 19–25 years of age had the highest prevalence of anti-HPV IgG (10.0%).This was followed by age group 26–35 years (3.3%) and ages 35–45 years had least prevalence (1.6%). Like most populations studied so far, HPV prevalence was high among young women. This deviated from the findings of Thomas et al.[21] who reported that unlike most populations studied so far, HPV prevalence was high not only among young women, but also in middle and old age in their study in Ibadan. Peak infection of HPV in this study occurred among women less than 30 years and would, therefore, not explain the high HPV prevalence reported by Thomas et al.[21] among women of middle and old age in Ibadan.

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The study also showed that 8 (88.9%) of the 9 seropositive women were in age group 19–35 years and the seropositivity drastically decreased with increase in age. There was association between age and IgG seropositivity. This is similar to the findings of previous studies.[12,17] In three studies from sub-Saharan Africa,[21,33,35,38] the prevalence of HPV declined with age. In a study by Xi et al.,[37] high-risk, but not low-risk HPV types, were more frequently detected in older than younger women.[21] High prevalence of HPV in all age groups may be a distinctive feature of populations where HPV transmission continues into middle age and cervical cancer incidence is very high.[21] Burd[17] reported that HPV infection is most common in sexually active young women (18–30 years old), with a sharp decrease in prevalence after 30 years of age. Adekunle et al.[12] reported in their study that 83.3% of the 6 seropositive women were in the 19–30 years age range while the remaining woman was between 31–40 years of age. A similar trend was observed in this study as 6 (66.7%) of the 9 seropositive women were in the 19–25 years age range and 2 (22.2%) of the 9 seropositive women were in the 26–35 years age range while the remaining woman was between 36–45 years of age. The age pattern similar to the one in Ibadan[21] was also reported in another population at very high-risk for cervical cancer, namely, Chennai, Southern India.[39] The high prevalence of HPV in middle and old age in Port Harcourt, Nigeria may have different explanations. A fraction of men and women in Port Harcourt may continue to have multiple sexual contacts throughout their life and therefore re-infect themselves and their spouses.[21] Women in Port Harcourt may also have decreased ability to clear HPV infections, possibly due to concomitant genital infections or nutritional deficiencies.[21] The women used in this study generally had high level of education (84.6% had tertiary education). Women with tertiary education had higher prevalence of HPV IgG 8 (5.1%) than their other counterparts. Zero prevalence was observed among women with primary education while women with secondary education had prevalence of 4.5%. However, 8 (88.9%) of the 9 seropositive women had high educational background. This finding deviated from that of Thomas et al. (2004) who reported that illiterate women showed increased HPV positivity in Ibadan. The prevalence of anti-HPV IgG reported in this study was reported higher among married women (5.6%) than their other counterparts (3.5%). The study also showed that 7 (77.8%) of the 9 seropositive women were married. Additionally, since 7 (77.8%) of the 9 seropositives were married, 8 (88.9%) of them expectedly responded “no” to use of condom during sexual intercourse. This supports the fact that married people with only one life-time sexual partner can be infected with HPV.[12] This deviated from that of Thomas et al.[21] who reported that single women showed increased HPV positivity in Ibadan. From the

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results obtained in this study, majority of the women used in this study were Christians 164 (90.1%). Higher prevalence of HPV IgG was observed among the Muslims 1 (5.5%) than their Christian counterparts (4.9%). The study also showed that 8 (88.9%) of the 9 seropositive women were Christians. In this study, only 9 (4.9%) women in this study had IgG antibodies against, at least, one of the HPV VLPs while 7.7% of the women who responded “yes” to itching/wound in the private part tested positive to the HPV VLPs. Also, one (5.9%) of the women who responded “yes” to previous history of sexually transmitted infections (STIs) tested positive to the HPV VLPs. It also showed that 1 (4.8%) of the women who responded “yes” to previous history of sexually transmitted infections (STIs) tested positive to the HPV VLPs, none among the 12 women who responded “yes” to alcohol consumption tested positive. One (2.4%) among the 42 women who responded “yes” to awareness of HPV as a sexually transmitted infection tested positive to the HPV VLPs, 1 (9.1%) among the 11 women who responded “yes” to awareness of association of HPV with tumor/cancer tested positive to the HPV VLPs and 1 (1.9%) among the 54 women who responded “yes” to use of condom during sexual intercourse tested positive to the HPV VLPs. It also showed that all the 9 (100.0%) who tested positive to the HPV VLPs responded “yes” to no information on the source of HPV information. In this study, all the seropositive women respond ‘no’ to HPV vaccination. Since these seropositive women responded “no” to HPV vaccination, it can be inferred that they had been naturally exposed to at least one of HPV6/11/16/18.[12] Since the World Health Organization (WHO) reported that quadrivalent and bivalent HPV vaccines offer more than 90% protection against persistent infection by the vaccine genotypes in women with no evidence of past or present HPV infection,[40] vaccination against HPV types 6, 11, 16, and 18 is recommended for sexually active women attending the hospital who have no evidence of protection against the HPVs.[12] This observation is buttressed by the fact that all of them had never heard of HPV and were unaware it causes a sexually transmitted infection (STI), and most were sexually active being in the 19–35 years age range.[12] A study by Ogoina et al.[11] in Zaria, Northern Nigeria showed that cumulative HPV infection occurs more frequently in HIV-infected patients than in HIVnegative healthy adults. This finding is in agreement with studies from other African countries,[11,41−43] and may be attributed to poor clearance of HPV infection in HIV-infected patients relative to HIV-negative adults[11,44,45] and the fact that both HIV and HPV infections share similar route and risk factors for infection.[11,46] All the women responded “no” to cigarette smoking, previous tumor/cancer diagnosis and history of cancer in the family. One hundred and eighty (98.9%) women responded no to HPV vaccination, 171

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(94.0%) to awareness of association of HPV with tumor/cancer, 156 (85.7%) to itching/wound in private part, 151 (83.0%) women responded no to use of oral contraceptives, 144 (79.1%) to previous STI diagnosis, 143 (78.6%) to ever heard of HPV, 140 (76.9%) to awareness of HPV as a sexually transmitted infections (STIs), 128 (70.3%) to use of condom during sexual intercourse while 12 (6.6%) women responded “yes” to alcohol consumption. However, only 6 (3.3%) ever heard of HPV from school. Moreover, our observation that majority of the women involved in this study had never heard of HPV nor received vaccination against it irrespective of their educational status indicates a paucity of information regarding HPV in Port Harcourt. This is also in consonance with the findings of Adekunle et al.[12] in Ilesha, Osun State, Nigeria. It is also reassuring that the distribution of some of the characteristics investigated (e.g., multiple sexual partners, parity, use of oral contraceptives or condoms, etc.) was consistent with those reported nationwide by publications of the World Health Organization. In addition, our observation of high level of ignorance regarding association of HPV with cancer is similar to that of Adekunle et al.[12] in Ilesha, Osun State, Nigeria and Amosu et al.[47] in Iwo, another town in Osun State, Nigeria. CONCLUSION Our study confirmed the occurrence of common HPV types among the women of childbearing age in Port Harcourt, Nigeria. It showed that IgG antibodies to any of the HPV types 6/11/16/18 were very common as reported among Nigerian women. HPV positive women (positive for any of the HPV types 6/11/16/18) had an increased risk of being seropositive for other HPV type. It clearly shows that although the prevalence was higher among younger Port Harcourt women than older ones, probably due to sexual activities and other immunological and environmental factors. Mass HPV vaccination will be most effective in the fight against cervical cancer by significantly reducing the causative agent (HPV) in a low developing country like Nigeria. We advocate a statewide HPV enlightenment campaign and quadrivalent HPV vaccination of sexually active women in Rivers State, Nigeria. REFERENCES 1. Newall, A.T.; Brotherton, J.M.; Quinn, H.E.; McIntyre, P.B.; Backhouse, J.; Gilbert, L.; Esser, M.T.; Erick, J.; Bryan, J.; Formica, N.; MacIntyre, C.R. Population seroprevalence of Human Papillomavirus Types 6, 11, 16, and 18 in Men, Women, and Children in Australia. Clin. Infect. Dis. 2008, 46, 1647–1655. 2. Skjeldestad, F.E.; Mehta, V.; Sings, H.L.; Ovreness, T.; Turpin, J.; Su, L.; Boerckel, P.; Roberts, C.; Bryan, J.; Jansen, K.U.; Esser, M.T.; Liaw, K.L. Seroprevalence and Genital DNA Prevalence of

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