Prevalence of Long-term Symptoms Varies When Using Different Post-COVID-19 Definitions in Positively and Negatively Tested Adults: The PRIME Post-COVID Study

Decreases in frequency-dependent intrinsic activity of the default mode network are associated with depression and cognition in patients with postacute sequelae of SARS-CoV-2 infection

A significant proportion of patients who have recovered from COVID-19 suffer from persistent symptoms, referred to as "post-acute sequelae of SARS-CoV-2 infection (PASC)". Abnormal brain intrinsic activity has been observed in PASC patients, but the patterns of frequency-dependent intrinsic activity in the PASC and non-PASC (recovered COVID-19 patients without persistent symptoms) groups and their association with neuropsychiatric sequelae remain unclear in PASC. Twenty-nine PASC patients, 27 non-PASC subjects, and 31 healthy controls (HCs) were recruited. The voxel-level fractional amplitude of low-frequency fluctuation (fALFF) was calculated in different frequency bands (typical frequency band: 0.01-0.10 Hz; slow 5: 0.01-0.023 Hz; slow 4: 0.023-0.073 Hz) to assess regional intrinsic activity patterns within different groups. Correlation analyses were performed to explore the associations between frequency-dependent alterations and clinical variables. Significant frequency-dependent alterations in intrinsic activity patterns were observed in both the PASC and non-PASC groups, primarily involving regions of the default mode network (DMN). The decreased fALFF values of the DMN in different frequency bands were associated with different symptoms in PASC. For example, decreased fALFF in the left precuneus in the typical frequency band was related to general attention impairment in PASC, whereas decreased fALFF in the left superior frontal gyrus appeared in non-PASC. The fALFF alterations in the left precuneus/posterior cingulate gyrus in the slow 5 band were also related to cognitive performance in PASC. Additionally, in the slow 4 band, decreased fALFF in the right angular gyrus was associated with depressive symptoms in the PASC. Our results may provide insights into the potential neural mechanisms underlying symptoms in PASC patients.

Persistent symptoms and clinical findings in adults with post-acute sequelae of COVID-19/post-COVID-19 syndrome in the second year after acute infection: A population-based, nested case-control study

BACKGROUND

Self-reported health problems following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are common and often include relatively non-specific complaints such as fatigue, exertional dyspnoea, concentration or memory disturbance and sleep problems. The long-term prognosis of such post-acute sequelae of COVID-19/post-COVID-19 syndrome (PCS) is unknown, and data finding and correlating organ dysfunction and pathology with self-reported symptoms in patients with non-recovery from PCS is scarce. We wanted to describe clinical characteristics and diagnostic findings among patients with PCS persisting for >1 year and assessed risk factors for PCS persistence versus improvement.

METHODS AND FINDINGS

This nested population-based case-control study included subjects with PCS aged 18-65 years with (n = 982) and age- and sex-matched control subjects without PCS (n = 576) according to an earlier population-based questionnaire study (6-12 months after acute infection, phase 1) consenting to provide follow-up information and to undergo comprehensive outpatient assessment, including neurocognitive, cardiopulmonary exercise, and laboratory testing in four university health centres in southwestern Germany (phase 2, another 8.5 months [median, range 3-14 months] after phase 1). The mean age of the participants was 48 years, and 65% were female. At phase 2, 67.6% of the patients with PCS at phase 1 developed persistent PCS, whereas 78.5% of the recovered participants remained free of health problems related to PCS. Improvement among patients with earlier PCS was associated with mild acute index infection, previous full-time employment, educational status, and no specialist consultation and not attending a rehabilitation programme. The development of new symptoms related to PCS among participants initially recovered was associated with an intercurrent secondary SARS-CoV-2 infection and educational status. Patients with persistent PCS were less frequently never smokers (61.2% versus 75.7%), more often obese (30.2% versus 12.4%) with higher mean values for body mass index (BMI) and body fat, and had lower educational status (university entrance qualification 38.7% versus 61.5%) than participants with continued recovery. Fatigue/exhaustion, neurocognitive disturbance, chest symptoms/breathlessness and anxiety/depression/sleep problems remained the predominant symptom clusters. Exercise intolerance with post-exertional malaise (PEM) for >14 h and symptoms compatible with myalgic encephalomyelitis/chronic fatigue syndrome were reported by 35.6% and 11.6% of participants with persistent PCS patients, respectively. In analyses adjusted for sex-age class combinations, study centre and university entrance qualification, significant differences between participants with persistent PCS versus those with continued recovery were observed for performance in three different neurocognitive tests, scores for perceived stress, subjective cognitive disturbances, dysautonomia, depression and anxiety, sleep quality, fatigue and quality of life. In persistent PCS, handgrip strength (40.2 [95% confidence interval (CI) [39.4, 41.1]] versus 42.5 [95% CI [41.5, 43.6]] kg), maximal oxygen consumption (27.9 [95% CI [27.3, 28.4]] versus 31.0 [95% CI [30.3, 31.6]] ml/min/kg body weight) and ventilatory efficiency (minute ventilation/carbon dioxide production slope, 28.8 [95% CI [28.3, 29.2]] versus 27.1 [95% CI [26.6, 27.7]]) were significantly reduced relative to the control group of participants with continued recovery after adjustment for sex-age class combinations, study centre, education, BMI, smoking status and use of beta blocking agents. There were no differences in measures of systolic and diastolic cardiac function at rest, in the level of N-terminal brain natriuretic peptide blood levels or other laboratory measurements (including complement activity, markers of Epstein-Barr virus [EBV] reactivation, inflammatory and coagulation markers, serum levels of cortisol, adrenocorticotropic hormone and dehydroepiandrosterone sulfate). Screening for viral persistence (PCR in stool samples and SARS-CoV-2 spike antigen levels in plasma) in a subgroup of the patients with persistent PCS was negative. Sensitivity analyses (pre-existing illness/comorbidity, obesity, medical care of the index acute infection) revealed similar findings. Patients with persistent PCS and PEM reported more pain symptoms and had worse results in almost all tests. A limitation was that we had no objective information on exercise capacity and cognition before acute infection. In addition, we did not include patients unable to attend the outpatient clinic for whatever reason including severe illness, immobility or social deprivation or exclusion.

CONCLUSIONS

In this study, we observed that the majority of working age patients with PCS did not recover in the second year of their illness. Patterns of reported symptoms remained essentially similar, non-specific and dominated by fatigue, exercise intolerance and cognitive complaints. Despite objective signs of cognitive deficits and reduced exercise capacity, there was no major pathology in laboratory investigations, and our findings do not support viral persistence, EBV reactivation, adrenal insufficiency or increased complement turnover as pathophysiologically relevant for persistent PCS. A history of PEM was associated with more severe symptoms and more objective signs of disease and might help stratify cases for disease severity.

SARS-CoV-2 Viral Load and Cytokine Dynamics Profile as Early Signatures of Long COVID Condition in Hospitalized Individuals

BACKGROUND

The global pandemic caused by SARS-CoV-2 has resulted in millions of people experiencing long COVID condition, a range of persistent symptoms following the acute phase, with an estimated prevalence of 27%-64%.

MATERIALS AND METHODS

To understand its pathophysiology, we conducted a longitudinal study on viral load and cytokine dynamics in individuals with confirmed SARS-CoV-2 infection. We used reverse transcriptase droplet digital PCR to quantify viral RNA from nasopharyngeal swabs and employed multiplex technology to measure plasma cytokine levels in a cohort of people with SARS-CoV-2 infection. Our study included individuals with long COVID condition and those without, all of whom had at least three nasopharyngeal and plasma samples collected within 55 days after diagnosis of SARS-CoV-2 infection.

RESULTS

Individuals affected with long COVID symptoms had delayed viral clearance and lower viral loads at diagnosis compared to those without symptoms. Additionally, cytokine analysis revealed variations in IL-18, MIG, and IP-10 levels, with delayed normalization in individuals affected by long COVID syndrome. Correlation analysis indicated associations between viral load and IP-10 and interrelations among cytokines IL-1β, IL-18, MIG, and IP-10.

CONCLUSION

Our study provides insights into the association between nasopharyngeal viral load, cytokine dynamics, and the development of long COVID syndrome, providing an early signature of this condition.

Persistent Symptoms After Lyme Disease: Clinical Characteristics, Predictors, and Classification

Persistent symptoms after an infection have been described for a number of infectious diseases, including Lyme disease. Studies have confirmed a moderate but consistent increase in the prevalence of such symptoms after Lyme disease, though the risk increase varies dependent on study design and the definition of persistent symptoms. Various possible predictors have been proposed, including a dysregulation of the immune system, metabolic changes, increased sensitization to pain signals, cognitive-behavioral factors, or-controversially-the persistence of the causative Borrelia bacteria or remnants thereof. Research on the precise roles of any of these factors is still ongoing. The lack of biological underpinning also makes it difficult to assess with certainty which patients' (generally nonspecific) persistent symptoms are etiologically related to the previous Lyme disease episode and which are not, particularly as these symptoms occur in the general population relatively frequently. The diagnostic criteria for posttreatment Lyme disease syndrome have shown their usefulness in both clinical and research settings but leave out a number of patients whose symptoms may fall just outside said criteria. Though the relationship between these symptoms and the previous Lyme disease episode may be very uncertain, we would argue that a uniform description and classification of these patients will aid in future research and patient management, regardless of the eventual underlying cause. Thus, we argue for an inclusive classification system for all persistent symptoms attributed to Lyme disease in order to promote validation of patient experiences and perspectives, while also maintaining scientific nuance regarding the very uncertain etiology of these patients' symptoms.

Impact of post-COVID-19 condition on health status and activities of daily living: the PRIME post-COVID study

OBJECTIVE

To assess health and activities of daily living (ADL) in SARS-CoV-2-positive adults with and without post-COVID-19 condition (PCC) and compare this with negative tested individuals. Furthermore, different PCC case definitions were compared with SARS-CoV-2-negative individuals.

METHODS

All adults tested PCR positive for SARS-CoV-2 at the Public Health Service South Limburg (Netherlands) between June 2020 and November 2021 (n=41 780) and matched PCR negative individuals (2:1, on age, sex, year-quarter test, municipality; n=19 875) were invited by email. Health (five-level EuroQol five-dimension (EQ5D) index and EuroQol visual analogue scale (EQVAS)) and ADL impairment were assessed. PCC classification was done using the WHO case definition and five other common definitions.

RESULTS

In total, 8409 individuals (6381 SARS-CoV-2 positive; 53±15 years; 57% female; 9 (7-11) months since test) were included. 39.4% of positives had PCC by the WHO case definition (EQVAS: 71±20; EQ5D index: 0.800±0.191; ADL impairment: 30 (10-70)%) and perceived worse health and more ADL impairment than negatives, that is, difference of -8.50 points (95% CI -9.71 to -7.29; p<0.001) for EQVAS, which decreased by 1.49 points (95% CI 0.86 to 2.12; p<0.001) in individuals with PCC for each comorbidity present, and differences of -0.065 points (95% CI -0.074 to -0.056; p<0.001) for EQ5D index, and +16.72% (95% CI 15.01 to 18.43; p<0.001) for ADL impairment. Health and ADL impairment were similar in negatives and positives without PCC. Replacing the WHO case definition with other PCC definitions yielded comparable results.

CONCLUSIONS

Individuals with PCC have substantially worse health and more ADL impairment than negative controls, irrespective of the case definition. Authorities should inform the public about the associated burden of PCC and enable adequate support.