To the Editor: Prone position ventilation has been shown to improve oxygenation and survival in patients with severe acute respiratory distress syndrome (ARDS) [1]. Facing the coronavirus disease 2019 (COVID-19) pandemic, prone positioning (PP) is of crucial importance to treat severe ARDS patients [2]. Nevertheless, the high number of ICU admissions quickly overwhelmed the ability of the daily ICU team to place patients in PP, a complex and time-consuming maneuver. Thus, we created a dedicated medical team with reassigned volunteers to cope with the large number of patients requiring PP. PP Team consisted of five volunteers: a senior medical non-intensivist physician placed at the patient's head to secure the endotracheal tube and four medical fellows or medical students placed at each side of the bed. For patients treated with VV-ECMO, a supplementary physician was added to secure the lines. Since PP is a complex procedure and has many potential adverse events requiring adequate and well-trained staff, volunteers received previously a theoretical training and a hands-on ad hoc training session. PP teams followed the guidelines for PP placement [1]. This retrospective observational study was performed in our extended ICU (from 22 to 46 beds), from the first day of deployment of PPT (March 23 to April 23, 2020). The main characteristics and outcomes of prone positioned patients (n = 63) are presented in Table 1.

The present study evaluated the frequency of seropositivity for anti-SARS-CoV-2 (S1 and S2) total antibodies and anti-SARS-CoV-2 (receptor binding domain-RBD-S1) neutralizing antibodies in individuals vaccinated with the immunizing agent Coronavac. This was a cross-sectional study involving 358 individuals divided into two groups. Group 1 consisted of 205 volunteers who were tested for anti-SARS-CoV-2 total antibodies; group 2 consisted of 153 individuals tested for the presence of anti-SARS-CoV-2 neutralizing antibodies. Seropositivity was greater than 70% in both groups, although 17.6% and 20.9% of individuals showed no neutralizing or total antibody reactivity, respectively. The frequency of anti-SARS-CoV-2 total antibodies displayed a significantly different distribution between the sexes but not according to age. The frequency of anti-SARS-CoV-2 neutralizing antibodies was 93.3% (95% CI 68.1–99.8) in the age group from 21 to 40 years but significantly decreased with advancing age, and was 76.2% (95% CI 52.8–91.8) for 41 to 60 years, 72.5% (95% CI 62.8–80.9) for 61 to 80 years, and 46.7% (95% CI 21.3–73.4) for >80 years. Our results reveal a high prevalence of anti-SARS-CoV-2 total antibodies and anti-SARS-CoV-2 neutralizing antibodies in individuals who received both doses of the Coronavac vaccine, suggesting a lower effectiveness of the humoral immune response among those older than 60 years of age, which might be associated with senescence of the immune system.

Background In this study, the prevalence and persistence of anti-SARS-CoV-2 (severe acute respiratory syndrome-coronavirus) IgG was evaluated in volunteers 90 days after COVID-19 (coronavirus disease 2019) diagnosis by correlating response dynamics with clinical conditions, epidemiological characteristics, and disease severity. Methods The study recruited 200 volunteers aged 18 years or older of both sexes diagnosed with COVID-19. Of the 200 volunteers initially selected, the 135 individuals who underwent serological testing for anti-SARS-CoV-2 antibodies on the first visit to the laboratory, were invited to return, after 90 days, and provide a new blood sample for a second assessment of the presence of anti-SARS-CoV-2 IgG antibody. Disease severity and longevity of symptoms were evaluated for each individual and associated with the serological profile. Results Among the 135 individuals who underwent a previous serological test for anti-SARS-CoV-2 antibody, 125 showed reactivity to IgG (92.6%). Of the 125 individuals with detectable IgG in the first test, 87 (69.6%) showed persistence of this antibody after 90 days and 38 (30.4%) lost IgG reactivity in the second evaluation. The frequency of all reported symptoms was higher in individuals who maintained IgG persistence after 90 days of symptoms. Symptom manifestations lasted ≥21 days in the group with a persistent IgG response (39.6%) and ≤ 7 days in the group with a nonpersistent IgG response (50.0%). The length of hospital stay and supplemental oxygen use were higher in individuals with a persistent IgG response. Conclusions The results of the present study show a high frequency of loss of anti-SARS-CoV-2 IgG antibodies within 3 months after COVID-19 diagnosis in the Brazilian Amazon.

Here, we present a longitudinal analysis of two patients who recovered from COVID-19 more than 8 months prior but showed persistent serological detection of anti-SARS-CoV-2 IgM. We still do not know the exact reason for this prolonged persistence of IgM in these patients. To our knowledge, these are the first reports of IgM persistence in the context of SARS-CoV-2 infection and point to the need for no longer using IgM as a diagnostic criterion for acute or recent COVID-19. One should opt for gold standard molecular methodologies due to their high sensitivity and specificity.

Background: In this study, the prevalence and persistence of anti-SARS-CoV-2 (severe acute respiratory syndrome-coronavirus) IgG was evaluated in volunteers 90 days after COVID-19 (coronavirus disease 2019) diagnosis by correlating response dynamics with clinical conditions, IL-1β and IL-6 cytokine levels, epidemiological characteristics, and disease severity. Methods: The study recruited 200 volunteers aged 18 years or older of both sexes diagnosed with COVID-19. ELISA testing was performed to detect IgG persistence and cytokine levels in 135 individuals with a previous serological test at the time of COVID-19 diagnosis.Results: Among the 135 individuals who underwent a previous serological test for anti-SARS-CoV-2 antibody and provided a new blood sample 90 days after the first examination, 125 showed reactivity to IgG (92.6%). Of the 125 individuals with detectable IgG in the first test, 69.6% showed persistence of this antibody after 90 days; however, in 10 (30.4%) individuals, IgG was nonreactive in the second evaluation. The frequency of all reported symptoms was higher in individuals who maintained IgG persistence after 90 days of symptoms, and no relationship with cytokine levels was observed. Conclusions: The results of the present study show a high frequency of loss of anti-SARS-CoV-2 IgG antibodies within three months after COVID-19 diagnosis in the Brazilian Amazon.