Kristjana Ásbjörnsdóttir

Compartmentalized Cytomegalovirus Replication and Transmission in the Setting of Maternal HIV-1 Infection

BACKGROUND Cytomegalovirus (CMV) infection is associated with adverse outcomes in human immunodeficiency virus (HIV)-exposed infants. Determinants of vertical CMV transmission in the setting of maternal HIV-1 infection are not well-defined. METHODS CMV and HIV-1 levels were measured in plasma, cervical secretions, and breast milk of 147 HIV-1-infected women to define correlates of maternal CMV replication and infant CMV acquisition. RESULTS Although few women had detectable CMV in plasma (4.8%), the majority had detectable CMV DNA in cervical secretions (66%) and breast milk (99%). There was a strong association between cervical CMV detection during pregnancy and later breast milk levels (β = 0.47; P = .005). Plasma HIV-1 level and CD4 counts were associated with CMV in the cervix and breast milk. However HIV-1 levels within the cervix and breast milk were not associated with CMV within these compartments. Maternal breast milk CMV levels (hazard ratio [HR], 1.4; P = .003) and maternal CD4 < 450 cells/mm(3) (HR, 1.8; P = .008) were independently associated with infant CMV acquisition; each log10 increase in breast milk CMV was associated with a 40% increase in infant infection. The breast milk CMV level required to attain a 50% probability of CMV transmission increased with higher maternal CD4 counts, increasing from 3.55 log10 CMV DNA copies/mL at a CD4 count of 350 cells/mm(3) to 5.50 log10 CMV DNA copies/mL at a CD4 count of 1000 cells/mm(3). CONCLUSIONS Breast milk CMV levels and maternal CD4 count are major determinants of CMV transmission in the setting of maternal HIV-1. Maternal immune reconstitution or lowering breast milk CMV levels may reduce vertical CMV transmission.

Maternal Valacyclovir and Infant Cytomegalovirus Acquisition A Randomized Controlled Trial among HIV-Infected Women

Background Studies in HIV-1-infected infants and HIV-1-exposed, uninfected infants link early cytomegalovirus (CMV) acquisition with growth delay and cognitive impairment. We investigated maternal valacyclovir to delay infant acquisition of CMV. Methods Pregnant women with HIV-1, HSV-2 and CD4 count >250 cells/µl were randomized at 34 weeks gestation to 500 mg twice-daily valacyclovir or placebo for 12 months. Maternal CMV DNA was measured in plasma at 34 weeks gestation, in cervical secretions at 34 and 38 weeks gestation, and in breast milk at 7 postpartum timepoints; infant CMV DNA was measured in dried blood spots at 8 timepoints including birth. Results Among 148 women, 141 infants were compared in intent-to-treat analyses. Maternal and infant characteristics were similar between study arms. Infant CMV acquisition did not differ between study arms, with 46/70 infants (66%) in placebo arm and 47/71 infants (66%) in the valacyclovir arm acquiring CMV; median time to CMV detection did not differ. CMV DNA was detected in 92% of 542 breast milk specimens with no difference in CMV level between study arms. Change in cervical shedding of CMV DNA between baseline and 38 weeks was 0.40-log greater in the placebo arm than the valacyclovir arm (p = 0.05). Conclusions In this cohort of HIV-1-seropositive mothers, two-thirds of infants acquired CMV by one year. Maternal valacyclovir had no effect on timing of infant CMV acquisition or breast milk CMV viral loads, although it modestly reduced cervical CMV shedding. Maternal prophylaxis to reduce infant CMV acquisition warrants further evaluation in trials with antiviral agents. Trials Registration ClinicalTrials.gov NCT00530777

Breastfeeding is associated with decreased pneumonia incidence among HIV-exposed, uninfected Kenyan infants

Objective:HIV-exposed uninfected (HEU) infants have higher infectious disease morbidity and mortality than unexposed infants. We determined the incidence and risk factors for pneumonia, a leading cause of infant mortality worldwide, in a cohort of HEU infants. Identifying predictors of pneumonia among HEU infants may enable early identification of those at highest risk. Design:A retrospective cohort of HEU infants participating in a Kenyan perinatal HIV study, enrolled between 1999 and 2002. Methods:Infants were followed monthly from birth to 12 months. Incidence of pneumonia diagnosed at monthly study visits, sick-child visits or by means of averbal autopsy was estimated with a 14-day window for new episodes. Cox proportional hazards regression was used to identify predictors of first pneumonia occurrence. Results:Among 388 HEU infants with 328 person-years of follow-up, the incidence of pneumonia was 900/1000 child-years [95% confidence interval (CI) 800–1000]. Maternal HIV viral load at 32 weeks’ gestation [hazard ratio 1.2 (1.0–1.5) per log10 difference] and being underweight (weight-for-age Z-score <−2) at the previous visit [hazard ratio 1.8 (1.1–2.8)] were associated with increased risk of pneumonia. Breastfed infants had a 47% lower risk of pneumonia than those never breastfed [hazard ratio 0.53 (0.39–0.73)], independent of infant growth, maternal viral load and maternal CD4%. Breastfeeding was also associated with a 74% lower risk of pneumonia-related hospitalization [hazard ratio 0.26 (0.13–0.53)]. Conclusions:The incidence of pneumonia in this cohort of HEU infants was high. Our observations suggest that maternal viral suppression and breastfeeding may reduce the burden of pneumonia among HEU infants.

Assisted partner services for HIV in Kenya: a cluster randomised controlled trial

BACKGROUND Assisted partner services for index patients with HIV infections involves elicitation of information about sex partners and contacting them to ensure that they test for HIV and link to care. Assisted partner services are not widely available in Africa. We aimed to establish whether or not assisted partner services increase HIV testing, diagnoses, and linkage to care among sex partners of people with HIV infections in Kenya. METHODS In this cluster randomised controlled trial, we recruited non-pregnant adults aged at least 18 years with newly or recently diagnosed HIV without a recent history of intimate partner violence who had not yet or had only recently linked to HIV care from 18 HIV testing services clinics in Kenya. Consenting sites in Kenya were randomly assigned (1:1) by the study statistician (restricted randomisation; balanced distribution in terms of county and proximity to a city) to immediate versus delayed assisted partner services. Primary outcomes were the number of partners tested for HIV, the number who tested HIV positive, and the number enrolled in HIV care, in those who were interviewed at 6 week follow-up. Participants within each cluster were masked to treatment allocation because participants within each cluster received the same intervention. This trial is registered with ClinicalTrials.gov, number NCT01616420. FINDINGS Between Aug 12, 2013, and Aug 31, 2015, we randomly allocated 18 clusters to immediate and delayed HIV assisted partner services (nine in each group), enrolling 1305 participants: 625 (48%) in the immediate group and 680 (52%) in the delayed group. 6 weeks after enrolment of index patients, 392 (67%) of 586 partners had tested for HIV in the immediate group and 85 (13%) of 680 had tested in the delayed group (incidence rate ratio 4·8, 95% CI 3·7-6·4). 136 (23%) partners had new HIV diagnoses in the immediate group compared with 28 (4%) in the delayed group (5·0, 3·2-7·9) and 88 (15%) versus 19 (3%) were newly enrolled in care (4·4, 2·6-7·4). Assisted partner services did not increase intimate partner violence (one intimate partner violence event related to partner notification or study procedures occurred in each group). INTERPRETATION Assisted partner services are safe and increase HIV testing and case-finding; implementation at the population level could enhance linkage to care and antiretroviral therapy initiation and substantially decrease HIV transmission. FUNDING National Institutes of Health.

Changes in vaginal microbiota and immune mediators in HIV-1-seronegative Kenyan women initiating depot medroxyprogesterone acetate

Background:Depot medroxyprogesterone acetate (DMPA) is associated with HIV acquisition. We studied changes in vaginal microbiota and inflammatory milieu after DMPA initiation. Methods:In a cohort of HIV-negative Kenyan women, we collected monthly vaginal swabs over 1 year before and after DMPA. Using quantitative polymerase chain reaction, we compared quantities of Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus iners, Gardnerella vaginalis, and total bacterial load (16S ribosomal RNA gene levels). Six vaginal immune mediators were measured with enzyme-linked immunosorbent assay. Trends in the detection and quantity of bacteria were estimated by logistic and linear mixed-effects regression. Results:From 2010 to 2012, 15 HIV-seronegative women initiated DMPA, contributing 85 visits (median, 6 visits/woman; range, 3–8 visits/woman). The median time of DMPA-exposed follow-up was 8.4 months (range, 1.5–11.6 months). Seven women (46%) had bacterial vaginosis within 70 days before DMPA start. L. iners was detected in 13 women (87%) before DMPA start, but other lactobacilli were rarely detected. Gardnerella vaginalis decreased by 0.21 log10 copies per swab per month after DMPA exposure (P = 0.01). Total bacterial load decreased by 0.08 log10 copies per swab per month of DMPA (P = 0.02). Sustained decreases in interleukin (IL)-6 (P = 0.03), IL-8 (P = 0.04), and IL-1 receptor antagonist (P < 0.001) were also noted. Nine women (60%) had L. crispatus detected post-DMPA, which significantly correlated with reduced IL-6 (P < 0.01) and IL-8 (P = 0.02). Conclusions:Initiation of DMPA led to sustained shifts in vaginal bacterial concentrations and levels of inflammatory mediators. Further studies are warranted to outline components of the vaginal microbiota influenced by DMPA use and impact on HIV susceptibility.

Sustaining Progress towards NTD Elimination: An Opportunity to Leverage Lymphatic Filariasis Elimination Programs to Interrupt Transmission of Soil-Transmitted Helminths

In light of the unprecedented momentum to control or eliminate ten neglected tropical diseases (NTDs) by 2020, the NTD community is at a crossroads of opportunity. Efforts to eliminate lymphatic filariasis (LF) using mass drug administration (MDA) platforms have dramatically and simultaneously increased the number of individuals treated for soil-transmitted helminths (STHs) in many areas, owing to overlaps in endemicity and drug efficacy. A concomitant reduction in STH infection raises the possibility of moving beyond current World Health Organization (WHO) morbidity control guidelines to actual disease elimination for STHs [1]. We identify specific rationale, opportunities, and challenges associated with leveraging existing LF elimination platforms for the purpose of interrupting STH transmission.

Identifying optimal threshold statistics for elimination of hookworm using a stochastic simulation model

BackgroundThere is an increased focus on whether mass drug administration (MDA) programmes alone can interrupt the transmission of soil-transmitted helminths (STH). Mathematical models can be used to model these interventions and are increasingly being implemented to inform investigators about expected trial outcome and the choice of optimum study design. One key factor is the choice of threshold for detecting elimination. However, there are currently no thresholds defined for STH regarding breaking transmission.MethodsWe develop a simulation of an elimination study, based on the DeWorm3 project, using an individual-based stochastic disease transmission model in conjunction with models of MDA, sampling, diagnostics and the construction of study clusters. The simulation is then used to analyse the relationship between the study end-point elimination threshold and whether elimination is achieved in the long term within the model. We analyse the quality of a range of statistics in terms of the positive predictive values (PPV) and how they depend on a range of covariates, including threshold values, baseline prevalence, measurement time point and how clusters are constructed.ResultsEnd-point infection prevalence performs well in discriminating between villages that achieve interruption of transmission and those that do not, although the quality of the threshold is sensitive to baseline prevalence and threshold value. Optimal post-treatment prevalence threshold value for determining elimination is in the range 2% or less when the baseline prevalence range is broad. For multiple clusters of communities, both the probability of elimination and the ability of thresholds to detect it are strongly dependent on the size of the cluster and the size distribution of the constituent communities. Number of communities in a cluster is a key indicator of probability of elimination and PPV. Extending the time, post-study endpoint, at which the threshold statistic is measured improves PPV value in discriminating between eliminating clusters and those that bounce back.ConclusionsThe probability of elimination and PPV are very sensitive to baseline prevalence for individual communities. However, most studies and programmes are constructed on the basis of clusters. Since elimination occurs within smaller population sub-units, the construction of clusters introduces new sensitivities for elimination threshold values to cluster size and the underlying population structure. Study simulation offers an opportunity to investigate key sources of sensitivity for elimination studies and programme designs in advance and to tailor interventions to prevailing local or national conditions.

Vertical Cytomegalovirus Transmission From HIV-Infected Women Randomized to Formula-Feed or Breastfeed Their Infants

BACKGROUND Cytomegalovirus (CMV) is associated with morbidity and mortality in human immunodeficiency virus (HIV)-exposed infants. We assessed the effect of and relative contribution of breastfeeding to CMV acquisition among infants delivered by HIV-infected mothers. METHODS Between 1993 and 1998 pregnant, HIV-infected women in Nairobi, Kenya, were randomly assigned to breastfeed or formula-feed their infants in an HIV transmission study. Women were allocated equally between treatment arms, and the study was not blinded. The primary endpoint of this nested study was time to infant CMV infection. RESULTS CMV infection was assessed in 138 breastfed and 134 formula-fed infants. Baseline characteristics were similar between arms. Breastfed infants acquired CMV earlier than formula-fed infants (median age of acquisition, 4.26 vs 9.87 months; P < .001) and had a higher 1-year probability of CMV infection (0.89 vs 0.69; P < .001). Breastfeeding was associated with a 1.6-fold increased risk of infant CMV acquisition independent of infant HIV status (multivariable hazard ratio, 1.61; 95% confidence interval, 1.20-2.16; P = .002). Approximately one third of CMV infections occurred during the peripartum period, with 40% acquired through breastfeeding and the remainder acquired through modes other than breast milk. CONCLUSIONS Preventing CMV acquisition may be a priority for HIV-exposed infants, but there is a narrow window of opportunity for intervention. Approaches that reduce maternal cervical and breast milk CMV reactivation may help delay infant infection.

Breastfeeding Is Associated with Decreased Risk of Hospitalization among HIV-Exposed Uninfected Kenyan Infants.

Background: Human immunodeficiency virus (HIV)–exposed uninfected (HEU) infants are a growing population in sub-Saharan Africa, with higher morbidity and mortality than HIV-unexposed infants. HEU infants may experience increased morbidity due to breastfeeding avoidance. Objectives: We sought to describe the burden and identify predictors of hospitalization among HEU infants in the first year of life. Methods: Using a retrospective cohort of HIV-infected mothers and their HEU infants in Nairobi, Kenya, we identified infants who were HIV-uninfected at birth and were followed monthly until their last negative HIV test, death, loss to follow-up, or study exit at 1 year of age. Incidence, timing, and reason for hospitalization was assessed overall as well as stratified by feeding method. Predictors of first infectious disease hospitalization were identified using competing risk regression, with HIV acquisition and death as competing risks. Results: Among 388 infants, 113 hospitalizations were reported (35/100 infant-years [the combined years of observation contributed by all infants in the study]; 95% confidence interval [CI], 29-42). Ninety hospitalizations were due to 1 or more infectious diseases (26/100 infant-years; 95% CI, 21-32)—primarily pneumonia (n = 40), gastroenteritis (n = 17), and sepsis (n = 14). Breastfeeding was associated with decreased risk of infectious disease hospitalization (subhazard ratio = 0.39; 95% CI, 0.24-0.64), as was time-updated nutrition status (subhazard ratio = 0.73; 95% CI, 0.61-0.89). Incidence of infectious disease hospitalization among formula-fed infants was 51/100 infant-years (95% CI, 37-70) compared to 19/100 infant-years (95% CI, 14-25) among breastfed infants. Conclusion: Among HEU infants, breastfeeding and nutrition status were associated with reduced hospitalization during the first year of life.

A comparative analysis of preservation techniques for the optimal molecular detection of hookworm DNA in a human fecal specimen

Background Proper collection and storage of fecal samples is necessary to guarantee the subsequent reliability of DNA-based soil-transmitted helminth diagnostic procedures. Previous research has examined various methods to preserve fecal samples for subsequent microscopic analysis or for subsequent determination of overall DNA yields obtained following DNA extraction. However, only limited research has focused on the preservation of soil-transmitted helminth DNA in stool samples stored at ambient temperature or maintained in a cold chain for extended periods of time. Methodology Quantitative real-time PCR was used in this study as a measure of the effectiveness of seven commercially available products to preserve hookworm DNA over time and at different temperatures. Results were compared against “no preservative” controls and the “gold standard” of rapidly freezing samples at -20°C. The preservation methods were compared at both 4°C and at simulated tropical ambient temperature (32°C) over a period of 60 days. Evaluation of the effectiveness of each preservative was based on quantitative real-time PCR detection of target hookworm DNA. Conclusions At 4°C there were no significant differences in DNA amplification efficiency (as measured by Cq values) regardless of the preservation method utilized over the 60-day period. At 32°C, preservation with FTA cards, potassium dichromate, and a silica bead two-step desiccation process proved most advantageous for minimizing Cq value increases, while RNA later, 95% ethanol and Paxgene also demonstrate some protective effect. These results suggest that fecal samples spiked with known concentrations of hookworm-derived egg material can remain at 4°C for 60 days in the absence of preservative, without significant degradation of the DNA target. Likewise, a variety of preservation methods can provide a measure of protection in the absence of a cold chain. As a result, other factors, such as preservative toxicity, inhibitor resistance, preservative cost, shipping requirements, sample infectivity, and labor costs should be considered when deciding upon an appropriate method for the storage of fecal specimens for subsequent PCR analysis. Balancing logistical factors and the need to preserve the target DNA, we believe that under most circumstances 95% ethanol provides the most pragmatic choice for preserving stool samples in the field.