Immunization Regimen Research Articles

Assessment of an Enterobactin Conjugate Vaccine in Layers to Protect Their Offspring from Colibacillosis.

Colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is an important infectious disease in chickens and a major cause of mortality in young chicks. Therefore, protecting young chickens from colibacillosis is important for improving welfare and productivity in the poultry industry. Recently, we developed a novel enterobactin (Ent) conjugate vaccine that could induce high titers of anti-Ent immunoglobulin Y (IgY) in chicken serum and consequently mitigate the organ lesions caused by APEC infection. Considering that maternal immunization is a practical approach to confer instant immune protection to the hatchlings, in this study, we immunized breeder hens with the Ent conjugate vaccine and evaluated the maternal immune protection on the progenies challenged with APEC. Three doses of the vaccine induced high titers of anti-Ent IgY in the hens (about 16- and 64-fold higher than the control group in the sera and egg yolks, respectively), resulting in an eight-fold of increase in anti-Ent IgY in the sera of progenies. However, the anti-Ent maternal immunity did not display significant protection against APEC challenge in the young chicks as there was no significant difference in APEC load (in liver, lung, and spleen) or organ lesions (in heart, liver, spleen, lung, and air sac) between the vaccinated and control groups. In future studies, the APEC infection model needs to be optimized to exhibit proper pathogenicity of APEC, and the maternal immunization regimen can be further improved to boost the maternally derived anti-Ent IgY in the hatchlings.

The effectiveness of medical personnel vaccination against hepatitis B

Medical personnel belong to the occupational risk group of hepatitis B virus (HBV) infection due to the increase of parenteral interventions and procedures using sophisticated equipment, constant contact with biological fluids of patients, the widespread use of antibiotics and cytostatics that have an immunosuppressive effect, etc. Insufficient objectivity in assessing the quality of hepatitis B (HBV) immunoprophylaxis only according to documentation may be associated with a violation of immunization regimens, the presence of chronic pathology in vaccinated, age-related immunodeficiency. Despite the effectiveness of HCV vaccination, the protective activity of specific humoral immunity (antibodies to HBsAg — anti-HBs) among vaccinated medical workers has not been sufficiently studied. The results of studying the intensity and duration of the immune response in 2075 employees of two large multidisciplinary hospitals vaccinated against HBV (average age 46.3 ± 10.1 years) are presented. A high level of vaccination coverage of medical personnel in hospitals No. 1 and No. 2 was established, amounting to 96.6 % and 97.2 %, and the level of collective immunity was equal to 1645.5±72.5 IU/l and 886±123.7 IU/l, respectively. The absence of cases of HBV in vaccinated individuals during immunoprophylaxis according to the standard scheme was noted. It seems advisable to use an individual approach to the tactics of revaccination when reducing the content of anti-HBs in the blood to low concentrations (10–100 IU / l), preventing them from falling below the protective level.

Immune response to third coronavirus disease 2019 vaccine for vaccine recipient with underlying sickle-cell disorder: A clinical mathematical model prediction

Abstract Aim The aim is to address the role for the third dose of the COVID-19 immunization regimen in the development of infection immunogenicity. Objective/Background It has been proven that the coronavirus disease 2019 (COVID-19) vaccination is effective at preventing COVID-19. Usually, the vaccination calls for two doses. Following a complete series of vaccinations, immunity may start to decline. Usually, a booster dose is taken in addition. Additional immunizations are necessary for people with preexisting diseases such as systemic lupus erythematosus or cancer. However, there is still concern about the need for enhanced immunity in those with underlying diseases. There should be a third dose of the vaccination, according to the suggestion. In the event of the introduction of a new strain as well as the foreseeable loss of public immunityfollowing routine mass vaccination, several scientists are currently supporting the use of a third-dosage vaccine. The effectiveness of the third immunization is unknown, thus, any research into it is fascinating. The new COVID-19 strain is also causing a disease outbreak in persons who have had all of their vaccines. Methods The researchers used a clinical model to predict response when giving the third dose of COVID-19 vaccination to sickle-cell disease patients. Results This study discovered a role for the third dose of the COVID-19 immunization regimen in the development of infection immunogenicity. Conclusion If a third dosage is expected, there are a few mRNA COVID-19 vaccination options to consider.

Boost immunizations with NA-derived peptide conjugates achieve induction of NA inhibition antibodies and heterologous influenza protections

Neuraminidase is suggested as an important component for developing a universal influenza vaccine. Targeted induction of neuraminidase-specific broadly protective antibodies by vaccinations is challenging. To overcome this, we rationally select the highly conserved peptides from the consensus amino acid sequence of the globular head domains of neuraminidase. Inspired by the B cell receptor evolution process, a reliable sequential immunization regimen is designed to result in immuno-focusing by steering bulk immune responses to a selected region where broadly protective B lymphocyte epitopes reside. After priming neuraminidase protein-specific antibody responses in C57BL/6 or BALB/c inbred mice strains by immunization or pre-infection, boost immunizations with certain neuraminidase-derived peptide-keyhole limpet hemocyanin conjugates significantly strengthened serum neuraminidase inhibition activities and cross-protections. Overall, this study provides proof of concept for a peptide-based sequential immunization strategy for achieving targeted induction of cross-protective antibody response, which provides references for designing universal vaccines against other highly variable pathogens.

Reactogenicity and safety of COVID-19 primary immunisation and booster vaccination regimens: a comparative observational cohort study

BackgroundSince the beginning of the COVID-19 vaccination campaigns, recommendations regarding the vaccination have been very dynamic. Although the safety and efficacy of different vaccines have been analysed, data were scarce for vaccine regimens combining different vaccines. We therefore aimed to evaluate and compare the perceived reactogenicity and need for medical consultation after the most frequently applied homologous and heterologous COVID-19 vaccination regimens.MethodsIn an observational cohort study, reactogenicity and safety were assessed within a maximum follow-up time of 124 days using web-based surveys. Reactogenicity was assessed for different vaccination regimens 2 weeks after a vaccination (short-term survey). The following surveys, long-term and follow-up surveys, focused on the utilisation of medical services, including those that were not suspected to be vaccine-related.ResultsData of 17,269 participants were analysed. The least local reactions were seen after a ChAdOx1 − ChAdOx1 regimen (32.6%, 95% CI [28.2, 37.2]) and the most after the first dose with mRNA-1273 (73.9%, 95% CI [70.5, 77.2]). Systemic reactions were least frequent in participants with a BNT162b2 booster after a homologous primary immunisation with ChAdOx1 (42.9%, 95% CI [32.1, 54.1]) and most frequent after a ChAdOx1 − mRNA-1273 (85.5%, 95% CI [82.9, 87.8]) and mRNA-1273/mRNA-1273 regimen (85.1%, 95% CI [83.2, 87.0]). In the short-term survey, the most common consequences were medication intake and sick leave (after local reactions 0% to 9.9%; after systemic reactions 4.5% to 37.9%). In the long-term and follow-up surveys, between 8.2 and 30.9% of participants reported consulting a doctor and between 0% and 5.4% seeking hospital care. The regression analyses 124 days after the first and after the third dose showed that the odds for reporting medical consultation were comparable between the vaccination regimens.ConclusionsOur analysis revealed differences in reactogenicity between the COVID-19 vaccines and vaccination regimens in Germany. The lowest reactogenicity as reported by participants was seen with BNT162b2, especially in homologous vaccination regimens. However, in all vaccination regimens reactogenicity rarely led to medical consultations. Small differences in seeking any medical consultation after 6 weeks diminished during the follow-up period. In the end, none of the vaccination regimens was associated with a higher risk for medical consultation.Trial registrationDRKS DRKS00025881 (https://drks.de/search/de/trial/DRKS00025373). Registered on 14 October 2021. DRKS DRKS00025373 (https://drks.de/search/de/trial/DRKS00025881). Registered on 21 May 2021. Registered retrospectively.

Evaluation of Anti-S1 IgA Response to Different COVID-19 Vaccination Regimens.

IgA plays a crucial role in early virus neutralization. To identify the IgA stimulation by COVID-19 vaccine, this study aimed to evaluate the level of anti-S1 IgA in the serum of participants immunized with different COVID-19 vaccination regimens. Sera from 567 eligible participants vaccinated with two, three, or four doses of different types of COVID-19 vaccine were recruited. Post-vaccine anti-S1 IgA responses significantly varied according to vaccine type and regimen. The finding showed that heterologous boosters, especially after priming with an inactivated vaccine, elicited higher IgA levels than homologous boosters. Vaccination with SV/SV/PF produced the highest IgA level among all the immunization regimens after either two, three, or four doses. The different routes and amounts of vaccine used for vaccination showed non-significant differences in IgA levels. After the third dose of immunization for 4 months, the level of IgA decreased significantly from the level found on day 28 in both SV/SV/AZ and SV/SV/PF groups. In conclusion, our study showed that heterologous booster regimens for COVID-19 elicited higher anti-S1 IgA levels in serum, especially after priming with inactivated vaccine. The presented anti-S1 IgA may have advantages in preventing SARS-CoV-2 infection and severe disease.

Immunogenicity and efficacy of a novel multi-patch SARS-CoV-2/COVID-19 vaccine candidate.

While there has been considerable progress in the development of vaccines against SARS-CoV-2, largely based on the S (spike) protein of the virus, less progress has been made with vaccines delivering different viral antigens with cross-reactive potential. In an effort to develop an immunogen with the capacity to induce broad antigen presentation, we have designed a multi-patch synthetic candidate containing dominant and persistent B cell epitopes from conserved regions of SARS-CoV-2 structural proteins associated with long-term immunity, termed CoV2-BMEP. Here we describe the characterization, immunogenicity and efficacy of CoV2-BMEP using two delivery platforms: nucleic acid DNA and attenuated modified vaccinia virus Ankara (MVA). In cultured cells, both vectors produced a main protein of about 37 kDa as well as heterogeneous proteins with size ranging between 25-37 kDa. In C57BL/6 mice, both homologous and heterologous prime/boost combination of vectors induced the activation of SARS-CoV-2-specific CD4 and CD8 T cell responses, with a more balanced CD8+ T cell response detected in lungs. The homologous MVA/MVA immunization regimen elicited the highest specific CD8+ T cell responses in spleen and detectable binding antibodies (bAbs) to S and N antigens of SARS-CoV-2. In SARS-CoV-2 susceptible k18-hACE2 Tg mice, two doses of MVA-CoV2-BMEP elicited S- and N-specific bAbs as well as cross-neutralizing antibodies against different variants of concern (VoC). After SARS-CoV-2 challenge, all animals in the control unvaccinated group succumbed to the infection while vaccinated animals with high titers of neutralizing antibodies were fully protected against mortality, correlating with a reduction of virus infection in the lungs and inhibition of the cytokine storm. These findings revealed a novel immunogen with the capacity to control SARS-CoV-2 infection, using a broader antigen presentation mechanism than the approved vaccines based solely on the S antigen.

Immune response of heterologous versus homologous prime-boost regimens with adenoviral vectored and mRNA COVID-19 vaccines in immunocompromised patients.

Due to rare but major adverse reactions to the AstraZeneca adenoviral ChAdOx1-S-nCoV-19 vaccine (ChAd), German health authorities recommended adults under 60 who received one dose of ChAd, to receive a second dose of the BioNTech mRNA BNT162b2 vaccine (BNT) as a booster. Studies in the general population suggest an enhanced efficacy of the heterologous (ChAd-BNT) compared to the homologous (BNT-BNT) vaccination regimen. However, an analysis of the efficacy in patient populations with a high risk of severe COVID-19 due to acquired immunodeficiency is still missing. We therefore compared both vaccination regimens in healthy controls, patients with gynecological tumors after chemotherapy, patients on dialysis and patients with rheumatic diseases concerning the humoral and cellular immune response. The humoral and cellular immune response differed substantially in healthy controls compared to patients with acquired immunodeficiency. Overall, the most significant differences between the two immunization regimens were found in neutralizing antibodies. These were always higher after a heterologous immunization. Healthy controls responded well to both vaccination regimens. However, the formation of neutralizing antibodies was more pronounced after a heterologous immunization. Dialysis patients, on the other hand, only developed an adequate humoral and particularly cellular immune response after a heterologous immunization. Tumor and rheumatic patients also - to a weaker extent compared to dialysis patients - benefited from a heterologous immunization. In conclusion, the heterologous COVID-19 vaccination regimens (ChAd-BNT) seem to have an advantage over the homologous vaccination regimens, especially in immunocompromised patients such as patients with end-stage kidney disease treated with hemodialysis.

Status and Developing Strategies for Neutralizing Monoclonal Antibody Therapy in the Omicron Era of COVID-19.

The monoclonal antibody (mAb)-based treatment is a highly valued therapy against COVID-19, especially for individuals who may not have strong immune responses to the vaccine. However, with the arrival of the Omicron variant and its evolving subvariants, along with the occurrence of remarkable resistance of these SARS-CoV-2 variants to the neutralizing antibodies, mAbs are facing tough challenges. Future strategies for developing mAbs with improved resistance to viral evasion will involve optimizing the targeting epitopes on SARS-CoV-2, enhancing the affinity and potency of mAbs, exploring the use of non-neutralizing antibodies that bind to conserved epitopes on the S protein, as well as optimizing immunization regimens. These approaches can improve the viability of mAb therapy in the fight against the evolving threat of the coronavirus.

Tissue Microenvironment Reprograms the Circulating Memory T Cell Differentiation and Enhances Vaccine-Elicited Anti-Metastasis Immunity

Abstract During tumor ontogeny and viral infection, heterologous subsets of CD8+ T lymphocytes provide immediate clearance and durable protection. We utilized model antigen (HIV-1-Gag) expressing melanoma cell line and parabiosis model to investigate the role of different components of memory T cells, including circulating memory T cells (T cirm) and tissue-resident memory T cells (T RM), in melanoma lung metastasis protection. We first proved that T RMgenerated by DNA vaccine intramuscular prime followed by influenza-vectored vaccine intranasal boost immunization regime mediated potent and long-lasting anti-lung metastasis immunity, whereas T cirminduced in different vaccination combinations was not capable to provide sufficient protection. To further explain the mechanism behind the potent T RMgenerated by prime-boost immunization, we found that DNA vaccination elicited a large amount of central memory T cells (T CM) in the circulation and was preferentially differentiated into lung T RMafter the intranasal booster immunization. Single-cell RNA sequencing profile illustrated the tissue microenvironment post mucosal immunization reshaped the differentiation of circulating T CMelicited by systemic immunization and enhanced the anti-metastasis T cell immunity. Thus, our research highlighted the importance of T RMin lung metastasis protection and provided insight into the mechanism of lung T RMestablishment in the prime-boost vaccination.

Cholera toxin B scaffolded, focused SIV V2 epitope elicits antibodies that influence the risk of SIVmac251 acquisition in macaques.

An efficacious HIV vaccine will need to elicit a complex package of innate, humoral, and cellular immune responses. This complex package of responses to vaccine candidates has been studied and yielded important results, yet it has been a recurring challenge to determine the magnitude and protective effect of specific in vivo immune responses in isolation. We therefore designed a single, viral-spike-apical, epitope-focused V2 loop immunogen to reveal individual vaccine-elicited immune factors that contribute to protection against HIV/SIV. We generated a novel vaccine by incorporating the V2 loop B-cell epitope in the cholera toxin B (CTB) scaffold and compared two new immunization regimens to a historically protective 'standard' vaccine regimen (SVR) consisting of 2xDNA prime boosted with 2xALVAC-SIV and 1xΔV1gp120. We immunized a cohort of macaques with 5xCTB-V2c vaccine+alum intramuscularly simultaneously with topical intrarectal vaccination of CTB-V2c vaccine without alum (5xCTB-V2/alum). In a second group, we tested a modified version of the SVR consisting of 2xDNA prime and boosted with 1xALVAC-SIV and 2xALVAC-SIV+CTB-V2/alum, (DA/CTB-V2c/alum). In the absence of any other anti-viral antibodies, V2c epitope was highly immunogenic when incorporated in the CTB scaffold and generated highly functional anti-V2c antibodies in the vaccinated animals. 5xCTB-V2c/alum vaccination mediated non-neutralizing ADCC activity and efferocytosis, but produced low avidity, trogocytosis, and no neutralization of tier 1 virus. Furthermore, DA/CTB-V2c/alum vaccination also generated lower total ADCC activity, avidity, and neutralization compared to the SVR. These data suggest that the ΔV1gp120 boost in the SVR yielded more favorable immune responses than its CTB-V2c counterpart. Vaccination with the SVR generates CCR5- α4β7+CD4+ Th1, Th2, and Th17 cells, which are less likely to be infected by SIV/HIV and likely contributed to the protection afforded in this regimen. The 5xCTB-V2c/alum regimen likewise elicited higher circulating CCR5- α4β7+ CD4+ T cells and mucosal α4β7+ CD4+ T cells compared to the DA/CTB-V2c/alum regimen, whereas the first cell type was associated with reduced risk of viral acquisition. Taken together, these data suggest that individual viral spike B-cell epitopes can be highly immunogenic and functional as isolated immunogens, although they might not be sufficient on their own to provide full protection against HIV/SIV infection.

Patterns in the Prevalence of Unvaccinated Children Across 36 States and Union Territories in India, 1993-2021

Children who do not receive any routine vaccinations (ie, who have 0-dose status) are at elevated risk of death, morbidity, and socioeconomic vulnerabilities that limit their development over the life course. India has the world's highest number of children with 0-dose status; analysis of national and subnational patterns is the first important step to addressing this problem. To examine the patterns among children with 0-dose immunization status across all 36 states and union territories (UTs) in India over 29 years, from 1993 to 2021, and to elucidate the relative share of multiple geographic regions in the total geographic variation in 0-dose immunization. This repeated cross-sectional study analyzed all 5 rounds of India's National Family Health Survey (1992-1993, 1998-1999, 2005-2006, 2015-2016, and 2019-2021) to compare the prevalence of children with 0-dose status across time-space and geographic regions. The Integrated Public Use of Microdata Series was used to construct comparable geographic boundaries for states and UTs across surveys. The study included a total of 125 619 live children aged 12 to 23 months who were born to participating women. The outcome was a binary indicator of children's 0-dose vaccination status, coded as children aged 12 to 23 months at the time of the survey who had not received the first dose of the diphtheria-tetanus-pertussis-containing vaccine. The significance of each geographic unit was computed using the variance partition coefficient (VPC). Among 125 619 children, the national prevalence of those with 0-dose status in India decreased from 33.4% (95% CI, 32.5%-34.2%) in 1993 to 6.6% (95% CI, 6.4%-6.8%) in 2021. A substantial reduction in the IQR of 0-dose prevalence across states from 30.1% in 1993 to 3.1% in 2021 suggested a convergence in state disparities. The prevalence in the northeastern states of Meghalaya (17.0%), Nagaland (16.1%), Mizoram (14.3%), and Arunachal Pradesh (12.6%) remained relatively high in 2021. Prevalence increased between 2016 and 2021 in 10 states, including several traditionally high-performing states and UTs, such as Telangana (1.16 percentage points) and Sikkim (0.92 percentage points). In 2021, 53.0% of children with 0-dose status resided in the populous states of Uttar Pradesh, Bihar, and Maharashtra. A multilevel analysis comparing the share of variation at the state, district, and cluster (primary sampling unit) levels revealed that clusters accounted for the highest share of the total variation in 2016 (44.7%; VPC [SE], 1.04 [0.32]) and 2021 (64.3%; VPC [SE], 0.38 [0.12]). In this cross-sectional study, findings from approximately 3 decades of analysis suggest the need for sustained efforts to target populous states like Uttar Pradesh and Bihar and northeastern parts of India. The resurgence of 0-dose prevalence in 10 states highlights the importance of programs like Intensified Mission Indradhanush 4.0, a major national initiative to improve immunization coverage. Prioritizing small administrative units will be important to strengthening India's efforts to bring every child into the immunization regime.

CD4 binding site immunogens elicit heterologous anti-HIV-1 neutralizing antibodies in transgenic and wild-type animals.

Passive transfer of broadly neutralizing anti-HIV-1 antibodies (bNAbs) protects against infection, and therefore, eliciting bNAbs by vaccination is a major goal of HIV-1 vaccine efforts. bNAbs that target the CD4 binding site (CD4bs) on HIV-1 Env are among the most broadly active, but to date, responses elicited against this epitope in vaccinated animals have lacked potency and breadth. We hypothesized that CD4bs bNAbs resembling the antibody IOMA might be easier to elicit than other CD4bs antibodies that exhibit higher somatic mutation rates, a difficult-to-achieve mechanism to accommodate Env's N276gp120 N-glycan, and rare five-residue light chain complementarity-determining region 3.As an initial test of this idea, we developed IOMA germline-targeting Env immunogens and evaluated a sequential immunization regimen in transgenic mice expressing germline-reverted IOMA. These mice developed CD4bs epitope-specific responses with heterologous neutralization, and cloned antibodies overcame neutralization roadblocks, including accommodating the N276gp120 glycan, with some neutralizing selected HIV-1 strains more potently than IOMA. The immunization regimen also elicited CD4bs-specific responses in mice containing polyclonal antibody repertoires as well as rabbits and rhesus macaques. Thus, germline targeting of IOMA-class antibody precursors represents a potential vaccine strategy to induce CD4bs bNAbs.

Diversity of procedures for the enforcement of judicial acts covered by budgetary immunity

This article examines the applicability of the budgetary immunity regime to legal procedures for the judicial acts execution. While the title of the regime refers only to its applicability to the funds of budgets, amendments to the legislation have resulted in the inclusion of the funds of participants in treasury support in the text of the article itself. Over the years, the budgetary legislation has also introduced a procedure for the enforcement of funds recorded in the personal accounts of autonomous and budgetary institutions, which is similar to the procedure for the enforcement under the budgetary immunity. However, there is doubt as to whether these procedures are homogeneous and whether they can be referred to the same regime. This article represents the first study in the doctrine of budget law on the modification of the budget immunity caused by its extension to the funds of participants in treasury support. The author concludes that the application of a single regime of budgetary immunity to all of the above-mentioned relations is unjustified, thus several independent legal regimes are needed. The peculiarities of the legal status of participants in treasury support and autonomous and budgetary institutions and the funds provided to them from the budget cannot be taken into account by unified rules. However, the author notes the absence of legislative changes concerning the name of the immunity regime for budgets while changing its content suggests the desire of the public entity to preserve the immunity regime for budgets as the only one.

Low protease activity in B cell follicles promotes retention of intact antigens after immunization.

The structural integrity of vaccine antigens is critical to the generation of protective antibody responses, but the impact of protease activity on vaccination in vivo is poorly understood. We characterized protease activity in lymph nodes and found that antigens were rapidly degraded in the subcapsular sinus, paracortex, and interfollicular regions, whereas low protease activity and antigen degradation rates were detected in the vicinity of follicular dendritic cells (FDCs). Correlated with these findings, immunization regimens designed to target antigen to FDCs led to germinal centers dominantly targeting intact antigen, whereas traditional immunizations led to much weaker responses that equally targeted the intact immunogen and antigen breakdown products. Thus, spatially compartmentalized antigen proteolysis affects humoral immunity and can be exploited.

Enhancing the protection of influenza virus vaccines with BECC TLR4 adjuvant in aged mice

Influenza A virus (IAV) is a leading cause of respiratory disease worldwide often resulting in severe morbidity and mortality. We have previously shown that the Bacterial Enzymatic Combinatorial Chemistry (BECC) adjuvants, BECC438 and BECC470, formulated with an influenza virus hemagglutinin (HA) protein vaccine, offer greater protection from influenza virus challenge in mouse respiratory models using adult mice than standard HA:adjuvant combinations. In this study, we determined that immunization with HA + BECC adjuvants also significantly broadened the epitopes targeted on HA as compared with other adjuvants, resulting in increased titers of antibodies directed against the highly conserved HA stalk domain. Importantly, we demonstrate that BECC470 combined with an influenza virus HA protein antigen in a prime-only immunization regimen was able to achieve complete protection from challenge in a ~ 12-month-old mouse aged model. Together, this demonstrates the heightened protection provided by the BECC470 adjuvant in an influenza virus vaccine model and shows the enhanced immune response, as compared to other adjuvants elicited by the formulation of HA with BECC470.

B cell analyses after SARS-CoV-2 mRNA third vaccination reveals a hybrid immunity like antibody response

The continuous evolution of SARS-CoV-2 generated highly mutated variants able to escape natural and vaccine-induced primary immunity. The administration of a third mRNA vaccine dose induces a secondary response with increased protection. Here we investigate the longitudinal evolution of the neutralizing antibody response in four donors after three mRNA doses at single-cell level. We sorted 4100 spike protein specific memory B cells identifying 350 neutralizing antibodies. The third dose increases the antibody neutralization potency and breadth against all SARS-CoV-2 variants as observed with hybrid immunity. However, the B cell repertoire generating this response is different. The increases of neutralizing antibody responses is largely due to the expansion of B cell germlines poorly represented after two doses, and the reduction of germlines predominant after primary immunization. Our data show that different immunization regimens induce specific molecular signatures which should be considered while designing new vaccines and immunization strategies.

Safety and efficacy of the two doses conjugated protein-based SOBERANA-02 COVID-19 vaccine and of a heterologous three-dose combination with SOBERANA-Plus: a double-blind, randomised, placebo-controlled phase 3 clinical trial

SOBERANA-02 is a COVID-19 conjugate vaccine (recombinant RBD conjugated to tetanus toxoid). Phases 1/2 clinical trials demonstrated high immunogenicity, promoting neutralising IgG and specific T-cell response. A third heterologous dose of SOBERANA-Plus (RBD-dimer) further increased neutralising antibodies. The aim of this study is to evaluate the safety and efficacy of two immunisation regimes: two doses of SOBERANA-02 and a heterologous three-dose combination with SOBERANA-Plus added to it. From March 8th to June 24th, 2021 we conducted in Havana, Cuba a multicentre randomised, double-blind, placebo-controlled, phase-3 trial evaluating a two doses SOBERANA-02 scheme and a heterologous scheme with one dose SOBERANA-Plus added to it (RPCEC00000354). Participants 19-80 years were randomly assigned to receiving 28 days apart either the two or three dose scheme or placebo. The main endpoint was vaccine efficacy in preventing the occurrence of RT-PCR confirmed symptomatic COVID-19 at least 14 days after the second or third dose in the per-protocol population. We also assessed efficacy against severe disease and, in all participants receiving at least one vaccine/placebo dose, safety for 28 days after each dose. We included 44,031 participants (52.0% female, 48.0% male; median age 50 years, range 19-80 years; 7.0% black, 24.0% mixed-race, 59.0% white) in a context of initial Beta VOC predominance, with this variant being partially replaced by Delta near the trial's end. Vaccine efficacy in the heterologous combination was 92.0% (95%CI 80.4-96.7) against symptomatic disease. There were no severe COVID-19 cases in the vaccine group against 6 in the placebo group. Two doses of SOBERANA-02 was 69.7% (95%CI 56.5-78.9) and 74.9% (95%CI 33.7-90.5) efficacious against symptomatic and severe COVID-19, respectively. The occurrence of serious and severe adverse events (AE) was very rare and equally distributed between placebo and vaccine groups. Solicited AEs were slightly more frequent in the vaccine group but predominantly local and mostly mild and transient. Our results indicate that the straightforward to manufacture SOBERANA vaccines are efficacious in a context of Beta and Delta VOC circulation, have a favourable safety profile, and may represent an attractive option for use in COVID-19 vaccination programmes. This study received funds from the National Fund for Science and Technology (FONCI-CITMA-Cuba, contract 2020-20) of the Ministry of Science, Technology and Environment of Cuba.

Regulating Digital Platforms: Will the DSA Correct Its Predecessor’s Deficiencies?

The E-Commerce Directive 2000/31 (ECD) has been the law applicable to Internet intermediaries related to their liability for third-party content on their platform, electronic contracts, and e-commerce activities for more than twenty years. Its core is the harmonised immunity regime established in Articles 12–15. These rules grant immunity to the providers of mere conduit, caching, and hosting from liability arising from infringing content made available by their users on their platform. However, the ECD has been criticised for not fully achieving its objective of uniformity, not keeping up with the pace of the Internet, and not effectively protecting the parties’ fundamental rights as it gives crucial discretion to the intermediaries. The ECD is to be replaced with the Digital Services Act (DSA). The aim is to regulate new means of digital services (especially Big Tech) while benefiting from their ‘technical and operational ability to act against specific items of illegal content’ in preventing the availability of illegal content and protecting fundamental rights. Its framework is based on the prevailing idea of acknowledging digital platforms as responsible actors. It establishes new sets of tiered due-diligence obligations for digital platforms to comply with while reproducing the immunity regime of the ECD. Its framework appears to target those issues arising from the ECD. However, whether it can deliver this promise calls for discussion. This paper aims to address this question. To do so, it will first try to identify the deficits of the ECD. Second, and more importantly, it will seek to scrutinise the DSA to evaluate if it provides the answers to the issues that the ECD fell short of. Keywords: digital platforms, liability, immunity regime, E-Commerce Directive, Digital Services Act. DOI: https://doi.org/10.3935/cyelp.18.2022.485 This work is licensed under the Creative Commons Attribution − Non-Commercial − No Derivatives 4.0 International License. Suggested citation: B Genç-Gelgeç, ‘Regulating Digital Platforms: Will the DSA Correct Its Predecessor’s Deficiencies?’ (2022) 18 CYELP 25.

Iron Acquisition Proteins of Pseudomonas aeruginosa as Potential Vaccine Targets: In Silico Analysis and In Vivo Evaluation of Protective Efficacy of the Hemophore HasAp.

Pseudomonas aeruginosa (PA) is a Gram-negative pathogen responsible for fatal nosocomial infections worldwide. Iron is essential for Gram-negative bacteria to establish an infection. Therefore, iron acquisition proteins (IAPs) of bacteria are attractive vaccine targets. A "Reverse Vaccinology" approach was employed in the current study. Expression levels of 37 IAPs in various types of PA infections were analyzed in seven previously published studies. The IAP vaccine candidate was selected based on multiple criteria, including a high level of expression, high antigenicity, solubility, and conservation among PA strains, utilizing suitable bioinformatics analysis tools. The selected IAP candidate was recombinantly expressed in Escherichia coli and purified using metal affinity chromatography. It was further evaluated in vivo for protection efficacy. The novel immune adjuvant, naloxone (NAL), was used. HasAp antigen met all the in silico selection criteria, being highly antigenic, soluble, and conserved. In addition, it was the most highly expressed IAP in terms of average fold change compared to control. Although HasAp did excel in the in silico evaluation, subcutaneous immunization with recombinant HasAp alone or recombinant HasAp plus NAL (HasAP-NAL) did not provide the expected protection compared to controls. Immunized mice showed a low IgG2a/IgG1 ratio, indicating a T-helper type 2 (Th2)-oriented immune response that is suboptimal for protection against PA infections. Surprisingly, the bacterial count in livers of both NAL- and HasAp-NAL-immunized mice was significantly lower than the count in the HasAp and saline groups. The same trend was observed in kidneys and lungs obtained from these groups, although the difference was not significant. Such protection could be attributed to the enhancement of innate immunity by NAL. We provided a detailed in silico analysis of IAPs of PA followed by in vivo evaluation of the best IAP, HasAp. Despite the promising in silico results, HasAp did not provide the anticipated vaccine efficacy. HasAp should be further evaluated as a vaccine candidate through varying the immunization regimens, models of infection, and immunoadjuvants. Combination with other IAPs might also improve vaccination efficacy. We also shed light on several highly expressed promising IAPs whose efficacy as vaccine candidates is worthy of further investigation.