Vaccine Safety Research Articles

Development and validation of an Arabic tool for assessment of post-vaccination confidence in COVID-19 vaccines (ARAB-VAX-CONF)

Abstract Background Vaccine confidence is described as a belief that vaccines are effective, safe, and part of a trustworthy health system. The objective of this study was to develop and validate an Arabic tool to evaluate confidence in the received coronavirus disease 2019 (COVID-19) vaccines (ARAB-VAX-CONF). Methods The research team developed the ARAB-VAX-CONF based on three areas specified by the Centers for Disease Control and Prevention (CDC): confidence in vaccine effectiveness, confidence in vaccine safety, and confidence in the healthcare system. The analysis includes data from 406 eligible vaccinated persons (≥ 18 years). Cronbach’s alpha was used to measure internal consistency, while convergent, discriminant, exploratory, and confirmatory factor analyses were used to verify construct validity. Results A total of 406 adults were recruited, with a mean age of 33.0 ± 12.2 years. A total of 63.1% were males, 56.7% were married, 21.9% had chronic conditions, 93.3% were nonsmokers, and 39.6% were obligated to obtain vaccines. The three domains of the scale met the criterion of internal consistency (Cronbach’s alpha > 0.7). Convergent validity was identified by the significant inter-item and item-mean score of the domain correlation (P < 0.001). Discriminant validity was reported as the inter-factor correlation matrix (< 0.7). The Kaiser–Meyer–Olkin sampling adequacy measure was 0.80, and Bartlett’s sphericity test was significant (P < 0.001). Exploratory factor analysis indicated that the scale could be summarized into three factors. Confirmatory factor analysis confirmed the adequate psychometric properties and fit with observed data (root-mean-square error of approximation = 0.08, comparative fit index = 0.945, Tucker-Lewis index = 0.924, standardized root-mean-square residual = 0.086, normed fit index = 0.918, and goodness-of-fit index = 0.909). Conclusions The ARAB-VAX-CONF developed in this study is valid and reliable for assessing confidence in vaccine effectiveness, safety, and confidence in the healthcare system. The ARAB-VAX-CONF can support decision-makers in addressing the gap in vaccine confidence among various populations.

Does Policy Uncertainty Boost Vaccine Hesitancy? Political Controversy, the FDA and COVID-19 Vaccine Hesitancy in Fall 2020.

Vaccine hesitancy is associated with political and institutional distrust, but there is little research on how people's trust responds to political events. We revisit the fall of 2020 when evaluation of new COVID-19 vaccines collided with an impending national election. Drawing on a political Bayesian perspective, we assess abrupt changes in attention to political events and test hypotheses on subpopulation response: (1) partisan, (2) educational, and (3) ethnic and racial. Analysis of daily changes in news reporting and social media use in 2020, combined with detailed analysis of two-large scale surveys fielded at the time, focusing on questions of COVID-19 vaccine hesitancy and safety concerns about COVID-19 vaccines. Vaccine hesitancy in the US spiked from late August to early October 2020. We identify several plausible triggers for this spike, all pertaining to the FDA and electoral politics. Heightened vaccine hesitancy occurred among Democrats, Asian and Black citizens, as well as college-educated respondents. Turbulence mainly affected those who were initially most trusting in government and vaccines. Asian-American vaccine confidence recovered; that of Black Americans did not. Electoral politics may destabilize citizen assumptions about vaccine authorization and boost uncertainty, thereby undermining public willingness to take approved vaccines.

Stability of closed and needle-punctured vials of Porvac® subunit vaccine against classical swine fever subjected to thermal stress.

Classical Swine Fever (CSF) is still one of the most economically important viral diseases of pigs. In endemic countries, the disease is controlled mostly through vaccination; hence, the availability of safe and effective vaccines is of utmost importance. Vaccines intended for application in developing countries must also be thermally stable, since the infrastructure needed to maintain a cold chain in those countries is usually lacking. Porvac® is a second-generation subunit marker vaccine against CSF that has demonstrates to be safe and protective. Previous studies have also shown that the vaccine is stable for 1 week at 37 oC and have a shelf life of at least 36 months at 2-8 oC. The aim of this work was to further explore the accelerated stability of Porvac® by assessing the physicochemical properties of the emulsion, and the safety and immunogenicity of the vaccine subjected to more drastic conditions of thermal stress: (1) 25 oC for 12 months; (2) 30oC and 37 oC for one month and (3) 15 days at 37°C after the cap of the vials had been needle-punctured. The vaccine subjected to all these conditions did not show significant changes in the physicochemical properties of the emulsion; did not produce local or systemic adverse reactions in pigs, and the chromatographic profile of the recovered antigen was preserved. All vaccinated swine developed neutralizing antibody titers ≥ 1:1000 at 28 days post vaccination. Porvac® is stable in all the experimental conditions tested, even after cap puncture, and retains the capacity to induce high titers of neutralizing antibodies, well above the threshold of protection. These results reinforce the robustness of the vaccine, and support its use as a very attractive alternative to modified live vaccines in developing countries endemic for CSF.

Mapping global public perspectives on mRNA vaccines and therapeutics.

The development and rollout of mRNA vaccines during COVID-19 marked a significant advancement in vaccinology, yet public hesitation to vaccination was prevalent, indicating the potential risk that future mRNA-based medical innovations will fail to be adopted. Utilizing a combined approach of large language models with manual validation and unsupervised machine learning, we conducted a social listening analysis to assess attitudes towards mRNA vaccines and therapeutics on Twitter from June 2022 to May 2023, contrasting online perspectives with data from the Vaccine Adverse Event Reporting System. Our findings reveal widespread negative sentiment and a global lack of confidence in the safety, effectiveness, and trustworthiness of mRNA vaccines and therapeutics, with frequent discussions of severe vaccine side effects, rumors, and misinformation. This underscores the need for targeted communication strategies to foster acceptance of medical treatments and strengthen public trust in order to enhance societal resilience to future health challenges.

Global vaccination against hepatitis E virus: position paper from the ESGVH-ESCMID.

Hepatitis E Virus (HEV) is a significant global health issue, impacting both low- and middle-income countries (LMICs) and industrialized nations. HEV genotypes 1 and 2, primarily transmitted through contaminated water, are endemic in LMICs, while genotypes 3 and 4 are zoonotically transmitted in industrialized regions. Acute HEV infection poses severe risks, particularly to pregnant women and immunocompromised individuals, while chronic HEV infection leads to serious complications in those with pre-existing liver disease and transplant recipients. The development of an HEV vaccine offers new prevention opportunities, though its availability and integration into global immunization programs remain limited. This position paper was developed by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Viral Hepatitis Study Group (ESGVH) through an extensive review of clinical data, safety profiles, efficacy, and immunogenicity of HEV vaccines. The study group focused particularly on high-risk and special populations, synthesizing global health insights and incorporating recommendations from the Strategic Advisory Group of Experts (SAGE) to formulate strategies for wider HEV vaccination use. The position paper evaluates the efficacy and safety of HEV vaccines in both general and special populations. It identifies key barriers to the integration of HEV vaccines into routine immunization programs, including infrastructure limitations, costs, and vaccine accessibility. The paper also proposes strategies to overcome these challenges and improve vaccine distribution. Furthermore, it addresses ways to enhance public awareness and international cooperation to promote HEV vaccination efforts globally. ESGVH-ESCMID recommends HEV vaccination for high-risk groups, including women of childbearing age, patients with chronic liver diseases, and immunosuppressed individuals. Prioritizing investments in vaccine logistics, integrating diagnostics, and educational outreach can enhance uptake.

Machine learning algorithms for prediction of measles one vaccination dropout among 12–23 months children in Ethiopia

IntroductionDespite the availability of a safe and effective measles vaccine in Ethiopia, the country has experienced recurrent and significant measles outbreaks, with a nearly fivefold increase in confirmed cases from...

HPV Vaccine Awareness and Uptake Among Sexually Transmitted Infections Clinic Users: A Cross-Sectional Study in Bologna, Italy

Human Papillomavirus (HPV) infection poses a significant health risk, particularly for high-risk groups such as men who have sex with men (MSM), people living with HIV (PLHIV), and transgender individuals. Despite the availability of effective vaccines, uptake among these groups remains suboptimal due to various social and behavioral barriers (BeSD). A cross-sectional survey was conducted at the Sexually Transmitted Infections (STIs) clinic in Bologna, Italy, from 8 April to 12 April 2024 using a paper questionnaire, investigating HPV vaccine uptake and BeSD factors influencing vaccination decisions. Statistical analyses included descriptive statistics and multivariate logistic regression. Among the 236 respondents, PLHIV and transgender individuals demonstrated lower uptake rates (60.0% and 15.6%) if compared to women under 30 years old (72.7%). Concern about HPV infection varied significantly across groups, with MSM showing the highest worry (48.7%). Perceptions of vaccine safety and access were mixed, influencing vaccination decisions. Multivariate analysis indicated that age inversely correlated with infection worry (OR: 0.94, 95% CI: 0.91–0.98), while being a woman under 30 (OR: 164.0, 95% CI: 17.2–1560.18) or MSM (OR: 3.53, 95% CI: 1.37–9.11) was positively associated with vaccine uptake. The study identifies disparities in HPV vaccine uptake among STI clinic users in Bologna, Italy, emphasizing the need for targeted public health campaigns. These campaigns could engage STI clinics and address awareness, safety perceptions, and access barriers to enhance vaccination coverage among sexual and gender minorities.

Safety and immunogenicity of freeze-dried human rabies vaccines: A phase 3 clinical trial of Zagreb and Essen regimes

ABSTRACT Recently optimized freeze-dried rabies vaccines (Vero cell) are promising for rabies prevention; however, comparisons of Essen 5-dose and Zagreb 4-dose regimens are needed for clinical applications. This phase III clinical trial aimed to assess the safety and immunogenicity of candidate freeze-dried rabies vaccines developed for human use by Shandong Yeedo Biotechnology (Registration No.: CTR20182016, http://www.chinadrugtrials.org.cn/index.html). In total, 40 participants in stage I and 1797 subjects in stage II with an age range of 10–60 years were recruited. Both 4-dose and 5-dose experimental vaccines were well-tolerated in stage 1, with similar overall adverse event (AE) rates. In stage 2, systemic fever (35.39%) and local pain (48.91%) were common, and the rate of Grade 3 AEs was approximately 2.5%. Rates of local reactions and unsolicited AEs differed among groups (p = .045 and 0.011). Immunogenicity analyses showed higher antibody levels, seroconversion rates, and pre-immune seroconversion rates in the 4-dose experimental group versus the 5-dose group (p < .001) on day 7 post-first dose, with similar GMCs (geometric mean concentrations) by day 14. Pre-immune negative subjects had comparable antibody levels in the 4-dose and 5-dose experimental groups, outperforming the 5-dose control group (p = .039). The rate difference (95% CI) for first-dose seroconversion at 14 days post-vaccination among pre-immune antibody-negative subjects indicated non-inferiority between the 5-dose experimental and control groups. Overall, the Shandong Yeedo rabies vaccine demonstrated satisfactory safety and efficacy, offering a new option for rabies prevention.

Host Innate and Adaptive Immunity Against African Swine Fever Virus Infection

Africa swine fever virus (ASFV) is the causative agent of African swine fever (ASF), a highly contagious hemorrhagic disease that can result in up to 100% lethality in both wild and domestic swine, regardless of breed or age. The ongoing ASF pandemic poses significant threats to the pork industry and food security, with serious implications for the sanitary and socioeconomic system. Due to the limited understanding of ASFV pathogenesis and immune protection mechanisms, there are currently no safe and effective vaccines or specific treatments available, complicating efforts for prevention and control. This review summarizes the current understanding of the intricate interplay between ASFV and the host immune system, encompassing both innate and adaptive immune responses to ASFV infection, as well as insights into ASFV pathogenesis and immunosuppression. We aim to provide comprehensive information to support fundamental research on ASFV, highlighting existing gaps and suggesting future research directions. This work may serve as a theoretical foundation for the rational design of protective vaccines against this devastating viral disease.

Factors Impacting Vaccine Uptake Among Adult Medicaid Beneficiaries: A Systematic Literature Review

Abstract Vaccine uptake is suboptimal among adult Medicaid beneficiaries. To evaluate factors affecting vaccine uptake among adult Medicaid beneficiaries and/or affecting healthcare providers who vaccinate adult Medicaid beneficiaries, we conducted a systematic literature review in Embase, Medline, Database of Abstracts of Reviews of Effects, and the Cochrane Library for articles published from January 2005 through July 2022 and relevant conferences. For included studies, data were extracted on the study characteristics, patient and provider cost barriers, patient and provider perceived risks/benefits, and other barriers faced by patients and providers. Quality assessments were conducted using a checklist from the Joanna Briggs Institute. 21 studies analyzing patient-related factors (14 studies) and/or provider-related factors (8 studies). Reviewed studies indicate that vaccine uptake is influenced by insurance benefit and cost-coverage policies, including cost-sharing; access to vaccination services; and vaccine education and awareness. Financial factors, including reimbursement for vaccine acquisition and administration, influence providers’ vaccination practices for Medicaid beneficiaries. Our findings suggest that reducing or eliminating vaccination cost-sharing, promoting vaccine education and awareness about the importance and safety of vaccines, increasing access, and exploring reimbursement rates equivalent with other public or private insurance plans could mitigate barriers to vaccination for the adult Medicaid population.

The Processuality of ‘Sex’ in Biomedicine: Exploring Stem Cell Research, Cancer Medicine and Vaccine Safety Research

Incorporating sex into biomedical research is envisioned as key to addressing inequalities in health. However, feminist research suggests that it is a complicated task. This is, we argue, especially the case with research that seeks to mobilise sex across different scales involving bodies, samples and populations to provide a basis for personalised biomedical prevention and treatment. Through case studies from stem cell research, cancer medicine and vaccine safety research, we analyse how sex is enacted, foregrounded and sidelined at different stages of research. We argue that sex becomes suspended between individual bodies, samples and population groups, and that this postpones biomedical analysis of sex differences in health. Yet, research on sex differences in complex embodied processes, such as drug metabolism or immunity, appears as a future potentiality. This potentiality shapes research practices that may open biomedicine towards multi-disciplinary study settings that bring together physiological and social dimensions of bodily difference.

Safety observation of COVID-19 inactivated vaccine in immature mice

Objective To investigate the safety of COVID-19 inactivated vaccine in immature mice. Methods We selected 3-week-old immature BALB/c mice, continuously observed until 7 weeks old after continuous immunization with fully inactivated vaccine (initial strengthening), and sacrificed BALB/c mice at 7 weeks old, and used H&E, Masson, mast cells and Ki-67 staining to analyze the changes of heart, liver, spleen, kidney, lung and brain. In addition, RNA was extracted from important organs such as the heart, liver, spleen, kidney, lung, and brain, and to evaluate whether there was any effect after vaccination through bulk-RNA sequencing. Results After H&E, Masson, mast cells and Ki-67 staining analyses, there are no significant differences between tissues and organs in the vaccine group and the PBS group, and RNA-Seq did not show that the vaccine had any effect on immature mice. Conclusion COVID-19 inactivated vaccine is safe in immature mice.

PaedVacCOVID - safety of the BNT162b2 vaccine against the SARS-CoV-2 in children with and without comorbidities aged 5 to 11 years.

Little is known about specific safety aspects in children with significant comorbidities receiving the mRNA vaccine BNT162b2, as approval studies did not address this population. This study's purpose is to evaluate safety and adverse events in these children compared to healthy children. In this prospective, multicentre, industry-independent cohort study, caregivers whose children received BNT162b2 were asked to participate in an online questionnaire. Potential side effects were evaluated in ten organ related categories. Frequency of symptoms was compared in both cohorts by bivariate analysis. From a total of 1,294 responses to the questionnaire, 793 data sets were included into the analysis (179 children with comorbidities and 614 healthy children). Responses were given at a median of 17 days after vaccination. Overall, safety of BNT162b2 was high in both cohorts. Psychological (OR: 3.56, [95% CI: 1.461 to 8.629]), pulmonary (OR: 7.14, [95% CI: 2.039 to 21.48]), gastrointestinal (OR: 2.35, [95% CI: 1.231 to 4.665]), neurological (OR: 1.74, [95% CI: 1.078 to 2.796]) and dermatological (OR: 2.28, [95% CI: 1.220 to 4.172]) side effects were increased in children with comorbidities over healthy controls. The higher rate of reported post-vaccination symptoms could either be due to a higher susceptibility for symptomatic effects following immune stimulation, or due to a trained awareness to health-related symptoms. The data emphasizes the importance to evaluate safety of the new mRNA COVID-19 vaccines not only in healthy children but also in children with comorbidities. To perform such evaluation should be made mandatory for pharmaceutical enterprises.

Assessment of Single-Cycle M-Protein Mutated Vesicular Stomatitis Virus as a Safe and Immunogenic Mucosal Vaccine Platform for SARS-CoV-2 Immunogen Delivery.

The goal of the next-generation COVID-19 vaccine is to provide rapid respiratory tract protection with a single dose. Circulating antibodies do not protect the olfactory mucosa from viral infection, necessitating localized mucosal immunization. Live attenuated vesicular stomatitis virus (VSVMT)-based COVID-19 vaccines effectively stimulate mucosal immunity in animals, though safety concerns remain, particularly in immunocompromised populations. A viral vector capable of single-cycle replication may face less stringent regulatory requirements. A replication-defective VSVMT is developed with its G protein replaced by a SARS-CoV-2 spike protein (S) mutant, where residues K986 and V987 are substituted by prolines (S2P). This studies show that single-cycle VSVMT encoding Omicron subvariant S2P (VSVMT-S2P) is safe in both healthy and immunocompromised animals treated with cyclophosphamide (CP). Significant antibody and T-cell responses against the spike protein are observed in VSVMT-S2P vaccinated healthy animals. Intramuscular VSVMT-S2P administration induces neutralizing antibody responses comparable to those from replication-competent VSVMT-S. In immunocompromised animals, lower and delayed immune responses are observed. Thus, single-cycle M-protein mutated VSV offers a safe and effective platform for SARS-CoV-2 immunogen delivery. Remarkably, replication-competent VSVMT-S caused no pathogenicity and elicited potent mucosal immunity via intranasal administration, highlighting its potential as a mucosal COVID-19 vaccine.

Immunogenicity of intraperitoneal and intranasal liposome adjuvanted VLP vaccines against SARS-CoV-2 infection

Humans get SARS-CoV-2 infection mainly through inhalation; thus, vaccine that induces protective immunity at the virus entry site is important for early control of the infection. In this study, two anionic liposome (L)-adjuvanted VLP vaccines against SARS-CoV-2 were formulated. Baculovirus-Sf21 insect cell system was used for production of VLPs made of full-length S, M and E proteins. S protein of one vaccine (L-SME-VLPs) contained furin cleavage site at the S1/S2 junction, while that of another vaccine (L-S′ME-VLPs) did not. Both vaccines were innocuous and immunogenic when administered IP and IN to mice. Mice immunized IP with L-SME-VLPs/L-S′ME-VLPs (three doses, two-weeks intervals) had serum virus neutralizing (VN) antibodies (in falling order of isotype frequency): IgG3, IgA and IgG2a/IgG3, IgA and IgM, respectively. The L-S′ME VLPs vaccine induced significantly higher serum VN antibody titers than the L-SME-VLPs vaccine. All mice immunized IN with both vaccines had significant rise of VN antibodies in their bronchoalveolar lavage fluids (BALF). The VN antibodies in 67% of immunized mice were Th1- isotypes (IgG2a and/or IgG2b); the immunized mice had also other antibody isotypes in BALF. The intranasal L-S′ME-VLPs should be tested further step-by-step towards the clinical use as effective and safe vaccine against SARS-CoV-2.

The impact of COVID-19 on routine child immunisation in South Africa

BackgroundThe COVID-19 pandemic disrupted immunisation programs worldwide, reversing gains that had brought vaccine-preventable diseases largely under control. This study explored the impact of COVID-19 on the uptake of routine child immunisation services in South Africa.MethodsWe conducted qualitative research using in-depth interviews with 51 purposively selected parents/caregivers of children below the age of five who missed or delayed one or more scheduled immunisation doses in 2020–2022 and with 12 healthcare providers who provided public immunisation services during the pandemic.ResultsDuring the pandemic lockdowns, most caregivers perceived the risk of their child being infected with COVID-19 during a clinic visit as more salient than the risk of missing immunisation doses. Caregivers reported minimal exposure to routine immunisation communication, as well as shortages of routine vaccines for children at public health facilities, healthcare workers experienced anxiety and burnout. There was a post-pandemic shift to more active decision-making about immunisation, which had previously been an almost automatic behaviour, leading some caregivers to delay vaccinating their children. There was also evidence of a “bad vaccine” mental model among some caregivers regarding COVID vaccinations, which could lead to doubts about the safety of routine childhood vaccinations.DiscussionThe shift from default to active decision-making highlights a risk that routine immunisation will backslide in future pandemics. Governments should build resilient health systems at all levels and communicate clearly about the benefits and availability of RIs and the safety of vaccinations in general, alongside supply-side interventions.ConclusionRoutine immunisation is widely accepted in South Africa, driven by generational norms and provider recommendations. During the COVID-19 pandemic, many caregivers faced the dilemma of balancing COVID-19 exposure risk with the risk of their child developing a deadly VPD, leading to missed RI visits. This shift to active decision-making highlights a future pandemic risk. Governments should build resilient health systems and focus on understanding and engaging procrastinating and doubtful caregivers. Clear communication about RI benefits and vaccine safety is crucial, as misinformation can lead to distrust in new vaccines.

Identifying influential factors using machine learning techniques on the intention to receive a COVID-19 booster dose and vaccine fatigue among partially vaccinated individuals

This study assesses COVID-19 booster intentions and hesitancy in Texas, a state known for its diversity and libertarian values. A survey was conducted with 274 participants residing in Texas between June and July 2022. The analysis examined sociodemographic and health-related factors, trusted information sources, and preventive behaviors. The survey focused on vaccinated participants and their intention to receive the booster dose, which was categorized into three outcomes: yes, no, and not sure. Machine learning techniques were employed to analyze the survey responses of vaccinated participants to identify the most critical factors. Among the participants, 113 expressed their intention to get the booster (41.2%), 107 did not plan to receive the booster (39.1%), and 54 remained undecided (19.7%). Our findings indicate that the perception of vaccine safety significantly influenced the decision to receive the booster dose. Those who reported trust in social media contacts as reliable information sources were more likely to intend to boost. Additionally, among those hospitalized when diagnosed with COVID-19, the largest proportion were unwilling to receive the booster (47.0%) compared to those who intended to receive the booster (33.3%). In contrast, most of those who believed they would be hospitalized if infected with COVID-19 intended to get the booster. Other factors did not demonstrate a significant association. Our findings are highly transferable and can offer valuable insights, particularly for countries where COVID-19 remains prevalent and are pivotal both presently and in the future for developing strategies to improve booster uptake and shape public health initiatives in epidemic and pandemic outbreaks.

Exploring vaccine hesitancy in digital public discourse: From tribal polarization to socio-economic disparities.

This study analyzed online public discourse on Twitter (later rebranded as X) during the COVID-19 pandemic to understand key factors associated with vaccine hesitancy by employing deep-learning techniques. Text classification analysis reveals a significant association between attitudes toward vaccination and the unique socio-economic characteristics of US states, such as education, race, income or voting behavior. However, our results indicate that attributing vaccine hesitancy solely to a single social factor is not appropriate. Furthermore, the topic modeling of online discourse identifies two distinct sets of justifications for vaccine hesitancy. The first set pertains to political concerns, including constitutional rights and conspiracy theories. The second pertains to medical concerns about vaccine safety and efficacy. However, vaccine-hesitant social media users pragmatically use broad categories of justification for their beliefs. This behavior may suggest that vaccine hesitancy is influenced by political beliefs, unconscious emotions, and gut-level instinct. Our findings have further implications for the critical role of trust in public institutions in shaping attitudes toward vaccination and the need for tailored communication strategies to restore faith in marginalized communities.

Comparative assessment of a COVID-19 vaccine after technology transfer to Iran from critical quality attributes to clinical and immunogenicity aspects

During COVID-19 pandemic, international pharmaceutical companies put effort to build global manufacturing networks for vaccines. Soberana Plus vaccine, a recombinant protein based vaccine (RBD dimer), with the trade name of PastoCovac Plus in Iran, is based on a protein subunit platform in Cuba and completed preclinical and toxicological assessments. This study aimed at presenting the steps of vaccine technology transfer from Cuba to Iran. This study provides the first practical comparability results in Iran to ensure the quality, safety and efficacy of a protein subunit vaccine against COVID-19 after a successful technology transfer from Cuba. PastoCovac Plus was transferred to Iran at the formulation stage. The assessment of the active ingredient pharmaceutical (API) was achieved through physicochemical and clinical data collection and tests to assure if there was any adverse impact on the vaccination results. In order to assess the quality of the vaccine product after technology transfer, we sought different properties including regulatory features, physicochemical quality, vaccine potency and stability as well as its immunogenicity and safety. Following the evaluation of the clinical quality attributes (CQAs) based on the standard protocols, the results showed that the two vaccines are highly similar and comparable, with no considerable effect on safety or efficacy profiles. The CQAs were all in the acceptance limits in terms of safety and efficacy as well as clinical evaluation results. The immunogenicity evaluation also confirmed no significant differences between the vaccines regarding reinfection (P = 0.199) or vaccine breakthrough (P = 0.176). Furthermore, the level of anti-spike and neutralizing antibodies in the both vaccine groups was not significantly different indicating the equality of performance between the two vaccines. According to the results of the quality and clinical assessment of this study, we achieved an acceptable quality attributes and acceptant limits in terms of safety and efficacy of the vaccines pre and post technology transfer.

Quadrivalent HPV (4vHPV) vaccine immunogenicity and safety in women using immunosuppressive drugs due to solid organ transplant

IntroductionImmunocompromised persons are at high risk of persistent Human Papilloma Virus (HPV) infection and associated diseases. Few studies evaluated HPV vaccines in immunocompromised persons. This study aimed to evaluate the quadrivalent HPV vaccine (4vHPV) immunogenicity and safety in solid organ transplant (SOT) recipients, in comparison to immunocompetent women (IC).MethodsOpen-label clinical trial that enrolled SOT recipients and immunocompetent women aged 18 to 45 years. All participants received three doses of 4vHPV vaccine. Blood samples were drawn for evaluation of immune responses at baseline and one month after the third vaccination. Seroconversion rates and antibody geometric mean concentration (GMC) against HPV 6, 11, 16, 18, 31, 35, 52 and 58 were measured with in-house multiplexed serology assay (xMAP technology). Follow-up for the local and systemic adverse events (AEs) continued for seven days after each vaccination. Severe AEs were evaluated throughout the study.Results125 SOT and 132 immunocompetent women were enrolled; 105 (84%) SOT and 119 (90%) immunocompetent women completed the study. At baseline, HPV seropositivity was not significantly different between groups. Seroconversion rates were significantly lower in SOT (HPV18, 57%; HPV6 and 16, 69%; and HPV11, 72%) than in immunocompetent women (100% seroconversion to all vaccine types) (p&amp;lt;0.001). Antibody GMCs of all four HPV vaccine types were also significantly lower in SOT (p&amp;lt;0.001). Pain in the injection site and headache were the most frequent adverse event in both groups. Local pain was more frequent in immunocompetent women than in SOT recipients. Rates of other AEs were comparable in both groups.Conclusion4vHPV vaccine was well-tolerated by SOT recipients. We found strong evidence of lower humoral immune responses to 4vHPV vaccine in SOT compared to immunocompetent women, which strengthen recommendation of routine cervical cancer screening in SOT recipients regardless of HPV vaccination status.