Immunogenicity and safety of a tetravalent dengue vaccine in dengue-naïve adolescents in Mexico City.

OBJECTIVE: To describe the immunogenicity and safety of a tetravalent dengue vaccine (TAK-003) in healthy adolescents living in Mexico City, an area considered non-endemic for dengue (NCT03341637). METHODS: Participants aged 12-17 years were randomized 3:1 to receive two doses (Month 0 and Month 3) of TAK-003 or placebo. Immunogenicity was assessed by microneutralization assay of dengue neutralizing antibodies at baseline, Months 4 and 9. Solicited and unsolicited adverse events (AEs) were recorded after each vaccination. Serious (SAEs) and medically-attended AEs (MAAEs) were recorded throughout the study. RESULTS: 400 adolescents were enrolled, 391 (97.8%) completed the study. Thirty-six (9%) were baseline seropositive to ≥1 serotypes (reciprocal titer ≥10). Geometric mean titers (GMTs) in baseline seronegative TAK-003 recipients were 328, 1743, 120, and 143 at Month 4, and 135, 741, 46, and 38 at Month 9 against DENV-1, -2, -3, and -4, respectively. Placebo GMTs remained <10. Tetravalent seropositivity rates in vaccine recipients were 99.6% and 85.8% at Months 4 and 9, respectively. One MAAE in each group was considered treatment-related (TAK-003: injection-site erythema, and placebo: pharyngitis). CONCLUSION: TAK-003 was immunogenic against all four serotypes and was well tolerated in dengue-naïve adolescents living in Mexico City.

Aleatory Trypanosoma cruzi Vertical Transmission in Chiapas, Mexico: A Case Report.

Congenital Chagas disease is considered a form of dispersion of Trypanosoma cruzi related to human migration from endemic, often rural to previously non-endemic urban areas. This fact increases the Chagas disease establishment risk inside of family members by vertical transmission pathway. Congenital Chagas disease cases in newborns could not identified by the health professional even in endemic regions. Here we present the first family cluster of Chagas disease cases from Chiapas: one of the most important endemic areas in South of Mexico, where vertical T. cruzi transmission incidence rate is ranged between 2% to 22% revealing an important public health problem. Two cases inside a family from Chiapas, México with positive antibodies against T. cruzi detected by ELISA are presented; one of them got the infection through vertical pathway. We think that congenital Chagas disease should not be ignored in a newborn born from an asymptomatic Chagas disease mother, who may transmit the parasite infection randomly.

Co-infection of Dengue, Zika and Chikungunya in a group of pregnant women from Tuxtla Gutiérrez, Chiapas: Preliminary data. 2019.

INTRODUCTION: Dengue, Zika and Chikungunya are RNA Arboviruses present in some areas of Mexico, mainly in the endemic state of Chiapas that is characterized by presence of the vector that transmit them and an ecology that favors high transmission. According to the national epidemiological surveillance system, Dengue has intensified since 2018 and outbreaks continue in various states while for Zika and Chikungunya a decrease in cases has been reported in recent years. The main objective of this study was to determine the incidence of Dengue, Zika and Chikungunya infections during pregnancy in the state of Chiapas. PRINCIPAL FINDINGS: The presence of previous and current infections and coinfections diagnosed by molecular (RT-PCR) and immunological (ELISA for IgG determination) techniques indicates a wide circulation of viruses in asymptomatic people, specifically in pregnant women showing that silent infections in dry season contributes to the preservation of viruses. CONCLUSIONS: From 136 studied samples, 27.7% tested positive for DENV, 8% for ZIKV and 24.1% for CHIKV by RTPCR and the values of IgG in sera show that 83.9% were positive for IgG antibodies against DENV, 65% against ZIKV and 59.1% against CHIKV. Results demonstrated presence of ZIKV and CHIKV, not detected by the epidemiological surveillance system, so the importance of establishing proactive epidemiological systems more strict, especially because these infections in pregnant women can cause severe health problems for newborn children.

Comparative analysis of two alternative models for epidemiological surveillance in the Mexican Malaria Control Program.

The current surveillance model used by the Malaria Control Program in a Mexican state was analyzed using a systematic evaluation of the model ("PAATI" programs, actions, activities, tasks and inputs) through a diagrammatic evaluation of all the components in the process. The actions, activities tasks and inputs of this surveillance model (based on active and passive malaria case detection using tick blood smears examination), as well as those of an innovative alternative model (based on passive malaria case detection using immunodiagnostic strips, with an overall sensitivity of 93.3% and specificity of 99.5%) were identified and evaluated. It was documented that although the same actions are carried out in both models, many more activities are necessary with more tasks and inputs (traditional: 19 activities and 55 tasks, alternative: 13 activities and 32 tasks) in the current one. Adjusting to a population of 10,000 inhabitants, 1000 prospective cases and 2 years of surveillance, the cost of diagnosing and treating one malaria case was of 8.97 US dollars in this model and of 6.34 US dollars in the alternative one.