Vaccines, Volume 10, Issue 5 (May 2022) – 196 articles

Vaccination rates for human papillomavirus (HPV) in Japan are significantly lower than other countries, and Japanese people are reluctant to be vaccinated. Repeated daily reports of COVID-19 infections and restrictions have made people more health conscious and aware of the danger of infectious diseases. In this study, we used the health belief model (HBM) to examine perceived threats of cancer and infectious diseases and to ascertain whether the new COVID-19 vaccination in addition to these perceived threats would increase vaccination intention against cervical cancer. We conducted a cluster analysis to classify the segmentation regarding the perceived threat, and a logistic regression analysis to predict factors influencing people accepting vaccination. We received 1257 completed surveys during our research. We classified the participants into six clusters, and the logistic regression analysis indicated eight factors significantly associated with the willingness to get the HPV vaccine: reliable information sources such as doctors and social networking sites (SNS), the recognition of COVID-19 symptoms, the awareness of COVID-19 vaccination, the importance of HPV prevention through vaccination, one’s own intention of COVID-19 vaccination, their intention of COVID-19 vaccination toward children, and benefits of HPV vaccination. Further research on HPV and COVID-19 vaccination is encouraged. Full article

Hypersensitivity to a contact allergen is one of the most abundant forms of inflammatory skin disease. Today, more than 20% of the general population are sensitized to one or more contact allergens, making this disease an important healthcare issue, as re-exposure to the allergen can initiate the clinical disease termed allergic contact dermatitis (ACD). The current standard treatment using corticosteroids is effective, but it has side effects when used for longer periods. Therefore, there is a need for new alternative therapies for severe ACD. In this study, we used the versatile Tag/Catcher AP205 capsid virus-like particle (cVLP) vaccine platform to develop an IL-1β-targeted vaccine and to assess the immunogenicity and in vivo efficacy of the vaccine in a translational mouse model of ACD. We show that vaccination with cVLPs displaying full-length murine IL-1β elicits high titers of neutralizing antibodies, leading to a significant reduction in local IL-1β levels as well as clinical symptoms induced by treatment with 1-Fluoro-2,4-dinitrobenzene (DNFB). Moreover, we show that a single amino acid mutation in muIL-1β reduces the biological activity while maintaining the ability to induce neutralizing antibodies. Collectively, the data suggest that a cVLP-based vaccine displaying full-length IL-1β represents a promising vaccine candidate for use as an alternative treatment modality against severe ACD. Full article

The bacillus Calmette–Guérin (BCG) is an attenuated Mycobacterium bovis derivative that has been widely used as a live vaccine against tuberculosis for a century. In addition to its use as a tuberculosis vaccine, BCG has also been found to have utility in the prevention or treatment of unrelated diseases, including cancer. However, the protective and therapeutic efficacy of BCG against tuberculosis and other diseases is not perfect. For three decades, it has been possible to genetically modify BCG in an attempt to improve its efficacy. Various immune-modulatory molecules have been produced in recombinant BCG strains and tested for protection against tuberculosis or treatment of several cancers or inflammatory diseases. These molecules include cytokines, bacterial toxins or toxin fragments, as well as other protein and non-protein immune-modulatory molecules. The deletion of genes responsible for the immune-suppressive properties of BCG has also been explored for their effect on BCG-induced innate and adaptive immune responses. Most studies limited their investigations to the description of T cell immune responses that were modified by the genetic modifications of BCG. Some studies also reported improved protection by recombinant BCG against tuberculosis or enhanced therapeutic efficacy against various cancer forms or allergies. However, so far, these investigations have been limited to mouse models, and the prophylactic or therapeutic potential of recombinant BCG strains has not yet been illustrated in other species, including humans, with the exception of a genetically modified BCG strain that is now in late-stage clinical development as a vaccine against tuberculosis. In this review, we provide an overview of the different molecular engineering strategies adopted over the last three decades in order to enhance the immune-modulatory potential of BCG. Full article

In 2014–2015, we conducted a randomized controlled trial (RCT) assessing the effect of an advertising campaign for influenza vaccination using posters and pamphlets in general practitioner (GP) waiting rooms. No effect of the intervention could be demonstrated, but the immunization uptake increased in both arms of the study. In 2019, we deepened the investigations explaining the increased uptake conducting a registry-based 4/2/1 cluster RCT designed by Zelen with two extra years of follow-up of the study cohort. The study population included 23,024 patients eligible to be vaccinated who were registered with 175 GPs. The main outcome remained the number of vaccination units delivered per study group. Data were extracted from the SNIIRAM warehouse claim database for the Lille-Douai district (northern France). No difference in vaccination uptake was found in the Zelen versus the control group of the initial RCT. Overall, the proportion of vaccinated patients increased in the cohort from 51.4% to 70.4% over the three years. Being vaccinated the previous year was a strong predictor of being vaccinated in a subsequent year. The increase in vaccination uptake, especially among people older than 65, can be explained by a cohort effect. Health promotion and the promotion of primary health care may play an important role in this increase. Full article

Tuberculosis (TB), caused by the human pathogen Mycobacterium tuberculosis (Mtb), is an infectious disease that presents a major threat to human health. Bacillus Calmette-Guérin (BCG), the only licensed TB vaccine, is ineffective against latent TB infection, necessitating the development of further TB drugs or therapeutic vaccines. Herein, we evaluated the therapeutic effect of a novel subunit vaccine AEC/BC02 after chemotherapy in a spontaneous Mtb relapse model. Immunotherapy followed 4 weeks of treatment with isoniazid and rifapentine, and bacterial loads in organs, pathological changes, and adaptive immune characteristics were investigated. The results showed slowly increased bacterial loads in the spleen and lungs of mice inoculated with AEC/BC02 with significantly lower loads than those of the control groups. Pathological scores for the liver, spleen, and lungs decreased accordingly. Moreover, AEC/BC02 induced antigen-specific IFN-γ-secreting or IL-2-secreting cellular immune responses, which decreased with the number of immunizations and times. Obvious Ag85b- and EC-specific IgG were observed in mice following the treatment with AEC/BC02, indicating a significant Th1-biased response. Taken together, these data suggest that AEC/BC02 immunotherapy post-chemotherapy may shorten future TB treatment. Full article

Background. The high prevalence of HPV infection among Kazakhstani women and the absence of an HPV vaccination program are directly reflected in increasing rates of cervical cancer incidence and mortality. Kazakhstan made its first attempt at introducing the HPV vaccine in 2013, but was unsuccessful due to complications and low public acceptance. The attitudes of Kazakhstani women towards the vaccine were never measured. Therefore, this study aims to investigate the attitudes of women towards the HPV vaccine and determine factors associated with positive, negative, or neutral attitudes. Methods. A 29-item survey consisting of 21 demographic and contextual questions and 8 Likert-scale questions was distributed among women attending gynecological offices in four major cities of Kazakhstan from December 2021 until February 2022. Attitudes of women were measured based on their answers to the eight Likert-scale questions. Ordinal logistic regression was built to find associations between demographic characteristics and attitudes of women. Results. Two hundred thirty-three women were included in the final analysis. A total of 54% of women had positive attitudes towards the vaccine. The majority of women did not trust or had a neutral attitude towards the government, pharmaceutical industry, and traditional and alternative media. However, the trust of women was high in medical workers and scientific researchers. Women’s age, education, number of children, effect of the 2013 HPV program, and trust in alternative medicine were included in the ordinal logistic model. Women with a low level of education, a high number of children, who believe in alternative medicine, and who were affected by the failed 2013 vaccination program were less likely to have a positive attitude towards the vaccine. Conclusions. Contrary attitudes towards HPV vaccination exist among Kazakhstani women, with approximately half having positive and almost half having negative or neutral attitudes towards the vaccine. An informational campaign that takes into consideration women’s levels of trust in different agencies, as well as targets those who are the most uninformed, might help in a successful relaunch of the HPV vaccination program. However, more studies that cover a higher number of women are required. Full article

A 30-year-old male diagnosed three years previously with reversible cerebral vasoconstriction syndrome (RCVS) presented to the department of neurology with an accumulation of attacks mimicking previous RCVS attacks and fulfilling the diagnostic criteria for RCVS after receiving the first Pfizer COVID-19 vaccine. The neurologic exam, blood samples, electrocardiogram (ECG), and computer tomography of the head (CTC) were normal. The patient was treated with the angiotensin 2 receptor antagonist, losartan, with a good response and was discharged with a prescription for losartan lasting until three days after the second Pfizer COVID-19 vaccine. No further RCVS attacks were reported. These findings indicate that the COVID-19 vaccine might induce RCVS attacks in susceptible individuals, and targeting the angiotensin 2 receptor could be a preventive option. Full article

Vaccines against COVID-19 approved for use in the EU/EEA have been shown to be highly effective against wild-type SARS-CoV-2. However, their effectiveness against new variants may be reduced. This study aims to evaluate the effectiveness of vaccines against COVID-19 in the prevention of symptomatic and severe disease, during pre- and post-omicron phases. Individuals who sought treatment at the emergency department of a Portuguese hospital with COVID-19-like disease and were tested for SARS-CoV-2 are the subjects of the study. Patients who received a positive result are considered cases, while those with negative results are the controls. The test-negative case–control method is one of the study designs recommended by WHO to estimate the effectiveness of vaccines against COVID-19. The main advantage of this design is that it controls for the healthcare seeking bias, commonly present in traditional cohort and case–control designs. This study may have broad implications for understanding the real-world performance of the COVID-19 vaccines at the local level, which may play a key role in promoting adherence to vaccination. Moreover, this study may contribute to inform decisions regarding booster doses and variant-specific vaccine formulations leading to the control of this and future pandemics. Full article

An out-of-season H3N2 type A influenza epidemic occurred in the State of Rio de Janeiro, Brazil during October–November 2021, in between the Delta and Omicron SARS-CoV-2 surges, which occurred in July–October 2021 and January–April 2022, respectively. We assessed the contribution of climate change and influenza immunization coverage in this unique, little publicized phenomenon. State weather patterns during the influenza epidemic were significantly different from the five preceding years, matching typical winter temperatures, associated with the out-of-season influenza. We also found a mismatch between influenza vaccine strains used in the winter of 2021 (trivalent vaccine with two type A strains (Victoria/2570/2019 H1N1, Hong Kong/2671/2019 H3N2) and one type B strain (Washington/02/2019, wild type) and the circulating influenza strain responsible for the epidemic (H3N2 Darwin type A influenza strain). In addition, in 2021, there was poor influenza vaccine coverage with only 56% of the population over 6 months old immunized. Amid the COVID-19 pandemic, we should be prepared for out-of-season outbreaks of other respiratory viruses in periods of COVID-19 remission, which underscore novel disease dynamics in the pandemic era. The availability of year-round influenza vaccines could help avoid unnecessary morbidity and mortality given that antibodies rapidly wane. Moreover, this would enable unimmunized individuals to have additional opportunities to vaccinate during out-of-season outbreaks. Full article

The focus of coronavirus disease 2019 (COVID-19) vaccination campaigns has been the adult population, particularly the elderly and those with chronic diseases. However, COVID-19 can also affect children and adolescents. Furthermore, targeting this population can accelerate the attainment of herd immunity. The aim of the current study was to evaluate parental intentions to vaccinate their children and the variables associated with them. An online questionnaire was circulated via generic Iraqi Facebook groups to explore parental intentions regarding the vaccination of their children. Multinomial regression analysis was conducted to evaluate variables associated with parental vaccination acceptance. A total of 491 participants completed the study questionnaire. Only 38.3% of the participants were willing to vaccinate their children against COVID-19, while the rest either refused to vaccinate their children (35.6%) or were unsure whether they would (26.1%). Participants’ perceptions about the effectiveness (OR = 0.726, 95% CI = 0.541–0.975, p = 0.033) and safety (OR = 0.435, 95% CI = 0.330–0.574, p < 0.0001) of COVID-19 vaccines were significantly associated with parental acceptance of having children vaccinated. Participants who had received or who were planning to receive the COVID-19 vaccine were significantly less likely to reject vaccinating their children (OR = 0.156, 95% CI = 0.063–0.387, p < 0.0001). There is high refusal/hesitancy among Iraqi parents to vaccinate their children, which is associated with concerns related to the safety and efficacy of COVID-19 vaccines. More efforts, including educational and awareness campaigns to promote the safety and efficacy of COVID-19 vaccines, should be made to increase parental acceptance of childhood COVID-19 vaccinations in Iraq. Full article

Vaccinations are one of the most important preventive tools against infectious diseases. Over time, many different types of vaccines have been developed concerning the antigen component. Adjuvants are essential elements that increase the efficacy of vaccination practises through many different actions, especially acting as carriers, depots, and stimulators of immune responses. For many years, few adjuvants have been included in vaccines, with aluminium salts being the most commonly used adjuvant. However, recent research has focused its attention on many different new compounds with effective adjuvant properties and improved safety. Modern technologies such as nanotechnologies and molecular biology have forcefully entered the production processes of both antigen and adjuvant components, thereby improving vaccine efficacy. Microparticles, emulsions, and immune stimulators are currently in the spotlight for their huge potential in vaccine production. Although studies have reported some potential side effects of vaccine adjuvants such as the recently recognised ASIA syndrome, the huge worth of vaccines remains unquestionable. Indeed, the recent COVID-19 pandemic has highlighted the importance of vaccines, especially in regard to managing future potential pandemics. In this field, research into adjuvants could play a leading role in the production of increasingly effective vaccines. Full article

Objective: to identify factors associated with COVID19 vaccine hesitancy, including sources of information among residents of Maine. Methods: 148 study participants, recruited through community partners and primary care offices in Maine, completed an anonymous 15 item online survey. Recruitment and data collection occurred from May to September, 2021. Hesitancy was determined through a single question, “Will you get one of the COVID vaccines when it is offered to you?” Results: vaccine hesitant respondents were younger than not hesitant respondents (p = 0.01). Hesitant individuals were significantly more likely to report concerns regarding the speed of COVID-19 vaccine production, vaccine efficacy, and potential vaccine side effects (p < 0.05 for each). Hesitant individuals were also significantly more likely to have discussed vaccination with their primary physician (p = 0.04). Conclusions: overall, hesitant individuals are more likely to be younger and had less trust in information from government sources, but they sought input from primary care. They were also more concerned about efficacy, side effects, and the rapid development of COVID-19 vaccines. Primary care physicians are in key positions to address these concerns due to contact with individuals who need accurate information. Full article

The new Omicron variant of SARS-CoV-2, first identified in November 2021, is rapidly spreading all around the world. Omicron has become the dominant variant of SARS-CoV-2. There are many ongoing studies evaluating the effectiveness of existing vaccines. Studies on the neutralizing activity of vaccinated sera against the Omicron variant are currently being carried out in many laboratories. In this study, we have shown the neutralizing activity of sera against the SARS-CoV-2 Omicron variant compared to the reference Wuhan D614G variant in individuals vaccinated with two doses of Sputnik V up to 6 months after vaccination and in individuals who experienced SARS-CoV-2 infection either before or after vaccination. As a control to our study we also measured neutralizing antibody titers in individuals vaccinated with two doses of BNT162b2. The decrease in NtAb titers to the Omicron variant was 8.1-fold for the group of Sputnik V-vaccinated individuals. When the samples were stratified for the time period after vaccination, a 7.6-fold or 8.8-fold decrease in NtAb titers was noticed after up to 3 and 3-to-6 months after vaccination. We observed a 6.7- and 5-fold decrease in Sputnik V-vaccinated individuals experiencing asymptomatic or symptomatic infection, respectively. These results highlight the observation that the decrease in NtAb to the SARS-CoV-2 Omicron variant compared to the Wuhan variant occurs for different COVID-19 vaccines in use, with some showing no neutralization at all, confirming the necessity of a third booster vaccination. Full article

Prophylactic vaccination against infectious diseases is one of the most successful public health measures of our lifetime. More recently, therapeutic vaccination against established diseases such as cancer has proven to be more challenging. In the host, cancer cells evade immunologic regulation by multiple means, including altering the antigens expressed on their cell surface or recruiting inflammatory cells that repress immune surveillance. Nevertheless, recent clinical data suggest that two classes of antigens show efficacy for the development of anticancer vaccines: tumor-associated antigens and neoantigens. In addition, many different vaccines derived from antigens based on cellular, peptide/protein, and genomic components are in development to establish their efficacy in cancer therapy. Some vaccines have shown promising results, which may lead to favorable outcomes when combined with standard therapeutic approaches. This review provides an overview of the innate and adaptive immune systems, their interactions with cancer cells, and the development of various different vaccines for use in anticancer therapeutics. Full article

Background: Human papillomavirus (HPV) is epidemic among young people, especially those at highest risk of acquiring HPV-related cancers. Methods: Youth aged 14–24 years old (N = 1628) were recruited from 13 clinics, community agencies, and social media sites in Los Angeles, California, and New Orleans, Louisiana, that specialized in serving sexual and gender minority youths (SGMY), especially males at risk for HIV. A cross-sectional comparison of sociodemographic and risk histories of HPV vaccinated/unvaccinated youths was conducted using both univariate and multivariate regressions. Results: About half (51.9%) of youth were vaccinated, with similar percentages across states and across genders. Sexual and gender minority youths (SGMY, i.e., gay, bisexual, transgender, and non-heterosexual; 68.8%) and their heterosexual peers (15%) were equally likely to be vaccinated (54%), even though their risk for HPV-related cancers is very different. Vaccinations were higher among younger youth, those not using condoms, youth with greater education, that possessed a primary health care provider, and youth diagnosed with HIV. Vaccinations were lower among youth that were out-of-home due to mental health inpatient hospitalization, drug treatment, homelessness, or incarceration. Conclusions: Special programs are required to target youth experiencing multiple life stressors, especially out-of-home experiences, those with less education, and without the safety net of health insurance or a provider. Full article

(1) Background: Vaccine hesitancy remains a major public health concern. The reasons behind this attitude are complex and warrant careful consideration, especially in the context of the COVID-19 era. The purpose of this study was to estimate vaccine hesitancy towards the established childhood immunization programmes in a non-random sample of Greek parents and explore possible links with important drivers of this phenomenon. (2) Methods: An online self-administered questionnaire was used from October 2020 to April 2021 to collect socio-demographic, lifestyle, and health status data and evaluate knowledge, views, and attitudes of the Greek population on COVID-19 pandemic-related issues. Parents were further asked to complete the Parent Attitudes about Childhood Vaccines (PACV) questionnaire. (3) Results: A total of 1095 parents participated in the study with a mean age of 50 years (SD 9.5 years). The hesitancy against the established childhood vaccinations was estimated at 8.9% (95% CI, 7.3–10.8%). Married status and higher education and income were negatively correlated with hesitancy, whereas positive correlations were found for stress and depressive symptoms and current smoking. Variables related to proper awareness, sound knowledge, and trust toward authorities regarding the COVID-19 pandemic were strongly associated with being less hesitant against the established childhood vaccination programmes. (4) Conclusion: The estimated parental hesitancy against the established childhood vaccination programmes is worrisome. Variables related to good awareness and knowledge of the COVID-19 pandemic were strongly associated with being less hesitant against childhood vaccinations. Since controversy surrounding COVID-19 vaccinations may decrease parents’ confidence in routine childhood vaccinations, appreciating the complex reasons behind vaccine hesitancy may inform public health policies to overcome barriers and increase vaccine acceptance. Full article

Longitudinal data comparing SARS-CoV-2 serology in individuals following infection and vaccination over 12 months are limited. This study compared the magnitude, decay, and variability in serum IgG, IgA, and neutralizing activity induced by natural infection (n = 218) or mRNA vaccination in SARS-CoV-2 naïve (n = 143) or experienced (n = 122) individuals over time using enzyme-linked immunosorbent assays and an in vitro virus neutralization assay. Serological responses were found to be highly variable after natural infection compared with vaccination but durable through 12 months. Antibody levels in vaccinated, SARS-CoV-2 naïve individuals peaked by 1 month then declined through 9 months, culminating in non-detectable SARS-CoV-2-specific serum IgA. Individuals with both infection and vaccination showed SARS-CoV-2-specific IgG and IgA levels that were more robust and slower to decline than the other groups; neutralizing activity remained highest in this group at 9 months past vaccination. These data reinforce the benefit of vaccination after SARS-CoV-2 recovery. Full article

COVID-19 vaccines have achieved a significant reduction in mortality, yet objective estimates are needed in specific settings. We aimed to determine the effectiveness of COVID-19 vaccination at a referral hospital in Lambayeque, Peru. We conducted a retrospective cohort study from February to September 2021. We included hospitalized patients with COVID-19, whose data were stored in NotiWeb, a patient data system of the Peruvian Ministry of Health. We applied a propensity score-weighting method according to baseline characteristics of patients, and estimated hazard ratios (HR) using Cox regression models. Of 1553 participants, the average age was 55 years (SD: 16.8), 907 (58%) were male, and 592 (38%) deceased at 28-day follow-up. Before hospital admission, 74 (4.8%) had been immunized with at least one vaccine dose. Effectiveness against death in vaccinated patients was 50% at 90-day follow-up (weighted HR 0.50, 95% CI 0.28–0.89). Our results support the effectiveness of COVID-19 vaccination against death and provide information after early immunization in Peru. Full article

A preventive vaccination program is in operation in Poland. There are mandatory vaccinations for Polish residents under the age of 19 years. The law provides for financial penalties for parents who refuse to vaccinate their children. The aim of this study was to describe the attitudes of Polish residents aged 15–39 years to mandatory preventive vaccination and the level of acceptance for legal and financial sanctions for refusing mandatory vaccination of children. Materials and Methods: A face-to-face questionnaire-based study of a representative sample of 1560 residents of Poland aged 15–39 years. Data was collected in the fourth quarter of 2021. Results: In the study group, 51.5% of the respondents believed that preventive vaccination should be mandatory, and parents should have the right to decide only about additional vaccinations. Multivariate analyses (logistic regression) revealed a significant association between acceptance of mandatory vaccination and the following factors: positive COVID-19 vaccination status, self-declared religiosity, and having children. Of the 1560 respondents, 25.3% declared support for legal or financial sanctions for those refusing to vaccinate their children. In this group (n = 394), the highest percentage of respondents (59.4%) supported sanctions in the form of refusal to admit an unvaccinated child to a nursery or kindergarten. Conclusions: Despite preventive (mandatory) vaccination programs having been in operation in Poland since the 1960′s, only a little over 50% of adolescent Poles and young adults accept the vaccine mandate. Only 25% of this group declare their support for sanctions for refusing mandatory vaccination of children. Full article

Respiratory syncytial virus (RSV) is an important pathogen that causes acute respiratory tract infections in children. To understand the epidemiological and clinical characteristics of RSV in children, we analyzed the RSV diagnostic testing results from the 2014–2018 surveillance of acute respiratory infections in China. Among children aged <5 years, RSV incidence during 2014–2018 was 17.3% (3449/19,898), and 89.1% of RSV-positive individuals were inpatients. Children aged < 6 months had a high proportion in RSV infected individual (n = 1234; 35.8%). The highest RSV detection rate was in winter, RSV-A and RSV-B co-circulated year-round and jointly prevailed in 2015–2016. Cough was the common symptom of RSV infection 93.2% (3216/3449). Compared with older children, those aged <6 months were more likely to show breathing difficulty or lung rale that further developed into bronchopneumonia (p < 0.001). The symptoms such as cough, running nose, and diarrhea had significant differences between the RSV-A and RSV-B groups. The rate of RSV co-detection with other viruses or bacteria was 35.4%. Those coinfected with other viruses had a significantly higher incidence of fever, whereas those coinfected with bacteria had higher incidences of breathing difficulty and severe pneumonia. Our findings highlight the need for accumulating epidemiological information for the prevention and control of RSV. Full article

Hematopoietic stem cell transplant (HSCT) recipients have a high risk of developing primary varicella-zoster virus (VZV) infection and reactivation. VZV vaccination may prevent infection and reactivation. In the current study, recipients of allogeneic HSCT (34 females, 45 males) were vaccinated with adjuvanted, recombinant zoster vaccine Shingrix™, which contains the VZV glycoprotein E. Cellular immunity against various VZV antigens was analyzed by interferon-gamma ELISpot. Peripheral blood mononuclear cells (PBMC) of recipients with versus without prior shingles (n = 36 and n = 43, respectively) showed approximately twofold higher VZV-specific responses prior to and post vaccination. After the first and second vaccination, ELISpot responses towards the glycoprotein E were significantly higher in males versus females (median of spots increment 18 versus 1 and 17 versus 4, respectively, p ≤ 0.02 each). Multivariate analysis showed that shingles and sex both impacts significantly on VZV immunity. Whereas vaccination-induced changes could hardly be detected after stimulation with a whole VZV antigen, there was a significant increase in responses towards glycoprotein E after vaccination (p < 0.005). These data indicate that vaccination with Shingrix™ augmented cellular, VZV-specific immunity in HSCT recipients. Shingles and male sex could both be identified as factors leading to increased immunity. Full article

Little is known about the longevity of antibodies after a third dose of the mRNA-based SARS-CoV-2 vaccine BNT162b2 (BioNTech/Pfizer, Mainz, Germany). Therefore, serum antibody levels were evaluated after a third dose of BNT162b2 in healthy adult healthcare workers in Germany. These antibody levels dropped significantly within a short period of 11 weeks from 4155.59 ± 2373.65 BAU/mL to 2389.10 ± 1433.90 BAU/mL, p-value < 0.001 but remained higher than after the second dose (611.92 ± 450.31 BAU/mL). To evaluate the quality of the humoral immune response, we additionally measured neutralizing antibodies, which also showed a small but significant decrease within this short period. These data underline the positive effect of a third dose of BNT162b2 concerning antibody re-induction but also shows a drop of Anti-SARS-CoV-2-IgG within a short span of time. Full article

Due to the rapid global spread of the Omicron (B.1.1.529) variant, efforts to scale up COVID-19 booster vaccination have been improved, especially in light of the increasing evidence of reduced neutralizing antibody (NT Ab) over time in vaccinated subjects. In this study, neutralizing antibody responses against the Wild-Type, Delta, and Omicron strains were evaluated among vaccinees, both infected with Omicron or uninfected, and non-vaccinated subjects infected with Omicron. The aim of the study was to compare the cross-protective humoral response to the variant strains induced by vaccination and/or Omicron infection. The results showed a significant difference in the neutralizing antibody response between the vaccinees and the Omicron-infected vaccinated subjects against the three tested strains (p < 0.001), confirming the booster effect of the Omicron infection in the vaccinees. By contrast, Omicron infection only did not enhance the antibody response to the other variants, indicating a lack of cross-protection. These results suggest the importance of updating the current formulation of the SARS-CoV-2 vaccine to protect people against the Omicron subvariants. A specific Omicron vaccine, administered as a booster for the previously adopted mRNA vaccines, may protect against a wider range of SARS-CoV-2 variants. However, it is unlikely that the Omicron vaccine alone would be able to protect non-vaccinated subjects against other circulating variants. Full article

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

Healthcare students are clinicians-in-training likely to come into contact with COVID-19 as much as other frontline healthcare professionals. It is therefore necessary to prioritize vaccinations for this group. We conducted a global systematic assessment of COVID-19 vaccine acceptance rates and related factors among healthcare students using the PubMed, Scopus, and Web of Science databases and keyword searches in March of 2022. We found 1779 articles with relevant information and 31 articles that matched our inclusion criteria. We performed a random-effects meta-analysis and quality assessment using the eight-item Joanna Briggs Institute Critical Appraisal test for cross-sectional studies. A total of 30,272 individuals from 16 countries were studied. Most of the studies were carried out in the U.S. (n = 6), China (n = 5), Poland (n = 5), India (n = 2), Italy (n = 2), and Israel (n = 2). The prevalence of the COVID-19 vaccine acceptance rate was 68.8% (95% confidence interval [CI]: 60.8–76.3, I² = 100%), and the prevalence of the vaccine hesitancy rate was 25.8% (95% CI: 18.5–33.8, I² = 99%). In country-specific analyses, Romania showed the highest acceptance rate (88.0%, 95% CI: 44.5–100%), while Iraq showed the lowest acceptance rate (66.2%, 95% CI: 35.5–90.8%). In time-trend analyses, we found that acceptance rates among healthcare students decreased over time. Students concerned about potentially serious side effects of the vaccine were less willing to accept the vaccine. National and international interventions should be adopted to reduce COVID-19 vaccination hesitancy rates among these important frontline workers. Full article

Despite the use of vaccines, seasonal influenza remains a risk to public health. We previously proposed the inactivated whole virus particle vaccine (WPV) as an alternative to the widely used split vaccine (SV) for the control of seasonal and pandemic influenza based on the superior priming potency of WPV to that of SV. In this study, we further examined and compared the immunological potency of monovalent WPV and SV of A/California/7/2009 (X-179A) (H1N1) pdm09 (CA/09) to generate immune responses against heterologous viruses, A/Singapore/GP1908/2015 (IVR-180) (H1N1) pdm09 (SG/15), and A/duck/Hokkaido/Vac-3/2007 (H5N1) (DH/07) in mice. Following challenge with a lethal dose of heterologous SG/15, lower virus titer in the lungs and milder weight loss were observed in WPV-vaccinated mice than in SV-vaccinated ones. To investigate the factors responsible for the differences in the protective effect against SG/15, the sera of vaccinated mice were analyzed by hemagglutination-inhibition (HI) and neuraminidase-inhibition (NI) assays to evaluate the antibodies induced against viral hemagglutinin (HA) and neuraminidase (NA), respectively. While the two vaccines induced similar levels of HI antibodies against SG/15 after the second vaccination, only WPV-vaccinated mice induced significantly higher titers of NI antibodies against the strain. Furthermore, given the significant elevation of NI antibody titers against DH/07, an H5N1 avian influenza virus, WPV was also demonstrated to induce NA-inhibiting antibodies that recognize NA of divergent strains. This could be explained by the higher conservation of epitopes of NA among strains than for HA. Taking these findings together, NA-specific antibodies induced by WPV may have contributed to better protection from infection with heterologous influenza virus SG/15, compared with SV. The present results indicate that WPV is an effective vaccine for inducing antibodies against both HA and NA of heterologous viruses and may be a useful vaccine to conquer vaccine strain mismatch. Full article

Background: Protozoa of the genus Leishmania are characterized by their capacity to target macrophages and Dendritic Cells (DCs). These microorganisms could thus be exploited for the delivery of antigens to immune cells. Leishmania tarentolae is regarded as a non-pathogenic species; it was previously used as a biofactory for protein production and has been considered as a candidate vaccine or as an antigen delivery platform. However, results on the type of immune polarization determined by L. tarentolae are still inconclusive. Methods: DCs were derived from human monocytes and exposed to live L. tarentolae, using both the non-engineered P10 strain, and the same strain engineered for expression of the spike protein from SARS-CoV-2. We then determined: (i) parasite internalization in the DCs; and (ii) the capacity of the assayed strains to activate DCs and the type of immune polarization. Results: Protozoan parasites from both strains were effectively engulfed by DCs, which displayed a full pattern of maturation, in terms of MHC class II and costimulatory molecule expression. In addition, after parasite infection, a limited release of Th1 cytokines was observed. Conclusions: Our results indicate that L. tarentolae could be used as a vehicle for antigen delivery to DCs and to induce the maturation of these cells. The limited cytokine release suggests L. tarentolae as a neutral vaccine vehicle that could be administered in association with appropriate immune-modulating molecules. Full article

Mycobacterium bovis BCG has been used for a century as the only licensed vaccine against tuberculosis. Owing to its strong adjuvant properties, BCG has also been employed as an oncological immunotherapeutic as well as a live vaccine vector against other pathogens. However, BCG vaccination has limited efficacy in protecting against adult forms of tuberculosis (TB), raises concerns about its safety in immunocompromised populations, compromises the diagnosis of TB through the tuberculin test and lacks predictability for successful antigen expression and immune responses to heterologous antigens. Together, these factors propelled the construction and evaluation of auxotrophic BCG strains. Auxotrophs of BCG have been developed from mutations in the genes required for their growth using different approaches and have shown the potential to provide a model to study M. tuberculosis, a more stable, safe, and effective alternative to BCG and a vector for the development of recombinant live vaccines, especially against HIV infection. In this review, we provide an overview of the strategies for developing and using the auxotrophic BCG strains in different scenarios. Full article

The purpose of this study was to evaluate the efficacy and safety of the Moderna-1273 mRNA vaccine for SARS-CoV-2 in patients with immune-mediated diseases under different treatments. Anti-trimeric spike protein antibodies were tested in 287 patients with rheumatic or autoimmune diseases (10% receiving mycophenolate mofetil, 15% low-dose glucocorticoids, 21% methotrexate, and 58% biologic/targeted synthetic drugs) at baseline and in 219 (76%) 4 weeks after the second Moderna-1273 mRNA vaccine dose. Family members or caretakers were enrolled as the controls. The neutralizing serum activity against SARS-CoV-2-G614, alpha, and beta variants in vitro and the cytotoxic T cell response to SARS-CoV-2 peptides were determined in a subgroup of patients and controls. Anti-SARS-CoV-2 antibody development, i.e., seroconversion, was observed in 69% of the mycophenolate-treated patients compared to 100% of both the patients taking other treatments and the controls (p < 0.0001). A dose-dependent impairment of the humoral response was observed in the mycophenolate-treated patients. A daily dose of >1 g at vaccination was a significant risk factor for non-seroconversion (ROC AUC 0.89, 95% CI 0.80–98, p < 0.0001). Moreover, in the seroconverted patients, a daily dose of >1 g of mycophenolate was associated with significantly lower anti-SARS-CoV-2 antibody titers, showing slightly reduced neutralizing serum activity but a comparable cytotoxic response compared to other immunosuppressants. In non-seroconverted patients treated with mycophenolate at a daily dose of >1 g, the cytotoxic activity elicited by viral peptides was also impaired. Mycophenolate treatment affects the Moderna-1273 mRNA vaccine immunogenicity in a dose-dependent manner, independent of rheumatological disease. Full article

Vaccination is crucial for avoiding infection-associated morbidity and mortality among immunocompromised patients. However, immunocompromised patients respond less well to vaccinations compared to healthy people, and little is known about the relative efficacy of various vaccines among different immunocompromised states. A total of 54 systematic reviews (22 COVID-19; 32 non-COVID-19) published within the last 5 years in Pubmed^® were reviewed. They demonstrated similar patterns within three seroconversion response categories: good (about >60% when compared to healthy controls), intermediate (~40–60%), and poor (about <40%). Good vaccine responses would be expected for patients with chronic kidney disease, human immunodeficiency virus infection (normal CD4 counts), immune-mediated inflammatory diseases, post-splenectomy states, and solid tumors. Intermediate vaccine responses would be expected for patients with anti-cytotoxic T-lymphocyte antigen-4 therapy, hematologic cancer, and human immunodeficiency virus infection (low CD4 counts). Poor vaccine responses would be expected for patients with B-cell-depleting agents (e.g., anti-CD20 therapy), hematopoietic stem-cell transplant, solid organ transplant, and liver cirrhosis. For all vaccine response categories, vaccination should be timed when patients are least immunosuppressed. For the intermediate and poor vaccine response categories, high-dose vaccine, revaccination when patients are less immunosuppressed, checking for seroconversion, additional booster doses, and long-acting monoclonal antibodies may be considered, supplemented by shielding measures. Full article