William J Moss

University of California, San Francisco, San Francisco, California, United States

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Publications (126)802.1 Total impact

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    ABSTRACT: Background: The meningococcal conjugate vaccine (MCV4) and the tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine (Tdap) were first recommended for adolescents in the United States in 2005. The goal of our study was to determine MCV4 & Tdap vaccines coverage among perinatally and behaviorally HIV-infected adolescents in 2006 and to compare coverage estimates in our study population to similarly aged healthy youth in 2006. Methods: LEGACY is a retrospective cohort study of HIV-infected youth in 22 HIV specialty clinics across the United States. Among LEGACY participants ≥11 years of age in 2006, we conducted a cross-sectional analysis to determine MCV4, Tdap, and MCV4/Tdap vaccine coverage. We compared vaccine coverage among our study population to coverage among similarly aged youth in the 2006 NIS-Teen Survey. Multivariable mixed effects logistic regression modeling was used to examine associations between MCV4/Tdap vaccination and mode of HIV transmission. Results: MCV4 and Tdap coverage rates among 326 eligible participants were 31.6% and 28.8% respectively. Among adolescents 13-17 years of age, MCV4 and Tdap coverage was significantly higher among HIV-infected youth than among youth in the 2006 NIS-Teen Survey (p <0.01). In multivariable analysis, perinatally HIV-infected youth were significantly more likely to have received MCV4/Tdap vaccination compared with their behaviorally infected counterparts (AOR 5.1, 95% CI 2.0, 12.7). HIV infected youth with CD4 cell counts of 200-499 cells/µL were more likely to have had MCV4/Tdap vaccination compared with those with CD4 counts ≥500cells/µL (AOR 2.2, 95% CI 1.2, 4.3). Participants with plasma HIV RNA viral loads of >400 copies/ml were significantly less likely to have received MCV4/Tdap vaccination (p< 0.05). Conclusions: MCV4 and Tdap coverage among HIV-infected youth was suboptimal but higher than for healthy adolescents in the 2006 NIS-Teen Survey. Perinatal HIV infection was associated with increased likelihood of vaccination. Specific measures are needed to improve vaccine coverage among adolescents in the United States.
    No preview · Article · Feb 2016 · The Pediatric Infectious Disease Journal
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    ABSTRACT: Rapid diagnostic tests (RDTs) detecting histidine-rich protein 2 (PfHRP2) antigen are used to identify individuals with Plasmodium falciparum infection even in low transmission settings seeking to achieve elimination. However, these RDTs lack sensitivity to detect low-density infections, produce false negatives for P. falciparum strains lacking pfhrp2 gene and do not detect species other than P. falciparum. Results of a PfHRP2-based RDT and Plasmodium nested PCR were compared in a region of declining malaria transmission in southern Zambia using samples from community-based, cross-sectional surveys from 2008 to 2012. Participants were tested with a PfHRP2-based RDT and a finger prick blood sample was spotted onto filter paper for PCR analysis and used to prepare blood smears for microscopy. Species-specific, real-time, quantitative PCR (q-PCR) was performed on samples that tested positive either by microscopy, RDT or nested PCR. Of 3,292 total participants enrolled, 12 (0.4%) tested positive by microscopy and 42 (1.3%) by RDT. Of 3,213 (98%) samples tested by nested PCR, 57 (1.8%) were positive, resulting in 87 participants positive by at least one of the three tests. Of these, 61 tested positive for P. falciparum by q-PCR with copy numbers ≤ 2 x 10(3) copies/μL, 5 were positive for both P. falciparum and Plasmodium malariae and 2 were positive for P. malariae alone. RDT detected 32 (53%) of P. falciparum positives, failing to detect three of the dual infections with P. malariae. Among 2,975 participants enrolled during a low transmission period between 2009 and 2012, sensitivity of the PfHRP2-based RDT compared to nested PCR was only 17%, with specificity of >99%. The pfhrp gene was detected in 80% of P. falciparum positives; however, comparison of copy number between RDT negative and RDT positive samples suggested that RDT negatives resulted from low parasitaemia and not pfhrp2 gene deletion. Low-density P. falciparum infections not identified by currently used PfHRP2-based RDTs and the inability to detect non-falciparum malaria will hinder progress to further reduce malaria in low transmission settings of Zambia. More sensitive and specific diagnostic tests will likely be necessary to identify parasite reservoirs and achieve malaria elimination.
    Full-text · Article · Dec 2015 · Malaria Journal
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    ABSTRACT: Measles cases may cluster in densely populated urban centers in sub-Saharan Africa as susceptible individuals share spatially dependent risk factors and may cluster among human immunodeficiency virus (HIV)-infected children despite high vaccination coverage. Children hospitalized with measles at the University Teaching Hospital (UTH) in Lusaka, Zambia were enrolled in the study. The township of residence was recorded on the questionnaire and mapped; SaTScan software was used for cluster detection. A spatial-temporal scan statistic was used to investigate clustering of measles in children hospitalized during an endemic period (1998 to 2002) and during the 2010 measles outbreak in Lusaka, Zambia. Three sequential and spatially contiguous clusters of measles cases were identified during the 2010 outbreak but no clustering among HIV-infected children was identified. In contrast, a space-time cluster among HIV-infected children was identified during the endemic period. This cluster occurred prior to the introduction of intensive measles control efforts and during a period between seasonal peaks in measles incidence. Prediction and early identification of spatial clusters of measles will be critical to achieving measles elimination. HIV infection may contribute to spatial clustering of measles cases in some epidemiological settings.
    No preview · Article · Dec 2015 · BMC Infectious Diseases
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    ABSTRACT: Background: While care and treatment are available to many human immunodeficiency virus (HIV)-infected children, barriers remain that delay initiation of antiretroviral therapy (ART). Minimizing these barriers is critical to starting ART at earlier ages. Methods: Reasons for delay were evaluated among 200 children younger than 15 years of age initiating treatment in an HIV clinic in rural Zambia from 2011-2013. Results: The median age of children at ART eligibility was 2.9 years and 49% were male. After being determined eligible, 60% of children delayed ART initiation for a median of 28 days (IQR:14,75). Primary reasons for delay included waiting for test results, adherence issues, and concurrent treatment for tuberculosis. When reasons for delay were categorized by type, 36% of children had family-related delays, 32% had delays due to clinic logistics, 27% had health-related delays, and 6% had other or no identified reasons for delay. The median time between eligibility and ART initiation was shortest for children with delays due to clinic logistics (median:18 days; IQR:14,35). Children with family-related delays tended to be older and orphaned, whereas children with delays due to clinic logistics tended to be younger, and children with health-related delays tended to have more advanced disease. In the first year of ART, no association was found between adherence and type of delay. CD4 T-cell percentages and weight-for-age z-scores were lower for children with health-related delays. Conclusions: Strategies to reduce delays in ART initiation will need to address a diverse set of issues so children can benefit from earlier treatment.
    No preview · Article · Nov 2015 · The Pediatric Infectious Disease Journal
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    ABSTRACT: Malaria risk maps may be used to guide policy decisions on whether vector control interventions should be targeted and, if so, where. Active surveillance for malaria was conducted through household surveys in Nchelenge District, Zambia from April 2012 through December 2014. Households were enumerated based on satellite imagery and randomly selected for study enrollment. At each visit, participants were administered a questionnaire and a malaria rapid diagnostic test (RDT). Logistic regression models were used to construct spatial prediction risk maps and maps of risk uncertainty. A total of 461 households were visited, comprising 1,725 participants, of whom 48% were RDT positive. Several environmental features were associated with increased household malaria risk in a multivariable logistic regression model with seasonal variation. The model was validated using both internal and external evaluation measures to generate and assess root mean square error, as well as sensitivity and specificity for predicted risk. The final, validated model was used to predict and map malaria risk including a measure of risk uncertainty. Malaria risk in a high, perennial transmission setting is widespread but heterogeneous at a local scale, with seasonal variation. Targeting malaria control interventions may not be appropriate in this epidemiological setting.
    No preview · Article · Sep 2015 · The American journal of tropical medicine and hygiene
  • Shaun A Truelove · William J Moss · Justin Lessler
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    ABSTRACT: The Ebola outbreak in 2014-2015 devastated the populations, economies and healthcare systems of Guinea, Liberia and Sierra Leone. With this devastation comes the impending threat of outbreaks of other infectious diseases like measles. Strategies for mitigating these risks must include both prevention, through vaccination, and case detection and management, focused on surveillance, diagnosis and appropriate clinical care and case management. With the high transmissibility of measles virus, small-scale reactive vaccinations will be essential to extinguish focal outbreaks, while national vaccination campaigns are needed to guarantee vaccination coverage targets are reached in the long term. Rapid and multifaceted strategies should carefully navigate challenges present in the wake of Ebola, while also taking advantage of current Ebola-related activities and international attention. Above all, resources and focus currently aimed at these countries must be utilized to build up the deficit in infrastructure and healthcare systems that contributed to the extent of the Ebola outbreak.
    No preview · Article · Sep 2015 · Expert Review of Anti-infective Therapy
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    ABSTRACT: Understanding factors influencing sustained use of long-lasting insecticide-treated nets (LLIN) in areas of declining malaria transmission is critical to sustaining control and may facilitate elimination. From 2008 to 2013, 655 households in Choma District, Zambia, were randomly selected and residents were administered a questionnaire and malaria rapid diagnostic test. Mosquitoes were collected concurrently by light trap. In a multilevel model, children and adolescents of 5-17 years of age were 55% less likely to sleep under LLIN than adults (odds ratio [OR] = 0.45; 95% confidence interval [CI] = 0.35, 0.58). LLIN use was 80% higher during the rainy season (OR = 1.8; CI = 1.5, 2.2) and residents of households with three or more nets were over twice as likely to use a LLIN (OR = 2.1; CI = 1.4, 3.1). For every increase in 0.5 km from the nearest health center, the odds of LLIN use decreased to 9% (OR = 0.9; CI = 0.88, 0.98). In a second multilevel model, the odds of LLIN use were more than twice high if more than five mosquitoes (anopheline and culicine) were captured in the house compared with households with no mosquitoes captured (OR = 2.1; CI = 1.1, 3.9). LLIN use can be sustained in low-transmission settings with continued education and distributions, and may be partially driven by the presence of nuisance mosquitoes. © The American Society of Tropical Medicine and Hygiene.
    No preview · Article · Aug 2015 · The American journal of tropical medicine and hygiene
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    ABSTRACT: Understanding the epidemiological features and metrics of malaria in endemic populations is a key component to monitoring and quantifying the impact of current and past control efforts to inform future ones. The International Centers of Excellence for Malaria Research (ICEMR) has the opportunity to evaluate the impact of malaria control interventions across endemic regions that differ in the dominant Plasmodium species, mosquito vector species, resistance to antimalarial drugs and human genetic variants thought to confer protection from infection and clinical manifestations of plasmodia infection. ICEMR programs are conducting field studies at multiple sites with the aim of generating standardized surveillance data to improve the understanding of malaria transmission and to monitor and evaluate the impact of interventions to inform malaria control and elimination programs. In addition, these epidemiological studies provide a vast source of biological samples linked to clinical and environmental "meta-data" to support translational studies of interactions between the parasite, human host, and mosquito vector. Importantly, epidemiological studies at the ICEMR field sites are integrated with entomological studies, including the measurement of the entomological inoculation rate, human biting index, and insecticide resistance, as well as studies of parasite genetic diversity and antimalarial drug resistance. © The American Society of Tropical Medicine and Hygiene.
    Full-text · Article · Aug 2015 · The American journal of tropical medicine and hygiene
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    ABSTRACT: In Choma District, southern Zambia, the neonatal mortality rate is approximately 40 per 1000 live births and, although the rate is decreasing, many deliveries take place outside of formal facilities. Understanding local practices during the postnatal period is essential for optimizing newborn care programs. We conducted 36 in-depth interviews, five focus groups and eight observational sessions with recently-delivered women, traditional birth attendants, and clinic and hospital staff from three sites, focusing on skin, thermal and cord care practices for newborns in the home. Newborns were generally kept warm by application of hats and layers of clothing. While thermal protection is provided for preterm and small newborns, the practice of nighttime bathing with cold water was common. The vernix was considered important for the preterm newborn but dangerous for HIV-exposed infants. Mothers applied various substances to the skin and umbilical cord, with special practices for preterm infants. Applied substances included petroleum jelly, commercial baby lotion, cooking oil and breastmilk. The most common substances applied to the umbilical cord were powders made of roots, burnt gourds or ash. To ward off malevolent spirits, similar powders were reportedly placed directly into dermal incisions, especially in ill children. Thermal care for newborns is commonly practiced but co-exists with harmful practices. Locally appropriate behavior change interventions should aim to promote chlorhexidine in place of commonly-reported application of harmful substances to the skin and umbilical cord, reduce bathing of newborns at night, and address the immediate bathing of HIV-infected newborns.
    Full-text · Article · Jul 2015 · BMC Pregnancy and Childbirth
  • Marcia H Varella · William J Moss
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    ABSTRACT: To assess whether patterns of growth trajectory during infancy are associated with intelligence quotient (IQ) scores at 4years of age in children born small-for-gestational age (SGA). Children in the Collaborative Perinatal Project born SGA were eligible for analysis. The primary outcome was the Stanford-Binet IQ score at 4years of age. Growth patterns were defined based on changes in weight-for-age z-scores from birth to 4months and 4 to 12months of age and consisted of steady, early catch-up, late catch-up, constant catch-up, early catch-down, late catch-down, constant catch-down, early catch-up & late catch-down, and early catch-down & late catch-up. Multivariate linear regression was used to assess associations between patterns of growth and IQ. We evaluated patterns of growth and IQ in 5640 children. Compared with children with steady growth, IQ scores were 2.9 [standard deviation (SD)=0.54], 1.5 (SD=0.63), and 2.2 (SD=0.9) higher in children with early catch-up, early catch-up and later catch-down, and constant catch-up growth patterns, respectively, and 4.4 (SD=1.4) and 3.9 (SD=1.5) lower in children with early catch-down & late catch-up, and early catch-down growth patterns, respectively. Patterns in weight gain before 4months of age were associated with differences in IQ scores at 4years of age, with children with early catch-up having slightly higher IQ scores than children with steady growth and children with early catch-down having slightly lower IQ scores. These findings have implications for early infant nutrition in children born SGA. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
    No preview · Article · Jun 2015 · Early human development
  • Catherine G Sutcliffe · William J Moss · Philip E Thuma
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    ABSTRACT: This report summarizes 2 children misdiagnosed with HIV infection in a clinic in rural Zambia and discusses the implications of false-positive HIV DNA tests in HIV-exposed infants, including the potential magnitude of the problem. Recommendations are needed to address the management of children receiving antiretroviral therapy who are suspected of being uninfected.
    No preview · Article · Jun 2015 · The Pediatric Infectious Disease Journal
  • Catherine G Sutcliffe · William J Moss

    No preview · Article · Jun 2015 · The Lancet Infectious Diseases
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    ABSTRACT: Although malaria is preventable and treatable, it still claims 660,000 lives every year globally with children under five years of age having the highest burden. In Zambia, malaria rapid diagnostic tests (RDTs) that only detect Plasmodium falciparum are the main confirmatory means for malaria diagnosis in most health facilities without microscopy services. As a consequence of this P. falciparum species diagnostic approach, non-falciparum malaria is not only under-diagnosed but entirely missed, thereby making the exact disease burden unknown. We thus investigated the prevalence of various Plasmodium spp. and associated burden of infection in selected communities in Zambia. Data from two malaria hyper-endemic provinces (Eastern and Luapula) of the 2012 National Malaria Indicator Survey (MIS), conducted between April and May 2012, were used. The MIS is a nationally representative, two-stage cluster survey conducted to coincide with the end of the malaria transmission season. Social, behavioural and background information were collected from households as part of the survey. Thick blood smears, RDTs and dried blood spots (DBS) were collected from children below six years of age. Slides were stained using Giemsa and examined by microscopy while polymerase chain reaction (PCR) was used to analyse the DBS for malaria Plasmodium spp. Multivariate logistic regression was employed to examine the association between background factors and malaria. Overall, 873 children younger than six years of age were surveyed. The overall prevalence of Plasmodium spp. by PCR was 54.3% (95% CI 51-57.6%). Of the total Plasmodium isolates, 88% were P. falciparum, 10.6% were mixed infections and 1.4% were non-falciparum mono infections. Among the mixed infections, the majority were a combination of P. falciparum and P. malariae (6.5% of all mixed infections). Children two years and older (2-5 years) had three-fold higher risk of mixed malaria infections (aOR 2.8 CI 1.31-5.69) than children younger than two years of age. The high prevalence of mixed Plasmodium spp. infections in this population stresses review of the current malaria RDT diagnostic approaches. The observed less incidence of mixed infections in children under two years of age compared to their older two-to-five-year-old counterparts is probably due to the protective maternal passive immunity, among other factors, in that age group.
    Full-text · Article · May 2015 · BMC Infectious Diseases
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    ABSTRACT: The Ebola epidemic in West Africa has caused substantial morbidity and mortality. The outbreak has also disrupted health care services, including childhood vaccinations, creating a second public health crisis. We project that after 6 to 18 months of disruptions, a large connected cluster of children unvaccinated for measles will accumulate across Guinea, Liberia, and Sierra Leone. This pool of susceptibility increases the expected size of a regional measles outbreak from 127,000 to 227,000 cases after 18 months, resulting in 2000 to 16,000 additional deaths (comparable to the numbers of Ebola deaths reported thus far). There is a clear path to avoiding outbreaks of childhood vaccine-preventable diseases once the threat of Ebola begins to recede: an aggressive regional vaccination campaign aimed at age groups left unprotected because of health care disruptions. Copyright © 2015, American Association for the Advancement of Science.
    No preview · Article · Mar 2015 · Science

  • No preview · Article · Jan 2015 · The Lancet
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    ABSTRACT: High-resolution satellite imagery can be used to establish a sampling frame for epidemiologic research and to describe patterns of household distribution and movement. Assessing the frequency and geographic distribution of household movement by comparing satellite images taken over time may suggest a time period for satellite image accuracy and utility for epidemiological research. All households in a 575 km2 region of southern Zambia were enumerated based on satellite images taken in 2007 and in 2011. Movement of households in the study area was assessed by comparing the images to calculate the percentage of households that were built, removed or stayed the same. We created a spatial intensity map to identify geographic areas of household movement, and to describe the spatial variation in household movement. There were a total of 3,287 household enumerated in 2007 and 3,721 in 2011. 970 households were newly observed in 2011 and 536 were no longer present. Reporting a net change of 434 households occurring over the four year period does not adequately describe the population movement within this region. Spatial variation around key features, such as around the new sealed road, points to non-uniform dynamics in population movement. These population dynamics may have implications for field studies working in this area over this time period.
    No preview · Conference Paper · Nov 2014
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    ABSTRACT: While malaria transmission has declined substantially throughout parts of Zambia, some areas continue to experience high transmission levels despite deployment of malaria control efforts. Understanding factors associated with continued malaria transmission in these areas may inform control efforts. Household malaria surveys were conducted in Nchelenge District, Luapula Province, Zambia. Households were enumerated based on satellite imagery, 5 x 5 km grid cells were overlaid, and households were randomly chosen within selected grid cells. Households were enrolled into cross-sectional (one visit) or longitudinal (visits every other month) cohorts; analyses were restricted to cross-sectional and the first visit to longitudinal households. During study visits, adults and caretakers of children were administered a questionnaire and a blood sample was collected for a malaria rapid diagnostic test (RDT). Individual and household level factors associated with RDT positivity were analyzed using logistic regression models. A total of 1,201 individuals from 339 households were enrolled. Over the study period, 43% of participants were RDT positive. Over half of RDT positive individuals were between the ages of 5 and 17 years, and half of RDT positive individuals had visited a health center or health post for malaria in the past 6 months. In the multi-variable logistic regression analysis, RDT positive individuals were over twice as likely to be between the ages of 5 and 17 years as compared to children younger than 5 years (OR=2.06; 95% CI: 1.23, 3.44), over half as likely to report a fever within the past two weeks (OR=1.57; 95% CI: 1.04, 2.37), and 73% more likely to live in a household using an open well as the main water source (OR=1.73; 95% CI: 1.15, 2.6). RDT positivity was highest among children and adolescents between the ages of 5 and 17 years. RDT positives were likely to experience symptoms and have sought care. Open wells may be a breeding site for mosquito vectors, potentially contributing to malaria transmission.
    No preview · Conference Paper · Nov 2014
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    Full-text · Dataset · Aug 2014
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    ABSTRACT: Background Travel time and distance are barriers to care for HIV-infected children in rural sub-Saharan Africa. Decentralization of care is one strategy to scale-up access to antiretroviral therapy (ART), but few programs have been evaluated. We compared outcomes for children receiving care in mobile and hospital-affiliated HIV clinics in rural Zambia. Methods Outcomes were measured within an ongoing cohort study of HIV-infected children seeking care at Macha Hospital, Zambia from 2007 to 2012. Children in the outreach clinic group received care from the Macha HIV clinic and transferred to one of three outreach clinics. Children in the hospital-affiliated clinic group received care at Macha HIV clinic and reported Macha Hospital as the nearest healthcare facility. Results Seventy-seven children transferred to the outreach clinics and were included in the analysis. Travel time to the outreach clinics was significantly shorter and fewer caretakers used public transportation, resulting in lower transportation costs and fewer obstacles accessing the clinic. Some caretakers and health care providers reported inferior quality of service provision at the outreach clinics. Sixty-eight children received ART at the outreach clinics and were compared to 41 children in the hospital-affiliated clinic group. At ART initiation, median age, weight-for-age z-scores (WAZ) and CD4+ T-cell percentages were similar for children in the hospital-affiliated and outreach clinic groups. Children in both groups experienced similar increases in WAZ and CD4+ T-cell percentages. Conclusions HIV care and treatment can be effectively delivered to HIV-infected children at rural health centers through mobile ART teams, removing potential barriers to uptake and retention. Outreach teams should be supported to increase access to HIV care and treatment in rural areas.
    Preview · Article · Aug 2014 · PLoS ONE
  • William J. Moss · Diane E. Griffin
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    ABSTRACT: Measles is a highly contagious viral disease that is characterized by a prodromal illness of fever, cough, coryza, and conjunctivitis followed by the appearance of a generalized maculopapular rash. Before the widespread use of measles vaccines, it was estimated that measles caused between 5 million and 8 million deaths worldwide each year. Remarkable progress has been made in reducing global measles incidence and mortality rates through measles vaccination. Progress in global measles control has renewed discussion of measles eradication. In contrast to poliovirus eradication, the eradication of measles virus will not entail challenges posed by prolonged shedding of potentially virulent vaccine viruses and environmental viral reservoirs. However, higher levels of population immunity will be necessary to interrupt measles virus transmission, more highly skilled health care workers will be required to administer measles vaccines, and containment through case detection and ring vaccination will be more difficult for measles virus because of infectivity before rash onset. Despite enormous progress, measles remains a leading vaccine-preventable cause of childhood mortality worldwide and continues to cause outbreaks in communities with low vaccination. © 2014 Springer Science+Business Media New York. All rights are reserved.
    No preview · Article · Jun 2014

Publication Stats

2k Citations
802.10 Total Impact Points

Institutions

  • 2015
    • University of California, San Francisco
      • Department of Medicine
      San Francisco, California, United States
  • 2003-2015
    • Johns Hopkins Bloomberg School of Public Health
      • • Department of International Health
      • • Department of Epidemiology
      • • W. Harry Feinstone Department of Molecular Microbiology and Immunology
      Baltimore, Maryland, United States
  • 2002-2015
    • Johns Hopkins University
      • • Department of International Health
      • • Department of Epidemiology
      • • Department of Medicine
      Baltimore, Maryland, United States
    • University of Lusaka
      Lusaka, Lusaka, Zambia