Prevalence and risk factors for persistent symptoms after COVID-19: a systematic review and meta-analysis.

BACKGROUND: Long-term physical and mental persistent symptoms after COVID-19 represent a growing global public health concern. However, there remains a substantial knowledge gap regarding their prevalence and risk factors. OBJECTIVES: To estimate the prevalence and risk factors for persistent symptoms after COVID-19. METHODS OF DATA SYNTHESIS: We used a random-effects model to pool persistent symptom prevalence and risk ratios comparing COVID-19 patients with non-COVID-19 individuals. DATA SOURCES: Electronic databases were searched for studies published from December 2019 to January 2023. STUDY ELIGIBILITY CRITERIA: Eligible studies that reported the prevalence and risk factors for persistent symptoms after COVID-19 were included. PARTICIPANTS: Patients who recovered from COVID-19. ASSESSMENT OF RISK OF BIAS: The Joanna Briggs Institute critical appraisal tool was used to assess the risk of bias in prevalence studies, whereas the risk of bias in cohort studies was evaluated with the Newcastle-Ottawa Scale. RESULTS: After screening 4359 studies, a total of 211 eligible studies were included, covering a population of 13 368 074 individuals. Fatigue, dyspnoea, post-traumatic stress disorder, anxiety, and depression were the most frequently reported persistent symptoms after COVID-19. Subgroup analyses revealed that individuals with more severe illness in the acute phase or from Europe exhibited a higher prevalence of certain symptoms, whereas children demonstrated a lower prevalence. Furthermore, COVID-19 patients had a significantly higher prevalence of most persistent symptoms compared with non-COVID-19 individuals. Factors frequently associated with a higher prevalence of persistent symptoms included female gender, advanced age, severe illness during the acute phase of COVID-19, multiple comorbidities, an extended duration of hospital stay, and a high body mass index. CONCLUSION: This meta-analysis provides a thorough review of the prevalence and risk factors for persistent symptoms following COVID-19. The findings underscore the importance of long-term monitoring and support for individuals recovering from COVID-19.

Immunogenicity of COVID-19 vaccines in solid organ transplant recipients: a systematic review and meta-analysis.

BACKGROUND: Solid organ transplant (SOT) recipients are at increased risks of morbidity and mortality associated with COVID-19. OBJECTIVES: This study aimed to evaluate the immunogenicity of COVID-19 vaccines in SOT recipients. DATA SOURCES: Electronic databases were searched for eligible reports published from 1 December 2019 to 31 May 2022. STUDY ELIGIBILITY CRITERIA: We included reports evaluating the humoral immune response (HIR) or cellular immune response rate in SOT recipients after the administration of COVID-19 vaccines. PARTICIPANTS: SOT recipients who received COVID-19 vaccines. ASSESSMENT OF RISK OF BIAS: We used the Newcastle-Ottawa scale to assess bias in case-control and cohort studies. For randomised-controlled trials, the Jadad Scale was used. METHODS: We used a random-effects model to calculate the pooled rates of immune response with 95% CI. We used a risk ratio (RR) with 95% CI for a comparison of immune responses between SOT and healthy controls. RESULTS: A total of 91 reports involving 11 886 transplant recipients (lung: 655; heart: 539; liver: 1946; and kidney: 8746) and 2125 healthy controls revealed pooled HIR rates after the 1st, 2nd, and 3rd COVID-19 vaccine doses in SOT recipients were 9.5% (95% CI, 7-11.9%), 43.6% (95% CI, 39.3-47.8%) and 55.1% (95% CI, 44.7-65.6%), respectively. For specific organs, the HIR rates were still low after 1st vaccine dose (lung: 4.4%; kidney: 9.4%; heart: 13.2%; liver: 29.5%) and 2nd vaccine dose (lung: 28.4%; kidney: 37.6%; heart: 50.3%; liver: 64.5%). CONCLUSIONS: A booster vaccination enhances the immunogenicity of COVID-19 vaccines in SOT; however, a significant share of the recipients still has not built a detectable HIR after receiving the 3rd dose. This finding calls for alternative approaches, including the use of monoclonal antibodies. In addition, lung transplant recipients need urgent booster vaccination to improve the immune response.

Immunogenicity of COVID-19 vaccines in chronic liver disease patients and liver transplant recipients: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Chronic liver disease (CLD) patients and liver transplant (LT) recipients have an increased risk of morbidity and mortality from coronavirus disease 2019 (COVID-19). The immunogenicity of COVID-19 vaccines in CLD patients and LT recipients is poorly understood. The present study aimed to evaluate the immunogenicity of COVID-19 vaccines in CLD patients and LT recipients. METHODS: We searched electronic databases for eligible studies. Two reviewers independently conducted the literature search, extracted the data and assessed the risk of bias of included studies. The rates of detectable immune response were pooled from single-arm studies. For comparative studies, we compared the rates of detectable immune response between patients and healthy controls. The meta-analysis was conducted using the Stata software with a random-effects model. RESULTS: In total, 19 observational studies involving 4191 participants met the inclusion criteria. The pooled rates of detectable humoral immune response after two doses of COVID-19 vaccination in CLD patients and LT recipients were 95% (95% confidence interval [CI] = 88%-99%) and 66% (95% CI = 57%-74%) respectively. After two doses of vaccination, the humoral immune response rate was similar in CLD patients and healthy controls (risk ratio [RR] = 0.96; 95% CI = 0.90-1.02; p = .14). In contrast, LT recipients had a lower humoral immune response rate after two doses of vaccination than healthy controls (RR = 0.68; 95% CI = 0.59-0.77; p < .01). CONCLUSIONS: Our meta-analysis demonstrated that COVID-19 vaccination induced strong humoral immune responses in CLD patients but poor humoral immune responses in LT recipients.

Whole-cell tumor vaccines desialylated to uncover tumor antigenic Gal/GalNAc epitopes elicit anti-tumor immunity.

BACKGROUND: Aberrant sialoglycans on the surface of tumor cells shield potential tumor antigen epitopes, escape recognition, and suppress activation of immunocytes. α2,3/α2,6Gal- and α2,6GalNAc (Gal/GalNAc)-linked sialic acid residues of sialoglycans could affect macrophage galactose-type lectins (MGL) mediated-antigen uptake and presentation and promote sialic acid-binding immunoglobulin-like lectins (Siglecs) mediated-immunosuppression. Desialylating sialoglycans on tumor cells could present tumor antigens with Gal/GalNAc residues and overcome glyco-immune checkpoints. Thus, we explored whether vaccination with desialylated whole-cell tumor vaccines (DWCTVs) triggers anti-tumor immunity in ovarian cancer (OC). METHODS: Sialic acid (Sia) and Gal/GalNAc residues on OC A2780, OVCAR3, and ID8 cells treated with α2-3 neuraminidase (α2-3NA) and α2-6NA, and Sigec-9 or Siglec-E and MGL on DCs pulsed with desialylated OC cells were identified using flow cytometry (FCM); RT-qPCR determined IFNG expression of T cells, TRBV was sequenced using Sanger sequencing and cytotoxicity of αß T cells was measured with LDH assay; Anti-tumor immunity in vivo was validated via vaccination with desialylated whole-cell ID8 vaccine (ID8 DWCTVs). RESULTS: Gal/GalNAc but not Sia residues were significantly increased in the desialylated OC cells. α2-3NA-modified DWCTV increased MGL but decreased Siglec-9 or Siglec E expression on DCs. MGLbright/Siglec-9dim DCs significantly up-regulated IFNG expression and CD4/CD8 ratio of T cells and diversified the TCR repertoire of αß T-cells that showed enhanced cytotoxic activity. Vaccination with α2-3NA-modified ID8 DWCTVs increased MGLbright/Siglec-Edim DCs in draining lymph nodes, limited tumor growth, and extended survival in tumor-challenged mice. CONCLUSION: Desialylated tumor cell vaccine could promote anti-tumor immunity and provide a strategy for OC immunotherapy in a clinical setting.