Background The relationship of host immune response and viral replication with health outcomes in patients with COVID-19 remains to be defined. We aimed to characterize the medium and long-term clinical, virological, and serological outcomes after hospitalization for COVID-19, and to identify predictors of long-COVID. Methods Prospective, longitudinal study conducted in COVID-19 patients confirmed by RT-PCR. Serial blood and nasopharyngeal samples (NPS) were obtained for measuring SARS-CoV-2 RNA and S-IgG/N-IgG antibodies during hospital stay, and at 1, 2, and 6 months post-discharge. Genome sequencing was performed where appropriate. Patients filled out a COVID-19 symptom questionnaire (CSQ) at 2-month and 6-month visits, and those with highest scores were characterized. Results Of 146 patients (60% male, median age 64 years) followed-up, 20.6% required hospital readmission and 5.5% died. At 2 months and 6 months, 9.6% and 7.8% patients, respectively, reported moderate/severe persistent symptoms. SARS-CoV-2 RT-PCR was positive in NPS in 11.8% (median Ct = 38) and 3% (median Ct = 36) patients at 2 months and 6 months, respectively, but no reinfections were demonstrated. Antibody titers gradually waned, with seroreversion occurring at 6 months in 27 (27.6%) patients for N-IgG and in 6 (6%) for S-IgG. Adjusted 2-month predictors of the highest CSQ scores (OR [95%CI]) were lower peak S-IgG (0.80 [0.66-0.94]) and higher WHO severity score (2.57 [1.20-5.86]); 6-month predictors were lower peak S-IgG (0.89 [0.79-0.99]) and female sex (2.41 [1.20-4.82]); no association was found with prolonged viral RNA shedding. Conclusions Long-COVID is associated with weak anti-SARS-CoV-2 antibody response, severity of illness, and female gender. Late clinical events and persistent symptoms in the medium and long term occur in a significant proportion of patients hospitalized for COVID-19.

Background From 1958–70, >100,000 people in northern Chile were exposed to a well-documented, distinct period of high drinking water arsenic concentrations. We previously reported ecological evidence suggesting that early-life exposure in this population resulted in increased mortality in adults from several outcomes including lung and bladder cancer. Methods We have now completed the first study ever assessing incident cancer cases after early-life arsenic exposure, and the first study on this topic with individual participant exposure and confounding factor data. Subjects included 221 lung and 160 bladder cancer cases diagnosed in northern Chile from 2007–2010, and 508 age and gender-matched controls. Results Odds ratios (ORs) adjusted for age, sex, and smoking in those only exposed in early-life to arsenic water concentrations of ≤110, 110–800, and >800 μg/L were 1.00, 1.88 (95% confidence interval (CI), 0.96–3.71), and 5.24 (3.05–9.00) (p-trend<0.001) for lung cancer, and 1.00, 2.94 (1.29–6.70), and 8.11 (4.31–15.25) (p-trend<0.001) for bladder cancer. ORs were lower in those not exposed until adulthood. The highest category (>800 μg/L) involved exposures which started 49–52 years before, and ended 37–40 years before the cancer cases were diagnosed. Conclusion Lung and bladder cancer incidence in adults was markedly increased following exposure to arsenic in early-life, even up to 40 years after high exposures ceased. Findings like these have not been identified before for any environmental exposure, and suggest that humans are extraordinarily susceptible to early-life arsenic exposure. Impact Policies aimed at reducing early-life exposure may help reduce the long-term risks of arsenic-related disease.

Background The virological and immunological effects of the immunomodulatory drugs used for COVID-19 remain unknown. We evaluated the impact of interleukin (IL)-6 blockade with tocilizumab on SARS-CoV-2 viral kinetics and the antibody response in patients with COVID-19. Methods Prospective cohort study in patients admitted with COVID-19. Serial nasopharyngeal and plasma samples were measured for SARS-CoV-2 RNA and S-IgG/N-IgG titers, respectively. Findings 138 patients with confirmed infection were included; 76 (55%) underwent IL-6 blockade. Median initial SOFA ( p = 0•016) and SARS-CoV-2 viral load ( p <0•001, Mann-Whitney-Wilcoxon test) were significantly higher among anti-IL-6 users. Patients under IL-6 blockade showed delayed viral clearance in the Kaplan-Meier curves (HR 0•35 [95%CI] [0•15–0•81], log-rank p = 0•014), but an adjusted propensity score matching model did not demonstrate a significant relationship of IL-6 blockade with viral clearance (HR 1•63 [0•35–7•7]). Cox regression showed an inverse association between SARS-CoV-2 RNA clearance and the initial viral load (HR 0•35 [0•11–0•89]). Patients under the IL-6 blocker showed shorter median time to seropositivity, higher peak antibody titers, and higher cumulative proportion of seropositivity in the Kaplan Meier curves (HR 3•1 [1•9–5] for S-IgG; and HR 3•0 [1•9–4•9] for N-IgG; log-rank p <0•001 for both). However, no significant differences between groups were found in either S-IgG (HR 1•56 [0•41–6•0]) nor N-IgG (HR 0•96 [0•26–3•5]) responses in an adjusted propensity score analysis. Interpretation Our results suggest that in patients infected with SARS-CoV-2, IL-6 blockade does not impair the viral specific antibody responses. Although a delayed viral clearance was observed, it was driven by a higher initial viral load. The study supports the safety of this therapy in patients with COVID-19. Funding Instituto de salud Carlos III (Spain).

Objectives The interdependencies of viral replication and the host immune response in patients with COVID-19 remain to be defined. We investigated the viral determinants of antibody response, the predictors of non-seroconversion, and the role of antibodies on viral dynamics. Methods Prospective study in patients hospitalized with microbiologically confirmed COVID-19 by real-time polymerase-chain-reaction (RT-PCR). Serial nasopharyngeal and oropharyngeal swabs and plasma samples were obtained for measuring SARS-CoV-2 RNA and antibodies (total and S-IgG/N-IgG), respectively. Results Of 132 patients included, 99 (75%) showed positive antibody titers after a median (Q1-Q3) of 11 (8-14) days. Median (Q1-Q3) follow-up was 74.5 (63.0-87.0) days. In adjusted linear regression model, time to seropositivity was inversely associated with peak log SARS-CoV-2 viral load (p=0.009) and positively with time to viral clearance (p=0.004). Adjusted predictors of S-IgG levels were time to viral clearance (p&lt;0.001), bilateral lung infiltrates on admission (p=0.011), and the time-dependent SARS-CoV-2 RNA (p&lt;0.001) and SARS-CoV-2 RNA area under the curve (p=0.001). Thirty-three (25%) patients showed undetectable antibody titers. Patients who did not seroconvert had higher cycle threshold values of RT-PCR (38.0 vs 28.0; p&lt;0.001), shorter time to viral clearance (3.0 vs 41.0; p&lt;0.001) and were more likely to have SARS-CoV-2 only detected on fecal samples (p&lt;0.001). Non-seroconvertors had also lower levels of blood inflammatory biomarkers on admission and lower disease severity. Conclusions Viral replication determines the magnitude of antibody response to SARS-CoV-2 that, in turn, contributes to viral clearance. COVID-19 patients who do not seroconvert exhibit a differential virological and clinical profile.

Background Performance of point-of-care tests in different clinical scenarios and on different samples remains undetermined. We comprehensively evaluated the performance of the nasopharyngeal Panbio COVID-19 antigen Rapid-Test-Device. Method Prospective study including consecutive patients attending three primary care centers (PCC) and an emergency department. The antigen test was performed at point-of-care in nasopharyngeal and nasal swabs, and in saliva. Positive and negative percent agreement (PPA, NPA) were calculated with the RT-PCR assay as reference standard. Results Of 913 patients included, 296 (32.3%) were asymptomatic and 690 (75.6%) came from the PCC. Nasopharyngeal swabs were collected from 913, nasal swabs from 659, and saliva from 611 patients. RT-PCR was positive in 196 (21.5%) nasopharyngeal samples (NPS). Overall PPA (95% CI) in NPS was 60.5% (53.3-67.4), and it was lower in nasal swabs (44.7%) and saliva (23.1%). Test performance in NPS was largely dependent on the cycle threshold (Ct) in RT-PCR, with PPA of 94% for Ct≤25 and 80% for Ct&lt;30. In symptomatic patients, the PPA was 95% for Ct≤25; 85% for Ct&lt;30, and 89% for the symptom triad of fever, cough and malaise. Performance was also dependent on age, with PPA of 100% in symptomatic patients &gt;50 years with Ct&lt;25. In asymptomatic patients, the PPA was 86% for Ct&lt;25. In all cases, NPA was 100%. Conclusion The nasopharyngeal Panbio COVID-19 antigen test performed at point-of-care has a good sensitivity in symptomatic patients with Ct&lt;30 and older age. The test was useful to identify asymptomatic patients with lower Ct values.