Purpose This study aimed to investigate functional abnormalities in the brain of patients with neurological adverse effects following COVID-19 (coronavirus disease 2019) vaccination using 18 F-FDG PET/MRI and 15 O-water PET. Methods Eight patients (1 man and 7 women, aged 26–47 years [median age, 36.5 years]) who experienced neurological symptoms after the first COVID-19 vaccination underwent CT, MRI, 18 F-FDG PET/MRI, and 15 O-water PET of the brain. After 7 days, each patient underwent a follow-up 18 F-FDG PET/MRI and 15 O-water PET of the brain. Imaging data were analyzed using visual and semiquantitative analyses, which included a cluster subtraction workflow ( P = 0.05). Results There was no evidence of vascular abnormalities, acute infarction, or hemorrhage on the CT or MRI scans. On the 15 O-water PET images, 1 patient had mildly significant decreases in perfusion in the bilateral thalamus and bilateral cerebellum, and another patient showed a diffuse increase in perfusion in the cerebral white matter. The visual and semiquantitative analyses showed hypometabolism in the bilateral parietal lobes in all 8 patients on both the first and follow-up 18 F-FDG PET/MRI scans. Metabolic changes in the bilateral cuneus were also observed during the first visit; all patients exhibited neurological symptoms. Moreover, 6 patients showed hypometabolism, and 2 patients showed hypermetabolism. Conclusion All regions of metabolic abnormality were part of the fear network model that has been implicated in anxiety. Our study findings support the concepts of and provide evidence for the immunization stress-related response and the biopsychosocial model.

Purpose The study aimed to investigate imaging abnormalities associated with post-acute COVID-19 using F-18 FDG PET/CT and PET/ rsfMRI brain. Methods We retrospectively recruited 13 patients with post-acute COVID-19. The post-acute COVID-19 symptoms and neuropsychiatric tests were performed before F-18 FDG PET/CT whole body with PET/rsfMRI brain. Qualitative and semiquantitative analyses were also conducted in both whole body and brain images. Results Among the 13 patients, 8 (61.5%) had myositis, followed by 8 (61.5%) with vasculitis (mainly in the thoracic aorta), and 7 (53.8%) with lung abnormalities.. Interestingly, one patient with a very high serum RBD IgG antibody demonstrated diffuse myositis throughout the body which potentially associated with immune-mediated myositis. One patient experienced psoriasis exacerbation with autoimmune-mediated after COVID-19. Most patients had multiple areas of abnormal brain connectivity involving the frontal and parieto-temporo-occipital lobes, as well as the thalamus. Conclusion The whole body F-18 FDG PET can be a potential tool to assess inflammatory process and support the hyperinflammatory etiology, mainly for lesions in skeletal muscle, vascular wall, and lung, as well as, multiple brain abnormalities in post-acute COVID-19. Nonetheless, further studies are recommended to confirm the results.

Mass vaccination with a safe and effective vaccine may be the best way to control the COVID-19 pandemic. Heterologous prime-boost vaccination with the CoronaVac and AZD1222 vaccines may increase the immunogenicity elicited by either vaccine alone. This study sought to compare the immunogenicity of a heterologous CoronaVac and AZD1222 prime-boost with a homologous CoronaVac prime-boost. From July 13 to September 2, 2021, 88 participants were enrolled in the study. Half (n = 44) of the participants were assigned to the AZD1222/CoronaVac cohort and half were assigned to the CoronaVac/AZD1222 cohort. Both cohorts had a prime-boost interval of 4 weeks. A control group of 136 health care personnel who received the homologous CoronaVac/CoronaVac prime-boost was matched by age and sex to the experimental cohorts. The primary endpoint was the geometric mean ratio (GMR) of the anti-receptor binding domain (RBD) antibody concentration 4 weeks after the booster dose was administered. The CoronaVac/CoronaVac cohort served as the reference group. Baseline age and sex were similar, and the median age was 42.5 years. The GMR was 2.58 (95% confidence interval [CI] 1.80–3.71) and 8.69 (95% CI 6.05–12.47) in the AZD1222/CoronaVac and CoronaVac/AZD1222 cohorts, respectively. Reactogenicity was similar following prime and booster doses with the same vaccine. Findings indicated that the heterologous CoronaVac and AZD1222 prime-boost combination elicited a more robust immune response than the homologous CoronaVac prime-boost. While both heterologous prime-boost combinations showed similar reactogenicity, the immunogenicity of the CoronaVac/AZD1222 cohort was higher, indicating that the order of prime-boost vaccine administration was important.

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Adolescents can develop a severe form of Coronavirus disease 2019 (COVID-19), especially with underlying comorbidities. No study has examined the efficacy or effectiveness of inactivated COVID-19 vaccines in adolescents. This single-center, prospective cohort study was performed to evaluate the safety and effectiveness of an inactivated COVID-19 vaccine in adolescents using the immunobridging approach at Chulabhorn Hospital. The key eligibility criterion was a healthy clinical condition or stable pre-existing comorbidity. The anti-receptor-binding domain (anti-RBD) antibody concentration at 4 weeks after dose 2 of the vaccine was compared between participants aged 12 to 17 years and those aged 18 to 30 years. Safety profiles included adverse events within 7 days after each dose of the vaccine and any adverse events through 1 month after dose 2 of the vaccine. In the adolescent and adult cohorts, the geometric mean concentration of anti-RBD antibody was 102.9 binding antibody unit (BAU)/mL (95% CI, 91.0–116.4) and 36.9 BAU/mL (95% CI, 30.9–44.0), respectively. The geometric mean ratio of the adolescent cohort was 2.79 (95% CI, 2.25–3.46, p < 0.0001) compared with the adult cohort, meeting the non-inferiority criterion. The reactogenicity was slightly lower in the adolescent than in the adult cohort. No serious adverse events occurred. The inactivated COVID-19 vaccine appears safe and effective in adolescents.