Showing papers in "Expert Review of Vaccines in 2021"

Impact of the Delta variant on vaccine efficacy and response strategies.

Abstract: Introduction The Delta variant of SARS-CoV-2 has caused a new wave of the COVID-19 epidemic in many countries. It is the most infectious variant of SARS-CoV-2 to date, and its high infectivity means that a higher proportion of the population needs to be vaccinated to reduce the disease burden, which poses a substantial public health challenge. Areas covered The evolution of the Delta variant is reviewed, including an overview of the Delta Plus variant with a K417N mutation in the RBD, which may confer an improved immune evasion ability. Decreases in serum neutralizing antibody titers after vaccination against Delta were greater than those against Alpha but less than those against Beta. The protective efficacy of existing vaccines against the Delta variant have declined and is related to the number of doses and the time since vaccination. Expert opinion The currently used vaccines are effective against hospitalization/severe disease due to the Delta variant. Accelerating the popularization of vaccination, improving the coverage rate, and the implementation of intervention measures, such as wearing masks, are effective means to control the spread of the Delta variant and other variants. However, vaccination alone against SARS-CoV-2 without intervention measures may lead to continuous spread and the emergence of new variants.

Effects of SARS-CoV-2 variants on vaccine efficacy and response strategies.

Abstract: As the global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic continues to spread, several variants have emerged. Variants B.1.1.7 and B.1.351 have attracted significant atten...

COVID-19 vaccine hesitancy in South Africa: how can we maximize uptake of COVID-19 vaccines?

Abstract: Introduction: Acceptance of COVID-19 vaccines is critical to personal health, protecting vulnerable populations, reopening socio-economic life, and achieving population health and safety through immunity. The primary aim of this review was to investigate the extent and determinants of COVID-19 vaccine hesitancy in South Africa to inform the development of strategies to address it. A secondary aim was to enhance understandings of and responses to vaccine hesitancy more generally in South Africa, with potential positive effect on vaccination uptake during and beyond the COVID-19 pandemic.Areas covered: We reviewed the findings from surveys conducted in South Africa from February 2020 to March 2021 that investigated acceptance of COVID-19 vaccines. Surveys were identified through searching electronic databases of peer-reviewed and gray literature and contacting experts.Expert opinion: The review reveals the inherently social nature of COVID-19 vaccine hesitancy in South Africa, potentially influenced by age, race, education, politics, geographical location, and employment. Along with the provision of information, COVID-19 vaccine communication strategies need to form part of broader trust-building measures that focus on relationships, transparency, participation, and justice. The pandemic also provides a unique opportunity to positively intervene and reduce vaccine hesitancy trends more generally in South Africa and potentially elsewhere.

COVID-19 vaccine: where are we now and where should we go?

Abstract: The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has currently caused the pandemic with a high progressive speed, and has been considered as the global public health crisis in 2020....

To mix or not to mix? A rapid systematic review of heterologous prime-boost covid-19 vaccination.

Abstract: Coronavirus disease 2019 (COVID-19) has had an enormous impact worldwide, and vaccination is believed to be the method that will control the pandemic. Several types of vaccines developed using diff...

The emergence of new strains of SARS-CoV-2. What does it mean for COVID-19 vaccines?

Abstract: A novel strain of coronavirus, SARS-CoV-2, the causative agent of coronavirus disease (COVID-19) was first associated with severe acute respiratory disease in late 2019 and has triggered an ongoing...

DNA vaccines for SARS-CoV-2: toward third-generation vaccination era.

Abstract: INTRODUCTION: Coronavirus outbreak 2019 (COVID-19) has affected all the corners of the globe and created chaos to human life. In order to put some control on the pandemic, vaccines are urgently required that are safe, cost effective, easy to produce, and most importantly induce appropriate immune responses and protection against viral infection. DNA vaccines possess all these features and are promising candidates for providing protection against SARS-CoV-2.Area covered: Current understanding and advances in DNA vaccines toward COVID-19, especially those under various stages of clinical trials.Expert opinion: Through DNA vaccines, host cells are momentarily transformed into factories that produce proteins of the SARS-CoV-2. The host immune system detects these proteins to develop antibodies that neutralize and prevent the infection. This vaccine platform has additional benefits compared to traditional vaccination strategies like strong cellular immune response, higher safety margin, a simple production process as per cGMP norms, lack of any infectious agent, and a robust platform for large-scale production.

COVID-19 vaccines: concerns beyond protective efficacy and safety.

Abstract: Several vaccine candidates have been developed using different platforms, including nucleic acids (DNA and RNA), viral vectors (replicating and non-replicating), virus-like particles, peptide-based...

Determinants of parental hesitancy to vaccinate their children against COVID-19 in China.

Abstract: Vaccine hesitancy seriously hinders herd immunity. We explored the determinants of parental hesitancy to vaccinate children against Coronavirus Disease 2019 (COVID-19) in China.A population-based self-administered online questionnaire evaluating parental hesitancy in vaccinating their children against COVID-19 was conducted in Taizhou, China. Of the 2463 parents who received the invitation, 1788 (72.6%) responded to the survey.Of the repondents, 52.5% were hesitant. Mothers exhibited a greater proportion of vaccine hesitancy than fathers did (57.5% vs. 41.7%, P < 0.001). Multiple logistic regression analysis indicated that parents with children under 18 years of age (OR = 0.94, 95%CI: 0.90-0.99), lower knowledge scores about COVID-19 vaccination (Q1: OR = 1.92, 95%CI: 1.37-2.69; Q2: OR = 1.51, 95%CI: 1.10-2.08), lower awareness of the permission of vaccinating children (OR = 1.74, 95%CI: 1.36-2.23) and hesitancy to inoculate themselves (OR = 8.18, 95%CI: 6.48-10.33) were associated with parental hesitancy to inoculate their children. Results also revealed the disparity between fathers and mothers regarding associated factors.This study found that a substantial proportion of parents reported being hesitant to vaccinate children against COVID-19, implying the necessity of comprehensive assessment and health education programs for vaccination systems in China.

Surveying willingness toward SARS-CoV-2 vaccination of healthcare workers in Italy.

Abstract: Understanding healthcare workers (HCWs) willingness to receive a future vaccination against coronavirus disease 2019 (COVID-19) may be useful.Cross-sectional study, conducted in Italy from Septembe...

Safety of an inactivated SARS-CoV-2 vaccine among healthcare workers in China.

Abstract: Background: Although the inactivated SARS-CoV-2 vaccine (CoronaVac) has undergone preclinical tests and clinical trials evaluating its efficacy and safety, few data have been reported in the post-licensure real-world setting. We aimed to assess the safety of the vaccine among healthcare workers.Methods: A self-administered online survey on monitoring adverse reactions post vaccination was conducted among the staff who worked at and were vaccinated in a tertiary hospital in Taizhou, China, from February 24 to 7 March 2021. A total of 1526 subjects responded to the questionnaire when they received an e-mail or an e-poster on WeChat.Results: The incidences of overall adverse reactions after the first and second injections were 15.6% (238/1526) and 14.6% (204/1397), respectively. The most common adverse reaction was localized pain at the injection site, with an incidence of 9.6% and 10.7% after each dose, accounting for 61.8% and 73.0% of adverse reactions, respectively. Fatigue, muscle pain, and headache were the most common systemic adverse reactions.Conclusions: These findings implied that the inactivated CoronaVac vaccine has an acceptable safety profile among healthcare workers due to the low incidence of self-reported adverse reactions. This may boost public confidence in nationwide mass vaccination campaigns.

Inhaled vaccine delivery in the combat against respiratory viruses: a 2021 overview of recent developments and implications for COVID-19.

Abstract: Introduction: As underlined by the late 2019 outbreak of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), vaccination remains the cornerstone of global health-care. Although vaccines for SARS-CoV-2 are being developed at a record-breaking pace, the majority of those that are licensed or currently registered in clinical trials are formulated as an injectable product, requiring a tightly regulated cold-chain infrastructure, and primarily inducing systemic immune responses.Areas covered: Here, we shed light on the status of inhaled vaccines against viral pathogens, providing background to the role of the mucosal immune system and elucidating what factors determine an inhalable vaccine's efficacy. We also discuss whether the development of an inhalable powder vaccine formulation against SARS-CoV-2 could be feasible. The review was conducted using relevant studies from PubMed, Web of Science and Google Scholar.Expert opinion: We believe that the scope of vaccine research should be broadened toward inhalable dry powder formulations since dry vaccines bear several advantages. Firstly, their dry state can tremendously increase vaccine stability and shelf-life. Secondly, they can be inhaled using disposable inhalers, omitting the need for trained health-care personnel and, therefore, facilitating mass-vaccination campaigns. Thirdly, inhalable vaccines may provide improved protection since they can induce an IgA-mediated mucosal immune response.

COVID-19 vaccination in pregnant and lactating women: a systematic review.

Abstract: Introduction The concern of undergoing vaccination during pregnancy and lactation, in absence of data on safety and efficacy in these target populations, is subject of ongoing debate nationally and internationally. However, the only real prophylactic strategy against COVID-19 is still mass vaccination, which means to vaccinate infants and pregnant and lactating women. Areas covered This is a systematic review aiming to evaluate the safety and the efficacy of COVID-19 vaccines in pregnant and lactating women and their newborns. We did advanced research on PubMed and Google Scholar, and searched for any evidence also on ClinicalTrials.gov. Results refer to a timeline going until 12th June 2021. Expert opinion Our efforts must be directed to vaccine more and more population groups which have been preliminarily excluded from the vaccination campaign. Studies have not so far highlighted plausible adverse effects in vaccinated pregnant women or in their newborns. Reactogenicity across lactating and pregnant women does not seem to differ from general population. Likewise, abortion rate does not differ from non-vaccinated pregnant women studied before the COVID-19 pandemic. It also seems that a major amount of anti-SARS-CoV-2 immunoglobulins is transferred through the placenta and the breastmilk to the newborn, providing humoral immunity.

Transmission-Blocking Vaccines: Harnessing Herd Immunity for Malaria Elimination.

Abstract: Transmission-blocking vaccines (TBV) prevent community spread of malaria by targeting mosquito sexual stage parasites, a life-cycle bottleneck, and will be used in elimination programs. TBV rely on...

Social media strategies to affect vaccine acceptance: a systematic literature review.

Abstract: Introduction: Vaccine hesitancy, defined as a delay in the acceptance or the refusal of vaccines despite their availability, is a growing global threat. More individuals are turning to social media for health information, including vaccine information. As such, there is an opportunity to leverage online platforms as a means to disseminate and persuade individuals toward vaccine acceptance. We sought to review literature focused on the influence of exposure to social media content on vaccine acceptance or hesitancy.Areas covered: This review focused on social networking sites (e.g. Facebook) and content communities (e.g. YouTube), to understand how exposure to vaccine information affected vaccine knowledge, attitudes, and intentions/behaviors. We searched PubMed, CINAHL, Scopus, and Inspec. We included English-language materials published from 2004 to 2020 and included interventional studies, observational studies, and impacts of policies. We excluded systematic reviews, protocols, editorials, letters, case reports, case studies, commentaries, opinion pieces, narrative reviews, and clinical guidelines.Expert opinion: Social media interventions to affect vaccine acceptance is a new but growing area of study. How a communication message is framed, who delivers the message, and network structure are critical for affecting the vaccine decision-making process. Social media should be leveraged to impact vaccine uptake.

Nanovaccine: an emerging strategy

Abstract: Vaccination is so far the most effective way of eradicating infections. Rapidly emerging drug resistance against infectious diseases and chemotherapy-related toxicities in cancer warrant immediate ...

Examining the validity of the drivers of COVID-19 vaccination acceptance scale using Rasch analysis

Abstract: Background To well control the pandemic of COVID-19, herd immunity should be achieved. However, people, especially those with better physical conditions (e.g., young adults), may not accept COVID-19 vaccines. Understanding university students' willingness or reluctance to uptake COVID-19 vaccination is important. Aim This study aimed to examine the psychometric properties of the DrVac-COVID19S, an instrument that helps assess motivations/drivers of COVID-19 vaccination uptake among university students. Research design and methods Using convenience sampling and cross-sectional design, university students (930 from Taiwan [38.0% males] and 1,244 from Ghana [63.3% males]) completed the DrVac-COVID19S using an online survey (Taiwanese students) or paper-and-pen method (Ghanaian students). Rasch analysis was used to examine the psychometric properties of the DrVac-COVID19S. Results All 12 items in the DrVac-COVID19S had a satisfactory fit in the Rasch models (infit MnSq=0.74 to 1.49; outfit MnSq=0.72 to 1.42). Moreover, the seven-point Likert scale used in the DrVac-COVID19S demonstrated monotonically increasing in their difficulties, which indicated the ordered category. Additionally, no differential item functioning was displayed in the DrVacCOVID-19S across Taiwanese and Ghanaian students. Conclusions The DrVacCOVID-19S has good psychometric features to help healthcare providers assess individuals' (especially university students) motivations or drivers to get the COVID-19 vaccination.

COVID-19 pandemic: SARS-CoV-2 specific vaccines and challenges, protection via BCG trained immunity, and clinical trials.

Abstract: Introduction: The coronavirus disease 2019 (COVID-19) pandemic continues to spread worldwide and vaccination remains the most effective approach to control COVID-19. Currently, at least ten COVID-19 vaccines have been authorized under emergency authorization. However, these vaccines still face many challenges.Areas covered: This study reviews the concept and mechanisms of trained immunity induced by the Bacille Calmette Guerin (BCG) vaccine and identifies questions that should be answered before the BCG vaccine could be used to combat COVID-19 pandemic. Moreover, we present for the first time the details of current BCG vaccine clinical trials, which are underway in various countries, to assess its effectiveness in combating the COVID-19 pandemic. Finally, we discuss the challenges of COVID-19 vaccines and opportunities for the BCG vaccine. The literature was found by searching the PubMed (https://pubmed.ncbi.nlm.nih.gov/), Web of Science (https://www.webofknowledge.com), Embase (https://www.embase.com), and CNKI (https://www.cnki.net/) databases. The date was set as the default parameter for each database.Expert opinion: The advantages of the BCG vaccine can compensate for the shortcomings of other COVID-19 vaccines. If the efficacy of the BCG vaccine against COVID-19 is confirmed by these clinical trials, the BCG vaccine may be essential to resolve the challenges faced by COVID-19 vaccines.

CpG-Adjuvanted Hepatitis B Vaccine (HEPLISAV-B®) Update.

Abstract: Introduction: HEPLISAV-B is a hepatitis B vaccine composed of rHBsAg mixed with a synthetic oligonucleotide containing CpG motifs that stimulate innate immunity through TLR9. This vaccine was recently approved by FDA in view of its superior efficacy.Areas covered: Published literature on HEPLISAV-B was critically reviewed. Four randomized controlled trials among 7,056 subjects receiving 2 doses of HEPLISAV-B and 3,214 subjects receiving 3 doses of Engerix-B showed superior seroprotection rate (SPR) (anti-HBs ≥10 mIU/mL) of 90-100%, compared with 71-90% in those receiving Engerix-B. Furthermore, the seroprotection rate was also significantly higher in HEPLISAV-B compared with Engerix-B recipients in persons with traditionally poor vaccine responses such as older adults, diabetics, and those with chronic kidney disease. The safety profiles among 9,871 subjects were similar between HEPLISAV-B and Engerix-B .Expert opinion: HEPLISAV-B, a CpG adjuvant mixed with HBsAg, is more efficacious and produced earlier seroprotection compared to existing vaccines, with a favorable safety profile. The shorter, two-dose regimen, earlier seroprotection, higher adherence, and a higher seroprotection rate, especially in populations with traditionally poor vaccine response, makes this an important therapeutic option in hepatitis B vaccination.

COVID-19 vaccine equity: a health systems and policy perspective.

Abstract: Introduction The global COVID-19 vaccine rollout has highlighted inequities in the accessibility of countries to COVID -19 vaccines. Populations in low- and middle-income countries have found it difficult to have access to COVID-19 vaccines. Areas covered This perspective provides analyses on historical and contemporary policy trends of vaccine development and immunization programs, including the current COVID-19 vaccination drive, and governance challenges. Moreover, we also provide a comparative health system analysis of the COVID-19 vaccine deployment in some countries from different continents. It recommends that the international Access to COVID-19 Tools Accelerator (ACT-A) partnership requires a strong governance mechanism and urgent financial investment. Expert opinion All WHO member states should agree on technology transfer and voluntary license-sharing via a commonly governed technology access pool and supported by a fair Intellectual Property regime. Contextualized, dynamic understandings and country-specific versions of health systems strengthening are needed to improve vaccine equity in a sustainable matter.

Efficacy and effectiveness of a 23-valent polysaccharide vaccine against invasive and noninvasive pneumococcal disease and related outcomes: a review of available evidence.

Abstract: Introduction: Routine pneumococcal vaccination for adults aged ≥60 or ≥65 years and those with underlying at-risk and high-risk conditions is recommended in many countries. However, studies estimating the effectiveness of 23-valent pneumococcal polysaccharide vaccine (PPSV23) have revealed mixed results, explained, in part, by variability in study design and endpoints used to assess outcomes.Areas covered: The authors conducted a literature review of independently randomized trials and real-world studies published from 2010-2020 that assessed the effectiveness and efficacy of PPSV23 against vaccine-type or any-serotype invasive and non-invasive pneumococcal disease in adults aged ≥60 years. The authors also evaluated differences in study design that may contribute to the heterogeneity of available evidence.Expert opinion: Policy decisions regarding the inclusion of vaccines into national immunization plans should be made taking the quality and limitations of studies into account. This review shows that PPSV23 is effective against vaccine-type invasive pneumococcal disease and vaccine-type pneumococcal pneumonia. It can also lower the burden of vaccine-type pneumococcal pneumonia. PPSV23-conferred protection may be lower in adults aged ≥75 years, those with certain underlying conditions, and individuals who were vaccinated >5 years before disease onset. This is an important finding that supports the benefit of PPSV23 vaccination for older adults.

Potential use of convalescent plasma for SARS-CoV-2 prophylaxis and treatment in immunocompromised and vulnerable populations.

Abstract: INTRODUCTION: : The ongoing SARS-CoV-2 pandemic is a serious threat for the health of immunocompromised patients. Among neutralizing antibody-based therapeutics, convalescent plasma containing polyclonal anti-SARS-CoV-2 immunoglobulins has promising results in both congenital and iatrogenic immunodeficiencies in oncohematological and transplant patients. AREAS COVERED: : This article discusses case reports, case series and controlled studies detailing the efficacy of convalescent plasma in immunocompromised patients. EXPERT OPINION: : Convalescent plasma, when administered at high neutralizing antibody titers, is a safe and effective treatment for frail immunocompromised patients. Genetic monitoring of refractory patients is recommended to intercept intra-host emergence of SARS-CoV-2 variants.

COVID-19 vaccines and thrombosis with thrombocytopenia syndrome.

Abstract: Introduction To combat COVID-19, scientists all over the world have expedited the process of vaccine development. Although interim analyses of clinical trials have demonstrated the efficacy and safety of COVID-19 vaccines, a serious but rare adverse event, thrombosis with thrombocytopenia syndrome (TTS), has been reported following COVID-19 vaccination. Areas covered This review, using data from both peer-reviewed and non-peer-reviewed studies, aimed to provide updated information about the critical issue of COVID-19 vaccine-related TTS. Expert opinion : The exact epidemiological characteristics and possible pathogenesis of this adverse event remain unclear. Most cases of TTS developed in women within 2 weeks of the first dose of vaccine on the receipt of the ChAdOx1 nCoV-19 and Ad26.COV2.S vaccines. In countries with mass vaccination against COVID-19, clinicians should be aware of the relevant clinical features of this rare adverse event and perform related laboratory and imaging studies for early diagnosis. Non-heparin anticoagulants, such as fondaparinux, argatroban, or a direct oral anticoagulant (e.g. apixaban or rivaroxaban) and intravenous immunoglobulins are recommended for the treatment of TTS. However, further studies are required to explore the underlying mechanisms of this rare clinical entity. Plain language summary What is the context?Thrombosis with thrombocytopenia syndrome (TTS) usually develops within 2 weeks of the first doses of the ChAdOx1 nCoV-19 and Ad26.COV2.S COVID-19 vaccines.TTS mainly occurs in patients aged 50 × 109/L and there is no serious bleeding. Intravenous immunoglobulins and glucocorticoids may help increase the platelet count within days and reduce the risk of hemorrhagic transformation when anticoagulation is initiated.What is the impact?TTS should be a serious concern during the implementation of mass COVID-19 vaccination, and patients should be educated about this complication along with its symptoms such as severe headache, blurred vision, seizure, severe and persistent abdominal pain, painful swelling of the lower leg, and chest pain or dyspnea. The incidence of TTS is low; therefore, maintenance of high vaccination coverage against COVID-19 should be continued.

COVID-19 vaccine mandate for healthcare workers in the United States: a social justice policy.

Abstract: Introduction Vaccination is the most effective strategy to mitigating the COVID-19 pandemic and restoring societal function. As the pandemic evolves with no certainty of a herd immunity threshold, universal vaccination of at-risk populations is desirable. However, vaccine hesitancy threatens the return to normalcy, and healthcare workers (HCWs) must embrace their ambassadorial role of shoring up vaccine confidence. Unfortunately, voluntary vaccination has been suboptimal among HCWs in the United States, a priority group for whom immunization is essential for maintaining health system capacity and the safety of high-risk patients in their care. Consequently, some health systems have implemented mandates to improve compliance. Areas covered This article discusses the ethical and practical considerations of mandatory COVID-19 vaccination policies for HCWs utilizing some components of the World Health Organization's framework and the unique context of a pandemic with evolving infection dynamics. Expert opinion COVID-19 vaccine mandates for universal immunization of HCWs raise ethical and practical debates about their appropriateness, especially when the vaccines are pending full approval in most jurisdictions. Given the superiority of the vaccines to safety and testing protocols and their favorable safety profile, we encourage health systems to adopt vaccination mandates through participatory processes that address the concerns of stakeholders.

Disproportionate COVID-19 vaccine acceptance rate among healthcare professionals on the eve of nationwide vaccine distribution in Bangladesh.

Abstract: Background : Acceptance of the COVID-19 vaccine by the target groups would play a crucial role in stemming the pandemic. Healthcare professionals (HCPs) are the priority group for vaccination due to them having the highest risk of exposure to infection. This survey aimed to assess their acceptance of COVID-19 vaccines in Bangladesh. Research design and methods A cross-sectional survey using an online questionnaire was conducted between January 3 to 25, 2021, among HCPs (n=834) in Bangladesh. The main outcome measures were vaccine acceptance by HCPs if one was available. Results Less than 50% of HCPs would receive the vaccine against COVID-19 if available and 54% were willing to take the vaccine at some stage in the future. Female participants (OR:1.64;95%CI:1.172-2.297), respondents between 18-34 years old (OR:2.42; 95% CI:1.314-4.463), HCPs in the public sector (OR:2.09; 95% CI:1.521-2.878), and those who did not receive a flu vaccine in the previous year (OR:3.1; 95% CI:1.552-6.001) were more likely to delay vaccination. Conclusions The study revealed that, if available, less than half of the HCPs would accept a COVID-19 vaccine in Bangladesh. To ensure the broader success of the vaccination drive, tailored strategies and vaccine promotion campaigns targeting HCPs and the general population are needed.

Reported adverse effects following COVID-19 vaccination at a tertiary care hospital, focus on cerebral venous sinus thrombosis (CVST).

Abstract: Objectives: Several cases of unusual thrombotic events with thrombocytopenia were reported in several countries, in association with AstraZeneca's COVID-19 vaccine. The European medicines agency conducted a detailed review and concluded that there was no evidence to suggest an association of thrombotic events with the use of COVID-19 vaccine AstraZeneca.Methods: King Abdulaziz Medical City is a 1500 bed tertiary care hospital in Riyadh, Saudi Arabia; this study describes spontaneously reported vaccine adverse effects received through the hospital's internal electronic safety reporting system from December 2020 to 13 April 2021.We assessed each report for causality association utilizing the world health organization's (WHO) causality assessment of an adverse event following immunization (AEFI) classification 2nd Edition 2019.Results: The majority of the reported events were mild to moderate, there were five serious events, one reported cardiac arrest, two cerebral venous sinus thrombosis, and two pulmonary embolism. Clinical and laboratory summary of the five patients are presented in detail.Conclusions: Efforts of pharmacovigilance in mediating the rare risk of thrombosis associated with COVID-19 vaccine are crucial in providing awareness on the possible risk factors and signs/symptoms that should raise red flags.

Vaccine development against Helicobacter pylori: from ideal antigens to the current landscape.

Abstract: Introduction: The interest of the world scientific community for an effective vaccine against Helicobacter pylori infection arises from its high prevalence and association with many diseases. Moreover, with an immunological response that is not always effective for the eradication of the bacteria and an increasing antibiotic resistance in the treatment of this infection, the search for a vaccine and new therapeutic modalities to control this infection is urgent.Areas covered: We bring an overview of the infection worldwide, discussing its prevalence, increasing resistance to antibiotics used in its therapy, in addition to the response of the immune system to the infection registered so far. Moreover, we address the most used antigens and their respective immunological responses expected or registered up to now. Finally, we address the trials and their partial results in development for such vaccines.Expert opinion: Although several studies for the development of an effective vaccine against this pathogen are taking place, many are still in the preclinical phase or even without updated information. In this sense, taking into account the high prevalence and association with important comorbidities, the interest of the pharmaceutical industry in developing an effective vaccine against this pathogen is questioned.

Chlamydia trachomatis vaccines for genital infections: where are we and how far is there to go?

Abstract: Introduction Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen in the world. Antibiotic treatment does not prevent against reinfection and a vaccine is not yet available. Areas covered We focus the review on the progress made of our understanding of the immunological responses required for a vaccine to elicit protection, and on the antigens, adjuvants, routes of immunization and delivery systems that have been tested in animal models. PubMed and Google Scholar were used to search publication on these topics for the last 5 years and recent Reviews were examined. Expert opinion The first Phase 1 clinical trial of a C. trachomatis vaccine to protect against genital infections was successfully completed. We expect that, in the next five years, additional vaccine clinical trials will be implemented.

SARS-CoV-2 subunit vaccine adjuvants and their signaling pathways.

Abstract: Introduction: Vaccines are the agreed upon weapon against the COVID-19 pandemic. This review discusses about COVID-19 subunit vaccines adjuvants and their signaling pathways, which could provide a ...

Gap between willingness and behavior in the vaccination against influenza, pneumonia, and herpes zoster among Chinese aged 50-69 years.

Abstract: Vaccination uptake of influenza vaccine, 23-valent pneumococcal polysaccharide vaccine (PPV23) and herpes zoster vaccine (HZV) remains low among Chinese aged 50–69 years, posing a significant publi...