RESUMO
Background: The continuous evolution of the SARS-CoV-2 pandemic has led to a high demand for diagnostic testing and major shortages in testing materials, especially in low- and middle-income countries. As an alternative to testing individual samples, pooling of respiratory samples has been suggested. Previous studies have assessed performance of pooling, mainly using nasopharyngeal samples for the detection of SARS-CoV-2, but few studies have examined the performance of pooling the more practical nasal swabs or saliva samples. Objective: To evaluate the sensitivity, specificity, and potential cost reduction of pooling of nasal swab (NS) and saliva (SL) samples for detection of SARS-CoV-2 in a community-based cohort study in Lima, Peru. Study design: A prospective cohort study was conducted in a community setting in San Juan de Lurigancho, Lima-Peru. NS and SL samples were collected from 132 participants twice-a-week for a 2-month period. Pools of 2 to 12 samples of the same type, from participants of the same household, were tested by RT-PCR. After pooled testing, all individual samples from positive pools and all individual samples from randomly chosen negative pools were evaluated. For assessment of diagnostic performance, pool testing results were compared with results from individual testing, which served as reference, and concordance in pooled and individual test detections was evaluated. Laboratory costs for both types of samples and testing were compared. Results: A total of 2008 NS and 2002 SL samples were collected from 132 study participants. We tested 329 NS and 333 SL pools. The mean pool size for NS and SL pools was 6.22 (SD = 0.92) and 6.39 (SD = 1.71), respectively. Using individual testing as reference, NS pooling of 6 had a sensitivity and specificity of 94% and 100%, respectively, with kappa of 0.97 (CI 95%: 0.93-1.00). The corresponding values for SL pooling of 6 were 83%, 100%, and 0.90 (CI 95%: 0.83-0.97). Compared with individual testing, pooling resulted in a cost reduction of 74.8% for NS and 72.4% for SL samples. Conclusions: Pooling easy-to-collect respiratory samples, especially NS, demonstrated very high diagnostic performance for detection of SARS-CoV-2 with substantial cost savings. This approach could be considered in large population screening programs, especially in LMIC.
RESUMO
Objetivo: determinar la relación entre el Ret-He con diferentes categorías según la concentración de hemoglobina en candidatos a donar sangre. Materiales y Métodos: Se realizó un estudio transversal a partir de la revisión de 227 historias clínicas de candidatos a donar sangre durante el mes de diciembre del 2021 en el Servicio de Banco de Sangre y Hemoterapia del Hospital Cayetano Heredia. Se categorizó en 3 grupos según los niveles de hemoglobina: Grupo 1: ≥12,5 g/dl (mujeres) - ≥13,5 g/dl (varones). Grupo 2: 12 g/dl ≥ mujeres <12.5 g/dl y 13 g/dl ≥ varones<13.5 g/dl. Grupo 3: <12 g/dl (mujeres) - <13 g/dl (varones). Se tomaron datos de hematocrito, hemoglobina, VCM, HCM, CHCM y Ret-He. Para el análisis bivariado se utilizó el análisis de varianza (ANOVA) y se consideró un nivel de significancia del 5 %. Resultados: La mediana de Ret-He fue mayor en el grupo 1 que en el grupo 2 (33.5 frente a 32.5; p=0.002) y en el grupo 3 (33.5 frente a 27.8; p<0.001). Se encontró relación estadísticamente significativa entre los grupos estudiados y Ret-He (p<0.001), además de una correlación positiva moderada fuerte entre Ret-He y los índices eritrocitarios. Conclusiones: Se encontró una asociación significativa entre los grupos basados en categorías de hemoglobina y la Ret-He en candidatos a donar sangre.
Objective: to determine the relationship between Ret-He with different categories according to hemoglobin concentration in candidates for blood donation. Methods: A cross-sectional study was carried out based on the review of 227 medical records of candidates to donate blood during the month of December 2021 in the Blood Bank and Hemotherapy Service of the Cayetano Heredia Hospital. They were categorized into 3 groups according to hemoglobin levels: Group 1: ≥12.5 g/dl (females) - ≥13.5 g/dl (males). Group 2: 12 g/dl ≥ females <12.5 g/dl and 13 g/dl ≥ males<13.5 g/dl. Group 3: <12 g/dl (females) - <13 g/dl (males). Hematocrit, hemoglobin, VCM, HCM, CHCM and Ret-He data were collected. For the bivariate analysis, analysis of variance (ANOVA) was used and a significance level of 5% was considered. Results: The median Ret-He was higher in group 1 than in group 2 (33.5 vs. 32.5; p=0.002) and in group 3 (33.5 vs. 27.8; p<0.001). A statistically significant relationship was found between the groups studied and Ret-He (p<0.001), in addition to a moderate-strong positive correlation between Ret-He and erythrocyte indices. Conclusions: An association was found between groups based on hemoglobin categories and Ret-He in blood donation candidates.
RESUMO
[This corrects the article DOI: 10.1016/j.jvacx.2022.100189.].
RESUMO
Objetivo : Determinar la correlación entre la glucosa salival con la glucosa en ayunas, HbA1c y el péptido C en personas con Diabetes Mellitus tipo 2 (DM2). Materiales y métodos : Estudio transversal llevado a cabo en el Centro de Investigación en Diabetes, Obesidad y Nutrición (CIDON) en Lima, Perú durante el año 2021. Se categorizó en buen control metabólico (HbA1c<7 %) y mal control metabólico (HbA1c≥7 %). Se midió la glucosa basal, HbA1c y el péptido C en sangre. La glucosa salival se midió con el método glucosa oxidasa. La correlación de Spearman fue usada para determinar la asociación entre la glucosa salival con la glucosa en ayunas, HbA1c y el péptido- C. Resultados : Participaron un total de 142 personas con DM2. La concentración de glucosa salival fue significativamente más elevada en DM2 con mal control metabólico (p<0.01). Se observó una correlación positiva débil significativa entre la glucosa salival y la glucosa basal (r=0.23, p=0.04) y HbA1c (r=0.26, p=0.02) en DM2 con mal control metabólico y una correlación negativa insignificante (r=-0.08; p=0.47) con el péptido C. Conclusiones : La glucosa salival presenta una asociación significativa y positiva con la glucosa en sangre y la HbA1c, pero no con el péptido C en personas con DM2 con mal control metabólico. Sin embargo, hay muchos factores que deben ser considerados y analizados más a fondo para determinar su posible uso.
Objetivo : To determine the correlation between salivary glucose levels with fasting blood glucose, HbA1c, and C-peptide in patients with type 2 diabetes mellitus (T2DM). Materials and methods : This is a cross-sectional study performed at the Centro de Investigación en Diabetes, Obesidad y Nutrición (CIDON) in Lima, Peru, during 2021. Patients were categorized as those with good metabolic control (HbA1c<7 %), and poor metabolic control (HbA1c≥7 %). Baseline fasting blood glucose, as well as blood HbA1c and C-peptide values were measured. Salivary glucose was measured using the glucose oxidase method. Spearman's correlation was used for determining an association between salivary glucose levels and fasting blood glucose, HbA1c, and C-peptide. Results : One-hundred and forty-two subjects with T2DM participated in the study. Salivary glucose was significantly higher in T2DM subjects with poor metabolic control (p<0.01). A weak positive correlation between salivary glucose and fasting blood glucose (r= 0.23, p= 0.04) and HbA1c (r= 0.26, p= 0.02) was observed in subjects with T2DM and poor metabolic control, and also a non-significant negative correlation (r=-0.08; p= 0.47) with C-peptide. Conclusions : Salivary glucose levels show significant and positive association with fasting blood glucose and HbA1c, but not with C-peptide in persons with T2DM and poor metabolic control. However, there are many factors that should be considered and analyzed in detail aiming to determine its potential use.
RESUMO
Background: The COVID-19 vaccine candidate CVnCoV comprises sequence-optimized mRNA encoding SARS-CoV-2 S-protein encapsulated in lipid nanoparticles. In this phase 2a study, we assessed reactogenicity and immunogenicity of two or three doses in younger and older adults. Methods: Younger (18-60 years) and older (>60 years) adults were enrolled in two sites in Panama and Peru to receive either 6 or 12 µg doses of CVnCoV or licensed control vaccines 28 days apart; subsets received a 12 µg booster dose on Day 57 or Day 180. Solicited adverse events (AE) were reported for 7 days and unsolicited AEs for 4 weeks after each vaccination, and serious AEs (SAE) throughout the study. Humoral immunogenicity was measured as neutralizing and receptor binding domain (RBD) IgG antibodies and cellular immunogenicity was assessed as CD4+/CD8 + T cell responses. Results: A total of 668 participants were vaccinated (332 aged 18-60 years and 336 aged > 60 years) including 75 who received homologous booster doses. Vaccination was well tolerated with no vaccine-related SAEs. Solicited and unsolicited AEs were mainly mild to moderate and resolved spontaneously. Both age groups demonstrated robust immune responses as neutralizing antibodies or RBD-binding IgG, after two doses, with lower titers in the older age group than the younger adults. Neither group achieved levels observed in human convalescent sera (HCS), but did equal or surpass HCS levels following homologous booster doses. Following CVnCoV vaccination, robust SARS-CoV-2 S-protein-specific CD4 + T-cell responses were observed in both age groups with CD8 + T-cell responses in some individuals, consistent with observations in convalescing COVID-19 patients after natural infection. Conclusions: We confirmed that two 12 µg doses of CVnCoV had an acceptable safety profile, and induced robust immune responses. Marked humoral immune responses to homologous boosters suggest two doses had induced immune memory.
RESUMO
BACKGROUND: While the detection of SARS-CoV-2 in samples preserved in viral transport medium (VTM) by RT-PCR is a standard diagnostic method, this may preclude the study of bacterial respiratory pathogens from the same specimen. It is unclear if the use of skim milk, tryptone, glucose, and glycerin (STGG) transport media, used for study of respiratory bacteria, allows an efficient and concurrent study of SARS-CoV-2 infections. OBJECTIVES: To determine the concordance in SARS-CoV-2 detection by real time RT-PCR between paired nasopharyngeal (NP) swabs preserved in STGG and nasal (NS) swabs preserved in VTM. STUDY DESIGN: Paired samples of NP and NS swabs were collected between December 2020 and March 2021 from a prospective longitudinal cohort study of 44 households and 132 participants from a peri-urban community (Lima, Peru). NP and NS swabs were taken from all participants once and twice per week, respectively, independent of respiratory symptoms. STGG medium was used for NP samples and VTM for NS samples. Samples were analyzed for SARS-CoV-2 by RT-PCR for N, S and ORF1ab targets. We calculated the concordance in detections between sample types and compared the RT-PCR cycle thresholds (Ct). RESULTS: Among the 148 paired samples, we observed a high concordance in detections between NP and NS samples (agreement = 94.59%; Kappa = 0.79). Median Ct values were statistically similar between sample types for each RT-PCR target: N, S and ORF1ab (p = 0.11, p = 0.71 and p = 0.11, respectively). CONCLUSIONS: NP swabs collected in STGG medium are reliable alternatives to nasal swabs collected in VTM for the study of SARS-CoV-2.
Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Humanos , Estudos Longitudinais , Nasofaringe/microbiologia , Estudos Prospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SARS-CoV-2/genética , Sensibilidade e Especificidade , Manejo de Espécimes/métodosRESUMO
BACKGROUND: We assessed the prevalence and incidence of SARS-CoV-2 infections in a prospective study of households in Lima, Peru. METHODS: Households with a child, a young adult 18-50 years, and an adult age >50 years in peri-urban Lima were followed with twice-a-week household visits during a 2-month period. Nasal swabs and saliva specimens were collected twice weekly, and nasopharyngeal swabs were collected weekly from each participant, regardless of symptoms. Laboratory-confirmed SARS-CoV-2 infection was defined by two RT-PCR tests from any of the collected specimens within a week. Blood samples collected at enrollment and end of follow-up were tested with rapid serological tests. We calculated the prevalence and incidence of laboratory-confirmed SARS-CoV-2 infections. RESULTS: We enrolled 132 participants from 44 households: 44 children, 44 young adults, and 44 older adults. A total of 13 SARS-CoV-2 infections were detected in eight households, for an overall period prevalence of 9.85% (95% confidence interval [CI]: 5.35-16.25). Most (61.54%) infections were symptomatic. Eight of 11 (72.73%) SARS-CoV-2 detections corresponded to the Lambda variant. During 218.79 person-months at risk of follow-up, there were six new SARS-CoV-2 infections detected (2.74 per 100 person-month, 95% CI: 1.25-6.04). At enrollment, 59 of 128 participants tested had positive SARS-CoV-2 IgG serology (46.09%, 95% CI: 37.25-55.12). Five of six new infections occurred among participants with negative baseline serology. CONCLUSIONS: We demonstrated high incidence of SARS-CoV-2 infections in households, especially among subjects without evidence of prior infection, most of them not detected by the Ministry of Health system.
