ABSTRACT
The aim of this study was to determine whether Post-acute Sequelae of SARS-CoV-2 Infection (PASC) are associated with physical inactivity in COVID-19 survivors. This is a cohort study of COVID-19 survivors discharged from a tertiary hospital in Sao Paulo, Brazil. Patients admitted as inpatients due to laboratory-confirmed COVID-19 between March and August 2020 were consecutively invited for a follow-up in-person visit 6 to 11 months after hospitalization. Ten symptoms of PASC were assessed using standardized scales. Physical activity was assessed by questionnaire and participants were classified according to WHO Guidelines. 614 patients were analyzed (age: 56±13 years; 53% male). Frequency of physical inactivity in patients exhibiting none, at least 1, 1 to 4, and 5 or more symptoms of PASC was 51%, 62%, 58%, and 71%, respectively. Adjusted models showed that patients with one or more persistent PASC symptoms have greater odds of being physically inactive than those without any persistent symptoms (OR: 1.56[95%CI: 1.03 to 2.37], P=0.034). Dyspnea (OR: 2.22[1.50 to 3.33]), fatigue (OR: 1.96[0.43 to 0.95]), insomnia (OR: 1.59[1.10 to 2.31]), post-traumatic stress (OR: 1.53[1.06 to 2.23]), and severe muscle/joint pain (OR: 1.49[95%CI: 1.05 to 2.00]) were associated with greater odds of being physically inactive (all P<0.05). This study suggests that PASC is associated with physical inactivity, which itself may be considered as a persistent symptom among COVID-19 survivors. This may help in the early identification of patients who could benefit from interventions tailored to combat inactivity, with potential beneficial impacts on overall morbidity/mortality and health systems worldwide.
Subject(s)
COVID-19ABSTRACT
BackgroundPassive antibody therapy with convalescent plasma (CP) represents a promising alternative for the treatment of SARS-CoV-2 infection. The efficacy of CP therapy has been associated with high titers of neutralizing antibodies (nAbs) in the plasma of recovered patients, but the assays for quantifying nAbs are not widely available. Our goal was to develop a strategy to predict high titers of nAbs based on the results of anti-SARS-CoV-2 immunoassays and the clinical characteristics of the CP potential donors. MethodsTwo hundred and fourteen CP donors were enrolled and tested for the presence of anti-SARS-CoV-2 antibodies using two commercial immunoassays (IA): Anti-SARS-CoV-2 ELISA IgG EUROIMMUN and Anti-SARS-CoV-2 Chemiluminescence IgG Abbott. In parallel, quantification of neutralizing antibodies (nAbs) was performed using the Cytopathic effect-based virus neutralization test (CPE-VNT). Three criteria for identifying donors with high titers of nAbs ([≥]1:160) were tested: - Criterion1: Curve ROC Method; - Criterion 2: Conditional decision tree considering only the results from the IA and -Criterion 3: Conditional decision tree including both the IA results and the clinical variables. ResultsThe performance of Abbott and EUROIMMUN immunoassays was similar referring to both S/CO and predictive value for identifying nAbs titers [≥] 1:160. Regarding the three studied criteria for identifying CP donors with high nAbs titers ([≥] 1:160): 1) Criterion 1 showed 76.1% accuracy when the S/CO cut-off of 4.65 was used, 2) Criterion 2 presented 76.1% accuracy if the S/CO [≥] 4.57 was applied and 3) Criterion 3 had 71.6% accuracy if either S/CO [≥] 4.57 or S/CO between 2.68 and 4.57 and the last COVID-19-related symptoms occurred less than 19 days from donor recruiting were used. ConclusionThe results of SARS-CoV-2 immunoassays (S/CO) can be used to predict high nAbs titers of potential CP donors. This study has proposed three different criteria for identifying donors with [≥] 1:160 nAbs titer based on either solely S/CO results or S/CO together with clinical variables, all with high efficacy and accuracy.
Subject(s)
COVID-19ABSTRACT
The herd immunity threshold is the proportion of a population that must be immune to an infectious disease, either by natural infection or vaccination such that, in the absence of additional preventative measures, new cases decline and the effective reproduction number falls below unity. This fundamental epidemiological parameter is still unknown for the recently-emerged COVID-19, and mathematical models have predicted very divergent results. Population studies using antibody testing to infer total cumulative infections can provide empirical evidence of the level of population immunity in severely affected areas. Here we show that the transmission of SARS-CoV-2 in Manaus, located in the Brazilian Amazon, increased quickly during March and April and declined more slowly from May to September. In June, one month following the epidemic peak, 44% of the population was seropositive for SARS-CoV-2, equating to a cumulative incidence of 52%, after correcting for the false-negative rate of the antibody test. The seroprevalence fell in July and August due to antibody waning. After correcting for this, we estimate a final epidemic size of 66%. Although non-pharmaceutical interventions, plus a change in population behavior, may have helped to limit SARS-CoV-2 transmission in Manaus, the unusually high infection rate suggests that herd immunity played a significant role in determining the size of the epidemic.