Background Low infection and case-fatality rates have been thus far observed in Taiwan. One of the reasons for this major success is better use of big data analytics in efficient contact tracing and management and surveillance of those who require quarantine and isolation. Objective We present here a unique application of big data analytics among Taiwanese people who had contact with more than 3000 passengers that disembarked at Keelung harbor in Taiwan for a 1-day tour on January 31, 2020, 5 days before the outbreak of coronavirus disease (COVID-19) on the Diamond Princess cruise ship on February 5, 2020, after an index case was identified on January 20, 2020. Methods The smart contact tracing–based mobile sensor data, cross-validated by other big sensor surveillance data, were analyzed by the mobile geopositioning method and rapid analysis to identify 627,386 potential contact-persons. Information on self-monitoring and self-quarantine was provided via SMS, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tests were offered for symptomatic contacts. National Health Insurance claims big data were linked, to follow-up on the outcome related to COVID-19 among those who were hospitalized due to pneumonia and advised to undergo screening for SARS-CoV-2. Results As of February 29, a total of 67 contacts who were tested by reverse transcription–polymerase chain reaction were all negative and no confirmed COVID-19 cases were found. Less cases of respiratory syndrome and pneumonia were found after the follow-up of the contact population compared with the general population until March 10, 2020. Conclusions Big data analytics with smart contact tracing, automated alert messaging for self-restriction, and follow-up of the outcome related to COVID-19 using health insurance data could curtail the resources required for conventional epidemiological contact tracing.

Background For women of reproductive age, a population-level red blood cell (RBC) folate concentration below the threshold 906 nmol/L or 400 ng/mL indicates folate insufficiency and suboptimal neural tube defect (NTD) prevention. A corresponding population plasma/serum folate concentration threshold for optimal NTD prevention has not been established. Objective The aim of this study was to examine the association between plasma and RBC folate concentrations and estimated a population plasma folate insufficiency threshold (pf-IT) corresponding to the RBC folate insufficiency threshold (RBCf-IT) of 906 nmol/L. Methods We analyzed data on women of reproductive age (n = 1673) who participated in a population-based, randomized folic acid supplementation trial in northern China. Of these women, 565 women with anemia and/or vitamin B-12 deficiency were ineligible for folic acid intervention (nonintervention group); the other 1108 received folic acid supplementation for 6 mo (intervention group). We developed a Bayesian linear model to estimate the pf-IT corresponding to RBCf-IT by time from supplementation initiation, folic acid dosage, methyltetrahydrofolate reductase (MTHFR) genotype, body mass index (BMI), vitamin B-12 status, or anemia status. Results Using plasma and RBC folate concentrations of the intervention group, the estimated median pf-IT was 25.5 nmol/L (95% credible interval: 24.6, 26.4). The median pf-ITs were similar between the baseline and postsupplementation samples (25.7 compared with 25.2 nmol/L) but differed moderately (±3–4 nmol/L) by MTHFR genotype and BMI. Using the full population-based baseline sample (intervention and nonintervention), the median pf-IT was higher for women with vitamin B-12 deficiency (34.6 nmol/L) and marginal deficiency (29.8 nmol/L) compared with the sufficient group (25.6 nmol/L). Conclusions The relation between RBC and plasma folate concentrations was modified by BMI and genotype and substantially by low plasma vitamin B-12. This suggests that the threshold of 25.5 nmol/L for optimal NTD prevention may be appropriate in populations with similar characteristics, but it should not be used in vitamin B-12 insufficient populations. This trial was registered at clinicaltrials.gov as NCT00207558.

PurposeA pertussis patient from an elementary school, in Gyeonggi Province, Korea, was notified to public health authority on July 25, 2017. Epidemiologic investigation was conducted to identify the magnitude, possible source of infection and risk factors for this outbreak on August 17, 2017.Materials and MethodsA case was defined as the school student experiencing cough for more than two weeks with or without paroxysmal, whoop, or post-tussive vomiting. Control was defined as the student polymerase chain reaction-negative at the school. School based surveillance was implemented to identify additional cases.ResultsFrom June 29 to August 27, 2017, nine patients of pertussis were identified from an elementary school. Among nine cases, eight were confirmed by polymerase chain reaction positive. All cases had cough, one (11%) had post-tussive vomiting, and one (11%) had fever. Eight cases had macrolide for 7 days in outpatient clinic, and one case admitted in a hospital. There was no significant difference of demographic factors including gender (p=0.49), age group (p=0.97), number of series of vaccination of pertussis (p=0.52), the number of participation of after school activity (p=0.28), and the time elapsed since last vaccination (p=0.42). However, we found the history of contact within the classroom or after-school activity was only the independent risk factor among all the demographic factors collected (odds ratio, 63.61; 95% confidence interval, 4.35 to 930.79).ConclusionThe contributing factor for transmission is associated with the case-contact. Immediate identification of pertussis with use of appropriate diagnostic test may help to avoid a large number of cases.