Neutralizing antibody responses assessment after vaccination in people living with HIV using a surrogate neutralization assay.

OBJECTIVE: HIV has been reported to interfere with protective vaccination against multiple pathogens, usually through the decreased effectiveness of the antibody responses. We aimed to assess neutralizing antibody responses induced by COVID-19 vaccination in PLWH in Brazzaville, Republique of the Congo. METHOD: The study was conducted at the Ambulatory Treatment Center of the National HIV Program, in charge of over 6000 PLWH, and the health center of FCRM in Brazzaville, Republic of the Congo. Participants were divided into two groups: PLWH with well-controlled HIV infection (CD4 counts no older than one week ≥ 800 / mm3, undetectable viral load of a period no older than one week and regularly taking Highly Active Antiretroviral Therapy for at least 6 months) and PLWOH. These groups were subdivided by vaccination status: fully vaccinated with adenovirus-based vaccines (Janssen/Ad26.COV2.S and Sputnik/Gam-COVID-Vac) or inactivated virus vaccine (Sinopharm/BBIP-CorV) and a control group of unvaccinated healthy individuals. All participants were RT-PCR negative at inclusion and/or with no documented history of SARS-CoV-2 infection. ELISA method was used for detecting IgG and neutralizing Antibodies against SARS-CoV-2 antigens using a commercial neutralizing assay. RESULTS: We collected oropharyngeal and blood samples from 1016 participants including 684 PLWH and 332 PLWOH. Both PLWH and PLWOH elicited high levels of antibody responses after complete vaccination with inactivated virus vaccine (Sinopharm/BBIP-CorV) and adenovirus-based vaccines (Janssen/Ad26.COV2.S and Sputnik/Gam-COVID-Vac). Overall, no difference was observed in neutralization capacity between PLWOH and PLWH with well-controlled HIV infection. CONCLUSION: The results from this study underline the importance of implementing integrated health systems that provide PLWH the opportunity to benefit HIV prevention and care, at the same time while monitoring their vaccine-induced antibody kinetics for appropriate booster schedules.

Severity of SARS-CoV-2 infection among vaccinated individuals: A hospital-based study.

Introduction: Post-vaccination infections impart the need for real-world data on protection conferred by the vaccines against SARS-CoV-2. We aimed to evaluate the severity of post-vaccination COVID-19 and the predictors of severe disease. Methods: This cross-sectional study analysed data from 307 patients admitted to the University Hospital KDU with confirmed COVID- 19 from March 1st to November 1st, 2021, after receiving at least a single dose of a vaccine against SARS-CoV-2. Vaccination status and the disease severity were classified using standard definitions. A binary logistic regression model was fitted to investigate severe/critical disease predictors. Results: Of the surveyed patients, 122(39.7%) were fully vaccinated, 127(41.4%) were partially vaccinated and 58 (18.9%) had developed the disease within 14 days of the first vaccine dose. Most were Sinopharm vaccine recipients (52.4 %). Non- severe disease was observed among 249(81.1%) patients and 47(15.3%) had severe disease, while 11(3.6%) needed ICU care (critical illness). Severe/critical disease was reported among 32(25.2%) partially vaccinated and 13(22.4%) patients who developed the disease within 14 days of the first vaccine dose. Of the patients deemed to have vaccine breakthrough infections (122 fully vaccinated patients), 13(10.6%) suffered severe/critical disease. Patients with comorbidity experienced more severe/critical illness (adjusted odds ratio [AOR]= 3.684, P=0.003) than those without pre-existing medical conditions. Disease progression to severe or critical illness was significantly higher among Sinopharm recipients than Covisheild recipients (AOR:2.064, P=0.048). Conclusions: Comorbidity was the most important predictor of severe COVID-19 irrespective of the vaccination status. Observed higher incidence of severe disease among Sinopharm recipients warrants more extensive population studies.

A non-targeted metabolomics comparative study on plasma of pfizer and sinopharm COVID-19 vaccinated individuals, assessed by (TIMS-QTOF) mass spectrometry.

COVID-19 is a highly contagious infectious disease that has posed a global threat, leading to a widespread pandemic characterized by multi-organ complications and failures. AIMS: The present study was conducted to evaluate the impact of Pfizer and Sinopharm vaccines on metabolomic changes and their correlations with immune pathways. MAIN METHODS: The study used a cross-sectional design and implemented an untargeted metabolomics-based approach. Plasma samples were obtained from three groups: non-vaccinated participants, Sinopharm-vaccinated participants, and Pfizer-vaccinated participants. Comparative metabolomic analysis was conducted using TIMS-QTOF, and multiple t-tests with a 5 % false discovery rate (FDR) were performed using MetaboAnalyst software. KEY FINDINGS: Out of the 105 metabolites detected, 72 showed statistically significant changes (p-value < 0.05) across the different groups. Notably, several metabolites such as neopterin, pyridoxal, and syringic acid were markedly altered in individuals vaccinated with Pfizer. Conversely, in the Sinopharm-vaccinated group, significant alterations were observed in sphinganine, neopterin, and sphingosine. These metabolites hold potential as biomarkers for evaluating vaccine efficacy. Additionally, both Pfizer and Sinopharm vaccinations were found to influence sphingolipid and histidine metabolisms compared to the control group. The Sinopharm group also displayed changes in lysine degradation relative to the control group. When comparing the enriched pathways between the Pfizer and Sinopharm-vaccinated groups, differences were observed in purine metabolism. Furthermore, alterations in tryptophan and vitamin B6 metabolism were noted when comparing the Pfizer-vaccinated group with both the control and Sinopharm-vaccinated groups. SIGNIFICANCE: These findings highlight the importance of metabolomics in assessing vaccine effectiveness and identifying potential biomarkers for monitoring the efficacy of newly developed vaccines in a shorter timeframe.

Lipodystrophy following Covid-19 Vaccination: A case report.

Lipodystrophy is a medical condition characterized by complete or partial loss of adipose tissue. The etiology of lipoatrophy can be congenital or acquired, including traumatic, iatrogenic, or idiopathic. Rarely, vaccination can cause lipodystrophy. Here, we report the first case of lipodystrophy associated with the COVID-19 Sinopharm vaccine in a 55-year-old woman.

Evaluation of SARS-Cov-2 neutralizing antibody among Sinopharm Vero Cell (BBIBP-CorV) vaccinated medical students.

BACKGROUND: Information regarding seropositivity and vaccine efficacy among medical students is scarce. This study aims to detect the status of SARS-CoV-2 neutralizing antibodies among the Sinopharm's Vero Cell (BBIBP-CorV) vaccinated medical students. MATERIALS AND METHODS: A prospective, cross-sectional study was carried out among medical students of Gandaki Medical College Teaching Hospital, Pokhara, Nepal from March through August 2022. The level of SARS-CoV-2 serum- neutralizing IgG antibody was measured and its relation with participants' age and sex, duration of vaccination, and any comorbid condition was determined. RESULTS: A total of 110 medical students were included in the final analysis, the majority being females (65.5%) and the mean age is 23.1 ± 3.2 years. Most of the students (96.4%) had neutralizing antibodies against SARS-CoV-2. Among the 29 (26.36%) students who received a booster dose, the positivity rate was 100%. The mean IgG levels were 9.57 ± 9.58 µg/ml and 2.91 ± 2.47 µg/ml among students receiving an additional booster dose and among those not receiving it, respectively. In the cohort receiving a booster dose of the vaccine, the average value of neutralizing IgG antibodies was high. In contrast, the ones not receiving it, the titers were low and showed a declining trend. CONCLUSION: Though the dose strategy of the Sinopharm vaccine is effective, booster vaccination may be an important strategy to ensure protection among medical students, who are at high risk of COVID-19 due to constant patient exposure during their training. Further studies should assess vaccine efficacy among individuals who received other vaccines as well.

Immunogenicity and adverse events of the COVID-19 vaccines in healthy and individuals with autoimmune diseases in an Iranian population.

Introduction: Recent studies have proposed various COVID-19 vaccines to control the disease and protect susceptible individuals. However, immunogenicity and safety of COVID-19 vaccines in various populations are not well identified yet. Therefore, this study aimed to elucidate the efficacy and safety of the BBIBP-CorV (Sinopharm) and ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines in healthy subjects and patients with autoimmune diseases.Methods: Study population included 121 healthy subjects and 100 patients with autoimmune diseases. Immunization was performed based on the national vaccination protocols. Of the 221 volunteers, 201 subjects received Sinopharm and 20 cases were vaccinated with Oxford-AstraZeneca. During a 1-year follow-up, the immunogenicity was measured by ELISA before primary vaccination and 1 to 3 months after secondary immunization. Side effects were studied before entering the study and 1 week after the second dose.Results: Vaccination had a positive impact on the induction of immunogenic response (p < .0001). The rates of seropositive vaccine responses were 80% and 75% in subjects vaccinated with the Sinopharm and Oxford-AstraZeneca, respectively. The neutralizing antibody values were significantly higher in subjects with autoimmune diseases than those without autoimmunity (p < .05). The rate of adverse events were 38% and 42% in subjects vaccinated with the Sinopharm and Oxford-AstraZeneca, respectively. The rates of immunogenic responses induced with the Sinopharm and Oxford-AstraZeneca were, respectively, 76% and 81.5% in seropositive subjects, while they were 63.8% and 79.1% in seronegative subjects vaccinated with the Sinopharm and Oxford-AstraZeneca, respectively. Individuals previously infected with SARS-CoV-2 showed a significant reduction in the value of SARS-CoV-2 neutralizing antibodies compared with seronegative subjects (p < .01-.05). Seropositive individuals vaccinated with the Sinopharm had significantly higher the percentages of vaccine-related adverse events than seronegative persons (p < .05). There was no significant difference between seronegative and seropositive individuals vaccinated with the Oxford-AstraZeneca.Conclusion: Our findings revealed that the Sinopharm and Oxford-AstraZeneca vaccines are effective in the production of neutralizing antibodies in healthy subjects and patients with autoimmune disorders undergoing immunosuppressive therapies without considerable reactogenicity.

Evaluation of SARS-CoV-2 Humoral Response Following Vaccination with ChAdOx1 nCoV-19 (Covishield™) and/or Sinopharm, BBIBP-CorV (Vero cell™).

BACKGROUND: Billions of doses of COVID-19 vaccine have been introducing in the world to prevent pandemic COVID-19. Higher efficacy but limited data are available for its longevity. We aimed to find out the IgG Anti-SARS Cov-2 antibody level among frontline healthcare workers after two doses of vaccines. METHODS: A cross-sectional study was carried among 170 HCPs of Seti Provincial Hospital of western Nepal, who were more than 18 years, and had taken two doses of either one of COVID 19 vaccine. All those participants, who were on leave during the data collection tenure (1st February 2022 to 28th February 2022) and/or did not consent to participate were excluded. Mindray SARS-CoV-2 S-RBD IgG assay kit based on CLIA method, was used whose target antigen is S-RBD (spike protein of receptor binding domain) antigen. The IgG immunoglobulin is detected and cut off value ≥10 AU/ml is considered positive. RESULTS: Based on the recommended cut off, the antibody was present in more than 90% across both groups of vaccinee i.e. the positive antibody titer at a mean duration of 7.31 months was 93.53% overall (93.75% and 93.44% in Vero cell™ and Covishield™ vaccinees respectively). There were 3.92 times high odds of high antibody titer (≥250 AU/ml) in Covishield™ group (OR: 3.92, 95% CI: 1.86-8.26, P-value: <0.001) than in Vero cell™ group of vaccinee. Similarly, there were significant difference of high titer of antibody across groups with more than six months of elapse of vaccination (OR: 2.18, 95% CI: 1.06-4.49, P-value: <0.001) than with less than six months of elapse of vaccination. CONCLUSIONS: The humoral response was higher among HCPs who received two-doses vaccination with ChAdOx1 nCoV-19 (Covishield™) and/or Sinopharm, BBIBP-CorV (Vero cell™) vaccine, and among those with six or more months of elapse of vaccination. The seroprevalence of SARS-CoV-2 following two-doses vaccination among HCPs was more than nine-tenths.

Bilateral Acute Posterior Multifocal Placoid Pigment Epitheliopathy With Bacillary Layer Detachment Following Sinopharm COVID-19 Vaccination: A Case Report.

Various ocular manifestations associated with COVID-19 and vaccines, affecting both the anterior and posterior segments of the eye have been documented in the literature. In this report, we present the case of a 25-year-old male who complained of sudden-onset blurred vision and metamorphopsia in both eyes one day after receiving the second dose of the Sinopharm COVID-19 vaccine. The visual loss was painless, with no reported flashes or floaters. The patient had no significant medical or surgical history, no history of trauma, and no drug intake. Upon ocular examination, the best-corrected visual acuity was 6/60 (Snellen chart) in both eyes. The anterior segments appeared unremarkable, while fundoscopy revealed multiple yellowish-white subretinal lesions at the posterior pole of both eyes. Spectral domain optical coherence tomography (SD-OCT) confirmed the presence of subretinal fluid (SRF) with neurosensory detachment in each eye, along with bacillary layer detachment (BALAD). There were no signs of inflammation in the vitreous cavity. A diagnosis of acute posterior multifocal plaque pigment epitheliopathy (APMPPE) was established. The patient was prescribed nepafenac 0.1% drops to be instilled three times a day in both eyes and was advised to return for a follow-up examination in two weeks. At the follow-up visit, the patient's vision had improved to 6/9 in the right eye and 6/6 in the left eye, with most of the SRF absorbed. Unilateral APMPPE with BALAD has been mentioned in the literature following various COVID-19 vaccinations, but, to the best of our knowledge, this is the first case report where bilateral APMPPE with BALAD is reported. This case emphasizes the importance of a thorough eye examination for individuals experiencing ocular symptoms after receiving the COVID-19 vaccine.

Antibody Response Before and After the Booster Dose of Inactivated Corona Vaccine in Antibody Deficient Patients.

Patients with inborn errors of immunity (IEI) are among the high-risk groups regarding COVID-19. Receiving booster doses (third and fourth) in addition to the standard doses is recommended in these patients. This study investigated the antibody response before and after a booster dose of Sinopharm vaccine in IEI patients.  Thirty patients (>12 years) with antibody deficiencies, referred to Imam Khomeini Hospital and Children's Medical Center in Tehran, were enrolled in this prospective cross-sectional study. All patients were fully vaccinated with the BBIBP-CorV vaccine (2 doses of Sinopharm). Initial measurements of anti-receptor-binding domain (anti-RBD) and anti-nucleocapsid (anti-N) IgG antibody responses were conducted by enzyme-linked immunosorbent assay (ELISA). Subsequently, all patients received a booster dose of the vaccine. Four to six weeks after booster injection, the levels of antibodies were re-evaluated.  Twenty patients with common variable immunodeficiency (CVID), 7 cases with agammaglobulinemia and 3 patients with hyper IgM syndrome were studied. Anti-RBD IgG and anti-N IgG antibodies increased in all patients after the booster. Our results indicated the need of receiving booster doses of the COVID-19 vaccine in patients with antibody deficiencies, even for enhancing humoral immune response specially in patients with CVID.

Humoral and Cellular Immune Response after Three Doses of Sinopharm [Vero Cell]-Inactivated COVID-19 Vaccine in Combination with SARS-CoV-2 Infection Leads to Hybrid Immunity.

BACKGROUND: Several vaccines against COVID-19 have been developed and licensed to enhance the immune response against SARS-CoV-2. Similarly, previous infection with SARS-CoV-2 has been shown to provide significant protection against severe infection and hospitalization. METHODS: We investigated the effect of three doses of the Sinopharm vaccine and SARS-CoV-2 infection on the specific immune response in 103 volunteers, measuring neutralizing antibodies, anti-S1 IgG, anti-RBD IgM, anti-N IgM, anti-N IgG antibodies, and INF γ. RESULTS: Our results showed that the presence of cardiovascular diseases increased the level of anti-N-IgG antibodies, while endocrinological diseases decreased the level of neutralizing antibodies and anti-N IgG antibodies, suggesting that these diseases alter the effect of vaccine-induced immunity. In addition, there was a significant decrease in anti-S1 IgG levels at 6 months and in anti-N IgG levels 18 months post-infection, while neutralizing antibodies and INF γ levels were constant at 3, 6, and 18 months post-infection. CONCLUSIONS: Our results confirm the emergence of hybrid immunity, which is the strongest and most durable compared to natural immunity or vaccine-induced immunity. Significant positive correlations were found between humoral and cellular immunity markers: neutralizing antibodies, anti-S1 IgG and anti-N IgG antibodies, and INF γ, indicating a unique coordinated response specific to COVID-19.

A Systematic Review of the COVID Vaccine's Impact on the Nervous System.

AIMS & OBJECTIVES: The objective of this study was to conduct a systematic review of research pertaining to the COVID-19 vaccine and its association with neurological complications. METHOD: We performed a comprehensive search of the literature using Google Scholar, PubMed, and NCBI databases from December 2021 to December 2022. For Google Scholar, PubMed, and NCBI databases we used the following key search terms: "neurological adverse effects", "COVID-19 vaccination", "SARS-CoV-2", CNS complications, and CNS adverse effects. Two reviewer authors individually searched and assessed the titles and abstracts of all articles. The third reviewer resolved the disagreement between them. Data were documented regarding title, study location, type of study, type of COVID-19 vaccine, type of neurological complications/adverse effects, and sample size. RESULTS: From our findings, it is confirmed that these neurological complications like GuillainBarre syndrome (23.6%), Neuromyelitis Optica spectrum disorder (5.5%), Neuropathy (6.9%), Transverse Myelitis (8.3%) and Acute disseminated Encephalomyelitis (4.1%) are majorly affected in most of the people. The increase in risks associated with SARS-CoV-2 infection far outweighs any previously reported associations with vaccination. CONCLUSION: We found no safety signal was observed between COVID-19 vaccines and the immune-mediated neurological events. Before assuming a causal relationship, the side effects of the COVID-19 vaccine should first be carefully examined to rule out known associated factors. Symptom onset was within two weeks of vaccination in the majority of cases; as such, this seems to be a high-risk period warranting vigilance.

Acute disseminated encephalomyelitis following the COVID-19 Vaccine Sinopharm in low- and middle-income country: a case report.

Introduction and importance: Coronavirus disease 2019 (COVID-19) is a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and various vaccines against it have been developed. Acute disseminated encephalomyelitis (ADEM) is a disease of the central nervous system that cause inflammation and demyelination and manifests as a multi-symptom acute neurological condition. Although infections are usually the cause of ADEM, vaccines may cause 5-10% of cases. Case presentation: A 40-year-old woman had received a second dose of the Sinopharm COVID-19 vaccine 4 months before her visit and experienced sudden gait imbalance and vertigo a day after her vaccination, which lasted for more than a month. On examination, no signs of skin bruising or bleeding were observed, and her vital signs were within the normal range. On neurological assessment, the patient had a Glasgow Coma Scale score of 14/15 (E4V5M5), had normal pupil size and light reaction, normal fundus, normal deep tendon reflexes and bilateral extensor plantar response. Meningeal symptoms were absent, and SARS-CoV-2 RNA tests using NAAT (Nucleic Acid Amplification Test) were negative. Development of central nervous system (CNS) manifestations during the recovery phase of fever, along with typical MRI findings; the diagnosis of para-infectious ADEM with COVID-19 vaccination was made. After the treatment with methylprednisolone sodium succinate injection, the patient showed improvement. Clinical discussion: ADEM associated with post-vaccinations is a rare condition. There has been growing evidence that shared epitopes between neuronal proteins and SARS-CoV-2 antigens may trigger autoimmune reactions against the CNS through molecular mimicry as its pathogenesis. Conclusion: We suggest the need for a strict vaccine safety monitoring system and post-vaccine monitoring and surveillance.

Eventos adversos de la vacuna sinopharm en adultos en la paz - bolivia / Sinopharm Vaccine Adverse Events in Adults in La Paz - Bolivia

INTRODUCCIÓN: La vacunación es la única herramienta práctica para detener la expansión y erradicar la pandemia COVID-19, la mayoría de las vacunas han demostrado capacidad de inducir respuestas inmunitarias. Es predecible que existan varias vacunas con distintos niveles de protección por lo que su uso dependerá en cada país de las autoridades sanitarias y recomendaciones de la Organización Mundial de la Salud (OMS). OBJETIVO: Determinar los Eventos Adversos (ESAVIS) de la vacuna Sinopharm administrada en personas adultas en el punto de vacunación masivo de la Red de salud N°4 ESTE de la ciudad de La Paz, meses de abril a octubre gestión 2021. MATERIAL Y MÉTODOS: Se realizó un estudio descriptivo, observacional, muestra de 60 casos, con diagnóstico de Eventos Supuestamente atribuibles a la vacunación y/o inmunización. Los métodos empleados fueron análisis documental, instrumentos usados fichas ESAVIS del Ministerio de Salud y Deportes. Se recogieron datos sociodemográficos, sexo y edad. RESULTADOS: Las personas que presentaron eventos adversos a la Vacuna Sinopharm son del sexo femenino en un 78,3% con un promedio de edad 44 años, con antecedentes patológicos de Hipertensión Arterial Sistèmica en un 5%, el medicamento administrado en un 83,3% es el oxígeno, el síntoma más frecuente son los mareos 58,3%, se presentó más ESAVIS leves en un 98,3%. CONCLUSIÓN: Las personas que recibieron la vacuna Sinopharm presentan ESAVIS Leves.

INTRODUCTION: Vaccination is the only practical tool to stop the expansion and eradicate the COVID-19 pandemic, most vaccines have demonstrated the ability to induce immune responses. It is predictable that there are several vaccines with different levels of protection, so their use will depend in each country on the health authorities and recommendations of the World Health Organization (WHO). OBJECTIVE: To determine the Adverse Events (ESAVIS) of the Sinopharm vaccine administered to adults at the mass vaccination point of the Health Network No. 4 ESTE of the city of La Paz, from April to October, 2021. MATERIAL AND METHODS: A descriptive, observational study was carried out, a sample of60 cases, with a diagnosis of Events Supposedly attributable to vaccination and/or immunization. The methods used were documentary analysis, instruments used ESAVIS files from the Ministry of Health and Sports. Sociodemographic data, sex and age were collected. RESULTS: The people who presented adverse events to the Sinopharm Vaccine are 78.3% female with an average age of 44 years, with a pathological history of Systemic Arterial Hypertension in 5%, the medication administered in 83.3% is oxygen, the most frequent symptom is dizziness 58.3%, more mild ESAVIS occurred in 98.3%. CONCLUSION: People who received the Sinopharm vaccine have Mild ESAVIS.

Elevacion de anticuerpos neutralizantes contra sars cov-2 post vacunacion con sinopharm y astrazeneca hasta la tercera dosis, en el personal del banco de sangre materno infantil cns la paz - bolivia / Elevation of neutralizing antibodies against SARS CoV-2 after vaccination with Sinopharm and AstraZeneca up to the third dose, in the staff of the Maternal and Child Blood Bank CNS La Paz - Bolivia

Introducción: Después de la COVID-19, surgieron luego de muchas investigaciones un suministro de vacunas aprobadas a nivel mundial, dichas vacunas deben conferir una protección eficaz por un tiempo prolongado, poseer un buen perfil de seguridad, ser asequible y ser fácilmente accesible para todos, un reto difícil de conseguir por el tiempo y las características del virus. Objetivo: determinar la concentración de anticuerpos neutralizantes (A. N.) post vacunación en una población de trabajadores del Banco de Sangre Material y métodos: Se realizó un estudio prospectivo, descriptivo, transversal, tomando como población de estudio a todo el personal del Banco de Sangre, varones y mujeres con un rango de edad entre 26 y 72 años, se evaluó el aumento de A. N. después de inoculada la segunda dosis de Sinopharm en fecha 19/05/21, luego se midió la cantidad de anticuerpos generados en fecha 20/10/21 previo a la tercera dosis de refuerzo de Astrazeneca, evaluando nuevamente a los 35 días luego de la tercera dosis 02/12/2021 para finalmente evaluar estos niveles en fecha 26/01/2022. La técnica utilizada fue (ELISA) de la marca EUROIMMUN Anti-SARS- CoV-2 S1 del tipo IgG. Resultados y conclusiones: Se puede verificar que la concentración de A. N. producidos por la vacunación desde Sinopharm y el refuerzo con Astrazeneca favoreció a que dichos anticuerpos se mantengan altos en el tiempo (322 días luego de la primera dosis) llegando a un 80% de la concentración máxima en la lectura final. Concluimos que con cada refuerzo de vacuna anti SARS-CoV-2 el título de A.N. sube de manera significativa, motivo por el cual consideramos importante en nuestro pais una cuarta dosis como método preventivo y de inmunidad.

Introduction: After COVID-19, emerged after much research a supply of vaccines approved worldwide, these vaccines must confer effective protection for a prolonged time, possess a good safety profile, be affordable and be easily accessible to all, a challenge difficult to achieve due to the time and characteristics of the virus. Objective: to determine the concentration of neutralizing antibodies post vaccination in a population of Blood Bank workers; Material and methods: A prospective, descriptive, observational, cross-sectional study was carried out, taking as study population all the Blood Bank personnel, among men and women with an age range between 26 and 72 years old. the increase of Neutralizing Antibodies was evaluated after inoculation of the second dose of Sinopharm on 05/19/21, then the amount of antibodies generated was measured on 10/20/21 prior to the third booster dose of Astrazeneca, evaluating again 35 days after the third dose on 12/02/2021 and finally evaluating these levels on 01/26/2022. The technique used was the EUROIMMUN Anti-SARS-CoV-2 S1 ELISA. Results and conclusions: It can be verified that the concentration of N.A. produced by vaccination from Sinopharm and the booster with Astrazeneca favored that these antibodies remained high over time (322 days after the first dose) reaching 80% of the maximum concentration in the final reading. We conclude that with each booster of anti SARS CoV 2 vaccine, the titer of N.A. rises significantly, which is why we consider important in our country a fourth dose as a preventive and immunity method.