Impact on the time elapsed since SARS-CoV-2 infection, vaccination history, and number of doses, on protection against reinfection.

SARS-CoV-2 reinfections have been frequent, even among those vaccinated. The aim of this study is to know if hybrid immunity (infection + vaccination) is affected by the moment of vaccination and number of doses received. We conducted a retrospective study in 746 patients with a history of COVID-19 reinfection and recovered the dates of infection and reinfection and vaccination status (date and number of doses). To assess differences in the time to reinfection(tRI) between unvaccinated, vaccinated before 6 months, and later; and comparing one, two or three doses (incomplete, complete and booster regime) we performed the log-rank test of the cumulative incidence calculated as 1 minus the Kaplan-Meier estimator. Also, an adjusted Cox-regression was performed to evaluate the risk of reinfection in all groups. The tRI was significantly higher in those vaccinated vs. non-vaccinated (p < 0.001). However, an early incomplete regime protects similar time than not receiving a vaccine. Vaccination before 6 months after infection showed a lower tRI compared to those vaccinated later with the same regime (adj-p < 0.001). Actually, early vaccination with complete and booster regimes provided lower length of protection compared to vaccinating later with incomplete and complete regime, respectively. Vaccination with complete and booster regimes significantly increases the tRI (adj-p < 0.001). Vaccination increases the time it takes for a person to become reinfected with SARS-CoV-2. Increasing the time from infection to vaccination increases the time in which a person could be reinfected and reduces the risk of reinfection, especially in complete and booster regimes. Those results emphasize the role of vaccines and boosters during the pandemic and can guide strategies on future vaccination policy.

Environmental Dissemination of SARS-CoV-2 in a University Hospital during the COVID-19 5th Wave Delta Variant Peak in Castile-León, Spain.

The dominant SARS-CoV-2 Delta variant (B.1.617.2) became the main circulating variant among countries by mid 2021. Attention was raised to the increased risk of airborne transmission, leading to nosocomial outbreaks even among vaccinated individuals. Considering the increased number of COVID-19 hospital admissions fueled by the spread of the variant, with Spain showing the highest COVID-19 rates in mainland Europe by July 2021, the aim of this study was to assess SARS-CoV-2 environmental contamination in different areas of a University Hospital in the region of Castile-León, Spain, during the peak of the 5th wave of COVID-19 in the country (July 2021). Air samples were collected from sixteen different areas of the Hospital using a Coriolis® µ air sampler. Surface samples were collected in these same areas using sterile flocked plastic swabs. RNA extraction followed by a one-step RT-qPCR were performed for detection of SARS-CoV-2 RNA. Of the 21 air samples, only one was positive for SARS-CoV-2 RNA, from the emergency waiting room. Of the 40 surface samples, 2 were positive for SARS-CoV-2 RNA, both from the microbiology laboratory. These results may be relevant for risk assessment of nosocomial infection within healthcare facilities, thus helping prevent and minimize healthcare staff's exposure to SARS-CoV-2, reinforcing the importance of always wearing appropriate and well-fit masks at all times and proper PPE when in contact with infected patients.

Linfadenopatías por picaduras de garrapatas: a propósito de dos casos / Lymphadenopathy by tick bite: concerning two cases

Muchos niños manifiestan linfadenopatías en algún momento de su infancia, debidas sobre todo a enfermedades infecciosas. Es precisa una buena historia clínica, exploración física y pruebas complementarias que permitan su diagnóstico diferencial. Se describen los casos de dos niños que presentaban un cuadro clínico similar de linfadenopatías regionales, sin fiebre ni exantemas. Ambos tenían como antecedente la picadura de garrapata en el cuero cabelludo. El cuadro clínico y la serología positiva a rickettsias nos llevaron al diagnóstico de linfoadenopatía transmitida por garrapatas, TIBOLA, DEBONEL o SENLAT. El diagnóstico serológico en nuestros casos se encuentra limitado por la existencia de reacciones cruzadas con las distintas especies de rickettsias, en concreto con R. conorii (que es la habitualmente detectada en nuestro medio) e incluso con otras bacterias. La evolución de ambos casos fue favorable con tratamiento de azitromicina durante cinco días. Pese a la dificultad que supone la interpretación de los resultados serológicos, el diagnóstico de esta rickettsiosis se puede hacer a la luz de los datos clínicos y epidemiológicos. Debe plantearse la utilización simultánea de otras técnicas para aumentar la sensibilidad diagnóstica como pueden ser en la actualidad las técnicas de reacción en cadena de la polimerasa en biopsia cutánea que nos darán el diagnóstico etiológico de la infección

Many children manifest lymphadenopathy at some point in their childhood, mainly due to infectious diseases. A correct clinical history, physical examination and complementary tests are required to allow differential diagnosis. We describe the cases of two children who presented a similar clinical presentation of regional lymphadenopathies without fever or rash. Both had as antecedent the tick bite on the scalp. The clinical presentation and the positive serology to Rickettsias led us to the diagnosis of lymphadenopathy transmitted by ticks, TIBOLA, DEBONEL or SENLAT. The serological diagnosis in our cases is limited by the existence of cross reactions with the different species of Rickettsias in particular with R. conorii (which is the one usually detected in our environment) and even with other bacteria. The evolution of both cases was favorable with treatment of azithromycin for five days. Despite the difficulty involved in the interpretation of serological results, the diagnosis of this rickettsiosis can be made in the light of clinical and epidemiological data. It should be considered the simultaneous use of other techniques to increase diagnostic sensitivity, such as PCR techniques in skin biopsy that will give us the etiological diagnosis of the infection