Lower prevalence of Post-Covid-19 Condition following Omicron SARS-CoV-2 infection. (preprint)

Background: Different SARS-CoV-2 variants can differentially affect the prevalence of Post Covid-19 Condition (PCC). This prospective study assesses prevalence and severity of symptoms three months after an Omicron infection, compared to Delta, test-negative and population controls. This study also assesses symptomology after reinfection and breakthrough infections . Methods: After a positive SARS-CoV-2 test, cases were classified as Omicron or Delta based on [≥] 85% surveillance prevalence. Population controls were representatively invited and symptomatic test-negative controls enrolled after a negative SARS-CoV-2 test. Three months after enrolment, participants indicated point prevalence for 41 symptoms and severity of four symptoms. Permutation tests identified significantly elevated symptoms in cases compared to controls. PCC prevalence was estimated as the difference in prevalence of at least one elevated symptom in cases compared to population controls. Findings: At three months follow-up, five symptoms and severe dyspnea were significantly elevated in Omicron cases (n = 4138) compared to test-negative (n= 1672) and population controls (n= 2762). PCC prevalence was 10.4% for Omicron cases and 17.7% for Delta cases (n = 6855). Prevalence of severe fatigue and dyspnea were higher in reinfected compared to primary infected Omicron cases, while severity of symptoms did not significantly differ between Omicron cases with a booster or primary vaccination course. Interpretation: Three months after Omicron, prevalence of PCC is 41% lower than after Delta. Reinfection seems associated with more prevalent severe long-term symptoms compared to a first infection. A booster prior to infection does not seem to improve the outcome of long-term symptoms. Funding: The study is executed by the National Institute for Public Health and the Environment by order of the Ministry of Health, Welfare and Sport.

Prevalence and severity of symptoms 3 months after infection with SARS-CoV-2 compared to test-negative and population controls in the Netherlands (preprint)

Background: More information is needed on prevalence of long-term symptoms after SARS-CoV-2-infection. This prospective study assesses symptoms three months after SARS-CoV-2-infection compared to test-negative and population controls, and the effect of vaccination prior to infection. Methods: Participants enrolled after a positive (cases) or negative (test-negative controls) SARS-CoV-2-test, or after invitation from the general population (population controls). After three months, participants indicated presence of 41 symptoms, and severity of four symptoms. Permutation tests were used to select symptoms significantly elevated in cases compared to controls and to compare symptoms between cases that were vaccinated or unvaccinated prior to infection. Findings: Between May 19th and December 13th 2021 9166 cases, 1698 symptomatic but test-negative controls, and 3708 population controls enrolled. At three months, 13 symptoms, and severity of fatigue, cognitive impairment and dyspnoea, were significantly elevated between cases and controls. Of cases, 48.5% reported [≥]1 significantly elevated symptom, compared to 29.8% of test-negative controls and 26.0% of population controls. Effect of vaccination could only be determined for cases <65yrs, and was found to be significantly protective for loss of smell and taste but not for other symptoms. Interpretation: Three months after SARS-CoV-2 infection, almost half of the cases still report symptoms, which is higher than the background prevalence and prevalence in test-negative controls. Vaccination prior to infection was protective against loss of smell and taste as assessed in cases aged <65.

Long COVID is associated with extensive in-vivo neuroinflammation on [18F]DPA-714 PET (preprint)

Summary A significant number of COVID-19 patients develop ‘long COVID’, a condition defined by long-lasting debilitating, often neurological, symptoms. The pathophysiology of long COVID is unknown. Here we present in-vivo evidence of widespread neuroinflammation in long COVID, using a quantitative assessment, [ 18 F]DPA-714 PET, in two long COVID patients. We reanalyzed historical data from three matched healthy control subjects, for comparison purposes. Both patients with long COVID had widespread increases in [ 18 F]DPA-714 binding throughout the brain. Quantitative measures of binding (BP ND values) were increased on average by 121% and 76%, respectively. This implicates profound neuroinflammation in the pathophysiology of long COVID.

Prevalence and determinants of persistent symptoms after infection with SARS-CoV-2: Protocol for an observational cohort study (LongCOVID-study) (preprint)

Background: A substantial proportion of individuals infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) report persisting symptoms weeks and months following acute infection. Estimates on prevalence vary due to differences in study designs, populations, heterogeneity of symptoms and the way symptoms are measured. Common symptoms include fatigue, cognitive impairment and dyspnea. However, knowledge regarding the nature and risk factors for developing persisting symptoms is still limited. Hence in this study we aim to determine the prevalence, severity, risk factors and impact on quality of life of persisting symptoms in the first year following acute SARS-CoV-2 infection. Methods: The LongCOVID-study is both a prospective and retrospective cohort study with a one year follow up. Participants aged 5 years and above with self-reported positive or negative tests for SARS-CoV-2 will be included in the study. The primary outcome is the prevalence and severity of persistent symptoms in participants that tested positive for SARS-CoV-2 compared to controls. Symptom severity will be assessed for fatigue using the Checklist Individual Strength (CIS subscale fatigue severity), pain (Rand-36/SF-36 subscale bodily pain), dyspnea (Medical Research Council (mMRC)) and cognitive impairment using the Cognitive Failure Questionnaire (CFQ). Secondary outcomes include loss of health-related quality of life (HRQoL) and risk factors for persisting symptoms following infection with SARS-CoV-2. Discussion: A better understanding regarding the nature of persisting symptoms following SARS-CoV-2 infection will enable better diagnosis, management and will consequently minimize negative consequences on quality of life. Keywords: SARS-CoV-2, post COVID-19 condition, LongCovid, prevalence, HRQoL, risk factors