Bacterial vaginosis (BV) enhances the acquisition and transmission of a range of sexually transmitted infections including human immunodeficiency virus. This has made it more important to uncover the reasons why some populations have very high BV prevalences and others not. This systematic review describes the global epidemiology of BV. It summarizes data from peer-reviewed publications detailing the population prevalence of BV as diagnosed by a standardized and reproducible methodology–Nugent scoring system. BV variations between countries, and between ethnic groups within countries, are described. We evaluated 1692 English- and non-English-language articles describing the prevalence of BV using MEDLINE and the Web of Science databases. A total of 86 articles met our inclusion criteria. BV prevalences were found to vary considerably between ethnic groups in North America, South America, Europe, the Middle East, and Asia. Although BV prevalence is, in general, highest in parts of Africa and lowest in much of Asia and Europe, some populations in Africa have very low BV prevalences and some in Asia and Europe have high rates.
“Bacterial vaginosis” (BV) is a term used to describe a disturbed vaginal microbiota dominated by mixed anaerobes, such as Gardnerella species, Prevotella species, and Atopobium species. Although mostly an asymptomatic condition, the key importance of BV is in the range of associated adverse outcomes. Women who have BV are also at increased risk for the development of infection with herpes simplex virus type 2, Trichomonas vaginalis , Neisseria gonorrhoeae , and Chlamydia trachomatis . BV has also been associated with an increased risk of human immunodeficiency virus (HIV) acquisition and transmission.
Both its etiology and the reason for the widely differing prevalences around the world remain unclear. BV has thus been referred to as “one of the most prevalent enigmas in the field of medicine.” There has been considerable debate in the literature as to whether BV is a sexually enhanced disease or a sexually transmitted disease. The balance of evidence suggests that sexual transmission is at least an important aspect of its epidemiology. A systematic review and metaanalysis of the relationship between sexual activity and BV found that BV “is significantly associated with sexual contact with new and multiple male and female partners and that decreasing the number of unprotected sexual encounters may reduce incident and recurrent infection.” Other reported risk factors include the intrauterine device, black race/ethnicity, douching, smoking, menses, lack of male circumcision, poverty, low vitamin-D levels, other dietary factors, chronic stress, and genetic variants of a wide range of host genes. In many cases, however, follow-up studies have failed to reproduce these findings. The use of hormonal contraception has been associated with a decreased incidence of BV.
A significant omission in the literature on BV is a study describing the global epidemiology of BV. A first step in the investigation of a disease of unknown etiology is the mapping of its frequency distribution, followed by an analysis of what possible explanatory variables covary with it. This is especially important in the field of sexually transmitted infections (STIs), where recent theoretical and empirical work has demonstrated the increasing importance of sexual networks in differential STI prevalences. Since networks are properties of populations that cannot be reduced to the attributes of individuals, ecological type studies of population differences in STIs are an important and necessary type of investigation. Evidence from the United States and Africa reveals that sexual networks are to a significant degree segregated along the lines of ethnicity/race. Other lines of evidence have demonstrated that this segregation combined with differences in the structure of these sexual networks constitute an important determinant of the often large differences in STI rates between ethnic groups. These considerations provide the rationale for describing the variations in BV prevalence by ethnic group alongside those of the international variations in BV prevalence.
An important development in BV epidemiology in the last 2 decades has been the development and validation of a standardized, reproducible, reliable, and widely used method of assessing the presence or absence of BV. Nugent scoring system (NSS) bases the diagnosis of BV on the interpretation of a Gram stain of vaginal secretions. The diagnosis of BV is defined as a Nugent score of ≥7 of 10. The degree of interobserver and intraobserver variability is low compared to Amsel criteria (AC) and it has been established as a reproducible and reliable test. NSS has thus been recommended to be used as the gold standard for the diagnosis of BV by a number of groups, including a National Institute of Health–sponsored working group on the topic. The objective of this article is to describe the global epidemiology of BV by reviewing the available evidence of the prevalences of BV in different populations around the world.
Methods
A search was conducted in the PubMed/MEDLINE and Web of Science databases in April 2012. Search terms included “bacterial vaginosis,” “bacterial vaginitis,” “bacterial vaginoses,” “epidemiology,” “incidence,” and “prevalence.” This resulted in the retrieval of 1692 articles. Cited references were also assessed for inclusion. Articles in English, French, Spanish, and Polish were considered for inclusion. No date restrictions were applied. Studies were then selected according to a 3-step process. First, studies were preferentially included if they were representative population-based or antenatal-based samples and the diagnosis of BV was based on NSS. This step yielded 46 studies. Second, if no studies based on representative samples from a particular country were available then other convenience samples where the diagnosis of BV was based on NSS were considered. These included studies sampling outpatient attendees, as long as the populations sampled were not constituted only by individuals presenting with STI symptoms. Surveys that exclusively sampled sex workers or HIV-positive populations were not included. This step yielded 21 studies. In addition, 4 studies that based the diagnosis of BV on Spiegel or Hay-Ison method were included. Like the NSS, these methods are Gram stain–based techniques that produce results so similar to NSS that they have been classified by some pathologists as interchangeable with the NSS. One additional study that used BVBlue test (Gryphus Diagnostics, L.L.C., Birmingham, AL) was included. When compared to NSS, this test has a sensitivity of 92-100% and a specificity of 98%. This step yielded a total of 26 studies. Third, if countries were still not represented, then we repeated steps 1 and 2 using surveys based on the less sensitive (and non-Gram stain–based) AC. In general, AC underestimates the BV prevalence as diagnosed by the NSS by 30-40%. This step yielded 14 studies. The search strategy produced a total of 86 BV surveys that were utilized for our study.
To describe the epidemiology of BV by region, we developed a BV summary indicator. This summary indicator consisted of the percentage of studies done in the whole region that revealed a BV prevalence of ≥30%. Only studies using NSS were used in these calculations. For the purposes of presenting the BV summary indicator results, the regions of the world were grouped into low (0.1-0.2%), moderate (0.3-1%), and high (>1%) HIV prevalence regions. The regional HIV prevalence data are taken from the 2010 UNAIDS (the Joint United Nations Programme on HIV/AIDS) Global Report.
Eleven studies where BV prevalences were broken down by ethnicity/race were used to describe the intranational epidemiology of BV.
Data extraction
For each study, we extracted the following information: date and location of study, study methodology including method of sample selection, exclusion criteria, response rate, and type of population sampled; mean or median age of sample, with range where available; method of diagnosis of BV, sample size; and prevalence of BV. Available evidence was then prepared in figure form to summarize the key study findings.
Data were grouped into 9 geographic regions, based largely on the World Health Organization classificatory system (a listing of countries in each region is presented in Table 1 ). These regions were: North America; Latin America and the Caribbean; North Africa and the Middle East; sub-Saharan Africa; western Europe; eastern Europe and central Asia; East Asia and the Pacific; South Asia and Southeast Asia; and Australia and New Zealand.
| Australia and New Zealand |
| Australia, New Zealand |
| East Asia and the Pacific |
| Brunei Darussalam, China, Democratic People’s Republic of Korea, Japan, Mongolia, Republic of Korea, Singapore, Cook Islands, Fiji, Kiribati, Marshall Islands, Micronesia (Federated States of), Nauru, Niue, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga, Tuvalu, Vanuatu |
| East Europe and central Asia |
| Albania, Armenia, Azerbaijan, Belarus, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Estonia, Georgia, Hungary, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Montenegro, Poland, Romania, Russian Federation, Serbia, Slovakia, Tajikistan, former Yugoslav Republic of Macedonia, Turkey, Turkmenistan, Ukraine, Uzbekistan |
| Latin America and Caribbean |
| Antigua and Barbuda, Argentina, Bahamas, Barbados, Belize, Bolivia, Brazil, Chile, Colombia, Costa Rica, Cuba, Dominica, Dominican Republic, Ecuador, El Salvador, Grenada, Guatemala, Guyana, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, Paraguay, Peru, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and Grenadines, Suriname, Trinidad and Tobago, Uruguay, Venezuela (Bolivarian Republic of) |
| North Africa and Middle East |
| Algeria, Bahrain, Cyprus, Djibouti, Egypt, Iran (Islamic Republic of), Iraq, Israel, Jordan, Kuwait, Lebanon, Libyan Arab Jamahiriya, Malta, Morocco, Oman, Qatar, Saudi Arabia, Syrian Arab Republic, Tunisia, United Arab Emirates, Yemen |
| North America |
| Canada, United States |
| South and Southeast Asia |
| Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, Sri Lanka, Cambodia, Indonesia, Lao People’s Democratic Republic, Malaysia, Myanmar, Philippines, Thailand, Timor-Leste, Vietnam |
| Sub-Saharan Africa |
| Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Congo, Côte d’Ivoire, Democratic Republic of Congo, Equatorial Guinea, Eritrea, Ethiopia, Gabon, The Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mozambique, Namibia, Niger, Nigeria, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, South Africa, Sudan, Swaziland, Togo, Uganda, United Republic of Tanzania, Zambia, Zimbabwe |
| Western Europe |
| Andorra, Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Monaco, Netherlands, Norway, Portugal, San Marino, Slovenia, Spain, Sweden, Switzerland, United Kingdom |
Results
Comparisons of the prevalence of BV by geographic area or country are hampered by a number of factors including differences in how the samples were selected and differences in the type of population surveyed–such as age composition and pregnancy. Despite these difficulties, certain trends are apparent.
Intranational comparisons
One of the most striking features is the extent to which BV prevalences vary by ethnic group within countries ( Table 2 ). This has been most extensively documented and investigated in the United States. A series of surveys spanning 20 years (1 nationally representative, 1 of all women entering the US Marines, and 2 large samples of the antenatal population ) all revealed similar findings. BV prevalence was highest in blacks, and lowest in whites and Asians, with Hispanics having an intermediate prevalence. These differences remained remarkably stable through the period investigated.
| Location | Study location, date | Study type, a selection process, and sample size | Median or mean age (±SE; range), y | Diagnostic process | Prevalence, % |
|---|---|---|---|---|---|
| United States | United States, 1984 through 1989 | In 7 urban medical centers in the United States, 13,747 predominantly low-socioeconomic-status women at 23-26 wks’ gestation were recruited according to ethnic origin | 24.1 | BV was diagnosed by NSS in conjunction with vaginal pH >4.5 | |
| Blacks, 5285 | 22.7 | ||||
| Whites, 4049 | 8.8 | ||||
| Hispanics, 4240 | 15.9 | ||||
| Asian-Pacific Islanders, 173 | 6.1 | ||||
| US Marines, 1999 | All 2157 women entering US Marine Corp in 1-y period; full data available for 1938 (94%) | 19.1 (±2.1; 17–33) | NSS | 27 | |
| Whites, 1092 | 24.7 | ||||
| Hispanics, 387 | 29.5 | ||||
| Blacks, 306 | 32 | ||||
| Asian-Pacific Islanders, 63 | 11.1 | ||||
| Native Americans, 44 | 34.1 | ||||
| Other, 46 | 26.1 | ||||
| NHANES, 2001 through 2004 | 4646 women in nationally representative sample of US civilian noninstitutionalized population were interviewed; 3739 of these completed vaginal swab examination, were assessed for BV, and are presented here | 15–49 | NSS | 29.2 | |
| Non-Hispanic blacks, 978 | 15–49 | 51.4 | |||
| Hispanics, 971 | 15–49 | 31.9 | |||
| Non-Hispanic whites, 1533 | 15–49 | 23.2 | |||
| Chapel Hill, NC, 1995 through 1996 | 819 women 24-29 wks pregnant were randomly selected at AN clinics; EC: nonsingleton pregnancy, mother age <17 y | 24 (IQR 21–29) | 19.3 | ||
| Blacks, 377 | 25.8 | ||||
| Others, 55 | 12.7 | ||||
| Whites, 387 | 14 | ||||
| Pittsburg, PA, 2005 through 2006 | Prospective observational cohort study exploring effect of race of male sex partner on BV prevalence and incidence; all women with singleton pregnancies seeking AN care from single hospital; 526 women eligible, 325 women enrolled; EC: vaginal bleeding, diabetes, HIV positive | NSS | |||
| Female white – male white, 27 | 25 (18–41) | 20.9 | |||
| Female white – male black, 16 | 23 (18–34) | 48.7 | |||
| Female black – male white, 5 | 23 (18–34) | 41.6 | |||
| Female black – male black, 68 | 25 (17–42) | 35.7 | |||
| United Kingdom | Harrow, pre-1994 | Prospective descriptive cohort study to evaluate if BV in early pregnancy increased risk of premature delivery; 783 women between 9-24 wks’ gestation who were making their first AN visit to Northwick Park Hospital, Harrow, were recruited | 28.6 | Spiegel criteria | 10.9 |
| White, 361 | 12 | ||||
| Afro-Caribbean, 24 | 41 | ||||
| Asian, 179 | 6 | ||||
| Other, 92 | 4 | ||||
| Iran | Fars Province, 1996 through 1997 | Stratified random sample in 2 tiers to yield numbers of women in proportions representative of 6 tribes of Qashqai; all 839 married women in selected subclans participated; EC: nonmarried, pregnant, menstruating | Ages given in 10-y categories only | NSS | 50 |
| Stratified random sample in 2 tiers to yield numbers of women in proportions representative of 4 tribes of Mamasani Lor; all 274 married women in selected subclans participated; EC: nonmarried, pregnant, menstruating | Ages given in 10-y categories only | NSS | 49 | ||
| 388 urban women living in Shiraz; selection process not described; EC: nonmarried, pregnant, menstruation | Ages given in 10-y categories only | NSS | 40 | ||
| Canada | Edmonton (Alberta), 1995 through 1996 | Prospective cohort study; all expectant mothers in all obstetric practices affiliated with single teaching hospital in Edmonton invited to participate; 2047 women enrolled; 1811 followed up to delivery; prevalences given for BV in second trimester; prevalences for BV at any stage in pregnancy were 43% and 23% for aboriginal and non-aboriginal groups, respectively | NSS | 13.6 | |
| Non-aboriginal | NS | NSS | 13 | ||
| Aboriginal | NS | NSS | 33 | ||
| Spain | Barcelona, 1995 through 1996 | 293 consecutive pregnant women attending routine AN care at hospital | 29.9 | NSS | 7.5 |
| White, 234 | 6.4 | ||||
| Gypsy, 24 | 12.5 | ||||
| Other, 35 | 11.4 | ||||
| Peru | Rural areas, 1997 through 1998 | All women from 18 rural villages invited to participate in survey; sampled 752 women | 36.9 (18–67) | NSS | 40.8 |
| Aymara adjusted odds ratio 2.5 (95% confidence interval, 1.2–5.2) for prevalent BV | |||||
| China | Tibetan region of Sichuan | 397 women; selection criteria not clearly specified; EC: pregnant, ABs in last 30 d | 18–72 | Hay-Ison criteria | 51.6 |
| Han, 61 | 44.2 | ||||
| Tibetan, 291 | 60.8 | ||||
| Other, 38 | 50.0 |
a All studies were cross-sectional unless otherwise specified.
BV prevalence in an antenatal population in the United Kingdom was considerably higher in Afro-Caribbeans than whites or Asians. In Canada, BV rates were almost 3 times higher in the aboriginal population than the non-aboriginals. Ethnically defined subpopulations in China, Iran, and Peru all showed evidence of elevated BV prevalences compared to other national groupings.
International comparisons
Table 3 provides the details of BV prevalence by country. Table 4 summarizes BV prevalence by region according to the BV prevalence summary indicator. The regions of the world have been grouped into low (0.1-0.2%), moderate (0.3-1%), and high (>1%) HIV prevalence regions. In general BV prevalence, as assessed with the summary indicator, covaries fairly closely with regional HIV prevalence. Sub-Saharan Africa has the highest BV and HIV prevalence. Latin America and the Caribbean have a somewhat higher prevalence of BV and HIV than the regions in the low HIV prevalence regions. Although BV prevalence tended to be highest in sub-Saharan Africa and lowest in Asia/Australasia/western Europe, there were populations with high and low BV prevalence in all of these regions.
| Location | Study location, date | Study type, a selection process, and sample size | Median or mean age (±SE; range), y | Diagnostic process | BV prevalence, % |
|---|---|---|---|---|---|
| Latin America/Caribbean | |||||
| Argentina | Santa Fe, 2001 through 2003 | 400 consecutive patients (with or without STI symptoms) presenting to gynecological practice, excluding pregnant patients | (15–55) | NSS | 13.5 |
| Brazil | Vitoria, Espirito Santo, 2003 through 2004 | Random women attending PHC clinic; EC: having been submitted to gynecological examination in <1 y before, and history of recent treatment (in last 3 mo) for genital infections | 30 (14–49) | NSS | 21.3 |
| Alagoas, 1997 | Random selection of 341 women from 4 rural villages; 83% response rate | 34.4 (15–63) | NSS | 15.3 | |
| Serra Pelada, Para, 2004 | All 1500 women in town were invited to participate in health survey; first 5 presenting each day were assessed, until 209 sampled | 38 (IQR 28–47) | NSS | 18.7 | |
| Botucatu, Sao Paulo, 2006 through 2007 | 245 random pregnant women attending routine AN services at 18 PHC clinics | 24.8 (14–44) | NSS | 21.6 | |
| Pacoti, Ceara, pre-2007 | Random survey of community; 592 women tested; response rate not reported | 32 (12–49) | NSS | 20.1 | |
| Chile | Santiago, 2006 | 100 randomly sampled women from FP clinics; EC: pregnant, menstruating, ABs in last 30 d | 15–49 | NSS | 32 |
| Colombia | Bogota, 1999 through 2001 | 155 women, 18-35 wks pregnant presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 28 (14–43) | NSS | 9 |
| Ecuador | La Concordia, pre-2010 | 213 adolescents sampled from 2 schools; not clear how random selection was | 14.9 (13–17) | Hay-Ison scoring | 31.5 |
| Jamaica | Kingston, 1999 | 269 pregnant women, who were first-time attendees, at 4 AN clinics in Kingston in their second or third trimester | 23 (14–40) | NSS | 49.1 |
| Peru | Rural areas, 1997 through 1998 | All women from 18 rural villages invited to participate in survey; sampled 752 women | 36.9 (18–67) | NSS | 40.8 |
| Lima, Trujillo, Chiclayo | 995 women between 18-30 y were randomly selected from 20 neighborhoods in Lima, 6 in Trujillo, and 8 in Chiclayo (3 coastal cities); all neighborhoods were poor; 779 (80.7%) were tested for BV | 23.8 (18–30) | BVBlue (Gryphus Diagnostics, L.L.C., Birmingham, AL) | 26.6 | |
| North America | |||||
| Canada | Toronto (Ontario), 2008 through 2009 | 73 women attending OPD for insertion of IUCD | NSS | 7.1 | |
| Edmonton, 1994 through 1995 | 2047 consecutive routine pregnant patients seen by 4 obstetricians (3 OPD-, 1 hospital-based); response rate 91.5% | 29.1 (±5.1) | NSS | 14 | |
| United States | NHANES, 2001 through 2004 | 4646 women in nationally representative sample of US civilian noninstitutionalized population were interviewed; of these 3739 completed vaginal swab examination and were assessed | 15–49 | NSS | 29.2 |
| United States, 1984 through 1989 | Random sample of 13,747 predominantly low-socioeconomic-status women at 23-26 wks’ gestation from 7 urban medical centers | 24.1 | NSS in conjunction with vaginal pH >4.5 | 16.3 | |
| US Marines, 1999 | All 2157 women entering US Marine Corp in 1-y period; full data available for 1938 (94%) | 19.1 (17–33) | NSS | 27 | |
| Philadelphia, PA, 1999 through 2001 | 69 women, 18-35 wks pregnant presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 31 (15–46) | NSS | 5.8 | |
| Western Europe | |||||
| Czech Republic | Brno, 1990 | 600 women randomly selected from local population; sampling methodology and response rate not clear | NS | AC | 11.5 |
| Denmark | Odense, 1992 through 1994 | Population-based sample of 2927 pregnant women; 81.4% response rate | 28 | AC | 13.7 |
| Finland | Aland Islands, 1993 through 2008 | Every 5 y, all women between ages of 20-60 y who turn 20, 25, 30, 35, 40, 45, 50, 55, or 60 y of age that year were invited to participate in cervical cancer screening program; Pap smears were evaluated for BV via NSS (no. screened for BV: 1993 = 819; 1998 = 824; 2003 = 790; 2008 = 771) | 20–60 | NSS | 15.6 (1993) 8.6 (2008) |
| Greece | Athens, 2005 | 1197 pregnant women between 22-25 wks’ gestation reporting for second-trimester fetal anomaly scan; response rate not reported; EC: previous preterm deliveries, abortion, recent AB use | Age reported in 4 ranges only | NSS and vaginal pH >4.5 | 7.9 |
| Ireland | Dublin, 1999 through 2001 | 203 women, 18-35 wks pregnant presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 28 (16–44) | NSS | 5.9 |
| Italy | Lombardo, Italy, 1989 through 1994 | 1955 consecutive AN women in their eighth and ninth month were screened; EC: AB use and any genitourinary symptoms; 514 women excluded on this basis | NS | NSS | 8.7 |
| Norway | Tromso, 1996 | 168 consecutive applicants for first-trimester abortion | NS | NSS | 24 |
| Portugal | Lisbon, 1993 through 1994 | All 840 who attended specific FP clinic in Lisbon over 2-y study period were recruited; response rate NS | 33% 20–29, 40% 30–39 | AC | 7 |
| Spain | Barcelona, 1998 | 492 randomly selected women with singleton pregnancies <28 wks’ gestation sampled from routine ANC clinics; EC: ABs in preceding 4 wks | 27 (±5.5) | NSS | 4.5 |
| Barcelona, 1995 through 1996 | 293 consecutive pregnant women attending routine ANC at hospital | 29.9 | NSS | 7.5 | |
| Sweden | Stockholm and Eskilstuna, 1989 through 1991 | 1011 women randomly selected from FP and youth clinics | 25.7 (±6.9) | AC | 13.7 |
| Turkey | Trabzon, 2002 | 86 consecutive women attending FP clinic for IUCD insertion | 27.3 (16–40) | NSS | 23.2 |
| United Kingdom | London, 1998 through 2000 | Prospective cohort study of 1216 pregnant women <10 wks’ gestation presenting to 34 GPs in South London | 31 (16–48) | NSS | 14.5 |
| Harrow, pre-1994 | Prospective descriptive cohort study to evaluate if BV in early pregnancy increased risk of premature delivery; 783 women between 9-24 wks’ gestation who were making their first AN visit to Northwick Park Hospital, Harrow, were recruited | 28.6 | Spiegel criteria | 10.9 | |
| Eastern Europe and central Asia | |||||
| Bulgaria | Plovdiv, pre-1998 | 200 sexually active women presenting to dermatology and venereology clinics for routine checkup | 17–34 (24.8) | NSS | 17.5 |
| Poland | Zabrze, 2001 through 2003 | 450 consecutive AN patients (6-39 wks’ gestation) EC: nonsingleton pregnancy, vaginal bleeding, placenta previa | NS | AC | 19.1 |
| Lodz, 2001 | A group of 196 pregnant women at 8-16 wks’ gestation were selected randomly from patients of 10 district maternity units in Lodz region; EC: nonsingleton pregnancies | NS | Spiegel criteria | 28.5 | |
| Middle East/North Africa | |||||
| Egypt | Assiut, 2001 through 2002 | 480 women 28-37 wks pregnant with threatened premature labor or premature rupture of membranes attending Assiut University Hospital were approached; 468 (97.5%) participated | NS | AC | 33.3 |
| Iran | Zanjan, pre-2009 | 500 nonpregnant, married women randomly selected from 5 PHC clinic attendees in Zanjan | 36 (15–45) | NSS | 16.2 |
| Fars Province, 1996 through 1997 | Stratified random sample in 2 tiers to yield numbers of women in proportions representative of 6 tribes of Qashqai all 839 married women in selected subclans participated; EC: nonmarried, pregnant, menstruating | Ages given in 10-y categories only | NSS | 50 | |
| Stratified random sample in 2 tiers to yield numbers of women in proportions representative of 4 tribes of Mamasani Lor; all 274 married women in selected subclans participated; EC: nonmarried, pregnant, menstruating | Ages given in 10-y categories only | NSS | 49 | ||
| 388 urban women living in Shiraz; selection process not described; EC: nonmarried, pregnant, menstruation | Ages given in 10-y categories only | NSS | 40 | ||
| Hamedan, 2005 | 540 women attending university hospital in Hamedan were recruited to case-control study (270 cases of vaginitis and 270 controls); controls were clients without symptoms of vaginitis; no clear definition of cases or controls provided; selection process NS; BV prevalence in cases and controls, 28.5% and 0.4%, respectively | NS | NSS | 0.4–28.5 | |
| Sudan | Haj Yousif District, pre-2000 | 338 women randomly sampled from periurban community; EC: menstruation | 15–69 | NSS | 17.2 |
| Australia/New Zealand | |||||
| Australia | Melbourne, 2008 | 528 university students who responded to posters on campus; received US$20 | 17–21 | NSS | 4.7 |
| New Zealand | Otago, 2005 through 2007 | 69 pregnant women randomly selected attending ANC; selected as controls for case-control study; EC: ABs or corticosteroids preceding 14 d, diabetes mellitus, vaginal bleeding | 32 | NSS | 8.7 |
| South and Southeast Asia | |||||
| Bangladesh | Dhaka, 2001 through 2002 | 399 randomly selected married women who were attending 5 PHC clinics in city | NS | NSS | 23.2 |
| India | Lucknow, pre-2010 | 200 pregnant women attending routine AN clinic at tertiary hospital | NS | NSS | 13 |
| New Delhi, 2003 through 2004 | 506 symptomatic pregnant women attending AN clinic; EC: ABs in last 14 d, medical illness | 22 (18–35) | NSS | 8.6 | |
| Goa, 2001 through 2003 | Random sample of 2494 nonpregnant women from communities in North Goa; response rate 83.1% | 32.3 (18–45) | NSS | 17.8 | |
| Mysore, 2005 through 2006 | 898 Sexually active women recruited at 2 reproductive health clinics; EC: no sex in last 3 mo | 15–30 | NSS | 19.1 | |
| Chennai, 2002 | 487 women from urban slum area who were enrolled into HIV intervention were evaluated for BV; response rate NS; EC: pregnant | 33 (18–40) | NSS | 24.6 | |
| Indonesia | Jakarta, 1989 through 1990 | 490 pregnant women at 3 hospitals in Jakarta tested for BV at 16-20 wks’ gestation | NS | NSS | 17 |
| Manado, 1999 | Women attending FP clinic were invited to participate; response rate NS; 406 women participated in study and 357 were fully tested for BV | NS | NSS | 32.5 | |
| Laos | Vientiane, 2001 through 2002 | 500 consecutive AN clients; EC: >20 wk pregnant, any bleeding in pregnancy | 25.7 (17–40) | NSS | 22 |
| Vientiane, 2000 through 2001 | 1125 patients attending gynecology OPD attached to referral hospital for first time; EC: ABs in preceding 2 wks, pregnant | 15–49 | NSS | 25 | |
| Myanmar | Yangon, 1999 through 2001 | 227 women, 18-35 wks pregnant, presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 28 (11–42) | NSS | 15.6 |
| Pakistan | Rawalpindi, 2007 through 2008 | 100 consecutive patients in preterm labor; EC: nonsingleton pregnancy | NS | AC | 21 |
| Rawalpindi, 2001 through 2002 | 500 married women randomly sampled from city of Rawalpindi via 2-stage sampling process; EC: unmarried, not living with husband | 15–49 | NSS | 10.3 | |
| Philippines | Manila, 1999 through 2001 | 202 women, 18-35 wks pregnant presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 26 (15–43) | NSS | 7.5 |
| Thailand | Khon Kaen, 1995 | 118 pregnant women attending ANC clinic at Srinagarind Hospital; EC: ABs in preceding 2 wks | 25 (15–40) | NSS | 15.9 |
| Khon Kaen, 1999 through 2001 | 200 women, 18-35 wks pregnant presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 25 (16–42) | NSS | 11.5 | |
| Bangkok, 1999 through 2001 | 200 women, 18-35 wks pregnant presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 25 (16–42) | NSS | 12.5 | |
| Vietnam | Nghe An Province, 2004 | Cross-sectional survey of 505 pregnant women attending AN clinics from 10 communes in Nghe An Province; all pregnant women in region attending PHC clinics were invited to participate; 86% response rate | 27 (15–49) | NSS | 7 |
| Bavi District, 2006 | Community-based cross-sectional random sample (2 stage) of 1012 married women from 17 randomly selected clusters; EC: menstruating | 36 (18–49) | NSS | 11 | |
| Haiphong, pre-2006 | 284 women were randomly selected from rural village and requested to participate in survey; 197 (69.7%) participated | 35.7 | NSS | 27.4 | |
| East Asia and the Pacific | |||||
| China | Beijing, 2009 | 6339 randomly sampled women from 12 districts in Beijing; 99.9% response rate; inclusion criteria: married, nonpregnant, 25-54 y, no gynecological treatment for 1 y | 39.6 (15–54) | AC | 8.7 |
| Shandong, 2004 | Population-based cluster-random sample of 4039 married women in rural part of province; EC: pregnant | 20–49 | AC | 5.9 | |
| Beijing, pre-2010 | 6337 women randomly sampled from 137 communes | 25–54 | AC | 8.7 | |
| Sichuan, 2003 through 2004 | 2000 married women sampled via community-based cluster random sample | 34.3 (20–49) | AC | 15.4 | |
| Tibetan region of Sichuan, 2007 | Conducted at Songpan County, where Tibetans make up about 37% of total population; all women aged 18-72 y were eligible for this study, but selection methodology not clearly outlined; 397 women studied; EC: pregnant, ABs in last 30 d | 18–72 | Hay-Ison criteria | 51.6 | |
| Japan | Hokkaido, 1993 through 2000 | 6083 consecutive AN clients (4-40 wks) attending Otaru Kyokai Hospital | 27.6 (14–46) | NSS | 18.2 |
| Gifu, 1995 | 118 pregnant women attending ANC clinic at Iwasa Hospital; EC: ABs in preceding 2 wks | 28 (21–37) | NSS | 13.6 | |
| Papua New Guinea | Asaro Valley, 1995 | 2-stage randomly selected sample of 201 women from 15 villages from rural Asaro Valley | 15–45 | AC | 9 |
| Sub-Saharan Africa | |||||
| Botswana | Gaborone, 2000 | 703 randomly selected women attending AN clinics; EC: used ABs in previous 2 wks | 25 (15–43) | NSS | 38.1 |
| Burkina Faso | Boulgou, Poni, Seno, and Yatenga Provinces, 2003 | 2133 randomly sampled pregnant women from 98 AN clinics in 4 provinces; 93% response rate | 24 (15–49) | NSS | 6.4 |
| Ouagadougou, 2003 | 2-stage clustered population-based survey of 883 women aged 15-49 y in Ougadougou; response rate 77.7% | 15–49 | NSS | 7.9 | |
| Central African Republic | Bangui, 1996 | 481 women seen at 3 AN clinics; response rate NS | NSS | 29.1 | |
| The Gambia | Farafenni, 1999 | 20 of 40 villages in region were sampled; all women aged 15-54 y were invited to participate; 1348 of 1871 (72%) participated; no EC | 15–54 | NSS | 37 |
| Ghana | Accra, 2001 | 100 nonpregnant women sampled from FP clinic | 28 (19–48) | NSS | 25 |
| Mozambique | Maputo, 2003 | 435 first-time female attendees of youth-friendly clinic | 19.2 (14–24) | NSS | 12.9 |
| Nigeria | Benin City, 2005 | 241 healthy premenopausal women (healthy defined as “having no symptoms or signs of major disease including HIV”) attending reproductive health care service in Benin City | 32 (±16) | NSS | 14.2 |
| South Africa | Durban, 1994 through 1995 | 168 consecutive women presenting to large urban hospital for first AN visit; EC: >30 wks’ gestation | 24 (16–44) | NSS | 52 |
| Elandsdoorn, pre-2011 | 101 women coming for HIV testing at testing center; 51% tested HIV positive | NS | NSS | 34 | |
| Rural KwaZulu, 2002 | 277 consecutive clients presenting to ANC and FP clinics at 2 rural PHC clinics | 23 (14–52) | NSS | 58 | |
| Khayelitsha, 2000 through 2002 | Nested case-control study of 5110 women enrolled in cervical cancer screening trial in periurban, mostly informal housing settlement; trial was open to all women in community; during follow-up for up to 36 mo, 86 new HIV seroconverters (case patients) were identified; 324 nonseroconverting control subjects were frequency matched to case patients by age and duration of follow-up; BV prevalence was 58.3% and 68.7% in controls and cases, respectively | 35–65 | NSS | 58.3 | |
| Tanzania | Moshi, 1999 | 382 randomly selected women attending maternal and child health and FP clinics (179 were pregnant); BV prevalence in pregnant women 31.4%, nonpregnant women 36.0%, and all women 33.9% | 26.6 (16–46) | AC | 33.9 |
| Moshi, 2002 through 2004 | 2654 pregnant women in third trimester randomly selected from 2 PHC clinics (BV prevalence in HIV-positive and -negative women, 37.2% and 19.6%, respectively) | 24 (14–43) | AC | 20.9 | |
| Uganda | Rakai, pre-2006 | 1264 wives or long-term partners of men enrolled into RCT to evaluate effect of circumcision on HIV transmission; 95.2% of women were HIV negative at baseline | NS | NSS | 34.3 |
| Zimbabwe | Harare, 2000 | 393 consecutive, consenting women, presenting to 2 PHC clinics in Harare for ANC, FP, or bringing their children to attend preventive care clinics | 15–49 | NSS | 30.3 |
| Harare, 1999 through 2001 | 210 women, 18-35 wks pregnant, presenting for routine ANC were randomly selected; part of International Infections in Pregnancy study; all slides were analyzed at 1 central laboratory by experienced team; EC: ABs in preceding 2 wks, symptoms of vaginitis | 23 (12–41) | NSS | 24.4 |
a All studies were cross-sectional unless otherwise specified.
| Variable | HIV prevalence 2009 (% aged 15-49 y) a | BV summary indicator b |
|---|---|---|
| Low | ||
| Australia and New Zealand | 0.1 | 0 (0/2) |
| East Asia and the Pacific | 0.1 | 0 (0/2) |
| Western Europe | 0.2 | 0 (0/10) |
| North Africa and Middle East | 0.2 | 0 (0/6) |
| Range (median) | 0.1–0.2 (0.2) | (0-0) 0 |
| Moderate | ||
| South and Southeast Asia | 0.3 | 5 (1/19) |
| Latin America and Caribbean | 0.5 | 30 (3/10) |
| North America | 0.5 | 0 (0/6) |
| Eastern Europe and central Asia | 0.8 | 0 (0/1) |
| Range (median) | 0.3–0.8 (0.5) | 0-30 (5) |
| High | ||
| Sub-Saharan Africa | 5.0 | 50 (6/12) |
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