Outbreak of Typhoid Fever in Children of Urban Vellore: A Report from the Surveillance for Enteric Fever in India Cohort.

We report an outbreak of typhoid fever between April and June 2019 in the Surveillance for Enteric Fever in India cohort, a pediatric cohort from four contiguous semi-urban settlements of Vellore in South India. This cohort of children 6 months to 15 years of age was under surveillance from October 2017 to December 2019. A clustering of typhoid cases in the cohort was noted with reference to time, place, and person. The overall typhoid attack rate in the cohort was 0.9%, with the highest attack rate of 1.7% being documented in one of the four areas. The rate of hospitalization and complications in children who were typhoid positive during the outbreak was 28% and 2%, respectively. Given the background of suboptimal water, sanitation, and hygiene, and the risk of typhoid fever outbreaks in these settings, it is imperative that a typhoid vaccine be considered for introduction as a pragmatic preventive approach.

Factors Predicting Blood Culture Positivity in Children With Enteric Fever.

BACKGROUND: Blood culture, despite low sensitivity, is the gold standard for enteric fever diagnosis. Understanding predictors of blood culture positivity may help design strategies to optimize enteric fever diagnosis. METHODS: A cohort of 6760 children aged 0.5-15 years was followed for 3 years for enteric fever with blood cultures in an automated system, for fevers >3 days. Factors affecting test positivity in fevers and participant-level predictors for culture refusals were analyzed using regression models. RESULTS: Overall, 6097 suspected typhoid/paratyphoid fever (STF) episodes were reported, of which 5703 (93.5%) STFs had sampling for blood cultures, with 394 (6.5%) refusals. Salmonella enterica serovar Typhi/Paratyphi positivity was culture-confirmed in 3.8% (218/5703) of STF episodes. Older children (odds ratio [OR], 1.96 [95% CI, 1.39-2.77]), larger blood volume inoculated (OR, 2.82 [95% CI, 1.71-4.66]), higher temperatures during fever (OR, 3.77 [95% CI, 2.89-4.91]), and fevers diagnosed as suspected typhoid or acute undifferentiated fever (OR, 6.06 [95% CI, 3.11-11.78]) had a higher probability of culture positivity. Antibiotics before culture did not decrease culture positivity. Blood culture refusals were higher for children from wealthier households or with milder illness. CONCLUSIONS: Performing blood cultures in older children with fever, especially those fevers with toxic presentation and increasing blood volume for inoculation are strategies to improve enteric fever detection in surveillance settings.

Hospitalization Rates and Direct Medical Costs for Fever in a Pediatric Cohort in South India.

BACKGROUND: Primary data on causes and costs of hospitalization are necessary for costing and cost-effectiveness analysis. Data on incidence and causes of hospitalization and consequent expenses among Indian children are limited. METHODS: A cohort of 6000 children aged 0.5-15 years residing in urban Vellore was followed for 3 years, under the Vellore Typhoid Study, 2016-2017, and later under the Surveillance for Enteric Fever project, 2017-2019. Data on hospitalization events and associated antibiotic use, and direct medical costs for fever-related hospitalization of study children were obtained from caregivers through weekly follow-up by study field workers. RESULTS: The incidence of hospitalization was 33 per 1000 child-years of observation. Children aged 0.5-5 years had the highest incidence of hospitalization. The top 5 infectious causes for hospitalization were acute undifferentiated fevers, respiratory tract infections, acute gastroenteritis, enteric fever, and dengue. The overall median cost of hospitalization for fever was 4243 (interquartile range, 2502-7215) Indian rupees (INR). An episode of dengue had a median cost of 5627 INR, followed by acute undifferentiated fevers and enteric fever with median costs of 3860 and 3507 INR, respectively. CONCLUSIONS: Hospitalization for fever is common in young children and impacts household finances in low-income Indian households.