Emerging Challenges and Opportunities in Infectious Disease Epidemiology.

Much of the intellectual tradition of modern epidemiology stems from efforts to understand and combat chronic diseases persisting through the 20th century epidemiologic transition of countries such as the United States and United Kingdom. After decades of relative obscurity, infectious disease epidemiology has undergone an intellectual rebirth in recent years amid increasing recognition of the threat posed by both new and familiar pathogens. Here, we review the emerging coalescence of infectious disease epidemiology around a core set of study designs and statistical methods bearing little resemblance to the chronic disease epidemiology toolkit. We offer our outlook on challenges and opportunities facing the field, including the integration of novel molecular and digital information sources into disease surveillance, the assimilation of such data into models of pathogen spread, and the increasing contribution of models to public health practice. We next consider emerging paradigms in causal inference for infectious diseases, ranging from approaches to evaluating vaccines and antimicrobial therapies to the task of ascribing clinical syndromes to etiologic microorganisms, an age-old problem transformed by our increasing ability to characterize human-associated microbiota. These areas represent an increasingly important component of epidemiology training programs for future generations of researchers and practitioners.

Generalisability of vaccine effectiveness estimates: an analysis of cases included in a postlicensure evaluation of 13-valent pneumococcal conjugate vaccine in the USA.

OBJECTIVES: External validity, or generalisability, is the measure of how well results from a study pertain to individuals in the target population. We assessed generalisability, with respect to socioeconomic status, of estimates from a matched case-control study of 13-valent pneumococcal conjugate vaccine effectiveness for the prevention of invasive pneumococcal disease in children in the USA. DESIGN: Matched case-control study. SETTING: Thirteen active surveillance sites for invasive pneumococcal disease in the USA. PARTICIPANTS: Cases were identified from active surveillance and controls were age and zip code matched. OUTCOME MEASURES: Socioeconomic status was assessed at the individual level via parent interview (for enrolled individuals only) and birth certificate data (for both enrolled and unenrolled individuals) and at the neighbourhood level by geocoding to the census tract (for both enrolled and unenrolled individuals). Prediction models were used to determine if socioeconomic status was associated with enrolment. RESULTS: We enrolled 54.6% of 1211 eligible cases and found a trend toward enrolled cases being more affluent than unenrolled cases. Enrolled cases were slightly more likely to have private insurance at birth (p=0.08) and have mothers with at least some college education (p<0.01). Enrolled cases also tended to come from more affluent census tracts. Despite these differences, our best predictive model for enrolment yielded a concordance statistic of only 0.703, indicating mediocre predictive value. Variables retained in the final model were assessed for effect measure modification, and none were found to be significant modifiers of vaccine effectiveness. CONCLUSIONS: We conclude that although enrolled cases are somewhat more affluent than unenrolled cases, our estimates are externally valid with respect to socioeconomic status. Our analysis provides evidence that this study design can yield valid estimates and the assessing generalisability of observational data is feasible, even when unenrolled individuals cannot be contacted.

The "AMA-Brazil" cooperative project: a nation-wide assessment of the clinical and epidemiological profile of AIDS-related deaths in Brazil in the antiretroviral treatment era.

The objective of this study was to assess the profile of AIDS-related deaths in the post antiretroviral therapy (ART) scale up period in Brazil. A case-control study was conducted including a nationally probabilistic sample of AIDS deaths and living controls. Data were abstracted from medical records and nation-wide databases of AIDS cases, mortality, ART care, and laboratory testing. Interrupted (adjusted odds ratio--AOR 4.35, 95%CI: 3.15-6.00) or no use of ART (AOR 2.39, 95%CI: 1.57-3.65) was the strongest predictor of death, followed by late diagnosis (AOR 3.95, 95%CI: 2.68-5.82). Criterion other than CD4 < 350 had a higher likelihood of death (AOR 1.65, 95%CI: 1.14-2.40). Not receiving recommended vaccines (AOR, 1.76, 95%CI: 1.21-2.56), presenting AIDS-related diseases (AOR 2.19, 95%CI: 1.22-3.93) and tuberculosis (AOR 1.50, 95%CI: 1.14-1.97) had higher odds of death. Being an injecting drug user (IDU) had a borderline association with higher odds of death, while homo/bisexual exposure showed a protective effect. Despite remarkable successes, Brazilians continue to die of AIDS in the post-ART scale up period. Many factors contributing to continued mortality are preventable.

The "AMA-Brazil" cooperative project: a nation-wide assessment of the clinical and epidemiological profile of AIDS-related deaths in Brazil in the antiretroviral treatment era / Projeto cooperativo AMA-Brasil: um estudo nacional do perfil clinico e epidemiológico dos óbitos relacionados à AIDS na era da terapia antirretroviral

The objective of this study was to assess the profile of AIDS-related deaths in the post antiretroviral therapy (ART) scale up period in Brazil. A case-control study was conducted including a nationally probabilistic sample of AIDS deaths and living controls. Data were abstracted from medical records and nation-wide databases of AIDS cases, mortality, ART care, and laboratory testing. Interrupted (adjusted odds ratio - AOR 4.35, 95 percentCI: 3.15-6.00) or no use of ART (AOR 2.39, 95 percentCI: 1.57-3.65) was the strongest predictor of death, followed by late diagnosis (AOR 3.95, 95 percentCI: 2.68-5.82). Criterion other than CD4 < 350 had a higher likelihood of death (AOR 1.65, 95 percentCI: 1.14-2.40). Not receiving recommended vaccines (AOR, 1.76, 95 percentCI: 1.21-2.56), presenting AIDS-related diseases (AOR 2.19, 95 percentCI: 1.22-3.93) and tuberculosis (AOR 1.50, 95 percentCI: 1.14-1.97) had higher odds of death. Being an injecting drug user (IDU) had a borderline association with higher odds of death, while homo/bisexual exposure showed a protective effect. Despite remarkable successes, Brazilians continue to die of AIDS in the post-ART scale up period. Many factors contributing to continued mortality are preventable.

Analisou-se o perfil clínico e epidemiológico dos óbitos relacionados à AIDS no período posterior à implementação da terapia antirretroviral (TARV) no Brasil, em um estudo caso-controle, com amostra representativa de óbitos por AIDS e de pessoas vivendo com AIDS, utilizando dados secundários. Abandono (odds ratio ajustada - AOR = 4,35, IC95 por cento: 3,15-6,00) ou não uso da TARV (AOR = 2,39, IC95 por cento: 1,57-3,65) foi o mais forte preditor de morte, seguido de diagnóstico tardio (AOR = 3,95, IC95 por cento: 2,68-5,82). Critério de definição de AIDS que não o "CD4 < 350" esteve associado a uma maior probabilidade de morte (AOR = 1,65, IC95 por cento: 1,14-2,40). Pacientes que não receberam vacinas recomendadas (AOR = 1,76, 95 por centoCI: 1,21-2,56), apresentando doenças associadas à AIDS (AOR = 2,19, IC95 por cento: 1,22-3,93) e com tuberculose (AOR = 1,50, IC95 por cento: 1,14-1,97), tiveram maior risco de morte. A categoria de exposição UDI apresentou maior chance de óbito. Apesar do sucesso com as introduções precoces da TARV, brasileiros continuaram a morrer de AIDS no período posterior à implementação da terapia, e muitas das causas subjacentes a essa mortalidade são preveníveis.

Socioeconomic and racial/ethnic disparities in the incidence of bacteremic pneumonia among US adults.

OBJECTIVES: We examined associations between the socioeconomic characteristics of census tracts and racial/ethnic disparities in the incidence of bacteremic community-acquired pneumonia among US adults. METHODS: We analyzed data on 4870 adults aged 18 years or older with community-acquired bacteremic pneumonia identified through active, population-based surveillance in 9 states and geocoded to census tract of residence. We used data from the 2000 US Census to calculate incidence by age, race/ethnicity, and census tract characteristics and Poisson regression to estimate rate ratios (RRs) and 95% confidence intervals (CIs). RESULTS: During 2003 to 2004, the average annual incidence of bacteremic pneumonia was 24.2 episodes per 100 000 Black adults versus 10.1 per 100 000 White adults (RR = 2.40; 95% CI = 2.24, 2.57). Incidence among Black residents of census tracts with 20% or more of persons in poverty (most impoverished) was 4.4 times the incidence among White residents of census tracts with less than 5% of persons in poverty (least impoverished). Racial disparities in incidence were reduced but remained significant in models that controlled for age, census tract poverty level, and state. CONCLUSIONS: Adults living in impoverished census tracts are at increased risk of bacteremic pneumonia and should be targeted for prevention efforts.

Prevalence of Trichomonas vaginalis infection among young reproductive age women in India: implications for treatment and prevention.

BACKGROUND: Trichomonas vaginalis infection is the most common curable sexually transmissible infection (STI) worldwide. The present study describes the burden and correlates of T. vaginalis infection among young reproductive age women in Mysore, India. METHODS: Between November 2005 and March 2006, sexually active women aged 15-30 years were recruited from low-income peri-urban and rural neighbourhoods of Mysore, India. Participants were interviewed and offered a physical examination and testing for T. vaginalis, bacterial vaginosis, vaginal candidiasis, Neisseria gonorrheoea and herpes simplex virus type-2 antibodies. RESULTS: Of the 898 participating women, 76 had a T. vaginalis infection (8.5%, 95% confidence interval [95% CI]: 6.7-10.5%). Nearly all (98%) participants were married and most reported their spouse as their main sex partner. The mean age at marriage was 16.9 years (s.d. 2.9 years) and two-thirds of the sample reported having first sexual intercourse before the age of 19 years. Risk factors independently associated with T. vaginalis infection included early age at first intercourse (adjusted odds ratio [OR] 2.09; 95% CI: 1.09-4.00), concurrent bacterial vaginosis (OR 8.21; 95% CI: 4.30-15.66), vaginal candidiasis (OR 2.40; 95% CI: 1.48-3.89) and herpes simplex virus type-2 infection (OR 3.44; 95% CI: 1.97-6.02). CONCLUSION: The burden of T. vaginalis infection at 8.5% is relatively high among a community sample of young reproductive aged women. Because this infection increases the risk of HIV transmission and is associated with adverse pregnancy outcomes, there is a need for increased screening and treatment of this easily curable sexually transmissible infection in India.