Abstract INTRODUCTION The percentage of asymptomatic COVID-19 cases worldwide is estimated at 18–50%; 53% in Cuba specifically, and 58% in Havana, the Cuban capital and the 2020 epicenter of the country’s COVID-19 epidemic. These figures, however, do not represent the transmission capacity or behavior of asymptomatic cases. Understanding asymptomatic transmission’s contribution to SARS-CoV-2 spread is of great importance to disease control and prevention. OBJECTIVE Identify the epidemiological implications of asymptomatic SARS-CoV-2 infection in Havana, Cuba, during the first wave of the epidemic in 2020. METHODS We carried out a cross-sectional study of all confirmed COVID-19 cases diagnosed in Havana, Cuba, from March 16 through June 30, 2020. The information was obtained through review of the standardized form for investigation of suspected and confirmed cases. Examined variables included age, sex, occupation, case type and source of infection. Cases were divided into asymptomatic and symptomatic groups, and transmission was characterized through the creation of a contact matrix. Analysis was carried out in Epidat and R. RESULTS We studied 1287 confirmed cases, of which 57.7% (743) were asymptomatic, and 42.3% (544) were symptomatic. Symptomatic presentation was the most common for both imported and introduced cases, while asymptomatic presentation was more common in autochthonic cases and infections from an undetermined source. Asymptomatic infection was more common in groups aged <20 and 20–59 years, while symptomatic infection was more common in those aged >60 years. In the contact matrix, 34.6% of cases (445/1287) were not tied to other cases, and 65.4% (842/1287) were infectious–infected dyads, with symptomatic–symptomatic being the most common combination. The majority of primary cases (78.5%; 1002/1276) did not generate secondary cases, and 85.6% (658/743) of asymptomatic cases did not lead to other cases (although one asymptomatic superspreader led to 90 cases in a single event). However, 63.2% (344/544) of symptomatic primary cases generated secondary cases, and 11 symptomatic superspreaders spawned 100 secondary cases in different events. CONCLUSIONS Asymptomatic SARS-CoV-2 infection was the most common form of COVID-19 in Havana during the study period, but its capacity for contagion was lower than that of symptomatic individuals. Superspreader events under specific conditions played an important role in sustaining the epidemic.

Introduction: the low birth weight is an indicator that influence directly on the infant mortality and in the latter psychomotor development of the child. The Program for Reduction of the Low Birth Weight suggest that the children with a birth weight lower than 2 500 g have a death risk greater during the first year of life, compared with the children with a term normal weight. Objective: to characterize the behavior of the low birth weight during 2006-2010 in the "Héroes del Moncada" University Polyclinic. Methods: a cross-sectional, descriptive and observational study was conducted in 37 low weight newborns and their corresponding 34 mothers, three of them with twin pregnancy from a universe of 46 low weight newborns and 43 puerpera in total, from the above mentioned polyclinic. Authors excluded those low weight newborns during 2006-2010 whose medical records lacking of the necessary information. Results: the rate of low birth weight decreased until 2008 from which it start an increase to achieve the figure of 9.1 in 2010. The mother's mean age of the low weight newborns is over 30 years except for in 2006 and the mean weight behaved over 1 500 g. The 62.2 % of low weight newborns were white. The 29.7 % of mothers had an educational level of pre-university and a similar percentage in university graduate. There was predominance of vaginal sepsis and the gestational diabetes was present in 7 of the pregnants, where as the preeclampsia, the urinary sepsis and the multiple pregnancies were present in 18 of study women. The mothers of the 75.7 % of the total of low weight newborns not were admitted in the maternal home. Conclusions: the rate of low birth weight increased from the two past years and the month of august had the highest rate. The great percentage of the low weight newborns were of white race with a average weight over 1 500 g, whose mothers at moment of delivery were aged between 21 and 40. The was predominance of preterm deliveries and births of female sex. There was a higher rate of low birth weight newborns whose mothers had pathological backgrounds of non-communicable chronic diseases before pregnancy. There were more low birth weight children from women who during the study pregnancy had vaginal sepsis followed in frequency by gravidity high blood pressure and anemia. The mother's admission in maternal home was an indicator present in the minority of the low birth weight children whereas the hospital admission prevailed.

Introducción: el bajo peso al nacer es un indicador que incide de forma directa en la mortalidad infantil, y en el posterior desarrollo psicomotor del niño. El Programa para la Reducción del Bajo Peso al Nacer, señala que los niños nacidos con un peso inferior a los 2 500 g, presentan riesgo de mortalidad 40 veces mayor, durante el primer año de vida, en comparación con los niños que nacen con un peso normal a término. Objetivo: caracterizar el comportamiento del bajo peso al nacer, en el periodo 2006-2010, en el Policlínico Universitario "Héroes del Moncada". Métodos: se realizó un estudio observacional, descriptivo y transversal con 37 recién nacidos bajo peso y sus 34 madres correspondientes, 3 de ellas con embarazos gemelares, de un universo de 46 recién nacidos bajo peso y 43 puérperas en total, pertenecientes al Policlínico Universitario "Héroes del Moncada". Se excluyeron aquellos recién nacidos bajo peso del 2006-2010, cuyas historias clínicas no estuviesen disponibles con la información necesaria. Resultados: el índice de bajo peso al nacer, disminuyó hasta el año 2008, a partir del cual comienza un ascenso hasta alcanzar la cifra de 9,1 en el 2010. La edad media de las madres de los recién nacidos bajo peso, es mayor de 30 años, excepto en el año 2006, y el peso medio se comportó por encima de los 1 500 g. El 62,2 % de los recién nacidos bajo peso tenían el color de la piel blanco. El 29,7 % de las madres tenían un nivel educacional de preuniversitario e igual porcentaje hubo en las universitarias. Predominó la sepsis vaginal y la diabetes gestacional fue encontrada en 7 de las embarazadas, mientras que la preeclampsia, la sepsis urinaria y los embarazos múltiples, fueron encontrados en 18 de las mujeres estudiadas. Las madres del 75,7 % del total de recién nacidos bajo peso, no ingresaron en el hogar materno. Conclusiones: el índice de bajo peso al nacer, aumentó a partir de los dos últimos años, el mes de agosto es el de más alto índice. El mayor porcentaje de los recién nacidos bajo peso fueron de piel blanca, con un peso promedio superior a los 1 500 g, cuyas madres en su mayoría, al momento del parto, tenían edades entre los 21 y los 40 años. Predominaron los partos pretérminos y los nacimientos del sexo femenino. Hubo una mayor cantidad de niños nacidos con bajo peso, cuyas madres tenían antecedentes patológicos de enfermedades crónicas no transmisibles, antes del embarazo. Prevalecieron los niños bajo peso al nacer, que provenían de mujeres que tuvieron durante el embarazo en estudio, sepsis vaginal, seguida en frecuencia de la hipertensión arterial gravídica y la anemia. El ingreso de madres en el hogar materno, fue un indicador que estuvo presente en la minoría de los niños bajo peso al nacer, mientras que el ingreso hospitalario prevaleció.

Going though his notes, conferences, speeches, we found his entire legacy for the formation and practice of a doctor. He expressed: “…The need of studying, the need of interchange with medical letters”. In August 16th, 1960; during the Cycle of Public Health Conferences, he noted: “to be a revolutionary doctor, or to be a revolutionary, the first thing we must have is a revolution” He said: “The doctor, the medical worker, must go to the centre of his new job, which is the man within the conglomerate.” He states: “Every doctor, in his circle of action, must accumulate that precious treasure which is the people’s gratitude”.