Vaccinia Virus Vectors Research Articles

Comparative analysis of efficacy and safety of ChAdOx1 nCov-19 and AD26.COV2.S

Vaccine technology has been going through some radical and incremental advancement over the years for its importance as the most crucial tool in the prevention and elimination of transmissive diseases. Since the outbreak of COVID-19, several vaccine platforms were being studied, developed, and entered the market. Among the platforms, vector viral vaccines attracted particular attention for the cooperation of viral vectors to deliver genetic material of the pathogens. While the mechanism has improved the flexibility of vaccine design and efficacy, the adverse events after vaccination were worth attention at the same time. Taking ChAdOx12 nCov-19 and AD26.COV2.S. as the subjects, the efficacy and safety of the two vaccine platforms were compared and analyzed. In this paper, the initial vaccine efficacy, the resistances against virus variants, and various post vaccination adverse events were looked in more detail to identify the different factors that could affect the performance of viral vector vaccines.

Construction of a recombinant vaccine expressing Nipah virus glycoprotein using the replicative and highly attenuated vaccinia virus strain LC16m8.

Nipah virus (NiV) is a highly pathogenic zoonotic virus that causes severe encephalitis and respiratory diseases and has a high mortality rate in humans (>40%). Epidemiological studies on various fruit bat species, which are natural reservoirs of the virus, have shown that NiV is widely distributed throughout Southeast Asia. Therefore, there is an urgent need to develop effective NiV vaccines. In this study, we generated recombinant vaccinia viruses expressing the NiV glycoprotein (G) or fusion (F) protein using the LC16m8 strain, and examined their antigenicity and ability to induce immunity. Neutralizing antibodies against NiV were successfully induced in hamsters inoculated with LC16m8 expressing NiV G or F, and the antibody titers were higher than those induced by other vaccinia virus vectors previously reported to prevent lethal NiV infection. These findings indicate that the LC16m8-based vaccine format has superior features as a proliferative vaccine compared with other poxvirus-based vaccines. Moreover, the data collected over the course of antibody elevation during three rounds of vaccination in hamsters provide an important basis for the clinical use of vaccinia virus-based vaccines against NiV disease. Trial Registration: NCT05398796.

Gene-based COVID-19 vaccines: Australian perspectives in a corporate and global context

Pandemic management requires societal coordination, global orchestration, respect for human rights and defence of ethical principles. Yet some approaches to the COVID-19 pandemic, driven by socioeconomic, corporate, and political interests, have undermined key pillars of ethical medical science. We explore significant mistakes that may have occurred in recent pandemic control, in order to better navigate the future. Within corporate and geopolitical infrastructure, we review the COVID-19 pandemic and novel mRNA and viral-vector DNA COVID-19 vaccines, deployed by wealthy western countries. The pandemic, together with rollouts of unconventional, gene-based vaccine technology, has provided experimental opportunity to engineer social control of entire populations. The haste and scale of development, production, and distribution of these new pharmaceuticals is unprecedented in history. Key phase III clinical trials for these products are yet to be fully completed, despite administration to billions of people. Mass vaccination of workforces has been mandated, and vaccine mandates correlate with excess mortality. Many independent data sets concur - we have experienced a pandemic of viral illness, followed by a pandemic of vaccine injury. For Australia, matters have operated the other way around. Vaccination followed later by the main viral wave. Australian excess mortality data correlates with this. Neither risk nor cost can justify these products for the vast majority of people. Lack of efficacy against infection and transmission, and the equivalent benefits of natural immunity, obviate mandatory therapeutics. With the many gene-based pharmaceuticals planned, a new era of pathology lies ahead. We should pause, reflect, and reaffirm essential freedoms, welcome the end of the COVID-19 pandemic, embrace natural immunity, and lift all mandated medical therapy.

Safety profiles of homologous and heterologous regimens containing three major types of COVID-19 vaccine among people living with HIV.

Existing data on adverse effects (AEs) of homologous and heterologous COVID-19 vaccine regimens among people living with HIV (PLHIV) are limited. A prospective cohort study was conducted among Thai PLHIV during 2021-2022. Vaccine types and AEs were collected using an online survey. Of the 398 vaccinated PLHIV, 92% had CD4 count ≥200cells/µL and 96% were virologically suppressed at enrolment; 38% received two doses and 62% received three doses of COVID-19 vaccines. Inactivated, viral vector and mRNA were the most common vaccine types received as the first, second, and booster doses, respectively. For the first and second vaccine doses, the most common AEs were fever (15% and 11%) and injection site pain (11% and 11%). The mRNA vaccine significantly caused more overall AEs, injection pain, fatigue, and rashes than the other two types. For a booster dose, viral vector vaccine significantly caused more injection site pain and headache than the other two types. The majority of AEs of the first, second and booster doses spontaneously recovered without treatment. By multivariable analysis, receipt of viral vector or mRNA vaccine and age less than 40years were independently associated with AEs of the primary series vaccines, while having AEs from the previous dose and female sex were independent factors associated with AEs of a booster vaccine. Our study suggested the safety of homologous and heterologous regimens containing the three types of COVID-19 vaccines among PLHIV and identified those who required close monitoring for vaccine AEs.

Assessment of Immune Responses to a Trivalent Pichinde Virus-Vectored Vaccine Expressing Hemagglutinin Genes from Three Co-Circulating Influenza A Virus Subtypes in Pigs.

Pichinde virus (PICV) can infect several animal species and has been developed as a safe and effective vaccine vector. Our previous study showed that pigs vaccinated with a recombinant PICV-vectored vaccine expressing the hemagglutinin (HA) gene of an H3N2 influenza A virus of swine (IAV-S) developed virus-neutralizing antibodies and were protected against infection by the homologous H3N2 strain. The objective of the current study was to evaluate the immunogenicity and protective efficacy of a trivalent PICV-vectored vaccine expressing HA antigens from the three co-circulating IAV-S subtypes: H1N1, H1N2, and H3N2. Pigs immunized with the trivalent PICV vaccine developed virus-neutralizing (VN) and hemagglutination inhibition (HI) antibodies against all three matching IAV-S. Following challenge infection with the H1N1 strain, five of the six pigs vaccinated with the trivalent vaccine had no evidence of IAV-S RNA genomes in nasal swabs and bronchoalveolar lavage fluid, while all non-vaccinated control pigs showed high number of copies of IAV-S genomic RNA in these two types of samples. Overall, our results demonstrate that the trivalent PICV-vectored vaccine elicits antibody responses against the three targeted IAV-S strains and provides protection against homologous virus challenges in pigs. Therefore, PICV exhibits the potential to be explored as a viral vector for delivering multiple vaccine antigens in swine.

Efficient delivery of the immunodominant genes of African swine fever virus by adeno-associated virus serotype 2.

Adeno-associated virus serotype 2 (AAV2) represents a promising basis for developing a virus-vector vaccine against African swine fever (ASF). This study aimed to create genetic constructs based on AAV2 to deliver the immunodominant genes of ASF virus (ASFV) and to evaluate their functionality in vitro. The efficiency and specificity of transgene expression, as well as their non-toxicity in cells of target animals, were evaluated. Bioinformatics analysis methods were used to identify the immunodominant genes of ASFV. The target genes B646L, E183L, CP204L, and CP530R were identified and subsequently cloned into the pAAV-MCS vector. Assembly of recombinant AAV2 (rAAV2) was performed by cotransfection of AAV293 cells with the following plasmids: pAAV-MCS with the gene of interest, envelope, and packaging. Quantitative polymerase chain reaction was used to determine the AAV2 titer. The functionality of the constructs was evaluated in HEK293 and SPEV cells by determining the presence of mature proteins in the cell lysate and the expression levels of messenger RNA. The specificity of the target proteins in cell lysates was confirmed by Western blotting. The proposed AAV2 assembly protocol makes it possible to achieve a concentration of mature viral particles of at least 280 billion/mL of virus-containing material. The rAAV2 could effectively transduce host SPEV cells. The expression of both cistrons was detectable during the transduction of cells; therefore, the combined expression of immunogens in the cells of target animals should be possible using this method. This study demonstrated the potential of using genetic constructs based on AAV2 for the delivery of ASFV genes in vitro.

Evaluation of Serum Anticardiolipin Antibodies and D-dimer in Recipients of COVID-19 Vaccines in Ado-Ekiti, Ekiti State, Nigeria

Coronavirus disease 2019 (COVID-19) manifests itself in a variety of ways, implying a wide range of host autoimmune responses which could lead to disseminated intravascular coagulation. This study was designed to evaluate serum anticardiolipin antibodies and D-dimer in recipients of COVID 19 vaccines in Ado-Ekiti, Ekiti State, Nigeria. The study population comprised sixteen (16) fully vaccinated subjects, fifteen (15) partially vaccinated subjects and fifteen (15) unvaccinated subjects (control). Anticardiolipin antibodies and D-dimer were analyzed using ELISA. D-dimer and anticardiolipin antibodies were significantly higher in fully and partially vaccinated subjects compared to control (p<0.05). D-dimer and anticardiolipin were insignificantly higher in fully vaccinated subjects compared to partially vaccinated subjects (p>0.05). Anticardiolipin and D-dimer were significantly higher in recipients of mRNA vaccines compared to viral vector vaccines (p<0.05). This study discovered that recipients of the COVID-19 immunization have a higher risk of developing antiphospholipid syndrome due to increased anticardiolipin. If disseminated intravascular coagulations is present and its complications are not adequately handled, this could become more serious

2358. Safety Profiles of Three Major Types of COVID-19 Vaccine among Two Cohorts of People Living with HIV

Abstract Background Existing data on adverse effects (AEs) of COVID-19 vaccines among people living with human immunodeficiency virus (PLHIV) are currently limited. Methods A cohort study was conducted among PLHIV receiving care at two clinics during COVID-19 epidemics in Thailand (2021-2022). The PLHIV received various types and regimens of COVID-19 vaccines based on vaccine availability and the national policies. Data on vaccine types and AEs were collected and assessed using the online survey system. Results Of the 398 vaccinated PLHIV, 365 (92%) had CD4 count at enrollment ≥ 200 cells/µL, 382 (96%) were virologic suppressed, 153 received two doses and 245 received three doses of COVID-19 vaccines. Inactivated and viral vector were the most common vaccine types received by the PLHIV as the first and second doses (47% and 56%, respectively), while mRNA vaccine was the most commonly used as a booster dose (57%). For the first and second vaccine doses, the most common AEs were fever (15% and 11%) and injection site pain (11% and 11%). The mRNA vaccine significantly caused more overall AEs, injection pain, fatigue, and rashes than the other two types, while the mRNA and viral vector vaccines significantly caused more fever than the inactivated vaccine. For a booster dose, viral vector vaccine significantly caused more injection site pain and headache than the other two types. Most of the PLHIV reported that the AE intensity was similar between the first and second doses (49%) and was more for a booster dose compared to the first dose (50%). The majority of all AEs of the first, second and booster doses spontaneously recovered without treatment (55%, 59%, and 59%) or required symptomatic treatment without hospitalization (44%, 40% and 40%). By multivariable analysis, receipt of viral vector or mRNA vaccine and age less than 40 years were independently associated with any AEs of the primary series vaccines, while having AEs from the previous dose and female sex were factors associated with any AEs of a booster vaccine. Conclusion The three types of COVID-19 vaccines were generally safe among PLHIV. Most of the AEs were non-severe and did not require hospitalization. PLHIV who were elderly, female or had AEs from the previous vaccine dose should be closely monitored for AEs of the vaccines. Disclosures All Authors: No reported disclosures

Analysis of the protective efficacy of approved COVID-19 vaccines against Omicron variants and the prospects for universal vaccines.

By the end of 2022, different variants of Omicron had rapidly spread worldwide, causing a significant impact on the Coronavirus disease 2019 (COVID-19) pandemic situation. Compared with previous variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), these new variants of Omicron exhibited a noticeable degree of mutation. The currently developed platforms to design COVID-19 vaccines include inactivated vaccines, mRNA vaccines, DNA vaccines, recombinant protein vaccines, virus-like particle vaccines, and viral vector vaccines. Many of these platforms have obtained approval from the US Food and Drug Administration (FDA) or the WHO. However, the Omicron variants have spread in countries where vaccination has taken place; therefore, the number of cases has rapidly increased, causing concerns about the effectiveness of these vaccines. This article first discusses the epidemiological trends of the Omicron variant and reviews the latest research progress on available vaccines. Additionally, we discuss progress in the development progress and practical significance of universal vaccines. Next, we analyze the neutralizing antibody effectiveness of approved vaccines against different variants of Omicron, heterologous vaccination, and the effectiveness of multivalent vaccines in preclinical trials. We hope that this review will provide a theoretical basis for the design, development, production, and vaccination strategies of novel coronavirus vaccines, thus helping to end the SARS-CoV-2 pandemic.

COVID-19 Post- vaccination infection among hospital attendants in Qena city

BackgroundThe duration of immunological persistence in COVID-19-vaccinated individuals is considered a matter of concern. Some studies have shown that anti-SARS-CoV-2 antibodies degrade rapidly. Due to diminishing immunity after vaccination, some people may catch an infection again after receiving the COVID-19 vaccine.ObjectivesThe purpose of the present study was to measure the COVID-19 post-vaccination infection reported by the vaccinated participants and to identify possible associated risk factors among hospital attendants in Qena city.Material and methodA cross-sectional study was carried out on 285 participants who received COVID-19 vaccines and were aged 18 years or more. A structured questionnaire was used as a tool for data collection.Results13.7% of the vaccinated participants reported catching the COVID-19 infection after vaccination. Healthcare workers were more susceptible to the COVID-19 infection after vaccination than non-healthcare workers. Post-vaccination infection among participants who received Viral vector vaccines, Inactivated vaccines, and mRNA vaccines were 16.7%, 15.7%, and 3.6%, respectively.ConclusionHealthcare professionals need to take strict preventive measures since, even after receiving the COVID-19 vaccine, they are more vulnerable to infection than non-healthcare personnel. mRNA vaccines can be given in place of viral vector vaccinations because they show a reduced incidence of post-vaccination infection.

Comparison of post-COVID-19 vaccination hypermetabolic lymphadenopathy on 18F-fluorodeoxyglucose PET/CT between virus-vector vaccine and mRNA vaccine

PurposeWe compared hypermetabolic lymphadenopathy (HLN) on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) after virus-vector and mRNA vaccines for coronavirus disease 2019 (COVID-19).MethodsThis retrospective study included 573 participants who underwent FDG PET/CT after receiving a virus-vector vaccine (ChAdOx1, AstraZeneca [AZ] group) or an mRNA vaccine (mRNA-1273, Moderna [M] group) from July 2021 to October 2021. The incidence and avidity of HLN were evaluated and correlated with clinical features and vaccine type. The final analysis was conducted with 263 participants in the AZ group and 310 participants in the M group.ResultsThe HLN incidence was significantly lower in the AZ group than in the M group (38/263 [14%] vs. 74/310 [24%], p = 0.006). The FDG avidity of HLN was comparable between the two groups. The HLN incidence in both groups was significantly higher within 4 weeks after the vaccination compared with more than 4 weeks. The HLN incidence within 4 weeks of the vaccination was significantly higher in the M group than in the AZ group (p = 0.008), whereas a difference in HLN incidence between the two groups was not observed after the same duration (p = 0.11).ConclusionsThe mRNA mRNA-1273 COVID-19 vaccine was found to be associated with higher glucose hypermetabolism in regional lymph nodes within the first 4 weeks compared with the virus-vector vaccine, as indicated by the presence of HLN on FDG PET/CT. The degree of glucose hypermetabolism was comparable between the two vaccines.

Efficacy of Fowlpox Virus Vector Vaccine Expressing VP2 and Chicken Interleukin-18 in the Protection against Infectious Bursal Disease Virus.

In mammals, the role of interleukin-18 (IL-18) in the immune response is to drive inflammatory and, normally therefore, anti-viral responses. IL-18 also shows promise as a vaccine adjuvant in mammals. Chicken IL-18 (chIL-18) has been cloned. The aim of this study was to investigate the potential of chIL-18 to act as a vaccine adjuvant in the context of a live recombinant Fowlpox virus vaccine (fpIBD1) against Infectious bursal disease virus (IBDV). fpIBD1 protects against mortality, but not against damage to the bursa of Fabricius caused by IBDV infection. The Fowlpox virus genome itself contains several candidate immunomodulatory genes, including potential IL-18 binding proteins (IL-18bp). We knocked out (Δ) the potential IL-18bp genes in fpIBD1 and inserted (::) the cDNA encoding chIL-18 into fpIBD1 in the non-essential ORF030, generating five new viral constructs -fpIBD1::chIL-18, fpIBD1ΔORF073, fpIBD1ΔORF073::chIL-18, fpIBD1ΔORF214, and fpIBD1ΔORF214::chIL-18. The subsequent protection from challenge with virulent IBDV, as measured by viral load and bursal damage, given by these altered fpIBD1 strains, was compared to that given by the original fpIBD1. Complete protection was provided following challenge with IBDV in chicken groups vaccinated with either fpIBDIΔ073::IL-18 or fpIBD1Δ214::IL-18, as no bursal damage nor IBDV was detected in the bursae of the birds. The results show that chIL-18 can act as an effective vaccine adjuvant by improving the fpIBD1 vaccine and providing complete protection against IBDV challenge.

How successful are some existing vaccinations in preventing COVID?

The COVID-19 pandemic has placed immense pressure on the global healthcare sector. The rapid development of vaccines has significantly alleviated the rampant spread of the COVID-19 virus. This research paper aims to determine the success rates of various types of vaccines in preventing COVID. It will first list the brand of the vaccine, then identify the type of vaccine, and describe how the vaccine functions in providing the body immunity from the coronavirus, and finally it will compare the vaccines’ success rates in preventing the patient from being infected with COVID. Coronavirus vaccine types include recombinant subunit vaccines, which injects a part of the virus into the body; viral vector vaccines, which gene vaccines and whole virus vaccines. This comprehensive review will assist us in gaining a deeper understanding of COVID-19 vaccines and provide a foundation for subsequent efforts to further optimize vaccine development.

Antibodies elicited by Newcastle disease virus-vectored H7N9 avian influenza vaccine are functional in activating the complement system

H7N9 subtype avian influenza virus poses a great challenge for poultry industry. Newcastle disease virus (NDV)-vectored H7N9 avian influenza vaccines (NDVvecH7N9) are effective in disease control because they are protective and allow mass administration. Of note, these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition (HI) but high IgG antibodies in chickens. However, the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear. Herein, immunization with an NDVvecH7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin (HA)-binding IgG antibodies in chickens. Three residues (S150, G151 and S152) in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDVvecH7N9 immune serum. Passively transferred NDVvecH7N9 immune serum conferred complete protection against H7N9 virus infection in chickens. The NDVvecH7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity. These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor, suggesting the engagement of the complement system. Moreover, mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDVvecH7N9 immune serum, indicating the requirement of antibody-antigen binding for complement activity. Therefore, antibodies induced by the NDVvecH7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus. Our findings unveiled a novel role of the complement in protection conferred by the NDVvecH7N9, highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.

Recent advance in the development of tuberculosis vaccines in clinical trials and virus-like particle-based vaccine candidates.

Tuberculosis (TB) remains a serious public health threat around the world. An effective vaccine is urgently required for cost-effective, long-term control of TB. However, the only licensed vaccine Bacillus Calmette-Guerin (BCG) is limited to prevent TB for its highly variable efficacy. Substantial progress has been made in research and development (R&D) of TB vaccines in the past decades, and a dozen vaccine candidates, including live attenuated mycobacterial vaccines, killed mycobacterial vaccines, adjuvanted subunit vaccines, viral vector vaccines, and messenger RNA (mRNA) vaccines were developed in clinical trials to date. Nevertheless, many challenges to the successful authorization for the use and deployment of an effective tuberculosis vaccine remain. Therefore, it is still necessary and urgent to continue exploring new vaccine construction approaches. Virus-like particles (VLPs) present excellent prospects in the field of vaccine development because of their helpful immunological features such as being safe templates without containing viral nucleic acid, repetitive surface geometry, conformational epitopes similar to natural viruses, and enhancing both innate and adaptive immune responses. The marketization process of VLP vaccines has never stopped despite VLP vaccines face several shortcomings such as their complex and slow development process and high production cost, and several VLP-based vaccines, including vaccines against Human papillomavirus (HPV), Hepatitis B Virus (HBV) and malaria, are successfully licensed for use at the market. In this review, we provide an update on the current progress regarding the development of TB vaccines in clinical trials and seek to give an overview of VLP-based TB vaccine candidates.

Reinfection rates, change in antibody titers and adverse events after COVID-19 vaccination among patients previously infected with COVID-19 in Metro Manila, Philippines: a secondary analysis of a completed cohort study

BackgroundVariation in immune response to COVID-19 vaccines is observed among different ethnicities. We aimed to describe the reinfection rates, change in antibody titers, and adverse events among Filipinos.MethodsThis is a secondary analysis of a cohort study of 307 participants within one year of having COVID-19 infection. We measured COVID-19 antibody levels at pre-determined timepoints (Days 21, 90, 180, 270, and 360 from initial infection). We monitored for COVID-19 symptoms and obtained details on COVID-19 vaccination. An adjudication committee classified the participants as probable, possible, or unlikely COVID-19 reinfection. We determined the probable reinfection rate, adverse events, and the geometric mean titer (GMT) ratio of pre- and post-vaccination antibody levels according to type and brand of COVID-19 vaccine.ResultsAt the end of the follow-up period, 287 (93.5%) out of 307 study participants were fully vaccinated, 1 was partially vaccinated (0.3%), and 19 were unvaccinated (6.2%). Among the fully vaccinated participants, those given mRNA vaccines had the lowest reinfection rate (19.2 cases/100 person-years, 95% CI 9.6, 38.4), followed by viral vector vaccines (29.8 cases/100 person-years, 95% CI 16.9, 52.4). We observed the highest reinfection rate among those given inactivated virus vaccines (32.7 cases/100 person-years, 95% CI 23.6, 45.3). The reinfection rate was 8.6 cases/100 person-years (95% CI 4.1, 17.9) for unvaccinated participants and 3.6 cases/100 person-years (95% CI 0.5, 25.3) for partially vaccinated participants. We observed the largest rise in antibody titers among those given mRNA vaccines (GMT ratio 288.5), and the smallest rise among those given inactivated virus vaccines (GMT ratio 16.7). We observed the highest percentage of adverse events following immunization with viral vector vaccines (63.8%), followed by mRNA vaccines (62.7%), and the lowest for inactivated virus vaccines (34.7%). No serious adverse events were reported.ConclusionVaccinees given the mRNA vaccines had the lowest reinfection rate and the highest rise in antibody titers. Vaccinees given inactivated virus vaccines had the highest reinfection rate, smallest rise in antibody titers, and lowest percentage of adverse events. The small sample size and imbalanced distribution of the type of vaccines received limits the external generalizability of our results.Study RegistrationThe cohort study was registered at the Philippine Health Research Registry on December 14, 2020 (PHRR201214-003199).

Effectiveness of COVID-19 vaccines against hospitalisation in Latin America during three pandemic waves, 2021–2022: a test-negative case-control design

Vaccine effectiveness (VE) is essential to monitor the performance of vaccines and generate strategic information to guide decision making. We pooled data from six Latin American countries to estimate the effectiveness of COVID-19 vaccines in preventing laboratory-confirmed SARS-CoV-2 hospitalisation during three different pandemic waves from February 2021 to September2022. We used a test-negative case-control design in hospitalised adults in Chile, Costa Rica, Ecuador, Guatemala, Paraguay, and Uruguay. We estimated adjusted VE by age group (18-64 and≥65 years), vaccine type and product for primary series vaccination and booster vaccination and by time since last dose during the Omicron variant dominant period. We used mixed effects logistic regression models adjusting for sex, age, week of onset of symptom onset and pre-existing conditions with country fit as a random effect term. We included 15,241 severe acute respiratory infection (SARI) patients in the analysis. Among adults 18-64 years, VE estimates for primary series vaccination during pre-Delta and Delta periods ranged by product from 66.5% to 95.1% and from 33.5% to 88.2% for older adults. During the Omicron period, VE estimates for primary series were lower and decreased by time since last vaccination, but VE increased to between 26.4% and 57.4% when a booster was administered. mRNA and viral vector vaccines presented higher VE for both primary series and booster. While VE decreased over time, protection against severe COVID-19-associated hospitalisation increased when booster doses were administered. Vaccination with additional doses should be recommended, particularly for persons at increased risk of developing severe COVID-19. This work was supported by a grant from the U.S. Centers for Disease Control and Prevention (CDC) through cooperative agreements with the Pan American Health Organization/World Health Organization.

Myocardial Infarction Following Vaccination Against COVID-19: A Systematic Review

Context: Several reports have been presented regarding the occurrence of acute myocardial infarction following vaccination against COVID-19. Objectives: The current systemic review tried to review and summarize the published evidence and documents regarding the occurrence of myocardial infarction following various types of anti-COVID-19 vaccines (AstraZeneca and Pfizer) and, finally, take steps to clarify the causes of such incidents. Methods: The relevant databases, including Medline, Web of Knowledge, Google Scholar, Scopus, and Cochrane, were comprehensively searched by the two blinded researchers for all eligible studies based on the considered keywords. Of 76 articles initially collected by database searching, 20 articles were included in the last analysis. Results: The occurrence of acute myocardial infarction was mostly related to SARS-CoV-2-based messenger RNA and viral vector vaccines. This cardiac attack occurred after the first vaccination in 74% of patients affected. The time of occurrence of myocardial infarction was also very different between different types of vaccines and varied between 15 minutes and 21 days after vaccination. Most of the myocardial infarctions that occurred after vaccination were of the ST-segment elevation type (STEMI) (23 of 28 patients). More than two-thirds of myocardial infarction cases occurred in patients who had significant cardiovascular risk profiles (hypertension, diabetes mellitus, and ischemic heart disease). Overall, 22.2% of cases suffering post-vaccination myocardial infarction died within hospitalization. Conclusions: The occurrence of myocardial infarction following the vaccination against COVID-19 is rare, and due to the fatality of this event, it is necessary to modify the biotechnological production of existing vaccines and to accurately evaluate the pathophysiology of this event.

A Triple Gene-Deleted Pseudorabies Virus-Vectored Subunit PCV2b and CSFV Vaccine Protect Pigs against a Virulent CSFV Challenge.

Classical swine fever (CSF) remains one of the most economically significant viral diseases affecting domestic pigs and wild boars worldwide. To develop a safe and effective vaccine against CSF, we have constructed a triple gene-deleted pseudorabies virus (PRVtmv)-vectored bivalent subunit vaccine against porcine circovirus type 2b (PCV2b) and CSFV (PRVtmv+). In this study, we determined the protective efficacy of the PRVtmv+ against virulent CSFV challenge in pigs. The results revealed that the sham-vaccinated control group pigs developed severe CSFV-specific clinical signs characterized by pyrexia and diarrhea, and became moribund on or before the seventh day post challenge (dpc). However, the PRVtmv+-vaccinated pigs survived until the day of euthanasia at 21 dpc. A few vaccinated pigs showed transient diarrhea but recovered within a day or two. One pig had a low-grade fever for a day but recovered. The sham-vaccinated control group pigs had a high level of viremia, severe lymphocytopenia, and thrombocytopenia. In contrast, the vaccinated pigs had a low-moderate degree of lymphocytopenia and thrombocytopenia on four dpc, but recovered by seven dpc. Based on the gross pathology, none of the vaccinated pigs had any CSFV-specific lesions. Therefore, our results demonstrated that the PRVtmv+ vaccinated pigs are protected against virulent CSFV challenge.

Role of digital media in vaccination promotion. Second report on VaccinarSinToscana.org experience

Abstract Background Since March 27, 2017, the Department of Health Sciences, University of Florence, has been managing and editing an online portal of medical and scientific information, focused on preventive health care and vaccinations: “VaccinarSinToscana.org” (Get vaccinated in Tuscany). The aim of this study is to analyze website's consultation activity over the past four years by single users, visits and single webpage consultation. Methods VaccinarSinToscana website activity during the study period April 01, 2019-March 31, 2023 was investigated using Google Analytics. Microsoft Excel was used for data analysis. Results During the study period 365,070 new single users visited the portal and nearly 15% of them entered more than once for about 447,000 sessions. A total of 815,800 single web pages were visited individually, with an average of 2.23 web pages consulted per visit and an average session duration of 58 seconds. The largest increase in visits occurred in January 2021-June 2021 with the highest peak in March (155,737 single web pages). The most visited pages were about the national vaccination calendar, regional vaccine clinics, and the types of anti-COVID-19 vaccines available (particularly, the viral vector vaccines). Analysis of socio-demographic characteristics showed that the users most attracted to web consultation were female (57%) and the most ‘digital’ age group was 25-34 (24%). Other age groups account for 14% (18-24 years), 22% (35-44 years), 17% (45-54 years), 13% (55-64 years), and 11% (over 64 years). Mobile phones were the most used devices to access the portal (69%), personal computers for 28% and tablets for 3%. Conclusions The analysis of web pages consultation trend showed a relevant exponential increase of visits in the period January 2021-June 2021. The greatest interest of users, in this period marked by the early stages of the national SARS-CoV-2 vaccination campaign, was for searching news regarding anti-COVID-19 vaccination. Key messages • Institutional websites with evidence-based information could be useful tools for users to increase public confidence in vaccination. • The anti-COVID-19 vaccine campaign has increased website visit, demonstrating how this period has been characterized by curiosity, doubt, and citizens’ search for more information.