Systemic and Local Disease Manifestations Following COVID-19 Vaccination

Introduction/Objective COVID-19 vaccine-related lymphadenopathy, particularly in the ipsilateral axilla, is a relatively well-known side effect of mRNA vaccines with many reports in radiology, but less is known regarding histopathology and additional sites of lymphadenopathy, as well as other localized potential vaccine-related mass manifestations. In addition to a case of minimal change disease, we report two cases here with associated systemic and local pathologic changes related to COVID-19 vaccination. Methods/Case Report In case #1, a 17-year-old male presented with a 2.4 cm left postauricular mass. He had originally noticed the mass six months prior and thought that it had recently been growing. The mass was soft, nonfluctuant, and nontender to palpation. Given the risk of malignancy, a resection was performed. Histology showed an enlarged lymph node composed of mixed inflammatory cell components consistent with lymphoid hyperplasia and no evidence of malignancy. On further chart review, the patient had received his second COVID-19 vaccination just prior to noticing the mass enlarging. A SARS-CoV-2 Anti-Spike IgG assay was as high as 24,396 AU/ml, suggesting that this benign lymphadenopathy was most likely related to his vaccination. For case #2, a 47-year-old male developed a painless right deltoid mass shortly after receiving his vaccination at the same area that subsequently increased in size over seven months to 6.5 cm. Imaging showed a heterogeneous mass within the deltoid muscle concerning for malignancy and a biopsy was performed. Sections showed wavy, bland spindle cells with nuclei staining diffusely positive for beta-catenin, consistent with fibromatosis at his vaccination site. Results (if a Case Study enter NA) NA. Conclusion In summary, these case reports show potential systemic and local reactive effects in response to COVID-19 vaccination.

Natural Evolution of Porcine Epidemic Diarrhea Viruses Isolated from Maternally Immunized Piglets

Simple SummaryDuring the long-term co-evolution of the virus and the host, even closely related vaccines may emerge with incomplete protective immunity due to the mutations or deletions of amino acids at specific antigenic sites. The mutation of PEDV was accelerated by the recombination of different strains and the mutation of the strains adapting to the environment. These mutations either cause immune escape from conventional vaccines or affect the virulence of the virus. Therefore, researching and developing new vaccines with cross-protection through continuous monitoring, isolation and sequencing are important to determine whether their genetic characteristics are changed and to evaluate the protective efficacy of current vaccines. The porcine epidemic diarrhea virus (PEDV) can cause severe piglet diarrhea or death in some herds. Genetic recombination and mutation facilitate the continuous evolution of the virus (PEDV), posing a great challenge for the prevention and control of porcine epidemic diarrhea (PED). Disease materials of piglets with PEDV vaccination failure in some areas of Shanxi, Henan and Hebei provinces of China were collected and examined to understand the prevalence and evolutionary characteristics of PEDV in these areas. Forty-seven suspicious disease materials from different litters on different farms were tested by multiplex PCR and screened by hematoxylin-eosin staining and immunohistochemistry. PEDV showed a positivity rate of 42.6%, infecting the small and large intestine and mesenteric lymph node tissues. The isolated strains infected Vero, PK-15 and Marc-145 multihost cells and exhibited low viral titers in all three cell types, as indicated by their growth kinetic curves. Possible putative recombination events in the isolates were identified by RDP4.0 software. Sequencing and phylogenetic analysis showed that compared with the classical vaccine strain, PEDV SX6 contains new insertion and mutations in the S region and belongs to genotype GIIa. Meanwhile, ORF3 has the complete amino acid sequence with aa80 mutated wild strains, compared to vaccine strains CV777, AJ1102, AJ1102-R and LW/L. These results will contribute to the development of new PEDV vaccines based on prevalent wild strains for the prevention and control of PED in China.

Autopsy findings from patients diagnosed with COVID-19 demonstrate unique morphological patterns in bone marrow and lymph node.

AIMS: The identification of haemophagocytosis in bone marrow (BM) is recurrently identified in patients with severe COVID-19. These initial COVID-19 autopsy studies have afforded valuable insight into the pathophysiology of this disease; however, only a limited number of case series have focused on lymphoid or haematopoietic tissues. METHODS: BM and lymph node (LN) specimens were obtained from adult autopsies performed between 1 April 2020 and 1 June 2020, for which the decedent had tested positive for SARS-CoV-2. Tissue sections (H&E, CD3, CD20, CD21, CD138, CD163, MUM1, kappa/lambda light chains in situ hybridisation) were examined by two haematopathologists, who recorded morphological features in a blinded fashion. Haemophagocytic lymphohistiocytosis (HLH) was assessed based on HLH 2004 criteria. RESULTS: The BM demonstrated a haemophagocytic pattern in 9 out of 25 patients (36%). The HLH pattern was associated with longer hospitalisation, BM plasmacytosis, LN follicular hyperplasia and lower aspartate aminotransferase (AST), as well as ferritin at demise. LN examination showed increased plasmacytoid cells in 20 of 25 patients (80%). This pattern was associated with a low absolute monocyte count at diagnosis, lower white cell count and lower absolute neutrophil count at demise, and lower ferritin and AST at demise. CONCLUSIONS: Autopsy results demonstrate distinct morphological patterns in BM, with or without haemophagocytic macrophages, and in LN, with or without increased plasmacytoid cells. Since only a minority of patients met diagnostic criteria for HLH, the observed BM haemophagocytic macrophages may be more indicative of an overall inflammatory state.

Advancements in organs-on-chips technology for viral disease and anti-viral research

Disease models that can accurately recapitulate human pathophysiology during infection and clinical response to antiviral therapeutics are still lacking, which represents a major barrier in drug development. The emergence of human Organs-on-a-Chip that integrated microfluidics with three-dimensional (3D) cell culture, may become the potential solution for this urgent need. Human Organs-on-a-Chip aims to recapitulate human pathophysiology by incorporating tissue-relevant cell types and their microenvironment, such as dynamic fluid flow, mechanical cues, tissue–tissue interfaces, and immune cells to increase the predictive validity of in vitro experimental models. Human Organs-on-a-Chip has a broad range of potential applications in basic biomedical research, preclinical drug development, and personalized medicine. This review focuses on its use in the fields of virology and infectious diseases. We reviewed various types of human Organs-on-a-Chip-based viral infection models and their application in studying viral life cycle, pathogenesis, virus-host interaction, and drug responses to virus- and host-targeted therapies. We conclude by proposing challenges and future research avenues for leveraging this promising technology to prepare for future pandemics.

Impact of SARS-CoV-2 immunization on a breast screening programme

BACKGROUND: A common secondary effect after SARS-CoV-2 immunization is an increased in size of the axillary lymph nodes ipsilateral to the vaccinated site. Eventually, an increased in size of the axillary lymph nodes may lead to a misinterpretation of the breast screening mammogram, performed in asymptomatic women between the age 50 to 69 years old for early breast cancer diagnosis. The aim of our research was to evaluate the impact of the vaccination for SARS-CoV-2 in the breast screening programmes in terms of recall rates and number of false positive results. As a secondary purpose we would analysed the protocols adopted by different breast screening units around the world after SARS-CoV-2 vaccination. METHODS: Observational and retrospective study analysing breast screening mammograms from a single Breast Cancer Screening Unit in Madrid. The mammograms of previously vaccinated women were analysed, reviewing the axillary lymph nodes and the re-call rate secondary to axillary lymphadenopathies. RESULTS: Four hundred and twenty three screening mammograms were performed in May 2021 in the University Hospital Ramon y Cajal in Madrid, which is part of the Breast Screening Programme in Madrid, Spain. None of the women previously vaccinated for SARS-CoV-2 were recalled for complementary studies due to an increased in the axillary lymph nodes. CONCLUSIONS: The protocol stablished by the Spanish Society of Breast Image that stands up for a routine breast screening mammogram after SARS-CoV-2 immunization, has no increase in the recall rate or increase in number of false positives.

Nanovaccines to combat virus-related diseases.

The invention and application of vaccines have made tremendous contributions to fight against pandemics for human beings. However, current vaccines still have shortcomings such as insufficient cellular immunity, the lack of cross-protection, and the risk of antibody-dependent enhancement (ADE). Thus, the prevention and control of pandemic viruses including Ebola Virus, human immunodeficiency virus (HIV), Influenza A viruses, Zika, and current SARS-CoV-2 are still extremely challenging. Nanoparticles with unique physical, chemical, and biological properties, hold promising potentials for the development of ideal vaccines against these viral infections. Moreover, the approval of the first nanoparticle-based mRNA vaccine BNT162b has established historic milestones that greatly inspired the clinical translation of nanovaccines. Given the safety and extensive application of subunit vaccines, and the rapid rise of mRNA vaccines, this review mainly focuses on these two vaccine strategies and provides an overview of the nanoparticle-based vaccine delivery platforms to tackle the current and next global health challenges. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

A bleeding tumor on the scalp

A 83-year-old man presented with a large tumour on his head. He had been postponing his visit due to COVID. Physical examination revealed an ulcerating, bleeding tumour of 5.5x5x3 cm. Histologic analyses showed a poorly differentiated squamous cell carcinoma. Additional imaging displayed damage of the tabula externa without pathological lymph nodes.

18F-Fluciclovine-Avid Axillary Lymph Nodes After COVID-19 Vaccination on PET/CT for Suspected Recurrence of Prostate Cancer.

Abnormally increased 18F-FDG avidity of axillary lymph nodes has become a frequent diagnostic dilemma on PET/CT in the current climate of global vaccinations directed against severe acute respiratory syndrome coronavirus 2. This avidity is due to the inflammatory response evoked by vaccines and the nonspecific nature of 18F-FDG uptake, which is increased in both malignant and inflammatory processes. Similarly, 18F-fluciclovine, an amino acid analog indicated for the assessment of biochemical recurrence of prostate cancer, may also demonstrate nonspecific inflammatory uptake. We report a case of 18F-fluciclovine PET/CT obtained for concern about prostate cancer. In this case, isolated avid lymph nodes were seen in the left axilla. A screening questionnaire revealed that the patient had recently received the second dose of the Pfizer-BioNTech coronavirus disease 2019 vaccine in his left shoulder, and hence, the uptake was determined to be reactive.

Pathomorphology of lymph nodes in patients with severe SARS-CoV-2 infection observed in Primorsky Krai

Introduction. When studying COVID-19 pathology, considerable attention is paid to the damage to the respiratory and cardiovascular systems, which are associated with the manifestation of the infection. Data on changes in the organs of the lymphatic system are yet scarce. To date, COVID-19 is sure to cause the dysfunction of the immune system;however, information about the damage to the lymph nodes is ambigu-ous. The aim of the study was to characterize morphological changes in the hilar lymph nodes of patients who died from a new coronavirus infection COVID-19 in Vladivostok in 2021. Materials and methods. A morphological study of the lymph nodes was performed in 20 patients who died from the new coronavirus infection, diagnosed in vivo using a PCR test. The controls were patients who did not have diseases of the hematopoietic and lymphoid tissue in their medical histories but who died a violent death. The material for histological examination was processed according to generally accepted methods. Results. In all patients, we identified lymphadenopathy with hypoplasia of lymphoid tissue of varying se-verity. In the cortex, lymphatic follicles were detected, mainly without light (germinal) centers, as well as follicles with a pronounced rarefaction of cells and exposure to the reticular stroma, with no visualization of the paracortical zone. According to the severity of reactive changes in the T-and B-dependent zones of the lymph nodes, we distinguished two types of lymphadenopathy: 1) mixed follicular type;2) follicular involution with lymphoid depletion. Conclusion. Pathological changes in the hilar lymph nodes of the lungs in patients who died from COVID-19 indicated immunosuppressive effects of the SARS-CoV-2. The pathologic changes in lymph nodes mani-fested with lymphocytic depletion in T-and B-dependent zones. This indicates a deficiency of cellular and humoral immunity in moderate and severe COVID-19. © 2022, MDV Group. All rights reserved.

CEST MRI and MALDI imaging reveal metabolic alterations in the cervical lymph nodes of EAE mice.

BACKGROUND: Multiple sclerosis (MS) is a neurodegenerative disease, wherein aberrant immune cells target myelin-ensheathed nerves. Conventional magnetic resonance imaging (MRI) can be performed to monitor damage to the central nervous system that results from previous inflammation; however, these imaging biomarkers are not necessarily indicative of active, progressive stages of the disease. The immune cells responsible for MS are first activated and sensitized to myelin in lymph nodes (LNs). Here, we present a new strategy for monitoring active disease activity in MS, chemical exchange saturation transfer (CEST) MRI of LNs. METHODS AND RESULTS: We studied the potential utility of conventional (T2-weighted) and CEST MRI to monitor changes in these LNs during disease progression in an experimental autoimmune encephalomyelitis (EAE) model. We found CEST signal changes corresponded temporally with disease activity. CEST signals at the 3.2 ppm frequency during the active stage of EAE correlated significantly with the cellular (flow cytometry) and metabolic (mass spectrometry imaging) composition of the LNs, as well as immune cell infiltration into brain and spinal cord tissue. Correlating primary metabolites as identified by matrix-assisted laser desorption/ionization (MALDI) imaging included alanine, lactate, leucine, malate, and phenylalanine. CONCLUSIONS: Taken together, we demonstrate the utility of CEST MRI signal changes in superficial cervical LNs as a complementary imaging biomarker for monitoring disease activity in MS. CEST MRI biomarkers corresponded to disease activity, correlated with immune activation (surface markers, antigen-stimulated proliferation), and correlated with LN metabolite levels.

Systemic COVID-19 vaccines Adverse Events Following Immunizations and Their Associated Factors: A Comparative Study Using Iraqi Consumers' Self-Reported Data: An International Journal of Medical Toxicology and Drug Experience

Introduction: Three types of COVID-19 vaccines were deployed in Iraq;PfizerBioNTech, AstraZeneca, and Sinopharm. Spontaneous self-reported safety data received directly from consumers was an important source of COVID-19 vaccine reporting sources for the first time in Iraq. Objective: To study the common systemic AEFIs and factors influencing them, using self-reported data by Iraqi consumers vaccinated with different COVID-19 vaccine types. Methods: As a part of the national plan for COVID-19 vaccines safety surveillance, an online self-assessment form was designed by the national pharmacovigilance center for the public consumers across the country. The form was quadrilingual and captures the necessary information for a valid AEFI report. Demographic data, contact details, vaccination details, adverse event information, and medical history were collected. To facilitate the filling process and standardize the answers, a list of predefined common short-term AEFIs were included as a checklist, in addition to a free text for other unlisted AEFIs. A retrospective cross-sectional study using the collected responses from April, 2021 until April, 2022 was performed. Data was validated and cleaned. Analyses was performed using SPSS software version 26. Selected common short-term AEFIs were analysed. The incidence of these AEFIs were compared between vaccine types using chisquare test. Moreover, predictors of reporting these AEFIs were explored using binary logistic regression for each vaccine type. Results: A total of 2843 report were included, 62.0% of them were male. The age mean was 36.33 (SD ± 12.2). The participants were more likely to report after the 1st dose (79.4%). AstraZeneca vaccine was found to produce the highest number of AEFIs per report, 4.31 (SD ± 2.4). AstraZeneca and PfizerBioNTech were significantly associated with a higher incidence of multiple AEFIs as compared with Sinopharm (fatigue, joint pain, headache, fever, and chills). PfizerBioNTech vaccine was associated with 71 out of the 76 reported lymph nodes AEFIs. Factors that were significant predictors of higher reporting of systemic AEFIs were;for PfizerBioNTech (female gender, increased dose number, and increased likelihood of previous COVID-19 infection);AstraZeneca (younger age, female gender, and increased likelihood of previous COVID-19 infection);and in case of Sinopharm (younger age, and female gender) Conclusion: The results showed that AstraZeneca and Pfi-zerBioNTech vaccines were associated with more AEFIs than Sinopharm. Predictor factors of AEFIs include;female gender in all vaccines;the presence of previous COVID-19 infection in both PfizerBioNTech and AstraZeneca vaccines;second dose in PfizerBioNTech;and younger age for both AstraZeneca and Sinopharm.

Erythema Multiforme Reactions Following Pfizer/BioNTech (BNT162b2) and Oxford/AstraZeneca (chAdOx1-S) COVID-19 Vaccination: A Case Series: An International Journal of Medical Toxicology and Drug Experience

Introduction: Pfizer/BioNTech (BNT162b2) and Oxford/AstraZeneca (chAdOx1-S) COVID-19 vaccines were approved for emergency use. Clinical trials of both vaccines reported no safety concerns other than a few local and systemic reactions that resolved in few days for both vaccines. Cutaneous reactions to COVID-19 vaccination are generally minor and self-limited. The most common cutaneous reaction reported was a local injection-site reaction. Objective: Here we present 3 cases of erythema multiform following COVID-19 vaccination with positive rechallenge in 2 cases. Methods: Not applicable. Results: Case 1: A 51 year old woman with no past medical history presented with a macular, erythematous, round-shaped itchy rash on the hands, knees and soles. She denied having a neither recent illness nor sick contact. However, she received the first dose of the mRNA Pfizer/BioNTech (BNT162b2), 3 days earlier. Lesions disappeared in 7 days with local corticosteroid treatment. One month later and two days after receiving the second shot of the same vaccine, lesions reappeared and extended to upper members. Skin biopsy was compatible with erythema polymorph. Case 2: A 55 year old man with a past medical history of hypertension, presented 6 days following the 2nd shot of the mRNA Pfizer/ BioNTech (BNT162b2), vesicular eruptions on the upper and lower members. The outcome was favorable within 2 weeks under local corticosteroid. The patient reported that he had the same skin lesions in ankles and soles few days following the 1st shot of the same vaccine. Histological findings revealed an erythema polymorph. Case 3: A 57 year old woman with a medical history of hypertension and anxiety disorder presented with a worsening rash and fever for 6 days. The patient reported that she experienced fever, polyarthralgia and that she had received the second shot of Oxford/AstraZeneca (chAdOx1-S), the day before these symptoms appeared. On the physical examination, she had targetoid skin lesions over the trunk, on the ear, upper and lower members. Otherwise she had oral and genital mucosal ulcerations. A thoracic CT scan was performed because of the persistent fever and showed multiple enlarged lymph nodes, a layer of pericardial and plural effusion. A favorable outcome was observed in 3 weeks. Conclusion: Erythema multiform remains an exceptional COVID 19 vaccine adverse effect. Health care workers must be aware of this potential adverse effect or its recurrence and advise patients accordingly. Benefits of receiving a COVID 19 vaccine remains more important.

Investigation on the risk factors of blood infection in patients with lymphoma

Objectives: To investigate the risk factors for a blood infection in patients with lymphoma in order to guide the clinical prevention and control Of infection. Method: Clinical data were collected from 434 patients with lymphoma in 2019. including 231 males and 203 females. Blood samples were collected for culture, and the pathogens were identified by a VITEK-32 automated microbial identification system. PCR was used to detect Virulence genes of Klebsiella pneumoniae. Data were collected, such as patients' age, disease status, clinical stage, and pathological type. and risk factors affecting the incidence of infection in patients were analyzed using a Chi-square test.

Hybrid endoscopic ultrasound in the covid-19 era for the tissue diagnosis of solid lesions;an initial experience from a tertiary care centre from Pakistan

BackgroundEndoscopic Ultrasound (EUS) is a well-established mode of intervention for tissue acquisition in solid organs with rapid on-site evaluation (ROSE). In the Covid-19 era, the implementation of infection control mechanisms has led to modified hybrid techniques to get high diagnostic yield for tissue sampling. Combination of Covid-19 SOPs and tissue acquisition method outline this hybrid technique to get a high diagnostic Yield. We share our initial experience of EUS cases performed with this approach without ROSE.MethodsAll 125 cases who underwent EUS-guided biopsy from June 2020 till June 2022 were included. The Procedure was done in a negative pressure room with all SOPs as per institutional guidelines for patient and staff safety with a minimum number of persons during the procedure.ResultsAmong these cases, 85 were male, mean age of 56 years (range 22–90), Mean duration of procedure 28 minutes mean (10–90 min). 91 cases for organs targeted for malignant pathology include pancreas 53, liver 03, lymph nodes 22, subepithelial lesions 10, mediastinal lesions 15, common-bile duct/gall bladder 07, gastric and retroperitoneal 01 case, 13 cases had a multi-targeted biopsy for the additional staging of disease. The number of ‘passes’ with the needle was average 02 with single pass 20, two pass 60, three passes 20, multitarget single pass in 25. Needle size (Franseen design) used for procedures was 22G in 115 cases and 25G in 10. Common tissue diagnoses include pancreatic adenocarcinoma 38, neuroendocrine tumours 06, tuberculosis 07, gastrointestinal stromal tumours 03, leiomyoma 05, lymphoma 06, metastatic renal cell carcinoma 05, squamous cell carcinoma 05, cholangiocarcinoma/gall bladder adenocarcinoma 13, Sarcoma 03, solid pseudopapillary epithelial neoplasm of pancreas (SPEN) 03 and one case for Schwannoma, breast metastasis, accessory spleen, ectopic pancreas, sarcoidosis There were no immediate or early complications in all cases.ConclusionsHybrid EUS in Covid 19 Era has emerged as a useful/cost-effective and safe approach to get tissue yield without the need for ROSE.

Feline infectious peritonitis (FIP): a case report

A male Munchkin cat was brought to a small animal teaching hospital at Mahanakorn University of Technology. The patient presentation with vomiting, chronic diarrhea, and intermittent fever. From history-taking, the owner previously had a cat that was diagnosed with feline infectious peritonitis (FIP) living in the same house but had isolated in a separate area. Fecal examination revealed bacterial enteritis. Hematology and blood chemistry results shown lymphopenia, hypoalbuminemia, and low serum albumin/globulin ratio (0.3 A: G ratio). Abdominal ultrasound revealed mesenteric lymph node (MLN) enlargement and cholecystitis. Cell cytology from the liver and MLN revealed suppurative inflammation. Reverse transcription PCR (RT-PCR) was negative for the Feline coronavirus (FCoV) in the blood sample. On the 4th day of treatment, the cat developed pleural and peritoneal effusion. Thoracentesis and abdominocentesis were performed and submitted for analysis. The fluid's results were classified as modified transudate, low A: G ratio (0.3), Rivalta's test (positive), and positive for FCoV by using RT-PCR. On the 8th day of treatment, the cat died from systemic hypotension. Viscous straw yellow-colored fluid and pyogranulomatous lesions at the liver, lung, kidney, and MLN were observed from the necropsy. Histopathology's results shown severe suppurative inflammation in all the above organs. FIP was confirmed by detected FCoV antigen in the cytoplasm of macrophages in the kidney and lung tissue by immunohistochemistry staining.

COVID-19 Vaccine-Associated Lymphadenopathy in Breast Imaging Recipients: A Review of Literature.

The unpredictability of the coronavirus disease 2019 (COVID-19) pandemic has created an ongoing global healthcare crisis. Implementation of a mass vaccination program to accelerate disease control remains in progress. Although injection site soreness, fatigue, and fever are the most common adverse reactions reported after a COVID-19 vaccination, ipsilateral lymph node enlargement has increasingly been observed. In patients undergoing routine screening and surveillance for breast cancer, interpreting lymphadenopathy (LAP) is challenging in the setting of a recent COVID-19 vaccination. With a growing proportion of the population receiving the vaccine, a multifaceted approach is necessary to avoid unnecessary and costly workup. In this comprehensive review, we summarize the existing literature on COVID-19 vaccine-associated LAP in breast imaging patients.

Delivering an mRNA vaccine using a lymphatic drug delivery device improves humoral and cellular immunity against SARS-CoV-2.

The exploration and identification of safe and effective vaccines for the SARS-CoV-2 pandemic has captured the world's attention and remains an ongoing issue due to concerns of balancing protection against emerging variants of concern (VoCs) while also generating long lasting immunity. Here, we report the synthesis of a novel messenger ribonucleic acid encoding the spike protein in a lipid nanoparticle formulation (STI-7264) that generates robust humoral and cellular immunity following immunization of C57Bl6 mice. In an effort to improve immunity, a clinically-focused lymphatic drug delivery device (MuVaxx) was engineered to modulate immune cells at the injection site (epidermis and dermis) and draining lymph node (LN) and tested to measure adaptive immunity. Using MuVaxx, immune responses were elicited and maintained at a 10-fold dose reduction compared to traditional intramuscular (IM) administration as measured by anti-spike antibodies, cytokine-producing CD8 T cells, neutralizing antibodies against the Washington (wild type) strain and South African (Beta) variants, and LN-resident spike-specific memory B cells. Remarkably, a 4-fold elevated T cell response was observed in MuVaxx administered vaccination compared to that of IM administered vaccination. Thus, these data support further investigation into STI-7264 and lymphatics-mediated delivery using MuVaxx for SARS-CoV-2 and VoC vaccines.

Unilateral axillary lymph node fluorodeoxyglucose uptakes after coronavirus disease 2019 vaccination.

Vaccination against coronavirus disease 2019 (COVID-19) started in early December 2020 worldwide, and healthcare workers in Japan were vaccinated in February 2021. We encountered three patients who underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for cancer screening at our institution, showing FDG uptakes in the axillary lymph nodes, which seemed to be reactive changes. Two of them were males in their 40s and one was a female in her 50s; all of them were healthcare workers. The medical history revealed that they received the Pfizer-BioNTech COVID-19 vaccination twice at their left shoulders before the FDG PET/CT examination. The degree of FDG uptakes were maximum standardized uptake value (SUVmax)=3.2-9.9, SUVmax=5.9-10.3, and SUVmax=2.8-7.9, respectively. They were diagnosed with reactive lymph nodes because of vaccination owing to the absence of abnormal FDG PET/CT findings at other sites. As COVID-19 vaccination becomes more widespread in Japan, radiologists should be aware of these findings to avoid misdiagnosis of FDG uptakes in pathological lymph nodes and to prevent unnecessary additional examinations. Recently, similar FDG PET/CT findings have been reported after receiving the COVID-19 vaccination, and we will report it with a literature review.

Tissue immunity to SARS-CoV-2: Role in protection and immunopathology.

The SARS-CoV-2 pandemic has demonstrated the importance of studying antiviral immunity within sites of infection to gain insights into mechanisms for immune protection and disease pathology. As SARS-CoV-2 is tropic to the respiratory tract, many studies of airway washes, lymph node aspirates, and postmortem lung tissue have revealed site-specific immune dynamics that are associated with the protection or immunopathology but are not readily observed in circulation. This review summarizes the growing body of work identifying immune processes in tissues and their interplay with immune responses in circulation during acute SARS-CoV-2 infection, severe disease, and memory persistence. Establishment of tissue resident immunity also may have implications for vaccination and the durability of immune memory and protection.