[Comparison of postvaccinal antibodies to SARS-CoV-2 in asymptomatic cases, symptomatic cases, and non-cases in a cohort of general hospital workers]. / Comparación de anticuerpos postvacunales al SARS-CoV-2 en casos asintomáticos, casos sintomáticos, y no casos de una cohorte de trabajadores de un hospital general.

Estimada Sra. Directora: Agradecemos a los doctores Rujittika Mungmunpuntipantip y Viroj Wiwanitkit su interés por nuestra publicación(1) en la carta en la que se subrayan la importancia de los casos asintomáticos de COVID-19 en la evaluación de los efectos de la vacunación anti-SARS-CoV-2(2). Compartimos con ellos que las personas asintomáticas al COVID-19 pueden presentar unos niveles de anticuerpos anti-SARS-CoV-2 IgG-S mayores que las personas sin historia previa de COVID-19, y que pueden diferir en las reacciones a la vacunación, considerando que la prevalencia de COVID-19 asintomáticos se ha descrito como elevada(3).  En nuestra cohorte de trabajadores del Hospital General Universitario de Castellón, se detectaron 5 casos de COVID-19 asintomáticos (CA), incluyendo los dos seguimientos realizados(1,4), y 20 casos presentaron síntomas de COVID-19 (CS), con un total de 25 casos con confirmación por el laboratorio, 20 % tasa de asintomáticos (5/25). En la tabla 1 se recogen las características de los CA, CS, y de los participantes que no habían sufrido la enfermedad. Los CA eran más jóvenes que los otros 2 grupos, y la proporción de varones era significativamente mayor (p=0,027). En cuanto a los anticuerpos Anti-SARS-CoV-2 IgG-S al mes de la vacunación, los niveles de los CS fueron mayores que los de CA, y de los no casos, siendo estos últimos los que tuvieron significativamente menores niveles (p<0,001). Sin embargo, a los 8 meses de la vacunación la caída de IgG-S fue general, y los niveles de IgG-S eran mayores en los CA que en los CS y en los no casos (p<0,001). Los niveles de IgG-S considerados como protectores ? 4160 UA/ml, eran mayores en los CA y CS que el de los no casos (p=0,001). Si bien, el declive era similar en los tres grupos (p=0,084). Los síntomas y los efectos secundarios de las dos dosis de vacuna Pfizer-BioNTech no presentaron diferencias significativas entre los grupos. Estos resultados son coincidentes con númerosos estudios, en los que se constata que los casos de COVID-19 presentan niveles más elevados de IgG-S que las personas que no han sufrido la enfermedad(5), y se apreció que en valores medio no se alcanzaron los niveles de IgG-S protectores. De aquí la importancia de disponer de marcadores más efectivos de la situación de protección de la personas vacunadas tanto si han sufrido la enfermedad como sino. Además de los anticuerpos neutralizantes, la determinación de la inmunidad celular podría ser muy conveniente para conocer los niveles de protección.

Incidence, Mortality, and Risk Factors of COVID-19 in Nursing Homes.

During the period from March 2020 to January 2021, we performed an analysis of incidence, mortality, and risk factors of COVID-19 in nursing homes (NHs) in two health departments (HDs) of Castellon (Spain) 2021 through epidemiological surveillance and an ecological design. Laboratory-confirmed COVID-19 cases, cumulative incidence rate (CIR), and mortality rate (MR) of 27 NHs were collected. Information of residents, staff, and facilities was obtained by questionnaire. Multilevel Poisson regression models were applied. All NHs in the HDs participated with 2229 residents (median: 83 years old, 67.3% women) and 1666 staff. Among residents, 815 cases (CIR: 34.8 per 100) and 202 deaths (MR: 8.7 per 100, case fatality 21.0%) were reported and, among staff, 296 cases (CIR: 19.2 per 100) without deaths. Residents' CIR and MR increased with staff CIR, age of the building, residents/staff ratios, occupancy rate, and crowding index; CIR increased with private NH ownership, large NH size, large urban area, and the percentage of women residents; and MR was associated with residents' severe disabilities. In conclusion, several risk factors of COVID-19 incidence and mortality can be prevented by improving infection and quality controls, ameliorating residents/staff ratios, improving structural facilities, and increasing NH public ownership to avoid new outbreaks.

Incidence, Hospitalization, Mortality and Risk Factors of COVID-19 in Long-Term Care Residential Homes for Patients with Chronic Mental Illness.

Long-term care residential homes (LTCRH) for patients with chronic mental illness have suffered the enormous impact of COVID-19. This study aimed to estimate incidence, hospitalization, mortality, and risk factors of COVID-19 to prevent future epidemics. From March 2020 to January 2021 and before vaccination anti-SARS-CoV-2 begins, cumulate incidence rate (CIR), hospitalization rate (HR), mortality rate (MR), and risk factors of COVID-19 in the 11 LTCRH of two Health Departments of Castellon (Spain) were studied by epidemiological surveillance and an ecological design. Laboratory tests confirmed COVID-19 cases, and multilevel Poisson regression models were employed. All LTCRH participated and comprised 346 residents and 482 staff. Residents had a mean age of 47 years, 40% women, and suffered 75 cases of COVID-19 (CIR = 21.7%), five hospitalizations (HR = 1.4%), and two deaths (MR = 0.6%) with 2.5% fatality-case. Staff suffered 74 cases of the disease (CIR = 15.4%), one hospitalization (HR = 0.2%), and no deaths were reported. Risk factors associated with COVID-19 incidence in residents were private ownership, severe disability, residents be younger, CIR in municipalities where LTCRH was located, CIR in staff, and older age of the facilities. Conclusion: COVID-19 incidence could be prevented by improving infection control in residents and staff and modernizing facilities with increased public ownership.

Incidence, Mortality, and Risk Factors of COVID-19 in Nursing Homes

During the period from March 2020 to January 2021, we performed an analysis of incidence, mortality, and risk factors of COVID-19 in nursing homes (NHs) in two health departments (HDs) of Castellon (Spain) 2021 through epidemiological surveillance and an ecological design. Laboratory-confirmed COVID-19 cases, cumulative incidence rate (CIR), and mortality rate (MR) of 27 NHs were collected. Information of residents, staff, and facilities was obtained by questionnaire. Multilevel Poisson regression models were applied. All NHs in the HDs participated with 2229 residents (median: 83 years old, 67.3% women) and 1666 staff. Among residents, 815 cases (CIR: 34.8 per 100) and 202 deaths (MR: 8.7 per 100, case fatality 21.0%) were reported and, among staff, 296 cases (CIR: 19.2 per 100) without deaths. Residents' CIR and MR increased with staff CIR, age of the building, residents/staff ratios, occupancy rate, and crowding index;CIR increased with private NH ownership, large NH size, large urban area, and the percentage of women residents;and MR was associated with residents' severe disabilities. In conclusion, several risk factors of COVID-19 incidence and mortality can be prevented by improving infection and quality controls, ameliorating residents/staff ratios, improving structural facilities, and increasing NH public ownership to avoid new outbreaks.

[Vaccine response to SARS-CoV-2 in hospital workers]. / Respuesta vacunal frente a SARS-CoV-2 en trabajadores de un hospital.

INTRODUCTION: The aim of this study was to measure anti-SARS-CoV-2 immunity of hospital workers after a completed 2-dose Pfizer-BionTech vaccination, and to examine factors potentially associated with immunity status. Side effects of the vaccine were also studied. METHOD: This was a cross-sectional study of a representative sample of General University Hospital of Castellon workers, vaccinated with two doses in January and February 2021. We measured IgG antibodies against protein N (IgG-NP), IgM against protein S (IgM-S), and quantitative levles of IgG against protein S (IgG-Quant) one month after the last dose. We obtained information on demographic, risk factors, and vaccine side effects via a self-completed questionnaire. For the statistical analysis we used multiple regression models. RESULTS: Two hundred seventy-five workers participated (96.8%, 275/284). Positive IgG-Quant, IgM-S, and IgG-NP were 99.6%, 14.9% and 4.4%, respectively. Adjusted IgG-Quant levels increased significantly with obesity, nonsmoking status, positive IgM-S, and/or IgG-NP. The prevalence of IgM-S was higher in males, and associated with the same factors as those for IgG-Quant. Among those with a history of COVD-19 infection, 42.9% did not have IgG-NP. Overall 86.5% of participants had side effects, which were associated with positive IgG-NP, high IgG-Quant levels, younger age, and being female. CONCLUSIONS: All but one participant developed immunity. Those who had suffered from COVID-19 infection had higher antibody levels. A high proportion of participants had mild secondary effects, especially those with previous COVID-19 infection.

Introducción: Evaluar la inmunidad de los trabajadores de un hospital tras haber completado la vacunación Pfizer-BionTech, y su relación con factores individuales. También describir los efectos adversos de la vacuna. Método: Estudio transversal de una muestra de los trabajadores del Hospital General Universitario de Castellón vacunados con dos dosis en enero y febrero de 2021. Un mes después se detectaron: anticuerpos IgG frente a la proteína N (IgG-NP), de IgM frente a la proteína S (IgM-S) y detección cuantitativa de IgG frente a la proteína S (IgG-Quant). Se utilizó un cuestionario para recoger datos demográficos, factores de riesgo y efectos secundarios. En el análisis estadístico se utilizaron modelos de regresión múltiple. Resultados: La participación fue del 96,8% (275/284). Presentaron IgG-Quant el 99,6%, 14,9% IgM-S, y 4,4% IgG-NP. El nivel ajustado de IgG-Quant aumentó significativamente con la obesidad, en no fumadores y con positividad IgM-S y/o IgG-NP. La prevalencia de IgM-S era mayor en varones, y se asociaba con los mismos factores que la IgG-Quant. De los infectados por COVID-19, el 42,9% no presentaron IgG-NP. Un 86,5% sufrió algún efecto secundario que se asoció a tener IgG-NP, mayores niveles de IgG-Quant, y fue más frecuente en jóvenes y mujeres. Conclusiones: Todos los participantes desarrollaron inmunidad humoral excepto uno. Tuvieron mayores niveles de anticuerpos los que habían padecido la COVID-19. Un porcentaje alto desarrolló efectos secundarios leves, más frecuentes en los que habían padecido la enfermedad.

The first wave of the COVID-19 epidemic in Spain was associated with early introductions and fast spread of a dominating genetic variant.

The coronavirus disease 2019 (COVID-19) pandemic has affected the world radically since 2020. Spain was one of the European countries with the highest incidence during the first wave. As a part of a consortium to monitor and study the evolution of the epidemic, we sequenced 2,170 samples, diagnosed mostly before lockdown measures. Here, we identified at least 500 introductions from multiple international sources and documented the early rise of two dominant Spanish epidemic clades (SECs), probably amplified by superspreading events. Both SECs were related closely to the initial Asian variants of SARS-CoV-2 and spread widely across Spain. We inferred a substantial reduction in the effective reproductive number of both SECs due to public-health interventions (Re < 1), also reflected in the replacement of SECs by a new variant over the summer of 2020. In summary, we reveal a notable difference in the initial genetic makeup of SARS-CoV-2 in Spain compared with other European countries and show evidence to support the effectiveness of lockdown measures in controlling virus spread, even for the most successful genetic variants.