Short- and Long-Interval Prime-Boost Vaccination with the Candidate Vaccines MVA-SARS-2-ST and MVA-SARS-2-S Induces Comparable Humoral and Cell-Mediated Immunity in Mice.

The COVID-19 pandemic caused significant human health and economic consequences. Due to the ability of SARS-CoV-2 to spread rapidly and to cause severe disease and mortality in certain population groups, vaccines are essential for controlling the pandemic in the future. Several licensed vaccines have shown improved protection against SARS-CoV-2 after extended-interval prime-boost immunizations in humans. Therefore, in this study, we aimed to compare the immunogenicity of our two Modified Vaccinia virus Ankara (MVA) based COVID-19 candidate vaccines MVA-SARS-2-S and MVA-SARS-2-ST after short- and long-interval prime-boost immunization schedules in mice. We immunized BALB/c mice using 21-day (short-interval) or 56-day (long-interval) prime-boost vaccination protocols and analyzed spike (S)-specific CD8 T cell immunity and humoral immunity. The two schedules induced robust CD8 T cell responses with no significant differences in their magnitude. Furthermore, both candidate vaccines induced comparable levels of total S, and S2-specific IgG binding antibodies. However, MVA-SARS-2-ST consistently elicited higher amounts of S1-, S receptor binding domain (RBD), and SARS-CoV-2 neutralizing antibodies in both vaccination protocols. Overall, we found very comparable immune responses following short- or long-interval immunization. Thus, our results suggest that the chosen time intervals may not be suitable to observe potential differences in antigen-specific immunity when testing different prime-boost intervals with our candidate vaccines in the mouse model. Despite this, our data clearly showed that MVA-SARS-2-ST induced superior humoral immune responses relative to MVA-SARS-2-S after both immunization schedules.

Updated Guidance Regarding The Risk ofAllergic Reactions to COVID-19 Vaccines and Recommended Evaluation and Management: A GRADE Assessment, and International Consensus Approach.

This guidance updates 2021 GRADE recomendations regarding immediate allergic reactions following COVID-19 vaccines and addresses re-vaccinating individuals with 1st dose allergic reactions and allergy testing to determine re-vaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 re-vaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommenations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the UK, and the US formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy, and re-vaccination after a prior immediate allergic reaction. We suggest against >15-minute post-vaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest re-vaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise, in a properly equipped setting. We suggest against pre-medication, split-dosing, or special precautions because of a comorbid allergic history.

The efficiency of COVID-19 vaccines among taiwanese patients with varied comorbidities

Background/Aims: The global pandemic of COVID-19 has caused tremendous loss of human life since 2019. Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the best policies to control the pandemic. The vaccination efficacy in Taiwanese patients with different comorbidities is elusive and to be explored. Method(s): Uninfected subjects who received 3-doses of mRNA vaccines (Moderna, BioNTech), non-replicating viral vector-based vaccines (AstraZeneca, AZ) or protein subunit vaccines (Medigen COVID-19 vaccine, MVC) were prospectively enrolled. SARSCoV2- IgG spike antibody level was determined (Abbott [SARS-CoV- 2 IgG II]) within 3 months after the last dose of vaccination. Charlson Comorbidity Index (CCI) was applied to disclose the association of vaccine titer and underlying comorbidities. Result(s): A total of 824 subjects were enrolled in the current study. The mean age was 58.9 years and males accounted for 48.7% of the population. The proportion of CCI with 0-1, 2-3 and>4 was 52.8% (n = 435), 31.3% (n = 258) and 15.9% (n = 131), respectively. The most commonly used vaccination combination was AZ-AZ-Moderna (39.2%), followed by Moderna-Moderna-Moderna (27.8%) and AZAZ- BioNTech (14.7%), respectively. The mean vaccination titer was 3.11 log BAU/mL after a median 48 days of the 3rd dose. Subjects of male gender, lower body mass index, chronic kidney disease, higher CCI, and receiving AZ-AZ based vaccination were likely to have a lower titer of antibody. There was a decreasing trend of antibody titer with the increase of CCT (trend P<0.001). Linear regression analysis revealed that AZ-AZ-based vaccination (beta: 0.341, 95% confidence intervals [CI]: 0.144, 0.21, P<0.001) and higher CCI (beta: - 0.055, CI: - 0.096, - 0.014, P = 0.009) independently correlated with low IgG spike antibody levels. Conclusion(s): Patients with more comorbidities had a poor response to 3 doses of COVID-19 vaccination. Further studies are warranted to clarify the efficacy of booster vaccination in the population. The vaccine titer did not differ between patient with or without chronic liver disease.

Which strain of the avian coronavirus vaccine will become the prevalent one in China next?

Infectious bronchitis virus (IBV) is a vital pathogen in poultry farms, which can induce respiratory, nephropathogenic, oviduct, proventriculus, and intestinal diseases. Based on the phylogenetic classification of the full-length S1 gene, IBV isolates have been categorized into nine genotypes comprising 38 lineages. GI (GI-1, GI-2, GI-3, GI-4, GI-5, GI-6, GI-7, GI-13, GI-16, GI-18, GI-19, GI-22, GI-28, and GI-29), GVI-1 and GVII-1 have been reported in China in the past 60 years. In this review, a brief history of IBV in China is described, and the current epidemic strains and licensed IBV vaccine strains, as well as IBV prevention and control strategies, are highlighted. In addition, this article presents unique viewpoints and recommendations for a more effective management of IBV. The recombinant Newcastle Disease virus (NDV) vector vaccine expressed S gene of IBV QX-like and 4/91 strains may be the dominant vaccine strains against NDV and IBV.

Booster dose of mRNA vaccine augments waning T cell and antibody responses against SARS-CoV-2.

A gradual decay in humoral and cellular immune responses over time upon SAR1S-CoV-2 vaccination may cause a lack of protective immunity. We conducted a longitudinal analysis of antibodies, T cells, and monocytes in 25 participants vaccinated with mRNA or ChAdOx1-S up to 12 weeks after the 3rd (booster) dose with mRNA vaccine. We observed a substantial increase in antibodies and CD8 T cells specific for the spike protein of SARS-CoV-2 after vaccination. Moreover, vaccination induced activated T cells expressing CD69, CD137 and producing IFN-γ and TNF-α. Virus-specific CD8 T cells showed predominantly memory phenotype. Although the level of antibodies and frequency of virus-specific T cells reduced 4-6 months after the 2nd dose, they were augmented after the 3rd dose followed by a decrease later. Importantly, T cells generated after the 3rd vaccination were also reactive against Omicron variant, indicated by a similar level of IFN-γ production after stimulation with Omicron peptides. Breakthrough infection in participants vaccinated with two doses induced more SARS-CoV-2-specific T cells than the booster vaccination. We found an upregulation of PD-L1 expression on monocytes but no accumulation of myeloid cells with MDSC-like immunosuppressive phenotype after the vaccination. Our results indicate that the 3rd vaccination fosters antibody and T cell immune response independently from vaccine type used for the first two injections. However, such immune response is attenuated over time, suggesting thereby the need for further vaccinations.

Immunogenicity of Sars-Cov-2 Vaccines by Vaccine Type in Randomised Clinical Trials

Background: Currently five SARS-CoV-2 vaccines are approved in North America (FDA) and Europe (EMA). Across the world other vaccines have been developed but not approved in high-income countries. Of the approved vaccines, 2 are mRNA vaccines, 2 are viral vectored vaccines, and 1 is a protein subunit vaccine. As immunogenicity markers are increasingly being used by regulatory agencies as surrogate markers for vaccine efficacy to inform authorization decisions, this meta-analysis compared the size of immunogenicity responses response elicited by the different COVID-19 vaccine types (mRNA, protein subunit, inactivated virus, viral vectors) and approved and unapproved COVID-19 vaccines. Method(s): Systematic review of trial registers and databases identified RCTs for SARS-CoV-2 vaccines. Risk of bias analysis was conducted using the Cochrane Risk of Bias tool. High risk of bias studies were excluded from analysis. Meta-analysis of seroconversion rates and geometric antibody titers (GMT) for neutralising (NAb) and anti-spike antibodies was conducted, each compared with a placebo using random effects model Cochrane-Mantel Haenszel Tests. Result(s): All studies assessed immunogenicity of COVID-19 vaccines on healthy non-immunocompromised adults between the age of 18 and 59. Statistically significant difference was identified between the different vaccine types for NAb GMT, anti-spike GMT, NAb seroconversion, and anti-spike seroconversion (P< 0.00001 for all). Conversely, no statistical significant difference was identified between approved and unapproved vaccines for NAb seroconversion (P=0.39), Nab GMT (P=0.36), anti-spike seroconversion (P=0.07), and antispike GMT (P=0.54). mRNA vaccines had the best immunogenicity results for NAb seroconversion, GMT, and anti-spike seroconversion. Viral vector vaccines had the lowest results for NAb seroconversion and GMT, while inactivated viruses had the lowest result for anti-spike seroconversion and mRNA vaccines for anti-spike GMT. High heterogeneity was observed across the different studies. Conclusion(s): This metanalysis of 35 randomised trials in 33,813 participants showed approved and unapproved vaccines to be comparable in postvaccination GMT values and seroconversion for both NAb and anti-spike. However, while comparing COVID-19 vaccines by vaccine types, statistically significant differences are observed. Variations in study designs, populations enrolled, and infection prevalence during trial duration could have influenced results.

VSV-BASED COVID VACCINE FOR THE PREVENTION OF BREAKTHROUGH SARS-CoV-2 INFECTIONS

Background: More than 12 billion doses of COVID-19 vaccine administrations and over 630 million natural infections should have developed adequate levels of herd immunity over the last three years. However, there have been many new waves of coronavirus infections. The development of safe and effective vaccines to control breakthrough SARS-CoV-2 infections remain an urgent priority. We have developed a recombinant VSV vector-based vaccine to fulfill this worldwide need. Method(s): We have used a recombinant vesicular stomatitis virus (rVSV)-based prime-boost immunization strategy to develop an effective COVID-19 recall vaccine candidate. We have constructed an attenuated recombinant VSV genome carrying the full-length Spike protein gene of SARS-CoV-2. Adding the honeybee melittin signal peptide (msp) at the N-terminus enhanced the protein expression and adding the VSV G protein transmembrane domain and the cytoplasmic tail (Gtc) at the C-terminus of the Spike protein allowed efficient incorporation of the Spike protein into pseudotype VSV. Result(s): In immunized mice, rVSV with chimeric rVSV-msp-S-Gtc induced high levels of potent neutralizing antibodies (nAbs) and CD8+ T cell responses, while the full-length Spike with Gtc proved to be the superior immunogen. More importantly, rVSV-msp-S-Gtc-vaccinated animals were completely protected from subsequent SARS-CoV-2 challenges. Furthermore, rVSV-Wuhan and rVSV-Delta vaccines, and an rVSV-Trivalent (mixed rVSV-Wuhan, -Beta and -Delta) vaccine elicited potent nAbs against live SARS-CoV-2 Wuhan (USAWA1), Beta (B.1.351), Delta (B.1.617.2) and Omicron (B.1.1.529) viruses. Heterologous boosting of rVSV-Wuhan with rVSV-Delta induced strong nAb responses against Delta and Omicron viruses, with the rVSV-Trivalent vaccine consistently inducing effective nAbs against all the SARS-CoV-2 variants tested. All rVSV-msp-S-Gtc vaccines also elicited an immunodominant Spike-specific CD8+ T cell response. Conclusion(s): rVSV vaccines targeting SARS-CoV-2 variants of concern can be considered as an effective booster vaccine in the global fight against COVID-19.

Vaccination against COVID-19.

Vaccination is essential to manage the COVID-19 pandemic. Vaccination significantly protects against severe COVID-19, hospitalization and death;it also protects against symptomatic infection and reduces the risk of transmission to other people. Protection against the new SARS-CoV-2 variants may be lower, but protection against severe course and death remains high. Two mRNA vaccines (BNT162b2 and mRNA-1273) and two vector vaccines (AZD1222 and Ad26.COV2.S) are currently available in the Czech Republic. Vaccination of persons over 60 years of age and immunocompromised persons, who are demonstrably at the highest risk of a serious course of the disease, is of the utmost importance. In order to achieve adequate vaccination coverage, it is necessary to motivate other groups of people to be vaccinated, including children over 12 years of age and young adults. Vaccination is also recommended in preg-nant women in the 2nd and 3rd trimesters and in breastfeeding women. For selected groups of vaccines, a third dose of vaccination is recommended (additional third dose 4 weeks after the second dose or a booster dose 8 to 12 months after the second dose). The side effects are usually mild, with serious complications (including anaphylaxis, thrombocytopenia with thrombosis syndrome, myocardi-tis, Guillain-Barre syndrome and capillary leak syndrome) being rare.Copyright © 2021, Trios spol. s.r.o.. All rights reserved.

Recombinant human adenovirus type 5 based vaccine candidates against GIIa- and GIIb-genotype porcine epidemic diarrhea virus induce robust humoral and cellular response in mice.

Porcine epidemic diarrhea virus (PEDV) is a porcine enteropathogenic coronavirus causing severe watery diarrhea, vomiting, dehydration, and death in piglets. However, most commercial vaccines are developed based on the GI genotype strains, and have poor immune protection against the currently dominant GII genotype strains. Therefore, four novel replication-deficient human adenovirus 5-vectored vaccines expressing codon-optimized forms of the GIIa and GIIb strain spike and S1 glycoproteins were constructed, and their immunogenicity was evaluated in mice by intramuscular (IM) injection. All the recombinant adenoviruses generated robust immune responses, and the immunogenicity of recombinant adenoviruses against the GIIa strain was stronger than that of recombinant adenoviruses against the GIIb strain. Moreover, Ad-XT-tPA-Sopt-vaccinated mice elicited optimal immune effects. In contrast, mice immunized with Ad-XT-tPA-Sopt by oral gavage did not induce strong immune responses. Overall, IM administration of Ad-XT-tPA-Sopt is a promising strategy against PEDV, and this study provides useful information for developing viral vector-based vaccines.

Chronic spontanous urticaria following anti-covid 19 vaccine: Is there a link?

Background: Urticarial reactions following Covid-19 vaccine were rarely reported and have a short self-limited resolution. However only one case of chronic spontaneous urticaria (CSU) after mRNA vaccine was observed (1). Herein, we describe an original case series of patients who exhibited a CSU after Sars-Cov- 2 vaccination. Method(s): It was a retrospective case series of patients referred to the department of Clinical pharmacology of the University of Monastir for exploration of urticaria after Covid-19 vaccination., between January 2021 and January 2022. Result(s): Eight patients (8 F /5M) were included in this study. The median patient age was 36.5 years. None of them had a medical history of CSU. Urticaria was reported in 4 patients following mRNA vaccine (BNT162b2 and Moderna). Viral vector vaccine (Oxford/ AstraZeneca) was offended in 2 cases and inactivated virus vaccine (Sinovac, CoronaVac) was reported in 2 others cases. The mean time interval between vaccination and the onset of urticaria was 28.5 hours. The first shot of vaccine was the mostly offended dose (n = 6). Urticaria was associated with angioedema in 5 patients after Oxford/AstraZenecavaccine (n = 2) and following mRNA vaccine (n = 2). One case of urticaria was associated with angioedema and dyspnea after the CoronaVac administration. Blood tests showed polynuclear leucocytosis in 37% of patients. Positive anti-thyroperoxidase antibodies, and elevated polyclonal hypergammaglobulinemia were present in one patient 3 months after receiving BNT162b2 vaccine. Total serum IgE were high in 25% of patients following BNT162b2 and CoronaVac. All patients required antihistamines and 4 cases required intravenous betametasone. The median time to symptom resolution was 3 days but urticaria rapidly reccured throughout the entire body inspite the regular use of full dose of antihistamine. Intradermal test for the vaccine excipient as well as the offended Covid-19 vaccine was carried out in 5 patients, and were negative in all of them.Currently, all patients still has the pruritic rash daily. Conclusion(s): These cutaneous reactions seem to be particularly prolonged despite the use of symptomatic drugs, as compared with of drug induced-urticaria. Consequently, careful monitoring of urticaria over an extended period of time is needed.

COVID-19 infection in patients with severe hereditary angioedema in long term prophylaxis with subcutaneous C1-inhibitor -A prospective study

Background: Coronavirus disease 2019 (COVID-19) was suspected to trigger angioedema attacks, or cause more severe COVID-19 disease in patients with Hereditary angioedema (HAE). Our objective was to evaluate the severity of COVID-19 and its impact on disease control in patients with severe HAE in long-term prophylaxis(LTP) with subcutaneous C1-inhibitor( SC C1-INH). Method(s): We p erformed a retrospective s tudy of p atients w ith s evere course of HAE who maintained LTP with SC C1-INH during the pandemic. Date were collected under conditions of daily clinical practice. Patients were evaluated at least 2 times after switching to LTP with SC C1-INH. We analyzed COVID19 vaccine application and tolerance, COVID19 infection, disease control after COVID19 infection and the quality-of- life. Result(s): We evaluated 18 patients(12 female) who switched from LTP with IV C1-INH to LTP with SC C1 INH. Switching was followed by a significant decrease in the number of attacks, visits to the emergency department, and use of rescue dose of IV C1-INH or icatibant, as well as improved disease control (Angioedema Control Test). All patients were vaccinated against COVID19 (37 doses of mRNA vaccine and 4 doses of viral vector vaccine). Nor severe neither moderate adverse reactions were observed. 5 patients were infected with COVID19 (one 30 years-old female patient was infected twice) and had mild symptoms. None of the patients needed a hospital admission. Only one of the patients had worsening of the disease control after COVID19 infection and long -term post COVID repercussion (persistent headache and depressive mood). One of the infected patients was pregnant (7 gestational weeks) and had asymptomatic COVID19 infection with no impact on pregnancy. Conclusion(s): In our cohort of patients LTP with SC C1 INH and correct vaccination against COVID19 have shown that can maintain severe HAE patients with good clinical control even when infected with the virus.

Unusual Myositis of the Temporalis Muscle Occurring with Acute Covid-19

Background. SARS-CoV-2 infection can be accompanied by neuromuscular disorders. Rhabdomyolysis and Guillain-Barre syndrome have been described repeatedly. There are case reports of inflammatory myopathies manifesting during COVID-19, presenting as dermatomyositis, polymyositis or immune-mediated necrotizing myopathy, with dermatomyositis-like presentations most commonly reported. Larger cases series are from postmortem examinations of COVID-19 patients, where variable inflammatory pathology of the skeletal muscle has been found frequently but without local detection of the actual virus. Thus, autoimmune mechanisms or the systemic interferon response are discussed as causes. We report a case of focal inflammatory myopathy with perimysial pathology of the temporalis muscle occurring with acute, but mild COVID-19. Methods. Case report of clinical observations, cranial MRI, histopathological, and laboratory findings. 3T cranial MRI was performed with gadolinium contrast. Open temporalis muscle biopsy was performed. The sample underwent standard cryohistological studies as well as immunohistochemistry with antibodies against MHC-I and II, CD3, CD4, CD19, CD68, anti-MAC, p62 and MxA. Testing for auto-antibodies was based on immunoblots or ELISA. RT-PCR for SARS-CoV-2 was run with RNA extracted from cryopreserved muscle. Results. A Caucasian woman in her 60s with no history of autoimmune or muscle complaints developed swelling and pain of the right jaw musculature five days after testing positive for SARS-CoV-2 due to respiratory tract symptoms. In addition, she experienced trismus, but no further neuromuscular complaints. The course of respiratory tract symptoms stayed mild. She had been vaccinated previously with single shot SARS-CoV-2 vector vaccine. Due to persistent swelling and complaints, giant cells arteritis was excluded by unresponsiveness to five days oral steroids and sonography of the temporal artery. Cranial MRI was performed nearly four weeks after the SARS-CoV-2 infection and showed marked swelling and oedema of the temporalis muscle. Its biopsy showed numerous CD68 and acid phosphatase positive cells infiltrating from perimysial perivascular foci towards the endomysium with perimysial damage but little damage of adjacent, perifascicular muscle fibres. Muscle fibres did not react with anti-MHC-II, anti-MAC or -MxA. Capillaries did not react with anti-MAC or -MxA. SARS-CoV-2 RNA was not detected in muscle tissue. Serum creatine kinase was not elevated in the subacute phase. Slightly elevated ANA titre led to detection of autoantibodies against proliferating cell nuclear antigen (PCNA). No pathological results for other autoantibodies, including myositis-specific antibodies and anti-ds-DNA, were found in blood. Neither were antibodies against hepatitis C and B viruses. Retesting 15 weeks after infection, anti-PCNA immunoblot was still positive, but ELISA did not indicate a pathologic titre. The swelling, myalgia and trismus regressed spontaneously a month after onset, yet the latter still persists at the time of reporting. Conclusion. Our case diverges from the majority of COVID-19 associated my-ositis reports in the unusual location of the focal myositis and the histopathological pattern of predominantly perimysial damage and histiocytic infiltration. It concurs with the literature as no SARS-CoV2 RNA could be detected in the muscle. Anti-PCNA is associated very rarely with myositis. Other associated disorder (systemic lupus erythematosus, chronic viral hepatitis B or C) were not found. Increased levels of autoantibodies are reported in COVID-19 and mostly attributed to loss of self-tolerance during the acute disease phase. Interestingly, the structural protein M of SARS-CoV-2 appears to interact notably with PCNA in infected cells. Still, the causal connection between the myositis and COVID-19 in this case is based on the close temporal association in the absence of alternative, competing explanations from the medical history and findings.

Second-dose COVID-19 vaccines are well tolerated in patients with allergic reactions to the first dose -A single center experience

Background: COVID-19 vaccines contain additives such as Polyethylenglycol-2000 (PEG2000;mRNA vaccines) or Polysorbat 80 (vector vaccines), which have been described previously as culprits for anaphylactic events. Method(s): This retrospective study included 46 individuals, who were referred to the Allergy Center at the Depart. of Dermatology, University Hospital Linz with suspected allergic reactions to the first COVID-19 vaccine dose with either mRNA or vector-based vaccines. Patients underwent detailed anamnesis, clinical examination and in most cases skin prick testing using pure additive substances (PEG -different molecular weights, Polysorbate 80). Result(s): Out of 46, 7 patients' reactions were classified as possibly anaphylactic and graded according to Ring & Messmer. Forty patients out of 46 were assessed with skin prick tests for potential allergens in COVID-19 vaccines. Only one patient showed an immediate positive prick test to PEG2000. Second-dose vaccination with mRNA or vector-based vaccines were tolerated well in all patients, including the individual with a positive skin prick test against PEG2000. Conclusion(s): The currently available COVID-19 vaccines have an overall low allergic potential and may be administered safely in patients with suspected allergic reactions to the first dose.

ACHIEVEMENT OF MAXIMAL SARS-CoV-2 COLLECTIVE IMMUNITY AMONG THE TAJIK POPULATION BY MARCH 2022

Despite all efforts of the world community, the COVID-19 pandemic remains one of the main epidemiological challenges of our time. Even with its widespread distribution, the infection may have certain local features due to social, geographic, and climatic factors. Objective(s): to study collective immunity to SARS-CoV-2 in the population of the Republic of Tajikistan. A cross-sectional, randomized study of herd immunity was carried out according to a program developed by Rospotrebnadzor and the St. Petersburg Pasteur Institute, taking into account WHO recommendations. The ethics committees of the corresponding entities approved the study: Tajik Ministry of Health and Social Protection;and the St. Petersburg Pasteur Institute (Russia). Based on questionnaire results, 4,022 people were selected, representing 0.15% (95% CI: 0.14-0.15) of the total population randomized by age and region. In subsequent laboratory analysis, 3682 people took part. The distribution and quantitative content of antibodies (Abs) to viral nucleocapsid (N Ag) and receptor binding domain (RBD Ag) were determined by ELISA. When questioned, a history of SARS-CoV-2 vaccination was indicated by 69.7% (95% CI: 68.2-71.2) of the volunteer cohort. Vector vaccines were most frequently used (50.6%;95% CI: 48.7-52.5), with whole-virion inactivated preparations in second place (23.0%: 95% CI: 21.4-26.6) and mRNA vaccines in third place (21.0%;95% CI:19.4-22.6). The cohort (n = 3682) featured 27.5% men and 72.5% women. The overall seroprevalence was 98.5% (95% CI: 97.7-99.2) in men and 99.4% (95% CI: 99.0-99.6) in women (differences statistically insignificant). Overall seroprevalence in the cohort was 99.2% (95% CI: 98.8-99.4) and ranged from 97.2 to 100% in certain subgroups. Asymptomatic seropositivity in the whole cohort was 98.4% (95% CI: 97.6-99.1). As a result of a mandatory vaccination program introduced in Tajikistan under a COVID-19 Emergency Project, the level of herd immunity among vaccinated individuals reached 99.5% (95% CI: 99.1-99.7), which is similar to the level reached in the cohort as a whole. The epidemic situation that developed in Tajikistan by mid-March 2022 was characterized by an almost absolute level of herd immunity, as evidenced by an absence of detected overt COVID-19 cases since the end of February (2022).Copyright © Popova A.Yu. et al., 2023 The article can be used under the Creative Commons Attribution 4.0 License.

Pre-existing humoral immunity and CD4+ T cell response correlate with cross-reactivity against SARS-CoV-2 Omicron subvariants after heterologous prime-boost vaccination.

BACKGROUND: Information regarding the heterologous prime-boost COVID vaccination has been fully elucidated. The study aimed to evaluate both humoral, cellular immunity and cross-reactivity against variants after heterologous vaccination. METHODS: We recruited healthcare workers previously primed with Oxford/AstraZeneca ChAdOx1-S vaccines and boosted with Moderna mRNA-1273 vaccine boost to evaluate the immunological response. Assay used: anti-spike RBD antibody, surrogate virus neutralizing antibody and interferon-γ release assay. RESULTS: All participants exhibited higher humoral and cellular immune response after the booster regardless of prior antibody level, but those with higher antibody level demonstrated stronger booster response, especially against omicron BA.1 and BA.2 variants. The pre-booster IFN-γ release by CD4+ T cells correlates with post-booster neutralizing antibody against BA.1 and BA.2 variant after adjustment with age and gender. CONCLUSIONS: A heterologous mRNA boost is highly immunogenic. The pre-existing neutralizing antibody level and CD4+ T cells response correlates with post-booster neutralization reactivity against the Omicron variant.

A systematic review and meta-analysis of the seroconversion rates and adverse effects of COVID-19 mRNA vaccine and COVID-19 viral vector vaccine in kidney transplant recipient patients.

Patients received kidney transplantation (KTR) have a low seroconversion rate after vaccination. Our objective was to compare the seroconversion rates and adverse effects of additional different vaccinations in KTR patients in existing studies. Databases such as PubMed, Cochrane Library, Web of Science, Embase, ClinicalTrials.gov and others. Three high-quality RCT were included and showed no statistical difference in seroconversion rates between the two vaccines (RR = 0.93[0.76,1.13]). There was no statistical difference in seroconversion rates between the sexes, for men (RR = 0.93[0.69,1.25]) and women (RR = 0.91[0.62,1.33]). Among the adverse effects there was no statistically significant difference in fever (RR = 1.06[0.44,2.57]), while for injection site pain there was a statistically significant difference (RR = 1.14[1.18,1.84]). There was no significant difference in seroconversion rates in patients with KTR who received the two additional vaccines. Patients injected with the viral vector vaccine were less painful than those injected with the mRNA vaccine.

Vaccine effectiveness against transmission of alpha, delta and omicron SARS-COV-2-infection, Belgian contact tracing, 2021-2022.

OBJECTIVES: Vaccine effectiveness against transmission (VET) of SARS-CoV-2-infection can be estimated from secondary attack rates observed during contact tracing. We estimated VET, the vaccine-effect on infectiousness of the index case and susceptibility of the high-risk exposure contact (HREC). METHODS: We fitted RT-PCR-test results from HREC to immunity status (vaccine schedule, prior infection, time since last immunity-conferring event), age, sex, calendar week of sampling, household, background positivity rate and dominant VOC using a multilevel Bayesian regression-model. We included Belgian data collected between January 2021 and January 2022. RESULTS: For primary BNT162b2-vaccination we estimated initial VET at 96% (95%CI 95-97) against Alpha, 87% (95%CI 84-88) against Delta and 31% (95%CI 25-37) against Omicron. Initial VET of booster-vaccination (mRNA primary and booster-vaccination) was 87% (95%CI 86-89) against Delta and 68% (95%CI 65-70) against Omicron. The VET-estimate against Delta and Omicron decreased to 71% (95%CI 64-78) and 55% (95%CI 46-62) respectively, 150-200 days after booster-vaccination. Hybrid immunity, defined as vaccination and documented prior infection, was associated with durable and higher or comparable (by number of antigen exposures) protection against transmission. CONCLUSIONS: While we observed VOC-specific immune-escape, especially by Omicron, and waning over time since immunization, vaccination remained associated with a reduced risk of SARS-CoV-2-transmission.

Adenovirus vector vaccines.

Recently, importance of vaccines for treatment and prevention of emerging and re-emerging infectious diseases has been re-recognized. A replication-incompetent adenovirusAdvector DDS vaccine expressing virus antigen proteins is one of the most advanced platforms as a novel vaccine because an Ad vector vaccine can be rapidly applicable to pandemic. In this review, we describe the basic properties of an Ad vector for vaccine, in addition to the summary of the development of an Ad vector vaccine for emerging and re-emerging infectious diseases, including Coronavirus disease 2019COVID-19, worldwide.Copyright © 2022, Japan Society of Drug Delivery System. All rights reserved.

Adenovirus vector vaccines.

Recently, importance of vaccines for treatment and prevention of emerging and re-emerging infectious diseases has been re-recognized. A replication-incompetent adenovirus(Ad)vector DDS vaccine expressing virus antigen proteins is one of the most advanced platforms as a novel vaccine because an Ad vector vaccine can be rapidly applicable to pandemic. In this review, we describe the basic properties of an Ad vector for vaccine, in addition to the summary of the development of an Ad vector vaccine for emerging and re-emerging infectious diseases, including Coronavirus disease 2019(COVID-19), worldwide.Copyright © 2022, Japan Society of Drug Delivery System. All rights reserved.

Adenovirus vector vaccines.

Recently, importance of vaccines for treatment and prevention of emerging and re-emerging infectious diseases has been re-recognized. A replication-incompetent adenovirus(Ad)vector DDS vaccine expressing virus antigen proteins is one of the most advanced platforms as a novel vaccine because an Ad vector vaccine can be rapidly applicable to pandemic. In this review, we describe the basic properties of an Ad vector for vaccine, in addition to the summary of the development of an Ad vector vaccine for emerging and re-emerging infectious diseases, including Coronavirus disease 2019(COVID-19), worldwide.Copyright © 2022, Japan Society of Drug Delivery System. All rights reserved.