SARS-CoV-2 IgG seropositivity in a cohort of 449 non-hospitalized individuals during Spanish COVID-19 lockdown.

The Coronavirus Disease of 2019 (COVID-19) pandemic caused by SARS-CoV-2 led the Spanish government to impose a national lockdown in an attempt to control the spread of the infection. Mobility restrictions and the requirement of a medical prescription for serological testing for COVID-19 were included among the control measures. Under this scenario, between April 15th and June 15th, 2020, we performed an observational study including 449 individuals allowed to be tested according to the governmental restrictions, i.e. fulfilling the following prescription requirements: manifestation of COVID-19-compatible symptoms, contact with a confirmed COVID-19 patient, or employment as an essential worker, including health care workers, firefighters and public safety personnel such as police. Importantly, a relevant feature of the studied cohort was that none of the participants had been hospitalized. We analyzed SARS-CoV-2 IgG seropositivity in this specific cohort, uncovering intrinsic features of great demographic interest. The overall rate of IgG seropositivity was 33.69% (95% CI: 29.27-38.21). This frequency was comparable among the different participant occupations. A RT-PCR positive test, contact with a household member previously tested positive and the presence of COVID-19-compatible symptoms were positively associated with IgG + results. Among these symptoms, ageusia/anosmia was positively and independently associated with SARS-CoV-2 IgG seropositivity, while odynophagia was inversely associated. However, fever, ageusia/anosmia and asthenia were the most frequent symptoms described by IgG + subjects. Therefore, our data illustrate how specific cohorts display particular characteristics that should be taken into account when studying population-wide SARS-CoV-2 seroprevalence and key defining symptoms of COVID-19.

Dosimetric impact of bladder filling on organs at risk with barium contrast in the small bowel for adjuvant vaginal cuff brachytherapy.

PURPOSE: The aim of this prospective study was to analyze dosimetric impact of modifying bladder filling on dose distribution in organs at risk (OARs) when using contrast in the small bowel of patients under adjuvant therapy with high-dose-rate vaginal cuff brachytherapy (HDR-VCB) for endometrial cancer. MATERIAL AND METHODS: This research included 19 patients who underwent laparoscopic surgery. They were treated with HDR-VCB and 2.5-3.5 cm diameter cylinders. Two successive computerized tomography (CT) scans were performed, with empty bladder and with bladder filled with 180 cc of saline solution. Bladder, rectum, sigmoid, and small bowel were delineated as OARs. Oral barium contrast was used to clearly visualize small bowel loops. Prescription dose was 7 Gy. Dose-volume histograms were generated for each OAR, with full and empty bladder to compare doses received. RESULTS: Bladder distension had no dosimetric impact on the bladder, rectum, or sigmoid, unlike the small bowel. With full bladder, mean minimum dose at 2 cc (D2cc) was not significantly higher for full vs. empty bladder (5.56 vs. 5.06 Gy, p = 0.07), whereas there was a significant reduction in the small bowel (1.68 vs. 2.70 Gy, p < 0.001). With full bladder, the dose increased to 50% of the volume (D50%) of the bladder (2.11 vs. 1.28 Gy, p < 0.001), and decreased in the small bowel (0.70 vs. 1.09 Gy, p < 0.001). CONCLUSIONS: The present study describes the dose received by organs at risk during HDR-VCB, making it possible to define the dose received by small bowel loops, when visualized with oral barium contrast. In patients undergoing laparoscopic surgery, a full bladder during HDR-VCB reduces the dose to the small bowel without a clinically relevant dose increase in the bladder, and no dose increase in other OARs.