The impact of vaccination strategies for COVID-19 in the context of emerging variants and increasing social mixing in Bogotá, Colombia: a mathematical modelling study

In Bogotá by August 1st, more than 27,000 COVID-19 deaths have been reported, 29 while complete and partial vaccination coverage reached 30% and 37%, respectively. Although 30 reported cases are decreasing, the potential impact of new variants is uncertain.In Bogotá by August 1st, more than 27,000 COVID-19 deaths have been reported, 29 while complete and partial vaccination coverage reached 30% and 37%, respectively. Although 30 reported cases are decreasing, the potential impact of new variants is uncertain.Revista Nacional - Indexad

Prevalence of and factors associated with late diagnosis of HIV in Malawi, Zambia, and Zimbabwe: Results from population-based nationally representative surveys

Introduction Late diagnosis of HIV (LD) increases the risk of morbidity, mortality, and HIV transmission. We used nationally representative data from population-based HIV impact assessment (PHIA) surveys in Malawi, Zambia, and Zimbabwe (2015–2016) to characterize adults at risk of LD and to examine associations between LD and presumed HIV transmission to cohabiting sexual partners. Methods We estimated the prevalence of LD, defined as CD4 count <350 cells/μL, among adults newly diagnosed with HIV during the surveys and odds ratios for associated factors. We linked newly diagnosed adults (index cases) to their household sexual partners and calculated adjusted odds ratios for associations between LD of the index case, viral load of the index case, and duration of HIV exposure in the relationship, and the HIV status of the household sexual partner. Results Of 1,804 adults who were newly diagnosed with HIV in the surveys, 49% (882) were diagnosed late. LD was associated with male sex, older age, and almost five times the odds of having an HIV-positive household sexual partner (adjusted odds ratio [aOR], 4.65 [95% confidence interval: 2.56–8.45]). Longer duration of HIV exposure in a relationship and higher viral load of the index case were both independently associated with higher odds of having HIV-positive household sexual partners. Individuals with HIV exposure of more than 5 years had more than three times (aOR 3.42 [95% CI: 1.63–7.18]) higher odds of being HIV positive than those with less than 2 years HIV exposure. The odds of being HIV positive were increased in individuals who were in a relationship with an index case with a viral load of 400–3499 copies/mL (aOR 4.06 [95% CI 0.45–36.46]), 3,500–9,999 copies/mL (aOR 11.32 [95% CI: 4.08–31.39]), 10,000–49,999 copies/mL (aOR 17.07 [95% CI: 9.18–31.72]), and ≥50,000 copies/mL (aOR 28.41 [95% CI: 12.18–66.28]) compared to individuals who were in a relationship with an index case with a viral load of <400 copies/mL. Conclusions LD remains a challenge in Southern Africa and is strongly associated with presumed HIV transmission to household sexual partners. Our study underscores the need for earlier HIV diagnosis, particularly among men and older adults, and the importance of index testing

Cross-reactive humoral and CD4+ T cell responses to Mu and Gamma SARS-CoV-2 variants in a Colombian population

The SARS CoV-2 antibody and CD4+ T cell responses induced by natural infection and/or vaccination decline over time and cross-recognize other viral variants at different levels. However, there are few studies evaluating the levels and durability of the SARS CoV-2-specific antibody and CD4+ T cell response against the Mu, Gamma, and Delta variants. Here, we examined, in two ambispective cohorts of naturally-infected and/or vaccinated individuals, the titers of anti-RBD antibodies and the frequency of SARS-CoV-2-specific CD4+ T cells up to 6 months after the last antigen exposure. In naturally-infected individuals, the SARS-CoV-2 antibody response declined 6 months post-symptoms onset. However, the kinetic observed depended on the severity of the disease, since individuals who developed severe COVID-19 maintained the binding antibody titers. Also, there was detectable binding antibody cross-recognition for the Gamma, Mu, and Delta variants, but antibodies poorly neutralized Mu. COVID-19 vaccines induced an increase in antibody titers 15-30 days after receiving the second dose, but these levels decreased at 6 months. However, as expected, a third dose of the vaccine caused a rise in antibody titers. The dynamics of the antibody response upon vaccination depended on the previous SARS-CoV-2 exposure. Lower levels of vaccine-induced antibodies were associated with the development of breakthrough infections. Vaccination resulted in central memory spike-specific CD4+ T cell responses that cross-recognized peptides from the Gamma and Mu variants, and their duration also depended on previous SARS-CoV-2 exposure. In addition, we found cross-reactive CD4+ T cell responses in unexposed and unvaccinated individuals. These results have important implications for vaccine design for new SARS-CoV-2 variants of interest and concern

SARS-CoV-2 vaccination strategies: Should the extended dosing interval strategy be implemented in future pandemics?

La Organización Mundial de la Salud (OMS) consideró la COVID-19 desde hace más de tres años una emergencia de salud pública de importancia internacional (ESPII) a nivel de pandemia. Después de un acumulado de 770.875.433 casos confirmados, incluidas 6.959.316 muertes (hasta el 19 de septiembre de 2023), afortunadamente, la carga de mortalidad por COVID-19 ha disminuido significativamente en el último año (2022-2023) debido principalmente a la vacunación efectiva (un total de 13.505.262.477 Se han administrado dosis a nivel mundial) ( https://covid19.who.int/ ), a pesar de la aparición de Omicron y sus variantes de sublinaje [1,2]. Sin embargo, la asignación de vacunas no fue tan fluida como a todos les hubiera gustado, considerando la escasez o las dificultades para obtener rápidamente las vacunas en varios países, especialmente los de ingresos bajos y medianos (PIMB). En algunos casos, eso llevó a la necesidad de aplicar diferentes estrategias, como ampliar el intervalo de tiempo en que se administraba la segunda dosis. Aquí presentamos una perspectiva sobre la implementación de esta estrategia de vacunación, particularmente en países de bajos ingresos (LIC) y PIBM que enfrentan futuras pandemias.Q1Q1The World Health Organization (WHO) considered COVID-19 for more than three years a public health emergency of international concern (PHEIC) at a pandemic level. After a cumulate of 770,875,433 confirmed cases, including 6,959,316 deaths (up to September 19, 2023), fortunately, the COVID-19 mortality burden has significantly decreased in the last year (2022–2023) primarily due to effective vaccination (a total of 13,505,262,477 doses have been administered globally) (https://covid19.who.int/), despite Omicron and its sublineage variants’ emergence [1,2]. However, the vaccine allocation was not as smooth as everyone would have liked, considering shortages or difficulties in promptly obtaining the vaccines for several countries, especially low- and middle-income countries (LMIC). In some cases, that led to the necessity of applying different strategies, such as extending the time interval in which the second dose was administered. Here, we present a perspective on implementing this vaccination strategy, particularly in low-income (LIC) and LMIC countries facing future pandemics.Revista Internacional - IndexadaS

Toward elimination of mother-to-child transmission of HIV in Malawi: Findings from the Malawi Population-based HIV Impact Assessment (2015-2016)

Malawi encabezó el desarrollo y la implementación de la Opción B+ para la prevención de la transmisión maternoinfantil del VIH (PTMI), brindando TAR de por vida a todas las mujeres embarazadas y lactantes seropositivas. Utilizamos datos de la Evaluación del impacto del VIH basada en la población de Malawi (MPHIA, por sus siglas en inglés) de 2015-2016 para estimar el progreso hacia los objetivos 90-90-90 (el 90 % de las personas con VIH saben que son seropositivos; de estas, el 90 % está recibiendo TAR). ; y de estos, el 90% tiene supresión de la carga viral [VLS]) para mujeres VIH positivas que reportaron un nacimiento vivo en los 3 años anteriores. Métodos MPHIA fue una encuesta de hogares representativa a nivel nacional; Se entrevistó a mujeres elegibles de 15 a 64 años de edad que dieron su consentimiento sobre embarazos y resultados, incluido el estado del VIH durante su embarazo más reciente, aceptación de la PTMI y pruebas de diagnóstico infantil temprano (EID). Los análisis descriptivos se ponderaron para tener en cuenta el complejo diseño de la encuesta. Los resultados de la carga viral (VL) se clasificaron por VLS (<1000 copias/mL) y VL indetectable (objetivo no detectado/por debajo del límite de detección). Resultados De las 3.153 mujeres incluidas en nuestro análisis, 371 (10,1 %, intervalo de confianza [IC] del 95 %: 8,8 %-11,3 %) dieron positivo en la prueba del VIH en la encuesta. La mayoría de las mujeres seropositivas (84,2 %, IC del 95 %: 79,9 %-88,6 %) informaron conocer su estado serológico; de estos, el 94,9 % (IC 95 %: 91,7 %-98,2 %) estaban recibiendo TAR; y de estos, el 91,2% (IC 95%: 87,4%-95,0%) tenían VLS. Entre las 371 mujeres con VIH, el 76,0 % (IC 95 %: 70,4 %-81,7 %) tenía VLS y el 66,5 % (IC 95 %: 59,8 %-73,2 %) tenía LV indetectable. Entre 262 niños expuestos al VIH, el 50,8 % (IC 95 %: 42,8 %-58,8 %) se sometió a la prueba EID dentro de los 2 meses posteriores al nacimiento, mientras que el 17,9 % (IC 95 %: 11,9 %-23,8 %) no recibió la prueba EID. De 190 niños expuestos al VIH con un resultado de la prueba del VIH notificado, el 2,1 % (IC del 95 %: 0,0 %-4,6 %) tuvo resultados positivos. Conclusiones Los datos de MPHIA demuestran una alta captación de PTMI a nivel de población. Sin embargo, nuestros resultados identifican algunas brechas en VLS en mujeres posparto y pruebas de EID.Q1Malawi spearheaded the development and implementation of Option B+ for prevention of mother-to-child transmission of HIV (PMTCT), providing life-long ART for all HIV-positive pregnant and breastfeeding women. We used data from the 2015-2016 Malawi Population-based HIV Impact Assessment (MPHIA) to estimate progress toward 90-90-90 targets (90% of those with HIV know their HIV-positive status; of these, 90% are receiving ART; and of these, 90% have viral load suppression [VLS]) for HIV-positive women reporting a live birth in the previous 3 years. Methods MPHIA was a nationally representative household survey; consenting eligible women aged 15-64 years were interviewed on pregnancies and outcomes, including HIV status during their most recent pregnancy, PMTCT uptake, and early infant diagnosis (EID) testing. Descriptive analyses were weighted to account for the complex survey design. Viral load (VL) results were categorized by VLS (<1,000 copies/mL) and undetectable VL (target not detected/below the limit of detection). Results Of the 3,153 women included in our analysis, 371 (10.1%, 95% confidence interval [CI]: 8.8%-11.3%) tested HIV positive in the survey. Most HIV-positive women (84.2%, 95% CI: 79.9%-88.6%) reported knowing their HIV-positive status; of these, 94.9% (95% CI: 91.7%-98.2%) were receiving ART; and of these, 91.2% (95% CI: 87.4%-95.0%) had VLS. Among the 371 HIV-positive women, 76.0% (95% CI: 70.4%-81.7%) had VLS and 66.5% (95% CI: 59.8%-73.2%) had undetectable VL. Among 262 HIV-exposed children, 50.8% (95% CI: 42.8%-58.8%) received EID testing within 2 months of birth, whereas 17.9% (95% CI: 11.9%-23.8%) did not receive EID testing. Of 190 HIV-exposed children with a reported HIV test result, 2.1% (95% CI: 0.0%-4.6%) had positive results. Conclusions MPHIA data demonstrate high PMTCT uptake at a population level. However, our results identify some gaps in VLS in postpartum women and EID testing.N/AS

Cumulative incidence, prevalence, seroconversion, and associated factors for SARS-CoV-2 infection among healthcare workers of a University Hospital in Bogotá, Colombia

Q2Q1This study aimed to determine the cumulative incidence, prevalence, and seroconversion of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its associated factors among healthcare workers (HCWs) of a University Hospital in Bogotá, Colombia. An ambispective cohort was established from March 2020 to February 2021. From November 2020 to February 2021, SARS-CoV-2 antibodies were measured on two occasions 14–90 days apart to determine seroprevalence and seroconversion. We used multivariate log-binomial regression to evaluate factors associated with SARS-CoV-2 infection. Among 2,597 HCWs, the cumulative incidence of infection was 35.7%, and seroprevalence was 21.5%. A reduced risk of infection was observed among those aged 35–44 and ≥45 years (adjusted relative risks [aRRs], 0.84 and 0.83, respectively), physicians (aRR, 0.77), those wearing N95 respirators (aRR, 0.82) and working remotely (aRR, 0.74). Being overweight (aRR, 1.18) or obese (aRR, 1.24); being a nurse or nurse assistant (aRR, 1.20); working in the emergency room (aRR, 1.45), general wards (aRR, 1.45), intensive care unit (aRR, 1.34), or COVID-19 areas (aRR, 1.17); and close contact with COVID-19 cases (aRR, 1.47) increased the risk of infection. The incidence of SARS-CoV-2 infection found in this study reflects the dynamics of the first year of the pandemic in Bogotá. A high burden of infection calls for strengthening prevention and screening measures for HCWs, focusing especially on those at high risk.https://orcid.org/0000-0003-1833-1599https://orcid.org/0000-0001-8888-9411https://orcid.org/0000-0001-6623-5337https://orcid.org/0000-0001-5363-5729https://orcid.org/0000-0003-4946-8774https://orcid.org/0000-0003-4745-5339https://orcid.org/0000-0003-4579-6033https://orcid.org/0000-0002-2536-4471https://orcid.org/0000-0002-9013-5384https://orcid.org/0000-0002-0265-0563Revista Internacional - IndexadaA1N

Cross-reactive humoral and CD4+ T cell responses to Mu and Gamma SARS-CoV-2 variants in a Colombian population

Las respuestas del anticuerpo SARS CoV-2 y de las células T CD4 + inducidas por la infección natural y/o la vacunación disminuyen con el tiempo y reconocen de forma cruzada otras variantes virales en diferentes niveles. Sin embargo, existen pocos estudios que evalúen los niveles y la durabilidad del anticuerpo específico del SARS CoV-2 y la respuesta de las células T CD4 + contra las variantes Mu, Gamma y Delta. Aquí, examinamos, en dos cohortes ambispectivas de individuos infectados naturalmente y/o vacunados, los títulos de anticuerpos anti-RBD y la frecuencia de células T CD4+ específicas del SARS-CoV-2 hasta 6 meses después de la última exposición al antígeno . . En personas infectadas de forma natural, la respuesta de anticuerpos contra el SARS-CoV-2 disminuyó 6 meses después de la aparición de los síntomas. Sin embargo, la cinética observada dependió de la gravedad de la enfermedad, ya que los individuos que desarrollaron COVID-19 grave mantuvieron los títulos de anticuerpos vinculantes. Además, hubo reconocimiento cruzado de anticuerpos de unión detectables para las variantes Gamma, Mu y Delta, pero los anticuerpos neutralizaron mal a Mu. Las vacunas COVID-19 indujeron un aumento en los títulos de anticuerpos entre 15 y 30 días después de recibir la segunda dosis, pero estos niveles disminuyeron a los 6 meses. Sin embargo, como se esperaba, una tercera dosis de la vacuna provocó un aumento en los títulos de anticuerpos. La dinámica de la respuesta de anticuerpos tras la vacunación dependió de la exposición previa al SARS-CoV-2. Los niveles más bajos de anticuerpos inducidos por la vacuna se asociaron con el desarrollo de infecciones irruptivas. La vacunación dio lugar a respuestas de células T CD4 + específicas de picos de memoria central que reconocían de forma cruzada péptidos de las variantes Gamma y Mu, y su duración también dependía de la exposición previa al SARS-CoV-2. Además, encontramos respuestas de células T CD4 + con reactividad cruzada en individuos no expuestos y no vacunados. Estos resultados tienen implicaciones importantes para el diseño de vacunas para las nuevas variantes de interés y preocupación del SARS-CoV-2.Q1Q1The SARS CoV-2 antibody and CD4+ T cell responses induced by natural infection and/or vaccination decline over time and cross-recognize other viral variants at different levels. However, there are few studies evaluating the levels and durability of the SARS CoV-2-specific antibody and CD4+ T cell response against the Mu, Gamma, and Delta variants. Here, we examined, in two ambispective cohorts of naturally-infected and/or vaccinated individuals, the titers of anti-RBD antibodies and the frequency of SARS-CoV-2-specific CD4+ T cells up to 6 months after the last antigen exposure. In naturally-infected individuals, the SARS-CoV-2 antibody response declined 6 months post-symptoms onset. However, the kinetic observed depended on the severity of the disease, since individuals who developed severe COVID-19 maintained the binding antibody titers. Also, there was detectable binding antibody cross-recognition for the Gamma, Mu, and Delta variants, but antibodies poorly neutralized Mu. COVID-19 vaccines induced an increase in antibody titers 15-30 days after receiving the second dose, but these levels decreased at 6 months. However, as expected, a third dose of the vaccine caused a rise in antibody titers. The dynamics of the antibody response upon vaccination depended on the previous SARS-CoV-2 exposure. Lower levels of vaccine-induced antibodies were associated with the development of breakthrough infections. Vaccination resulted in central memory spike-specific CD4+ T cell responses that cross-recognized peptides from the Gamma and Mu variants, and their duration also depended on previous SARS-CoV-2 exposure. In addition, we found cross-reactive CD4+ T cell responses in unexposed and unvaccinated individuals. These results have important implications for vaccine design for new SARS-CoV-2 variants of interest and concern.Revista Internacional - IndexadaS