Search Results (249)

Background/Objectives: Guillain–Barré syndrome (GBS) is a rare but serious immune-mediated neurological disorder monitored as an adverse event of special interest during the COVID-19 pandemic. This study aimed to estimate the incidence of GBS following COVID-19 vaccination and SARS-CoV-2 infection and to compare the risk by vaccine platform. Methods: We conducted a population-based retrospective cohort study using data from the Valencia Health System Integrated Database (Spain) between January 2018 and March 2022. Two cohorts were defined: individuals receiving COVID-19 vaccines (mRNA-based vaccines (BNT162b2 [Pfizer–BioNTech] and mRNA-1273 [Moderna]) or non-virus-vectored (NVV) adenoviral vector-based vaccines (ChAdOx1-S [AstraZeneca] and Ad26.COV2.S [Janssen])) and individuals with laboratory-confirmed SARS-CoV-2 infection. Incident GBS cases were identified within a predefined 42-day risk window following vaccination or infection. Incidence rates were calculated per 100,000 vaccine doses administered or SARS-CoV-2 infections. Results: Among 5,109,919 individuals, 4,270,610 received at least one COVID-19 vaccine dose and 920,643 experienced at least one SARS-CoV-2 infection. A total of 69 GBS cases occurred within 42 days following vaccination (incidence: 0.67 per 100,000 doses), whereas 21 cases occurred after infection (incidence: 2.20 per 100,000 infections). Incidence was lower after mRNA-based vaccines (0.55 per 100,000 doses) than after NVV vaccines (1.57 per 100,000 doses). Conclusions: This study confirms that GBS occurrence following vaccination is rare. The incidence is lower among individuals who received mRNA vaccines compared to those who received NVV vaccines. Moreover, GBS appears to be more frequent after a COVID-19 infection than after vaccination. These findings highlight the importance of integrating pharmacoepidemiological analyses with pharmacovigilance data to contextualize rare but serious adverse events. Full article

Background: Healthcare workers are at the forefront of the global battle against COVID-19. Their vaccination perspectives, particularly in regions like Sierra Leone that have faced health crises such as the Ebola outbreak, are essential for shaping public health strategies in low-income countries that routinely face infectious disease outbreaks. Objective: This research sought to understand the perceptions and experiences of Sierra Leone’s healthcare workers concerning COVID-19 vaccination and booster doses, set against the backdrop of global health resource disparities and regional vaccine distribution challenges. Methods: Utilizing a mixed-methods approach, the study analyzed data from an online survey, which saw 1001 complete responses from 2060 participants across six Ebola-impacted districts (October–November 2022), and in-depth interviews with 24 health workers from three of these districts (February–July 2022). Results: Approximately 80% of respondents reported having received a COVID-19 vaccine, predominantly Sinopharm and AstraZeneca, yet only 34% of vaccinated participants had received a booster dose. In multivariable analyses, personally knowing someone who experienced serious COVID-19 illness or death was associated with higher odds of both initial vaccination and booster uptake (p < 0.05). By contrast, prior Ebola-related experiences were not consistently associated with vaccination outcomes. Qualitative findings contextualized these patterns, highlighting the roles of professional exposure, limited booster-related information, and inequities in vaccine availability and distribution. Conclusion: These findings indicate that vaccination strategies must move beyond initial rollout to address barriers to sustained engagement, particularly for booster uptake among healthcare workers. They also emphasize the need for equitable vaccine access and transparent, locally tailored communication to mitigate structural and informational constraints in low-income settings. Full article

Background: The acceptance of new vaccines under uncertainty—such as during the COVID-19 pandemic—poses a major public health challenge because efficacy and safety information is still evolving. Methods: We propose an integrative analytical framework that combines a theory-based model of vaccine acceptance—the cognitive–affective–normative (CAN) model—with machine-learning techniques (decision tree regression, random forest, and Extreme Gradient Boosting) and SHapley Additive exPlanations (SHAP) integrated into an importance–performance map (IPM) to prioritize determinants of vaccination intention. Using survey data collected in Spain in September 2020 (N = 600), when the AstraZeneca vaccine had not yet been approved, we examine the roles of perceived efficacy (EF), fear of COVID-19 (FC), fear of the vaccine (FV), and social influence (SI). Results: EF and SI consistently emerged as the most influential determinants across modelling approaches. Ensemble learners (random forest and Extreme Gradient Boosting) achieved stronger out-of-sample predictive performance than the single decision tree, while decision tree regression provided an interpretable, rule-based representation of the main decision pathways. Exploiting the local nature of SHAP values, we also constructed SHAP-based IPMs for the full sample and for the low-acceptance segment, enhancing the policy relevance of the prioritization exercise. Conclusions: By combining theory-driven structural modelling with predictive and explainable machine learning, the proposed framework offers a transparent and replicable tool to support the design of vaccination communication strategies and can be transferred to other settings involving emerging health technologies. Full article

Background: In 2019, a new virus caused by SARS-CoV-2, called COVID-19, spread throughout the world, causing a pandemic state. As the pandemic progressed and cases continued to increase, safe vaccines were developed for the entire population. In Brazil, AstraZeneca^® (ChAdOx1-S) and Pfizer^® (BNT162b2) vaccines were among those administered to the population. Objectives: The objective of this study was to analyze whether immunoglobulin G (IgG) is produced for COVID-19 in individuals immunized with two doses of AstraZeneca (ChAdOx1-S) and Pfizer (BNT162b2) vaccines and to evaluate several parameters in order to understand how our bodies respond to this immunization. Methods: The study involved the participation of 120 individuals: 49 in the control group, 44 vaccinated with the AstraZeneca vaccine, and 27 the vaccinated with Pfizer vaccine. Results: Hematological, biochemical, inflammatory, and oxidant/antioxidant parameters and the production of IgG antibodies were analyzed. An increase in some inflammatory parameters was observed in vaccinated individuals, which may have been caused by an immune reaction after vaccination. In terms of hematological parameters, the changes caused by vaccination appear to be transient and quickly resolved after immunization. In terms of biochemical parameters, an increase in IgG antibodies was observed in the group vaccinated with the Pfizer^® vaccine; however, the AstraZeneca^® and control groups also produced IgG, although to a lesser extent. In terms of the remaining parameters, there was little change after vaccination. Regarding the levels of oxidants/antioxidants, it was observed that there was a compensation by antioxidants due to the increase in oxidant parameters, which may act as corrective mechanism. Conclusions: Both the AstraZeneca^® and Pfizer^® vaccines induced anti-SARS-CoV-2 IgG production, accompanied by inflammatory, hematological, and oxidative changes. Full article

Background: Numerous studies have proved the efficacy of vaccination in reducing Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission and the coronavirus disease (COVID-19) burden. However, even though the COVID-19 vaccination coverage is high for primary doses, a booster dose is needed to sustain protection. Continuing our previous research, this study evaluates the immunogenicity and safety of full and half doses of two COVID-19 booster vaccines, ChAdOx1-S (AstraZeneca) and BNT162b2 (Pfizer-BioNTech), in individuals primed with ChAdOx1-S. Methods: This study was an observer-blind randomized controlled trial to evaluate the immunogenicity and safety of half and full doses of two COVID-19 booster vaccine types, BNT162b2 and ChAdOx1-S, among fully vaccinated, ChAdOx1-S-primed individuals in Jakarta, Indonesia. A total of 329 participants were randomized to receive either full or half doses of the booster vaccines, namely the ChAdOx1-S and BNT162b2 COVID-19 vaccines. Immunogenicity was assessed through SARS-CoV-2 antibody titers and neutralizing antibodies (NAbs) at 28 days post-booster, while safety was monitored via adverse event reporting. Results: The results showed that both vaccines demonstrated increased geometric mean titers (GMTs) post-booster. In the ChAdOx1-S booster group, at the baseline visit (day 0) and third visit (day 28), no statistically significant differences in GMT between the half- and full-dose groups were observed (p = 0.970 and 0.539, respectively). In the BNT162b2 group, no statistically significant difference was noted at the baseline visit, while the full dose was higher than the half dose at 28 days (Day 28, p = 0.011). Surrogate virus neutralization tests (sVNTs) and NAbs assays also revealed no significant differences between the half and full dose groups for both the Wuhan strain and the Delta variant. The BNT162b2 group compared to the ChAdOx1-S group revealed a statistically significant increase in IgG levels compared to ChAdOx1-S, with p-values of <0.001 and <0.001 for the half dose and full dose, respectively. This was also reflected in the NAbs test results, where BNT162b2 showed significantly higher levels against both the Wuhan strain and Delta variant. Adverse events were predominantly mild: 79.6% (n = 86/108) in the ChAdOx1-S full-dose group, 75.4% (n = 43/57) in the ChAdOx1-S half-dose group, 84.2% (n = 101/120) in the BNT162b2 full-dose group, and 92.6% (n = 88/95) in the BNT162b2 half-dose group, with pain at the injection site being the most common local reaction and myalgia and headache the most frequent systemic reactions. One serious adverse event was reported, assessed as unrelated to the vaccine. Conclusions: This study confirms that half doses of ChAdOx1-S and BNT162b2 are as immunogenic and safe as full doses, and a heterologous booster is more immunogenic than a homologous booster. Full article

Background: Poland was one of only 10 European countries listed teachers as a priority group for vaccination against COVID-19 among National Vaccination Program (NVP). The aim of this study was to analyse post-vaccination symptoms self-reported by teachers vaccinated under the national COVID-19 vaccination programme. Methods: The presented cross-sectional survey was conducted among teachers from all levels of education in public and non-public institutions, who received the SARS-CoV-2 virus vaccination campaign with the vaccine from AstraZeneca as part of the NVP. The survey was conducted using an original, self-designed questionnaire prepared for this study and distributed to teachers in the form of an online survey via email. Bayesian logistic and linear regression were used to estimate the relationship between predictors and dependent variables. Results: A total of 4622 teachers took part in the survey. Of this number, 3908 teachers declared that they had taken the vaccine. (84.5%). In the study group, self-reported late post-vaccination reactions were very strongly [logBF > 3.4] associated with both gender and age. In contrast, self-reporting of serious late post-vaccination symptoms other than fever was very strongly associated only with gender. Only a small proportion of teachers (from 1.45% to 5.34% depending on age and gender) self-reported immediate post-vaccination reaction (up to 15 min after injection). Conclusions: Self-reporting of symptoms is a valuable tool for monitoring the effectiveness and safety of vaccinations and can also contribute to increased satisfaction with the vaccination process, especially when patients are made aware that post-vaccination symptoms are a natural sign of the body’s immune response. Full article

Background: In the Kingdom of Saudi Arabia, various COVID-19 vaccines were administered during the pandemic. However, region-specific real-word comparative data on their immunogenicity remain limited. This study aimed to assess the serological responses to Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and AstraZeneca (ChAdOx1 nCoV-19) vaccines in a diverse population living in KSA. Methods: This observational study included 236 adults recruited from vaccination sites in Riyadh. Participants provided serum samples at predefined intervals: before the first dose, after the first dose, after the second dose, and post-vaccination infection (if applicable). IgG and neutralising antibodies were quantified using ELISA assays. Demographic and vaccination data, and their associations with antibody responses, were evaluated. Results: At baseline, 75.4% of participants were positive for SARS-CoV-2 IgG, suggesting high prior exposure. Marked incremental increases in IgG levels were observed after each vaccine dose. Both Moderna and Pfizer elicited stronger responses, with Pfizer inducing the strongest early response and Moderna achieving the highest overall titres. Among IgG-positive individuals, neutralising antibodies were detected in 98.1%. There were no statistically significant differences by age or gender, although males tended to show higher mean titres. Heterologous vaccine schedules induced comparable or enhanced immunogenicity relative to homologous schedules, supporting their use in flexible immunisation strategies. Conclusions: All COVID-19 vaccines administered in Saudi Arabia elicited robust antibody responses, particularly the mRNA-based vaccines. Our findings support their continued use and justify varied vaccination approaches, including mix-and-match booster strategies, to enhance community immunity. Full article

Background: Although the safety of COVID-19 vaccines has been demonstrated in clinical trials, real-world pharmacovigilance remains essential to detect rare or unexpected adverse events following immunization (AEFI). In Mexico, the national AEFI surveillance system is in place, yet there is limited analysis of state-level data. Objective: To characterize AEFI related to five COVID-19 vaccines and identify factors associated with AEFI type and seriousness in Nuevo León, Mexico. Methods: A retrospective analysis of the State of Nuevo León AEFI database was conducted, including all AEFI reports between December 2020 and June 2022 (n = 2213). Data included patient sex, age, vaccine type (Pfizer/BioNTech, AstraZeneca, Sinovac, Moderna, CanSino), number of doses (1 or ≥2), symptom categories, and AEFI seriousness. Symptoms were classified as local or systemic and grouped by organ systems. Descriptive analysis and binary multivariate logistic regression were used to examine associations between demographic and vaccine-related factors with AEFI type and severity. Odds ratios (OR) with 95% confidence intervals (CI) were estimated. Results: Most AEFI reports involved females aged 19–59 years and occurred after the first vaccine dose. The most frequently reported unexpected adverse events (UAEs) were mild to moderate, including injection-site reactions, headache, chills, fatigue, nausea, fever, dizziness, weakness, myalgia, and tachycardia. The Pfizer/BioNTech vaccine was associated with higher odds of arm pain and lower odds of hemorrhagic events. Receiving ≥2 doses increased the odds of arm pain and systemic symptoms. Less than 3% of AEFIs were classified as serious. Older adults (≥65 years) and second vaccine doses were associated with increased odds of a serious AEFI, while female sex and receiving the Pfizer/BioNTech vaccine were associated with reduced odds. Conclusions: In Nuevo León, most AEFIs related to COVID-19 vaccination were mild to moderate and resolved without complications. Serious AEFIs were uncommon, with older age and second doses associated with higher risk, and female sex and Pfizer/BioNTech vaccination associated with lower risk. These findings provide a local perspective on vaccine safety that complements national and international evidence. Full article

Background/Objectives: The COVID-19 pandemic was characterized by the rapid transmission of the virus and a global race for vaccines, with vaccines such as AstraZeneca, CoronaVac, Pfizer, and Janssen arriving in Brazil in 2020. Concurrently, an infodemic of information, driven by the media and social media, highlighted the importance of health communication. This study examines how online newspapers in a Brazilian state disseminated information about vaccination and its relationship with vaccine adherence among the population. Methods: Quantitative research, in which a total of 5308 journalistic articles were verified, using two databases, one for the publication of journalistic articles and the other for vaccinations in the state, which applied 9,577,567 doses in the period. Results: The analyses demonstrated a positive correlation between the number of publications of articles and the number of applications of vaccines (rho = 0.407, p-value < 0.0005), revealing a relationship of both increase and decrease in the publication of newspaper articles and the application of vaccines in specific weeks during the analysis period. Vaccination data revealed low adherence to the booster dose by the population, with unequal values among the cities of the state. Conclusions: The study highlighted the potential importance of newspapers in disseminating information about vaccines during the pandemic, underscoring the need for regional health strategies to increase vaccination coverage. Full article

The association between COVID-19 vaccination and thromboembolic events has garnered significant research attention, particularly with the advent of vaccines based on adenoviral vectors, including AstraZeneca’s and Johnson & Johnson’s vaccines. This review underscores the uncommon occurrence of venous thromboembolism (VTE), arterial thromboembolism (ATE), and vaccine-induced thrombotic thrombocytopenia (VITT) following COVID-19 vaccination. Although these complications are extremely rare compared to the heightened risk of thrombosis from COVID-19 infection, elements like age, biological sex, type of vaccine and underlying health conditions may contribute to their development. In addition, rare renal complications such as acute kidney injury and thrombotic microangiopathy have been documented, broadening the spectrum of potential vaccine-associated thrombotic manifestations. Current guidelines emphasize early detection, individualized risk assessment, and use of anticoagulation therapy to mitigate risks. Despite these events, the overwhelming majority of evidence supports the continued use of COVID-19 vaccines, given their proven efficacy in reducing severe illness and mortality. In addition, recent comparative data confirm that mRNA-based vaccines are associated with a significantly lower risk of serious thrombotic events compared to adenoviral vector platforms. Ongoing research is essential to further refine preventive and therapeutic strategies, particularly for at-risk populations. Full article

Objectives: Shoulder injury related to vaccine administration (SIRVA), previously observed with influenza vaccines, has gained clinical significance with widespread COVID-19 vaccination. However, few studies correlate vaccine types and demographic factors with the MRI findings of SIRVA. This study aimed to evaluate MRI findings of SIRVA following COVID-19 vaccination and assess associations with vaccine type and patient characteristics. Methods: A retrospective cohort study was conducted on 35 patients with new-onset shoulder complaints within six weeks of COVID-19 vaccination between May 2021 and May 2022. MRI findings suggestive of SIRVA were reviewed, including subacromial bursitis, rotator cuff tears, and adhesive capsulitis. Demographic data, vaccine type, clinical symptoms, and treatments were collected. Follow-up interviews (1–30 September 2024) assessed symptom persistence and vaccine hesitancy. Descriptive statistics and Chi-square tests were used to explore associations. Results: Of the 35 patients (mean age 53.6 ± 9.0 years; 54.3% female), subacromial bursitis was the most common MRI finding (89.5%), followed by tendonitis (47.4%) and adhesive capsulitis (36.8%). Tendonitis correlated with older age (p = 0.024) and AstraZeneca vaccination (p = 0.033). Subacromial bursitis was linked to female sex (p = 0.013) and higher BMI (p = 0.023). Adhesive capsulitis was associated with receiving the Sinopharm vaccine (p = 0.029). Persistent symptoms (22.9%) were more common in younger patients, women, and those with right-sided injections. Conclusions: SIRVA following COVID-19 vaccination showed different MRI patterns associated with female sex, higher BMI, and vaccine type. Awareness of these patterns may expedite recognition of COVID-19-associated SIRVA in routine practice. Full article

Vaccination has been instrumental in curbing the transmission of SARS-CoV-2 and mitigating the severity of clinical manifestations associated with COVID-19. Numerous COVID-19 vaccines have been developed to this effect, including BioNTech-Pfizer and Moderna’s mRNA vaccines, as well as adenovirus vector-based vaccines such as Oxford–AstraZeneca. However, the emergence of new variants and subvariants of SARS-CoV-2, characterized by enhanced transmissibility and immune evasion, poses significant challenges to the efficacy of current vaccination strategies. In this review, we aim to comprehensively outline the landscape of emerging SARS-CoV-2 variants of concern (VOCs) and sub-lineages that have recently surfaced in the post-pandemic years. We assess the effectiveness of existing vaccines, including their booster doses, against these emerging variants and subvariants, such as BA.2-derived sub-lineages, XBB sub-lineages, and BA.2.86 (Pirola). Furthermore, we discuss the latest advancements in vaccine technology, including multivalent and pan-coronavirus approaches, along with the development of several next-generation coronavirus vaccines, such as exosome-based, virus-like particle (VLP), mucosal, and nanomaterial-based vaccines. Finally, we highlight the key challenges and critical areas for future research to address the evolving threat of SARS-CoV-2 subvariants and to develop strategies for combating the emergence of new viral threats, thereby improving preparedness for future pandemics. Full article

Background/Objectives: Although the COVID-19 pandemic has largely concluded, the varied trajectories it has followed in different regions of the world remain incompletely understood. Intensive research is needed to fully grasp its course and the implications for future global health challenges. Notably, the milder trajectory of the COVID-19 pandemic in Sub-Saharan Africa has defied initial predictions. An emerging body of evidence suggests that, in addition to the continent’s younger average age and the lower prevalence of relevant comorbidities, co-infections with helminths may have also impressively shaped the pandemic’s milder trajectory in the region. Indeed, helminths are renowned for their ability to modulate human immune responses, which, while potentially beneficial in limiting excessive inflammation, could also diminish vaccine efficacy and impede viral clearance. This study investigated different aspects of the intricate interactions between COVID-19 and Lymphatic Filariasis (LF), a helminth infection caused by parasitic worms such as Wuchereria bancrofti, Brugia malayi, and Brugia timori and endemic to various regions in Sub-Saharan Africa and the tropics. Methods: For this purpose, samples of a larger and ongoing clinical trial (ethical approval codes: CHRPE/AP/525/17 and 325/21; trial registration number ISRCTN14042737) were collected from 222 individuals from endemic areas of Ghana, along with comprehensive clinical and demographic data. The samples include LF patients (n = 222) grouped according to their Lymphoedema (LE) stages, as well as COVID-19 vaccinated (n = 81) and non-vaccinated individuals (n = 141). All vaccinated participants received the COVID-19 vaccine ChAdOx1-S (also known as Vaxzevria) developed by the University of Oxford and AstraZenca. The expressions of SARS-CoV-2 and filarial-specific antibodies (IgG, IgA) were accessed using ELISA, while Luminex-based immunoassays were employed to measure the expression of SARS-CoV-2 variant-specific neutralizing antibodies. The interplay between vaccine responses and demographic factors was analyzed using group comparisons with the Kruskal-Wallis or Mann-Whitney U tests. Results: The results indicate that a remarkable portion of unvaccinated individuals (56% IgA seropositive, 39% IgG seropositive) developed antibodies against SARS-CoV-2 despite no confirmed infection. Notably, the study identified a robust antibody response to COVID-19 vaccination, which was independent of the degree of LF pathology or parasitic status. An important observation was the reduced SARS-CoV-2 antibody response in individuals seropositive for Ascaris lumbricoides (p = 0.0264), highlighting an interaction between roundworm infection and COVID-19. Conclusions: The study concludes that the ChAdOx1-S COVID-19 vaccine (AstraZeneca) triggers a strong immune response in LF patients; however, filarial and/or soil-transmitted helminth seropositivity might influence the COVID-19 infection-induced response. These findings emphasize the complexity of infectious disease dynamics in co-infected populations and the need to decipher parasite-induced immunomodulatory mechanisms on COVID-19 vaccination. Full article

The COVID-19 pandemic, caused by SARS-CoV-2, profoundly impacted global health systems and economies. Vaccination and diagnostic advancements were pivotal in managing the pandemic. This systematic review evaluates antibody levels in adults following complete COVID-19 vaccination and examines the prevalence of infections in vaccinated populations. A systematic review adhering to PRISMA guidelines was conducted, focusing on studies analyzing antibody levels at least 14 days after full vaccination with FDA- or EMA-approved vaccines. Five European studies meeting the inclusion criteria were selected. Data were extracted and synthesized from studies involving 6280 participants aged 19 to 105, with an average of 11% having prior exposure to SARS-CoV-2. Antibody levels were analyzed over time, and the incidence of post-vaccination COVID-19 cases was recorded. The reviewed studies demonstrated that antibody levels peaked shortly after vaccination but gradually declined over time. Individuals with prior SARS-CoV-2 infection exhibited higher antibody titers than those without prior exposure. After the first dose, the Pfizer–BioNTech vaccine led to significantly higher antibody levels than the Oxford–AstraZeneca vaccine, especially in those without prior infection. Across all studies, the incidence of COVID-19 among vaccinated individuals was low (0.1–3.8% for 144–302 days post-vaccination). Vaccination reduced severe outcomes despite decreasing antibody levels. The decline in new COVID-19 cases and related deaths is attributed to widespread vaccination, natural immunity, and virus mutations reducing severity. Further studies are warranted to explore antibody persistence and optimal vaccination strategies. Full article

Objective: To evaluate the humoral response to and impact of SARS-CoV-2 vaccination in patients with systemic lupus erythematosus in a multicenter cohort design. Methods: Data for this analysis were obtained from the Study of Safety, Effectiveness and Duration of Immunity after Vaccination against SARS-CoV-2 in Patients with Immune-Mediated Inflammatory Diseases (SAFER), a prospective, multicenter, phase IV, real-world study conducted across different regions of Brazil from June/2021 to March/2024. Patients aged >18 years with systemic lupus erythematosus (SLE) who received any one of the SARS-CoV-2 vaccines approved by the Brazilian health regulatory agency (CoronaVac [inactivated SARS-CoV-2 vaccine], ChAdOx-1 [AstraZeneca], or BNT162b2 [Pfizer-BioNTech]) were included. Immunogenicity was assessed in pre- and post-vaccination blood samples, and patients were monitored in person and remotely for the occurrence and severity of COVID-19. Results: Two hundred and thirty-five patients with SLE who had completed their vaccination schedules (two doses + booster dose) were included in this study. Most patients were female (89.3%) and had low disease activity or were in remission (72.4%); the majority were also on some form of immunosuppressive therapy (58.1%). One hundred and sixteen patients received two doses of CoronaVac followed by one dose of BNT162b2 (Pfizer-BioNTech) vaccine, eighty-seven received two doses of ChAdOx1-S (AstraZeneca) followed by one dose of BNT162b2 (Pfizer-BioNTech) vaccine, and thirty-two received three doses of BNT162b2 (Pfizer-BioNTech) vaccine. Twenty-eight cases of COVID-19, none meeting criteria for severe COVID-19, were recorded in patients with respiratory symptoms after the second dose of a SARS-CoV-2 vaccine. Regarding immunogenicity, an increase in seroconversion rate was observed following consecutive vaccine doses, with no difference between vaccination schedules, reaching 97.57% seropositivity after a booster dose. The geometric mean IgG titers differed between the different vaccination schedules after the first and the second vaccine dose, being lowest for the CoronaVac-based schedule, but titers were similar after the administration of a booster dose. Conclusion: In patients with SLE, SARS-CoV-2 vaccines are immunogenic, inducing a robust humoral response. No severe outcomes associated with death or hospitalization were found in the evaluated patient sample. Complete vaccination schedules including a booster dose induced higher humoral responses than incomplete schedules, especially in patients initially immunized with an inactivated virus vaccine schedule and those with a suboptimal humoral response. Full article