Objectives A decrease of both diffusion capacity (DLCO) and Quality of Life (QoL) was reported after discharge in hospitalized COVID-19 pneumonia survivors. We studied three and 6 month outcomes in hospitalized and non-hospitalized patients. Methods COVID-19 pneumonia survivors ( n = 317) were categorized into non-hospitalized “moderate” cases ( n = 59), hospitalized “severe” cases ( n = 180) and ICU-admitted “critical” cases ( n = 39). We studied DLCO and QoL (Short Form SF-36 health survey) 3 and 6 months after discharge. Data were analyzed using (repeated measures) ANOVA, Kruskal-Wallis or Chi-square test ( p < .05). Results At 3 months DLCO was decreased in 44% of moderate-, 56% of severe- and 82% of critical cases ( p < .003). Mean DLCO in critical cases (64±14%) was lower compared to severe (76 ± 17%) and moderate (81±15%) cases ( p < .001). A total of 159/278 patients had a decreased DLCO (<80%), of whom the DLCO improved after 6 months in 45% (71/159). However the DLCO did not normalize in the majority (89%) of the cases (63 ± 10% vs 68±10%; p < .001). At 3 months, compared to critical cases, moderate cases scored lower on SF-36 domain “general health” ( p < .05); both moderate and severe cases scored lower on the domain of “health change” ( p < .05). At 6 months, there were no differences in SF-36 between the subgroups. Compared to 3 months, in all groups “physical functioning” improved; in contrast all groups scored significantly lower on “non-physical” SF-36 domains. Conclusion Three months after COVID-19 pneumonia, DLCO was still decreased in the more severely affected patients, with an incomplete recovery after 6 months. At 3 months QoL was impaired. At 6 months, while “physical functioning” improved, a decrease in “non-physical” QoL was observed but did not differ between the moderate and severely affected patients.

Background The long-term effects of COVID-19 are still unknown. This study aims to assess the impact of COVID-19 among survivors after one year. Methods All confirmed COVID-19 cases who presented at OLVG hospital in Amsterdam during the first wave of the COVID-19 pandemic were invited to participate in our prospective observational cohort study. The participants were divided into three subgroups: patients not admitted, admitted to the general ward and admitted to the ICU. Questionnaires were sent at 3, 6 and 12 months after presentation. We used the Research and Development – 36-item health survey, the Hospital Anxiety and Depression Scale and the PTSS Checklist for DSM-5. We compared the RAND-36 scores at the timepoints with a Dutch healthy control population in 2020 and between the three subgroups using the Kruskal-Wallis test and the Mann-Whitney U test. Results Of the 466 confirmed cases, 75 patients died of COVID-19, 64 patients were lost to follow up and 12 patients were excluded because they were unable to complete the questionnaires due to mental illness or cognitive impairment, they moved back to their home country or refused to participate. Of the remaining 315 patients, 182 (57.8%) completed the questionnaires at 3 months. Subsequently, 163 patients provided informed consent for follow up. At 6 and 12 months, 98 (60.1%) and 131 (80.4%) completed the survey. The average score of all domains at 3 months was 58, compared to 79 at twelve months and 81 in the control group. There was a statistically significant increase from 3 and 12 and 6 and 12 months (figure 1). At twelve months participants recovered to levels of the healthy control group (N=459), except for the ICU group, who still experienced bodily pain and decreased physical function. The improvement was most noticeable in the domains of social functioning, role limitations – physical and role limitations – emotional. The percentage of patients with abnormal total HADS scores (cutoff at 16) and PCL5- scores (cutoff at 33) at 3 months decreased from 27.8 to 22.1% and 18.9 to 7.6% at 12 months, respectively (figure 2 and 3). Figure 1. RAND-36: Health-related quality of life after COVID-19 of all patients. Blue line is after 3 months, orange line is after 6 months, green line is after 12 months, yellow line is healthy control. The p-value in the right-upper corner shows statistical significant difference between all total scores, the asterisks indicate significance between groups. PF = physical functioning; SF = social functioning; RP = role limitations–physical; RE = role limitations–emotional; MH = mental health; VT = vitality; BP = pain; GH = general health; HC = health change. Figure 2 The blue column is after 3 months, the orange after 6 months and the green after 12 months. The numbers above the columns are percentages per group. Figure 3 The blue column is after 3 months, the orange after 6 months and the green after 12 months. The numbers above the columns are percentages per group. Conclusion Although, COVID-19 may cause a decreased health-related quality of life and impaired mental health, this study shows important recovery up to normal levels after one year. Disclosures All Authors: No reported disclosures

Background: It is unknown how long SARS-CoV-2 antibodies persist after COVID-19. The natural course of anti-SARS-CoV-2 antibodies was analyzed in a large post-COVID-19 cohort, until 12 months post-infection. Methods: The total antibodies SARS-CoV-2 (IgM and IgG) were tested in a cohort of patients with different COVID-19 disease severity sampled at 4 timepoints up to 12 months post COVID-19. In 23 randomly selected patients, the antibody isotypes: anti-spike IgM, IgA and IgG and anti-nucleocapsid IgG were analysed. Results: In total 152/153 patients (99%) tested positive for total anti-SARS-CoV-2 after 12 months of COVID-19; 3 patients tested positive at 8 to 10 months post infection just before vaccination. The SARS-CoV-2 antibody subclasses anti-nucleocapsid IgG, anti-spike IgG and IgA were all still detectable after 12 months. Anti-spike IgM waned after 12 months in the majority of patients.Conclusion: IgG and IgA antibodies against SARS-CoV-2 persisted 12 months post-COVID-19.