The kinetics and predictors of anti-SARS-CoV-2 antibodies up to eight months after symptomatic COVID-19: a Czech cross-sectional study

Predictors and characteristics of post-acute COVID-19 syndrome in healthcare workers

BACKGROUND

Post-acute COVID-19 syndrome (PCS) is a multisystem disorder degrading the quality of life. The study determined characteristics and predictors of PCS in unvaccinated healthcare workers (HCWs) suffering from PCS based on a comparison with their fully recovered counterparts.

METHODS

305 HCWs were examined at least 12 weeks post COVID-19 symptom onset to obtain data about their acute phase of COVID-19 and current health status and tested for complete blood count, C-reactive protein (CRP), electrophoresis of plasma proteins and SARS-CoV-2-specific immunoglobulin (Ig) G and M.

RESULTS

181 (59.3%) HCWs reported persisting symptoms attributable to PCS during the examination and 124 (40.7%) HCWs stated no symptoms. In the entire sample, the mean CRP level slightly exceeded the normal range (6.63 mg/L, 95% confidence interval [CI] 5.96-7.3) while all other laboratory results were within the normal range. No statistically significant differences in laboratory results were revealed between both subgroups except for the mean Ig levels, which were higher in HCWs with PCS. The average number of symptoms of PCS was 1.9 (median 2). The most frequent symptoms of PCS were fatigue that interfered with daily life (47.5%), shortness of breath (38.1%), muscle or joint aches (16%), loss of smell (14.9%), headache (14.9%) and sleep disorders (11%). The only statistically significant predictors of PCS were female sex (odds ratio [OR] 1.48, 95% CI 1.059-2.067, p = .022) and increasing age (OR 1.04, 95% CI 1.01-1.07, p = .008).

CONCLUSIONS

PCS appears to be a prevalent condition determined by female sex and increasing age.

Association of Lung Fibrotic Changes and Cardiological Dysfunction with Comorbidities in Long COVID-19 Cohort

Background. Long COVID-19 symptoms appeared in many COVID-19 survivors. However, the prevalence and symptoms associated with long COVID-19 and its comorbidities have not been established. Methods. In total, 312 patients with long COVID-19 from 21 primary care centers were included in the study. At the six-month follow-up, their lung function was assessed by computerized tomography (CT) and spirometry, whereas cardiac function was assessed by elec-trocardiogram (ECG), Holter ECG, echocardiography, 24 h blood pressure monitoring, and a six-minute walk test (6MWT). Results. Of the 312 persons investigated, significantly higher sys-tolic and diastolic blood pressure, left ventricular hypertrophy, and elevated NT-proBNP were revealed in participants with hypertension or type 2 diabetes. Left ventricular diastolic dysfunc-tion was more frequently present in patients with hypertension. The most common registered CT abnormalities were fibrotic changes (83, 36.6%) and mediastinal lymphadenopathy (23, 10.1%). Among the tested biochemical parameters, three associations were found in long COVID-19 patients with hypertension but not diabetes: increased hemoglobin, fibrinogen, and ferritin. Nine patients had persisting IgM antibodies to SARS-CoV-2. Conclusions. We demon-strated a strong association between signs of cardiac dysfunction and lung fibrotic changes with comorbidities in a cohort of long COVID-19 subjects.

Persistent humoral and CD4+ TH cell immunity after mild SARS-COV-2 infection-The CoNAN long-term study

Understanding persistent cellular and humoral immune responses to SARS-CoV-2 will be of major importance to terminate the ongoing pandemic. Here, we assessed long-term immunity in individuals with mild COVID-19 up to 1 year after a localized SARS-CoV-2 outbreak. CoNAN was a longitudinal population-based cohort study performed 1.5 months, 6 months, and 12 months after a SARS-CoV-2 outbreak in a rural German community. We performed a time series of five different IgG immunoassays assessing SARS-CoV-2 antibody responses on serum samples from individuals that had been tested positive after a SARS-CoV-2 outbreak and in control individuals who had a negative PCR result. These analyses were complemented with the determination of spike-antigen specific TH cell responses in the same individuals. All infected participants were presented as asymptomatic or mild cases. Participants initially tested positive for SARS-CoV-2 infection either with PCR, antibody testing, or both had a rapid initial decline in the serum antibody levels in all serological tests but showed a persisting T_H cell immunity as assessed by the detection of SARS-CoV-2 specificity of T_H cells for up to 1 year after infection. Our data support the notion of a persistent T-cell immunity in mild and asymptomatic cases of SARS-CoV-2 up to 1 year after infection. We show that antibody titers decline over 1 year, but considering several test results, complete seroreversion is rare.

Trial registration

German Clinical Trials Register DRKS00022416.

Relationship between Acute-Phase Symptoms and Immunoglobulin G Seropositivity up to Eight Months after COVID-19

Background and Objectives: Given the limited knowledge of antibody responses to COVID-19 and their determinants, we analyzed the relationship between the occurrence of acute-phase symptoms and infection-induced immunoglobulin (Ig) G seropositivity up to 8 months post-symptom onset. Materials and Methods: In this cross-sectional study, 661 middle-aged unvaccinated healthcare workers (HCWs) were interviewed about the presence of symptoms during the acute phase of their previously confirmed COVID-19 and were tested for specific IgG, targeting the spike protein (S1 and S2). The dependence of seropositivity on the symptom occurrence was explored through multiple logistic regression, adjusted for the interval between symptom onset and serology testing, and through classification and regression trees. Results: A total of 551 (83.4%) HCWs showed seropositivity and, inversely, 110 (16.6%) HCWs were seronegative. The chance of IgG seropositivity was increased by dyspnea (odds ratio (OR) 1.48, p < 0.001) and anosmia (OR 1.52, p = 0.021). Fever in HCWs with dyspnea resulted in the highest detected seropositivity rate, and anosmia in HCWs without dyspnea significantly increased the proportion of seropositivity. Conclusion: Clinical manifestation of the acute phase of COVID-19 predisposes to the development of infection-induced antibody responses. The findings can be applied for assessing the long-term protection by IgG, and thus, for creating effective surveillance strategies.