Estimated Incidence and Genotypes of HIV-1 among Pregnant Women in Central Brazil

Zelma Bernardes Costa,Marilia Dalva Turchi,Jose Vicente Macedo Filho,Noemia Teixeira De Siqueira Filha,Celina Maria Turchi Martelli,Yanna Andressa Ramos De Lima,Wayner Vieira De Souza,Mariane Martins De Araujo Stefani,Walter Costa Borges,Clidenor Gomes Filho,Ana Lucia Minuzzi,Julian W Tang

doi:10.1371/journal.pone.0079189

Abstract

ObjectiveTo estimate the incidence of HIV-1 infection among pregnant women from central-western Brazil.DesignObservational cross-sectional study.MethodsA total of 54,139 pregnant women received antenatal HIV screening from a network of public healthcare centers in 2011. The incidence of confirmed HIV-1 infection was estimated using the Serological Testing Algorithms for Recent HIV Seroconversion (STARHS) methodology and BED-capture enzyme immunoassay (BED-CEIA). The yearly incidence was calculated, and adjusted incidence rates were estimated. For a subgroup of patients, protease and partial reverse transcriptase regions were retrotranscribed from plasma HIV-1 RNA and sequenced after performing a nested polymerase chain reaction.ResultsOf the participants, 20% had a pregnancy before the age of 18 and approximately 40% were experiencing their first pregnancy. Of the 54,139 pregnant women screened, 86 had a confirmed HIV-1 diagnosis, yielding an overall prevalence of 1.59 cases per 1000 women (95% CI 1.27–1.96). A higher prevalence was detected in the older age groups, reflecting cumulative exposure to the virus over time. Among the infected pregnant women, 20% were considered recently infected according to the BED-CEIA. The estimated incidence of HIV infection was 0.61 per 1000 person-years (95% CI 0.33-0.89); the corrected incidence was 0.47 per 1000 person-years (95% CI 0.26-0.68). In a subgroup of patients, HIV-1 subtype C (16.7%) was the second most prevalent form after subtype B (66.7%); BF1 recombinants (11.1%) and one case of subtype F1 (5.5%) were also detected.ConclusionThis study highlights the potential for deriving incidence estimates from a large antenatal screening program for HIV. The rate of recent HIV-1 infection among women in their early reproductive years is a public health warning to implement preventive measures.

Highlights

Approximately 34.0 million people are living with HIV
According to the epidemic types defined by UNAIDS [4], the country has a concentrated epidemic because it has a high prevalence of HIV-1 (>5%) among vulnerable subpopulations, such as female sex workers, drug users and men who have sex with men [5], and less than a 1% infection rate among pregnant women in urban areas [6,7]
Of the 87 women who returned for ELISA and western blot confirmatory tests performed on venous blood samples, 86 had confirmed cases of HIV-1 infection (Figure 1)

Summary

Introduction

Approximately 34.0 million people are living with HIV. Sub-Saharan Africa (where 1.0% of adults are estimated to be infected with HIV) is the most seriously affected region of the world, followed by the Caribbean, Eastern Europe and Central Asia [1]. According to the epidemic types defined by UNAIDS [4], the country has a concentrated epidemic because it has a high prevalence of HIV-1 (>5%) among vulnerable subpopulations, such as female sex workers, drug users and men who have sex with men [5], and less than a 1% infection rate among pregnant women in urban areas [6,7]. This epidemiologic pattern is different from the profile of a generalized epidemic, which is characterized by a high HIV-1 prevalence in the general population, as several countries on the African continent have experienced [8]

Methods

Results

Conclusion