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Abstract The immune response of patients with chronic liver disease tends to be lower after receiving their second coronavirus disease 2019 (COVID‐19) vaccine dose, but the effect of a third vaccine dose on their immune response is currently unknown. We recruited 722 patients without previous severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection from three hospitals. The patients received homologous (MMM) and heterologous (AZAZBNT, AZAZM) boosters, where AZ, BNT, and M denoted the AZD1222, BNT162b2, and mRNA‐1273 vaccines, respectively. Serum IgG spike antibody levels were measured at a mean 1.5 ± 0.7 (visit 1) and 5.0 ± 0.5 (visit 2) months after the third vaccine booster. A threshold of 4160 AU/mL was considered significant antibody activity. In both visits, the patients who received the MMM booster had higher anti‐S‐IgG levels than those who received the AZAZBNT and AZAZM boosters. Patients with active hepatocellular carcinoma (HCC) had lower anti‐S‐IgG levels than the control group (761.6 vs. 1498.2 BAU/mL; p = 0.019) at visit 1. The anti‐S‐IgG levels decreased significantly at visit 2. The patients with significant antibody activity had a lower rate of liver cirrhosis with decompensation (0.7% decompensation vs. 8.0% non‐decompensation and 91.3% non‐liver cirrhosis, p = 0.015), and active HCC (1.5% active HCC vs. 3.7% non‐active HCC and 94.7% non‐HCC, p

The immune response of patients with chronic liver disease tends to be lower after receiving their second coronavirus disease 2019 (COVID‐19) vaccine dose, but the effect of a third vaccine dose on their immune response is currently unknown. We recruited 722 patients without previous severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection from three hospitals. The patients received homologous (MMM) and heterologous (AZAZBNT, AZAZM) boosters, where AZ, BNT, and M denoted the AZD1222, BNT162b2, and mRNA‐1273 vaccines, respectively. Serum IgG spike antibody levels were measured at a mean 1.5 ± 0.7 (visit 1) and 5.0 ± 0.5 (visit 2) months after the third vaccine booster. A threshold of 4160 AU/mL was considered significant antibody activity. In both visits, the patients who received the MMM booster had higher anti‐S‐IgG levels than those who received the AZAZBNT and AZAZM boosters. Patients with active hepatocellular carcinoma (HCC) had lower anti‐S‐IgG levels than the control group (761.6 vs. 1498.2 BAU/mL; p = 0.019) at visit 1. The anti‐S‐IgG levels decreased significantly at visit 2. The patients with significant antibody activity had a lower rate of liver cirrhosis with decompensation (0.7% decompensation vs. 8.0% non‐decompensation and 91.3% non‐liver cirrhosis, p = 0.015), and active HCC (1.5% active HCC vs. 3.7% non‐active HCC and 94.7% non‐HCC, p < 0.001). Receiving the MMM booster regimen (OR = 10.67, 95% CI 5.20–21.91, p < 0.001) increased the odds of having significant antibody activity compared with the AZAZBNT booster regimen. Patients with active HCC had a reduced immune response to the third COVID‐19 vaccine booster. These findings underscore the importance of booster vaccinations, especially in immunocompromised patients, with superior efficacy observed with the homologous mRNA‐1273 regimen. [ABSTRACT FROM AUTHOR]

Background: After licensing of the protein-based vaccine NVX-CoV2373, three technically different vaccines against the SARS-CoV-2 became available for application to the human population - and for comparison of efficacies. Methods: We here recruited 42 study participants who had obtained one initial dose of NVX-CoV2373 and analyzed their immune responses in contrast to 37 study participants who had obtained either the vector vaccine AZD1222 or the mRNA vaccine BNT162b2 a year earlier. 32 participants also donated blood before first vaccination to serve as a vaccine-naive control. In detail, we investigated and quantified at day 21 and approximately six months after primary immunization the amounts of vaccine-specific antibodies produced, their neutralization capacity, their quality in terms of binding different epitopes and their efficiency in inducing various isotypes. Cellular immunity and intracellular cytokine production following in vitro re-stimulation with BNT162b2 vaccine was analyzed via ELISpot or via flow cytometry. Results: Our results show that even though vaccination including the mRNA vaccine yielded best results in almost any aspect of antibody levels and binding efficiency, the neutralization capacities against the wild-type Wuhan strain and the Omicron BA.1 variant early and at six months were comparable among all three vaccination groups. As for the T cells, we observed a prevailing CD8 response at three weeks which turned into a predominant CD4 memory at six months which has not yet been observed for AZD1222 and BNT162b2. While additional infection with SARS-CoV-2 resulted in a boost for the humoral response, T cell memory appeared rather unaffected. Conclusion: Whether any of these differences translate into real world protection from infection, mitigation of severe disease courses and prevention of long/post COVID will need to be investigated in the future. [ABSTRACT FROM AUTHOR]

BackgroundAfter licensing of the protein-based vaccine NVX-CoV2373, three technically different vaccines against the SARS-CoV-2 became available for application to the human population - and for comparison of efficacies.MethodsWe here recruited 42 study participants who had obtained one initial dose of NVX-CoV2373 and analyzed their immune responses in contrast to 37 study participants who had obtained either the vector vaccine AZD1222 or the mRNA vaccine BNT162b2 a year earlier. 32 participants also donated blood before first vaccination to serve as a vaccine-naive control. In detail, we investigated and quantified at day 21 and approximately six months after primary immunization the amounts of vaccine-specific antibodies produced, their neutralization capacity, their quality in terms of binding different epitopes and their efficiency in inducing various isotypes. Cellular immunity and intracellular cytokine production following in vitro re-stimulation with BNT162b2 vaccine was analyzed via ELISpot or via flow cytometry.ResultsOur results show that even though vaccination including the mRNA vaccine yielded best results in almost any aspect of antibody levels and binding efficiency, the neutralization capacities against the wild-type Wuhan strain and the Omicron BA.1 variant early and at six months were comparable among all three vaccination groups. As for the T cells, we observed a prevailing CD8 response at three weeks which turned into a predominant CD4 memory at six months which has not yet been observed for AZD1222 and BNT162b2. While additional infection with SARS-CoV-2 resulted in a boost for the humoral response, T cell memory appeared rather unaffected.ConclusionWhether any of these differences translate into real world protection from infection, mitigation of severe disease courses and prevention of long/post COVID will need to be investigated in the future.

Key Clinical Message: Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by a low platelets count. In this paper, we present a case of ITP relapse in a 31‐year‐old Iranian woman as a potential complication of the AstraZeneca vaccine. [ABSTRACT FROM AUTHOR]

Abstract Background This study aimed to evaluate the reactogenicity effects of COVID-19 vaccines, used in Iran. Methods At least 1000 people were followed up with phone calls or self-report in a mobile application within 7 days after vaccination. Local and systemic reactogenicities were reported overall and by subgroups. Results The presence of one or more local and systemic adverse effects after the first dose of vaccines was 58.9% [(95% Confidence Intervals): 57.5–60.3)] and 60.5% (59.1–61.9), respectively. These rates were reduced to 53.8% (51.2–55.0) and 50.8% (48.8–52.7) for the second dose. The most common local adverse effect reported for all vaccines was pain in the injection site. During the first week after the first dose of vaccines, the frequency of the pain for Sinopharm, AZD1222, Sputnik V, and Barekat was 35.5%, 86.0%, 77.6%, and 30.9%, respectively. The same rates after the second dose were 27.3%, 66.5%, 63.9%, and 49.0%. The most common systemic adverse effect was fatigue. In the first dose, it was 30.3% for Sinopharm, 67.4% for AZD1222, 47.6% for Sputnik V, and 17.1% for Barekat. These rates were reduced to 24.6%, 37.1%, 36.5%, and 19.5%, in the second dose of vaccines. AZD1222 had the highest local and systemic adverse effects rates. The odds ratio of local adverse effects of the AZD1222 vaccine compared to the Sinopharm vaccine were 8.73 (95% CI 6.93–10.99) in the first dose and 4.14 (95% CI 3.32–5.17) in the second dose. Barekat and Sinopharm had the lowest frequency of local and systemic adverse effects. Compared to Sinopharm, systemic adverse effects were lower after the first dose of Barekat (OR = 0.56; 95% CI 0.46–0.67). Reactogenicity events were higher in women and younger people. Prior COVID-19 infection increased the odds of adverse effects only after the first dose of vaccines. Conclusions Pain and fatigue were the most common reactogenicities of COVID-19 vaccination. Reactogenicities were less common after the second dose of the vaccines. The adverse effects of AZD1222 were greater than those of other vaccines.

Key Clinical Message Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by a low platelets count. In this paper, we present a case of ITP relapse in a 31‐year‐old Iranian woman as a potential complication of the AstraZeneca vaccine.

Cases of thromboembolic events in 2021 flared up the discussion about the safety of Astra Zeneca’s AZD1222 vaccine. We hereby report three cases of pulmonary embolism (PE), one case of extended portal vein thrombosis, and one case of combined portal vein thrombosis and PE within 2 weeks after vaccination with the Astra Zeneca AZD1222 vaccine in a 60-year-old, a 50-year old, a 33-year-old, a 30-year old, and a 40-year-old male in that year. All patients were healthy before. In three patients, we observed thrombocytopenia and to some extent unusually low antibody levels for the Spike Protein (S-protein), while the other two had normal thrombocyte counts. Only one patient had anti-platelet factor 4 (PF4)-antibodies detectable as it has been described in the “heparin-induced thrombocytopenia (HIT)-like” disease of “vaccine-induced prothrombotic immune thrombocytopenia” (VIPIT) and we therefore assume that heterogeneous mechanisms led to PE. Therefore, we advise to collect and report more cases, in order to determine the age-related risks of vaccination balanced against the benefits of immunity to SARS-COV-2 for the AZD1222 vaccine in order to gain knowledge for the next pandemic.

Objectives: The SARS-CoV-2 Omicron variant presents numerous mutations potentially able to evade neutralizing antibodies (NAbs) elicited by COVID-19 vaccines. Therefore, this study aimed to provide evidence on a heterologous booster strategy to overcome the waning immunity against Omicron variants. Methods: Participants who completed the Oxford/AstraZeneca (hereafter AZD1222) vaccine dose for 5-7 months were enrolled. The reactogenicity and persistence of immunogenicity in both humoral and cellular response after a homologous or heterologous booster with the AZD1222 and messenger RNA (mRNA) vaccines (BNT162b2, full, or half-dose mRNA-1273) administered 6 months after primary vaccination were determined. Results: A total of 229 individuals enrolled, and waning of immunity was observed 5-7 months after the AZD1222-primed vaccinations. Total receptor-binding domain (RBD) immunoglobulin (Ig) levels, anti-RBD IgG, and focus reduction neutralization test against Omicron BA.1 and BA.2 variants and T cell response peaked at 14-28 days after booster vaccination. Both the full and half dose of mRNA-1273 induced the highest response, followed by BNT162b2 and AZD1222. At 90 days, the persistence of immunogenicity was observed among all mRNA-boosted individuals. Adverse events were acceptable for all vaccines. Conclusion: A heterologous mRNA booster provided a significantly superior boost of binding and NAbs levels against the Omicron variant compared with a homologous booster in individuals with AZD1222-primed vaccinations.

Background: This study aimed to evaluate the reactogenicity effects of COVID-19 vaccines, used in Iran. Methods: At least 1000 people were followed up with phone calls or self-report in a mobile application within 7 days after vaccination. Local and systemic reactogenicities were reported overall and by subgroups. Results: The presence of one or more local and systemic adverse effects after the first dose of vaccines was 58.9% [(95% Confidence Intervals): 57.5–60.3)] and 60.5% (59.1–61.9), respectively. These rates were reduced to 53.8% (51.2–55.0) and 50.8% (48.8–52.7) for the second dose. The most common local adverse effect reported for all vaccines was pain in the injection site. During the first week after the first dose of vaccines, the frequency of the pain for Sinopharm, AZD1222, Sputnik V, and Barekat was 35.5%, 86.0%, 77.6%, and 30.9%, respectively. The same rates after the second dose were 27.3%, 66.5%, 63.9%, and 49.0%. The most common systemic adverse effect was fatigue. In the first dose, it was 30.3% for Sinopharm, 67.4% for AZD1222, 47.6% for Sputnik V, and 17.1% for Barekat. These rates were reduced to 24.6%, 37.1%, 36.5%, and 19.5%, in the second dose of vaccines. AZD1222 had the highest local and systemic adverse effects rates. The odds ratio of local adverse effects of the AZD1222 vaccine compared to the Sinopharm vaccine were 8.73 (95% CI 6.93–10.99) in the first dose and 4.14 (95% CI 3.32–5.17) in the second dose. Barekat and Sinopharm had the lowest frequency of local and systemic adverse effects. Compared to Sinopharm, systemic adverse effects were lower after the first dose of Barekat (OR = 0.56; 95% CI 0.46–0.67). Reactogenicity events were higher in women and younger people. Prior COVID-19 infection increased the odds of adverse effects only after the first dose of vaccines. Conclusions: Pain and fatigue were the most common reactogenicities of COVID-19 vaccination. Reactogenicities were less common after the second dose of the vaccines. The adverse effects of AZD1222 were greater than those of other vaccines. [ABSTRACT FROM AUTHOR]

The changes in the severe acute respiratory syndrome coronavirus 2 and the tapering of immunity after vaccination have propelled the need for a booster dose vaccine. We aim to evaluate B and T cell immunogenicity and reactogenicity of mRNA-1273 COVID-19 vaccine (100 µg) as a third booster dose after receiving either two doses of inactivated COVID-19 vaccine (CoronaVac) or two doses of viral vector vaccine (AZD1222) in adults not previously infected with COVID-19. The anti-receptor-binding-domain IgG (anti-RBD IgG), surrogate virus neutralization test (sVNT) against the Delta variant, and Interferon-Gamma (IFN-γ) level were measured at baseline, day (D)14 and D90 after vaccination. In D14 and D90, the geometric means of sVNT were significantly increased to 99.4% and 94.5% inhibition in CoronaVac, respectively, whereas AZD1222 showed inhibition of 99.1% and 93%, respectively. Anti-RBD IgG levels were 61,249 to 9235 AU/mL in CoronaVac and 38,777 to 5877 AU/mL in AZD1222 after D14 and D90 vaccination. Increasing median frequencies of S1-specific T cell response by IFN-γ concentration were also elevated in D14 and were not significantly different between CoronaVac (107.8–2035.4 mIU/mL) and AZD1222 (282.5–2001.2 mIU/mL). This study provides evidence for the high immunogenicity of the mRNA-1273 booster after two doses of CoronaVac or AZD1222 in the Thai population. [ABSTRACT FROM AUTHOR]

BackgroundVaccination has proven the potential to control the COVID-19 pandemic worldwide. Although recent evidence suggests a poor humoral response against SARS-CoV-2 in vaccinated hematological disease (HD) patients, data on vaccination in these patients is limited with the comparison of mRNA-based, vector-based or inactivated virus-based vaccines.MethodsForty-nine HD patients and 46 healthy controls (HCs) were enrolled who received two-doses complete vaccination with BNT162b2, or AZD1222, or BBIBP-CorV, respectively. The antibodies reactive to the receptor binding domain of spike protein of SARS-CoV-2 were assayed by Siemens ADVIA Centaur assay. The reactive cellular immunity was assayed by flow cytometry. The PBMCs were reactivated with SARS-CoV-2 antigens and the production of activation-induced markers (TNF-α, IFN-γ, CD40L) was measured in CD4+ or CD8+ T-cells ex vivo.ResultsThe anti-RBD IgG level was the highest upon BNT162b2 vaccination in HDs (1264 BAU/mL) vs. HCs (1325 BAU/mL) among the studied groups. The BBIBP-CorV vaccination in HDs (339.8 BAU/mL ***p

Naif Khalaf Alharbi,1,2 Jaffar A Al-Tawfiq,3– 5 Amal Alwehaibe,1 Mohamed W Alenazi,1 Abdulrahman Almasoud,1 Abdullah Algaisi,6 Fahad A Alhumaydhi,7 Anwar M Hashem,8,9 Mohammed Bosaeed,1,2,10 Suliman A Alsagaby11 1Vaccine Development Unit, King Abdullah International Medical Research Center (KAIMRC), Riyadh, Saudi Arabia; 2College of Medicine, King Saud bin Abdulaziz University for Health Science (KSAU-HS), Riyadh, Saudi Arabia; 3Specialty Internal Medicine and Quality Department, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia; 4Infectious Diseases Division, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; 5Infectious Diseases Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 6Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia; 7Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia; 8Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia; 9Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia; 10King Abdulaziz Medical City (KAMC), Ministry of National Guard – Health Affairs (MNG-HA), Riyadh, Saudi Arabia; 11Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Al Majmaah, Saudi ArabiaCorrespondence: Naif Khalaf Alharbi, Email naifkhalaf2014@gmail.comPurpose: This study was conducted to investigate antibody immune responses induced by BNT162b2 and AZD1222 human COVID-19 vaccines in Riyadh city, Saudi Arabia.Patients and Methods: ELISA was used to evaluate antibodies, against the SARS-CoV-2 spike S1 protein, in serum samples from 432 vaccinated individuals at six time points: pre-vaccination (baseline), post-prime, post-boost, 6-months, and 1 year post-vaccination, and 3 weeks post a third dose. Virus microneutralization assay was used to confirm antibody responses in a subset of samples.Results: Anti-SARS-CoV-2 spike IgG were detected in most subjects post-prime, reached a peak level post-boost, and remained at high level at the 6-month follow-up. At 1 year post-vaccine, the antibody levels were low but increased to a significant level higher than the peak following a third dose. The third dose was given at an average of 250 days after the second dose. The virus microneutralization assay confirmed the neutralization activity of the induced SARS-CoV-2 IgG antibodies. The vaccines induced higher IgG titres at post-prime (p=0.0001) and 6 months (p=0.006) in previously infected individuals. An increased interval between prime and boost, more than recommended time, appeared to enhance the IgG levels (p=0004). Moreover, the vaccines induced higher IgG levels in younger subjects (p=0.01).Conclusion: These data provide insights and build on the current understanding of immune responses induced by these two vaccines; and support a third boosting dose for these COVID-19 vaccines.Keywords: COVID-19, vaccines, BNT162b2, AZD1222, Immune responses, antibody, IgG

Background: Two vaccines for COVID-19 have been approved and administered in the Kingdom of Saudi Arabia (KSA); Pfizer-BioNtech BNT162b2 and AstraZeneca-Oxford AZD1222 vaccines. The purpose of this study was to describe the real-world data on the outcome of single dose of these COVID-19 vaccines in a large cohort in KSA and to analyse demographics and co-morbidities as risk factors for infection post one-dose vaccination. Methods: In this prospective cohort study, a total of 18,543 subjects received one dose of either of the vaccines at a vaccination centre in KSA, and were followed up for three to eight months. Data were collected from three sources; clinical data from medical records, adverse events (AEs) from a self-reporting system, and COVID-19 infection data from the national databases. The study was conducted during the pandemic restrictions on travel, mobility, and social interactions. Results: The median age of participants was 33 years with an average body mass index of 27.3. The majority were males (60.1%). Results showed that 92.17% of the subjects had no COVID-19 infection post-vaccination as infection post-vaccination was documented for 1452 (7.83%). Diabetes mellitus 03), organ transplantation (p = 0.02), and obesity (p

ABSTRACT: Background: Immunogenicity and safety of the AZD1222 (ChAdOx1 nCoV-19) vaccine was evaluated in Japanese adults in an ongoing phase 1/2, randomized, double-blind, parallel-group, placebo-controlled, multi-centre trial (NCT04568031). Methods: Adults (n=256, age ≥18 years) seronegative for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) were stratified by age into 18–55- (n=128), 56–69- (n=86) and ≥70-year-old cohorts (n=42), and randomized 3:1 to receive AZD1222 or placebo (two intramuscular injections 4 weeks apart). Immunogenicity and safety were coprimary endpoints. Data collected up to Day 57 are reported. Results: Positive seroresponses to SARS-CoV-2 spike and receptor-binding domain antigens were seen in all 174 participants who received two doses of AZD1222. Neutralizing antibody seroresponses were seen in 67.5%, 60.3% and 50.0% of participants receiving AZD1222 aged 18–55, 56–69 and ≥70 years, respectively. Solicited adverse events (AEs) were typically mild/moderate in severity and included pain and tenderness at the injection site, malaise, fatigue, muscle pain and headache. Common unsolicited AEs included pain and tenderness at the injection site, fatigue and elevated body temperature. No vaccine-related serious AEs or deaths were reported. Conclusions: AZD1222 elicited a strong humoral immune response against SARS-CoV-2, and was well tolerated in Japanese participants, including elderly participants.

Abstract Background While vaccination programs against the severe acute respiratory syndrome virus 2 (SARS-CoV-2) are globally ongoing, disparate strategies for the deployment of spike antigen show varying effectiveness. Methods In order to explore this phenomenon, we sought to compare the early immune responses against AZD1222 and BNT162b2. SARS-CoV-2 seronegative participants received a single dose of either vaccine and were analyzed for immune cell, effector T cell, and antibody dynamics. Results AZD1222 induced transient leukopenia and major changes among innate and adaptive subpopulations. Both vaccines induced spike protein-specific effector T cells which were dominated by type 1 helper T cell responses following AZD1222 vaccination. A significant reduction of anti-inflammatory T cells upon re-stimulation was also restricted to AZD1222 vaccinees. While IgM and IgG were the dominant isotypes elicited by AZD1222, BNT162b2 led to a significant production of IgG and IgA. Conclusions Our results suggest that the strategy for spike protein delivery impacts on how and to what extent immune priming against the main SARS-CoV-2 antigen proceeds.

The global supply of COVID-19 vaccines has been limited, and concerns have arisen about vaccine supply chain disruptions in developing countries. Heterologous prime-boost vaccination, which involves using different vaccines for the first and second doses, has been proposed to enhance the immune response. We aimed to compare the immunogenicity and safety of a heterologous prime-boost vaccination using an inactivated COVID-19 vaccine and AZD1222 vaccine with that of a homologous vaccination using AZD1222. This pilot involved 164 healthy volunteers without prior SARS-CoV-2 infection aged 18 years or older assigned to receive either the heterologous or homologous vaccination. The results showed that the heterologous approach was safe and well-tolerated, although the reactogenicity of the heterologous approach was higher. At 4 weeks after receiving the booster dose, the heterologous approach elicited a non-inferior immune response compared to the homologous approach in neutralizing antibody and cell-mediated immune response. The percentage of inhibition was 83.88 (79.72–88.03) in the heterologous and 79.88 (75.50–84.25) in the homologous group, a mean difference of 4.60 (−1.67–10.88). The geometric mean of interferon-gamma was 1072.53 mIU/mL (799.29–1439.18) in the heterologous group and 867.67 mIU/mL (671.94–1120.40) in the homologous group, a GMR of 1.24 (0.82–1.85). However, the binding antibody test of the heterologous group was inferior to the homologous group. Our findings suggest that the use of heterologous prime-boost vaccination with different types of COVID-19 vaccines is a viable strategy, especially in settings where vaccine supply is limited or where vaccine distribution is challenging.

Vaccine-associated thrombotic thrombocytopenic purpura (TTP) is a rare type of acquired TTP recently reported after COVID-19 vaccination. Merely four cases are ascribed to the ChAdOx1 nCoV-19 vaccine in the medical literature till the preparation of this study. In this case report, we describe a 43-year-old man who developed symptoms of TTP four days after receiving the second dose of the ChAdOx1 nCoV-19 vaccine. Peripheral blood smear demonstrated multiple schistocytes. Given a high plasmic score, he received plasma exchange, corticosteroids, and rituximab, and later, low ADAMTS 13 activity and high-titer ADAMTS inhibition antibody confirmed the diagnosis of COVID-19 vaccine-associated TTP. COVID-19 vaccine-associated TTP is an infrequent consequence of SARS-CoV-2 vaccination but with a substantial mortality rate which must be considered as one of the crucial differential diagnoses of post-COVID-19 vaccine thrombocytopenia besides vaccine-induced immune thrombotic thrombocytopenia and Immune thrombocytopenic purpura.

Two vaccines, namely BBV-152 (COVAXIN®) and AZD1222 (COVISHIELD™), were deployed against SARS-CoV-2 in India from January 16, 2021. Frontline health care workers were vaccinated first, followed by the adult population. However, limited data on vaccine effectiveness are available for the population of India. Therefore, we aimed to evaluate the effectiveness of two doses of each of these two common vaccines against COVID-19 infection among hospitalized patients with pulmonary conditions. We adopted a test-negative case–control design and recruited a sample of adults who were admitted to one of six tertiary care hospitals in Odisha. All participants were hospitalized patients with COVID-19-like pulmonary signs and symptoms. Participants who tested positive for SARS CoV-2 via RT-PCR were treated as cases, and those who tested negative were treated as controls. Logistic regression, adjusted for participants' age, sex, and number of comorbidities, was used to calculate the effectiveness of the two vaccines, using the formula: 100*(1 – adjusted odds ratio). Between March and July of 2021, data were collected from 1,614 eligible adults (864 cases and 750 controls). Among all participants, 9.7% had received two doses of one of the two COVID-19 vaccines. Vaccine effectiveness was 74.0% (50.5%−86.0%) for two doses of BBV-152 and 79.0% (65.4%−87.2%) for two doses of AZD1222. Thus, two doses of either BBV-152 or AZD1222 nCoV-19 vaccine were found to be substantially effective in protecting against COVID-19-related infection.

Mass vaccination with a safe and effective vaccine may be the best way to control the COVID-19 pandemic. Heterologous prime-boost vaccination with the CoronaVac and AZD1222 vaccines may increase the immunogenicity elicited by either vaccine alone. This study sought to compare the immunogenicity of a heterologous CoronaVac and AZD1222 prime-boost with a homologous CoronaVac prime-boost. From July 13 to September 2, 2021, 88 participants were enrolled in the study. Half (n = 44) of the participants were assigned to the AZD1222/CoronaVac cohort and half were assigned to the CoronaVac/AZD1222 cohort. Both cohorts had a prime-boost interval of 4 weeks. A control group of 136 health care personnel who received the homologous CoronaVac/CoronaVac prime-boost was matched by age and sex to the experimental cohorts. The primary endpoint was the geometric mean ratio (GMR) of the anti-receptor binding domain (RBD) antibody concentration 4 weeks after the booster dose was administered. The CoronaVac/CoronaVac cohort served as the reference group. Baseline age and sex were similar, and the median age was 42.5 years. The GMR was 2.58 (95% confidence interval [CI] 1.80–3.71) and 8.69 (95% CI 6.05–12.47) in the AZD1222/CoronaVac and CoronaVac/AZD1222 cohorts, respectively. Reactogenicity was similar following prime and booster doses with the same vaccine. Findings indicated that the heterologous CoronaVac and AZD1222 prime-boost combination elicited a more robust immune response than the homologous CoronaVac prime-boost. While both heterologous prime-boost combinations showed similar reactogenicity, the immunogenicity of the CoronaVac/AZD1222 cohort was higher, indicating that the order of prime-boost vaccine administration was important.

The study aimed to evaluate vaccine-related adverse events (VRAEs) following ChAdOx1-nCoV-19 vaccine in solid cancer patients receiving treatment compared to healthy controls. 399 cancer patients and 90 healthy volunteers were enrolled. In the overall population, the incidence of VRAEs was significantly lower in cancer patients than in healthy volunteers (57% vs 80%, P

Introduction Cancer patients are more vulnerable to coronavirus disease 2019 (COVID-19) owing to their compromised immune status. However, data regarding COVID-19 vaccine safety and immune response in cancer patients are scarce. Method This prospective, age- and sex-matched, single-center cohort study included 61 cancer patients and 122 healthy control participants. Seropositivity was defined as anti-S IgG titer >0.8 units/ml. Primary end point was seroconversion rate of immunoglobulin (Ig)G antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein (anti-S IgG) in cancer patients vs. healthy control participants following the second dose of COVID-19 vaccine ChAdOx1 nCoV-19 (AZD1222). Results After the second-dose vaccination, there was no difference in seropositivity rate between groups (57 [93.44%] patients with cancer vs. 121 [99.18%] control participants; geometric mean ratio [GMR]: 0.39; 95%CI: 0.01–10.46; p-value = 0.571). In contrast, after the first-dose vaccination, the seropositivity rate was significantly lower in the cancer patients than in the control participants (50/61 [81.97%] vs. 121/122 [99.18%]; GMR: 0.07; 95%CI: 0.01–0.71; p = 0.025). The median anti-S IgG titer after the first-and second dose vaccination were not significantly different between groups. Female sex was significantly associated with a higher anti-S IgG titer. 5FU- and taxane-based chemotherapy regimens were associated with a lower IgG titer. Side effects of vaccination were tolerable. Conclusions The anti-S IgG seropositivity rate after completing the second vaccine dose did not differ between the cancer patients and control participants. However, the anti-S IgG seropositivity rate after the first-dose vaccination was lower in cancer patients.

We report the safety and immunogenicity results in participants administrated with a booster dose of protein subunit vaccine MVC-COV1901 at 12 (Group A) or 24 (Group B) weeks after two doses of AZD1222 (ChAdOx1 nCoV-19). The administration of the MVC-COV1901 vaccine as a booster dose in both groups was generally safe. There were no serious adverse events related to the intervention as adverse events reported were "mild" or "moderate" in nature. In subjects fully vaccinated with two doses of AZD1222, waning antibody immunity was apparent within six months of the second dose of AZD1222. At one month after the MVC-COV1901 booster dose, those who were vaccinated within 12 weeks after the last AZD1222 dose (Group A) had anti-SARS-CoV-2 spike IgG antibody titers and neutralizing antibody titers which were 14- and 6.5-fold increased, respectively, when compared to the titer levels on the day of the booster dose. On the other hand, fold-increase a month post-booster in people who had a booster 24 weeks after the last AZD1222 dose (Group B) were 19.5 and 14.0 times for anti-SARS-CoV-2 spike IgG antibody titers and neutralizing antibody titers, respectively. Among those who were vaccinated within 12 weeks after the last AZD1222 dose, we also observed 5.2- and 5.6-fold increases in neutralizing titer levels against ancestral strain and Omicron variant pseudovirus after the booster dose, respectively. These results support the use of MVC-COV1901 as a heterologous booster for individuals vaccinated with AZD1222. Furthermore, regardless of the dosing schedule, the combination of AZD1222 primary series and MVC-COV1901 booster can be cost-effective and suitably applied to low- and middle-income countries (LMIC). [ABSTRACT FROM AUTHOR]

Kidney transplant recipients (KTRs) have a suboptimal immune response to COVID-19 vaccination due to the effects of immunosuppression, mostly mycophenolic acid (MPA). This study investigated the benefits of switching from the standard immunosuppressive regimen (tacrolimus (TAC), MPA, and prednisolone) to a regimen of mammalian target of rapamycin inhibitor (mTORi), TAC and prednisolone two weeks pre- and two weeks post-BNT162b2 booster vaccination. A single-center, opened-label pilot study was conducted in KTRs, who received two doses of ChAdOx-1 and a single dose of BNT162b2. The participants were randomly assigned to continue the standard regimen (control group, n = 14) or switched to a sirolimus (an mTORi), TAC, and prednisolone (switching group, n = 14) regimen two weeks before and two weeks after receiving a booster dose of BNT162b2. The anti-SARS-CoV-2 S antibody level after vaccination in the switching group was significantly greater than the control group (4051.0 [IQR 3142.0–6466.0] BAU/mL vs. 2081.0 [IQR 1077.0–3960.0] BAU/mL, respectively; p = 0.01). One participant who was initially seronegative in the control group remained seronegative after the booster dose. These findings suggest humoral immune response benefits of switching the standard immunosuppressive regimen to the regimen of mTORi, TAC, and prednisolone in KTRs during vaccination. [ABSTRACT FROM AUTHOR]

Patients with diabetes and coexistent coronavirus disease 2019 (COVID-19) have a higher risk of COVID-19 complications. Therefore, it is critical that sustained and effective immunogenicity against COVID-19 is achieved in such patients. This study evaluates the antibody response for 56 days after the first dose of the AZD1222 vaccine in subjects with and without diabetes to assess the potential risk of delaying the second dose. This study included 282 people who received one dose of AZD1222. The geometric mean concentration of antibodies specific for severe acute respiratory syndrome coronavirus 2 IgG at 56 days was significantly (P < 0.001) lower in people with type 2 diabetes mellitus (T2D; 15.13 BAU/mL, 95% confidence interval [CI] = 10.7–21.4) than in those without diabetes (40.20 BAU/mL, 95% CI = 33.43–48.36), as confirmed by a geometric mean ratio of 0.37 (95% CI = 0.25–0.54). Weaker immune responses were also observed in diabetic patients ≥ 65 years old (10.09 BAU/mL, 95% CI = 6.09–16.71) compared with their younger counterparts (22.31 BAU/mL, 95% CI = 13.98–35.59, P = 0.034). People with T2D had weaker antibody responses than those without diabetes after the first dose of AZD1222. Older age was associated with weaker antibody responses in elderly patients with diabetes. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has particularly affected older adults residing in nursing homes, resulting in high rates of hospitalisation and death. Here, we evaluated the longitudinal humoral response and neutralising capacity in plasma samples of volunteers vaccinated with different platforms (Sputnik V, BBIBP-CorV, and AZD1222). A cohort of 851 participants, mean age 83 (60- 103 years), from the province of Buenos Aires, Argentina were included. Sequential plasma samples were taken at different time points after vaccination. After completing the vaccination schedule, infection-naïve volunteers who received either Sputnik V or AZD1222 exhibited significantly higher specific anti-Spike IgG titers than those who received BBIBP-CorV. Strong correlation between anti-Spike IgG titers and neutralising activity levels was evidenced at all times studied (rho=0.7 a 0.9). Previous exposure to SARS-CoV-2 and age <80 years were both associated with higher specific antibody levels. No differences in neutralising capacity were observed for the infection-naïve participants in either gender or age group. Similar to anti-Spike IgG titers, neutralising capacity decreased 3 to 9-fold at 6 months after initial vaccination for all platforms. Neutralising capacity against Omicron was between 10-58 fold lower compared to ancestral B.1 for all vaccine platforms at 21 days post dose 2 and 180 days post dose 1. This work provides evidence about the humoral response and neutralising capacity elicited by vaccination of a vulnerable elderly population. This data could be useful for pandemic management in defining public health policies, highlighting the need to apply reinforcements after a complete vaccination schedule. [ABSTRACT FROM AUTHOR]

• The messenger RNA (mRNA) booster produced a high cross-neutralization level against the Omicron variant. • The half-dose mRNA-1273 elicited total immunoglobulin (Ig) and anti-receptor-binding domain IgG equal to the full dose. • The neutralizing activity thwarting the BA.1 and BA.2 variants was comparable in the mRNA booster. • Clusters of differentiation (CD), CD4+ and CD8+ T cell responses were restored after the mRNA booster vaccination. • The additional fourth dose should be implemented for AZD1222-boosted individuals. The SARS-CoV-2 Omicron variant presents numerous mutations potentially able to evade neutralizing antibodies (NAbs) elicited by COVID-19 vaccines. Therefore, this study aimed to provide evidence on a heterologous booster strategy to overcome the waning immunity against Omicron variants. Participants who completed the Oxford/AstraZeneca (hereafter AZD1222) vaccine dose for 5-7 months were enrolled. The reactogenicity and persistence of immunogenicity in both humoral and cellular response after a homologous or heterologous booster with the AZD1222 and messenger RNA (mRNA) vaccines (BNT162b2, full, or half-dose mRNA-1273) administered 6 months after primary vaccination were determined. A total of 229 individuals enrolled, and waning of immunity was observed 5-7 months after the AZD1222-primed vaccinations. Total receptor-binding domain (RBD) immunoglobulin (Ig) levels, anti-RBD IgG, and focus reduction neutralization test against Omicron BA.1 and BA.2 variants and T cell response peaked at 14-28 days after booster vaccination. Both the full and half dose of mRNA-1273 induced the highest response, followed by BNT162b2 and AZD1222. At 90 days, the persistence of immunogenicity was observed among all mRNA-boosted individuals. Adverse events were acceptable for all vaccines. A heterologous mRNA booster provided a significantly superior boost of binding and NAbs levels against the Omicron variant compared with a homologous booster in individuals with AZD1222-primed vaccinations. [ABSTRACT FROM AUTHOR]

This study observed the antibody response and adverse events of AZD1222 (Oxford/AstraZeneca) vaccination in dialysis patients. A prospective cohort study was conducted in E-Da Healthcare Group hospitals between 1 July and 30 November 2021. Patients receiving hemodialysis (HD, n = 204) or peritoneal dialysis (PD, n = 116) were enrolled alongside healthy subjects (control, n = 34). Anti-SARS-CoV-2 S1 RBD IgG antibodies were measured before the first vaccination (T0), four to six weeks afterwards (T1), one week before the second dose (T2), and four to six weeks afterwards (T3). Adverse events were recorded one week after each dose. The positive IgG rates in the HD (T1: 72%; T2: 62%) and PD (T1: 69%; T2: 70%) groups were lower than the control group (T1: 97%; T2: 91%), with lower median antibody titers. At T3, the positive antibody response rates (HD: 94%; PD: 93%; control: 100%) and titers were similar. Titers were higher after the second dose in all groups. Adverse events were more severe after the first dose and less common with HD than PD or controls. Dialysis patients exhibited lower antibody responses than controls after the first dose of the AZD1222 vaccine but achieved similar responses after consecutive vaccination. Age, health status, two vaccine doses, and alcohol consumption may influence antibody levels. [ABSTRACT FROM AUTHOR]

Vaccine-induced thrombotic thrombocytopenia (VITT), or thrombosis with thrombocytopenia syndrome (TTS), is a rare but serious complication of adenovirus-based vaccines against severe respiratory syndrome coronavirus 2 (SARS-CoV-2). Observation of long-term outcomes is important to guide treatment of affected patients. This single-center consecutive cohort study included all patients diagnosed based on (1) vaccination 4 to 21 days before symptom onset, (2) signs or symptoms of venous or arterial thrombosis, (3) thrombocytopenia < 150/nL, (4) positive anti-platelet factor 4 (PF4) antibody, and (5) elevated D-Dimer > 4 times the upper limit of normal. Nine patients were enrolled. Acute management consisted of parenteral anticoagulants, corticosteroids, intravenous immunoglobulin (IVIG), and/or eculizumab. Eculizumab was successfully used in two patients with recurrent thromboembolic events after IVIG. Direct oral anticoagulants were given after hospital discharge. Median follow-up duration was 300 days (range 153 to 380). All patients survived the acute phase of the disease and were discharged from hospital. One patient died from long-term neurological sequelae of cerebral venous sinus thrombosis 335 days after diagnosis. Eight out of nine patients were alive at last follow-up, and seven had fully recovered. Anti-PF4 antibodies remained detectable for at least 12 weeks after diagnosis, and D-Dimer remained elevated in some patients despite oral anticoagulation. No recurrent thromboembolic events, other signs of VITT relapse, or bleeding complications occurred after discharge. In conclusion, VITT appears to be a highly prothrombotic condition. IVIG is not always successful, and eculizumab may be considered a rescue agent. Long-term management with direct oral anticoagulants appears to be safe and effective. [ABSTRACT FROM AUTHOR]

ABSTRACT: Objective: To determine whether severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibody levels after the first dose of vaccine can predict the final antibody response, and whether this is dependent on the vaccine type.Methods: Sixty-nine recipients of BNT162b2 (Pfizer/BioNTech) and 55 recipients of AZD1222 (AstraZeneca), without previous infection or immunosuppressive medication, were included in this study. Antibody levels were quantified 3 weeks after the first dose [directly before boostering in the case of AZD1222 (11 weeks after the first dose)] and 3 weeks after the second dose using the Roche Elecsys SARS-CoV-2 S total antibody assay.Results: Median pre-booster {BNT162b2: 80.6 [interquartile range (IQR) 25.5–167.0] binding antibody units (BAU)/mL; AZD1222: 56.4 (IQR 36.4–104.8) BAU/mL; not significant} and post-booster [BNT162b2: 2092.0 (IQR 1216.3–4431.8) BAU/mL; AZD1222: 957.0 (IQR 684.5–1684.8) BAU/mL; P

The COVID-19 pandemic has particularly affected older adults residing in nursing homes, resulting in high rates of hospitalisation and death. Here, we evaluated the longitudinal humoral response and neutralising capacity in plasma samples of volunteers vaccinated with different platforms (Sputnik V, BBIBP-CorV, and AZD1222). A cohort of 851 participants, mean age 83 (60-103 years), from the province of Buenos Aires, Argentina were included. Sequential plasma samples were taken at different time points after vaccination. After completing the vaccination schedule, infection-naïve volunteers who received either Sputnik V or AZD1222 exhibited significantly higher specific anti-Spike IgG titers than those who received BBIBP-CorV. Strong correlation between anti-Spike IgG titers and neutralising activity levels was evidenced at all times studied (rho=0.7 a 0.9). Previous exposure to SARS-CoV-2 and age

The rapid spread of SARS-CoV-2 variants in the global population is indicative of the development of selective advantages in emerging virus strains. Here, we performed a case-control investigation of the clinical and demographic characteristics, clinical history, and virological markers to predict disease progression in hospitalized adults for COVID-19 between December 2021 and January 2022 in Chennai, India. COVID-19 diagnosis was made by a commercial TaqPath COVID-19 RT-PCR, and WGS was performed with the Ion Torrent Next Generation Sequencing System. High-quality (

Using levels of neutralizing antibodies (nAbs), we evaluate the successful Chilean SARS-CoV-2 vaccine campaign, which combines different vaccine technologies and heterologous boosters. From a population-based study performed in November 2021, we randomly selected 120 seropositive individuals, organized into six groups of positive samples (20 subjects each) according to natural infection history and the five most frequent vaccination schemes. We conclude that the booster dose, regardless of vaccine technology or natural infection, and mRNA vaccines significantly improve nAbs response. [ABSTRACT FROM AUTHOR]

Chile is among the most successful nations worldwide in terms of its COVID-19 vaccine rollout. By 31 December 2021, 84.1% of the population was fully vaccinated, and 56.1% received booster doses using different COVID-19 vaccines. In this context, we aimed to estimate the prevalence of anti-SARS-CoV-2 antibodies following the infection and vaccination campaign. Using a three-stage stratified sampling, we performed a population-based cross-sectional serosurvey based on a representative sample of three Chilean cities. Selected participants were blood-sampled on-site and answered a short COVID-19 and vaccination history questionnaire using Wantai SARS-CoV-2 Ab ELISA to determine seroprevalence. We recruited 2198 individuals aged 7–93 between 5 October and 25 November 2021; 2132 individuals received COVID-19 vaccinations (97%), 67 (3.1%) received one dose, 2065 (93.9%) received two doses, and 936 received the booster jab (42.6%). Antibody seroprevalence reached 97.3%, ranging from 40.9% among those not vaccinated to 99.8% in those with booster doses (OR = 674.6, 154.8–2938.5). SARS-CoV-2 antibodies were associated with vaccination, previous COVID-19 diagnosis, age group, and city of residence. In contrast, we found no significant differences in the type of vaccine used, education, nationality, or type of health insurance. We found a seroprevalence close to 100%, primarily due to the successful vaccination program, which strongly emphasizes universal access. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), is a member of the genus Betacoronavirus. This virus was first detected in December 2019, and the situation quickly escalated to cause a global pandemic within a few months. COVID-19 had caused more than 5.5 million deaths as of January 2022. Hence, the urgency of effective vaccination contributed to the fastest rate of vaccine development seen to date (i.e., within 1.5 years). Despite reports of good vaccine efficacy without severe systemic reactions at the clinical trial stage, hypersensitivity reactions have been reported following worldwide vaccination campaigns. We provide a brief review regarding the structure of SARS-CoV-2. We also review the most acceptable types of vaccines in terms of safety profiles, namely the BNT162b2, mRNA-1273, and AZD1222 vaccines. This review aims to facilitate an understanding of the possible immune mechanisms regarding COVID-19-vaccination-related hypersensitivity reactions, such as thrombosis and thrombocytopenia, cutaneous adverse reactions, myocarditis, and perimyocarditis. [ABSTRACT FROM AUTHOR]

To characterize the IgG and IgA responses to different SARS-CoV-2 proteins, we investigated the antibody responses to SARS-CoV-2 following natural infection and following a single dose of AZD1222 (Covishield), in Sri Lankan individuals. The IgG and IgA responses were assessed to S1, S2, RBD, and N proteins in patients at 4 weeks and 12 weeks since the onset of illness or following vaccination. Antibodies to the receptor-binding domain of SARS-CoV-2 wild type (WT), α, β, and λ and ACE2 (Angiotensin Converting Enzyme 2) receptor blocking antibodies were also assessed in these cohorts. For those with mild illness and in vaccines, the IgG responses to S1, S2, RBD, and N protein increased from 4 weeks to 12 weeks, while it remained unchanged in those with moderate/severe illness. In the vaccines, IgG antibodies to the S2 subunit had the highest significant rise (P < 0.0001). Vaccines had several-fold lower IgA antibodies to all the SARS-CoV-2 proteins tested than those with natural infection. At 12 weeks, the haemagglutination test (HAT) titres were significantly lower to the α in vaccines and significantly lower in those with mild illness and in vaccines to β and for λ. No such difference was seen in those with moderate/severe illness. Vaccines had significantly less IgA to SARS-CoV-2, but comparable IgG responses those with natural infection. However, following a single dose vaccines had reduced antibody levels to the VOCs, which further declined with time, suggesting the need to reduce the gap between the two doses, in countries experiencing outbreaks due to VOCs. Those with mild infection, vaccinees (AZD1222) and unexposed individuals had similar antibody levels to S2. Those with mild infection had highest antibody responses to S2, while hose with moderate/severe illness had highest responses to the receptor binding domain. Vaccinees had several fold lower IgA antibodies to all the SARS-CoV-2 proteins tested than those with natural infection. [ABSTRACT FROM AUTHOR]

In the era of globally predominant omicron strains, a COVID-19 booster vaccine is needed. Our study aimed to evaluate the immunogenicity of a half-dose BNT162b2 booster after AZD1222 in healthy adults. A randomized trial of volunteers aged 18–69 years who received two-dose AZD1222 was conducted. The participants were randomized to receive the BNT162b2 vaccine intramuscularly—half (15 µg) vs. standard dose (30 µg). The immunogenicity was evaluated by a surrogate virus neutralization test (sVNT) against omicron variants and anti-spike-receptor-binding-domain IgG (anti-S-RBD IgG). From November–December 2021, 100 adults with a median age of 59.3 years (IQR 33.4–65.5) were enrolled. A booster dose was given at median of 98 days (IQR 92–128) after AZD1222. At day 14, the geometric means (GMs) of anti-S-RBD IgG in half- vs. standard-dose group were 2329.8 vs. 2574.7 BAU/mL, with a geometric mean ratio (GMR) of 0.90 (0.77–1.06). The GMs of sVNT against the omicron variant in the half- and standard-dose groups were 74.4% inhibition (95% CI 68.8–80.5) and 67.3% inhibition (57.9–78.1), respectively, with GMR of 0.95 (0.69–1.30). At day 90, the sVNT indicated 22.3% inhibition (95% CI 14.9–33.4) and 20.4% inhibition (13.1–32.0), respectively, with GMR of 1.09 (0.60–1.98). The fractional low-dose BNT162b2 mRNA booster vaccine provided non-inferior immunogenicity responses. During a shortage of vaccine supply, a fractional low dose should be considered for a booster vaccination program. [ABSTRACT FROM AUTHOR]

Two vaccines for COVID-19 have been approved and administered in the Kingdom of Saudi Arabia (KSA); Pfizer-BioNtech BNT162b2 and AstraZeneca-Oxford AZD1222 vaccines. The purpose of this study was to describe the real-world data on the outcome of single dose of these COVID-19 vaccines in a large cohort in KSA and to analyse demographics and co-morbidities as risk factors for infection post one-dose vaccination. In this prospective cohort study, a total of 18,543 subjects received one dose of either of the vaccines at a vaccination centre in KSA, and were followed up for three to eight months. Data were collected from three sources; clinical data from medical records, adverse events (AEs) from a self-reporting system, and COVID-19 infection data from the national databases. The study was conducted during the pandemic restrictions on travel, mobility, and social interactions. The median age of participants was 33 years with an average body mass index of 27.3. The majority were males (60.1%). Results showed that 92.17% of the subjects had no COVID-19 infection post-vaccination as infection post-vaccination was documented for 1452 (7.83%). Diabetes mellitus 03), organ transplantation (p = 0.02), and obesity (p < 0.01) were associated with infection post-vaccination. Unlike vaccine type, being Saudi, male, or obese was associated with the occurrence breakthrough infections more than other parameters. AEs included injection site pain, fatigue, fever, myalgia, headache and was reported by 5.8% of the subjects. Single dose COVID-19 vaccines showed a protection rate of 92.17% up to eight months follow-up in this cohort. This rate in AZD1222 was higher than what have been previously reported in effectiveness studies and clinical trials. Obese, male, and Saudi were at higher risk of contracting the infection post-vaccination, Saudi and male might have more social interaction with the public when mobility and social interactions were limited during the pandemic. Side effects and AEs were within what has been reported in clinical trials. [ABSTRACT FROM AUTHOR]

Abstract Vaccination for SARS-CoV-2 provides significant protection against the infection in the general population. However, only limited data exist for patients with cancer under systemic therapy. Based on this, our site has initiated a study evaluating safety and efficacy of SARS-CoV-2 vaccination in patients with solid and hematological malignancies under several systemic therapies. The initial results of the cohort of 59 patients receiving Immune Checkpoint Inhibitors are presented here. Despite no new safety issues have been noticed, the levels of SARS-CoV-2 neutralizing antibodies are significantly lower in comparison to matched healthy volunteers up to day 22 post the first dose. These results should be taken into consideration for the patients under treatment.

Only some cases of pityriasis rosea (PR)/pityriasis rosea-like eruption (PRLE) after anti-SARS-CoV-2 vaccination have been reported. In the period May 2021 - February 2022 we observed five cases of clinically typical PR that appeared 2 to 3 weeks after anti-SARS-CoV-2 vaccination with BNT162b2 (3 patients) or mRNA-1273 (2 patients). In four patients PR appeared after the first vaccination; in one patient after the second one. In three patients a biopsy for histopathological examinations was carried out. Results were typical for PR. In all patients laboratory examinations were within normal ranges. All patients were treated with cetirizine. Complete remission was observed within 14-30 days. Four patients were subjected to the second vaccination, but no skin lesions appeared. All patients are currently in good general health. It is possible that a relationship anti-Sars-CoV-2 vaccination−PR/PRLE exists; however, it is very rare, in consideration of millions of vaccinated subjects and the low number of reported cases of PR/PRLE. The pathogenesis of this relationship is unknown. However, some hypotheses may be advanced: PR/PRLE following anti-Sars-CoV-2 vaccination may be just a coincidence; anti-Sars-CoV-2 vaccines cause a reactivation of HHV-6 and/or HHV-7; vaccines can induce a delayed hypersensitivity response clinically similar to drug-induced PRLE.

BackgroundThe magnitude of protection conferred following recovery from COVID-19 or by vaccine administration, and the duration of protective immunity developed, remains ambiguous.MethodsWe investigated the factors associated with anti-SARS-CoV-2 S1 IgG decay in 519 individuals who recovered from COVID-19 illness or received COVID-19 vaccination with two commercial vaccines, viz., an adenoviral vector-based (AZD1222) and a whole-virion-based inactivated (BBV152) vaccine in Chennai, India from March to December 2021. Blood samples collected during regular follow-up post-infection/-vaccination were examined for anti-SARS-CoV-2 S1 IgG by a commercial automated chemiluminescent immunoassay (CLIA).ResultsAge and underlying comorbidities were the two variables that were independently associated with the development of a breakthrough infection. Individuals who were >60 years of age with underlying comorbid conditions (viz., hypertension, diabetes mellitus and cardiovascular disease) had a ~15 times and ~10 times greater odds for developing a breakthrough infection and hospitalization, respectively. The time elapsed since the first booster dose was associated with attrition in anti-SARS-CoV-2 IgG, where each month passed was associated with an ebb in the anti-SARS-CoV-2 IgG antibody levels by a coefficient of −6 units.ConclusionsOur findings advocate that the elderly with underlying comorbidities be administered with appropriate number of booster doses with AZD1222 and BBV152 against COVID-19.

The changes in the severe acute respiratory syndrome coronavirus 2 and the tapering of immunity after vaccination have propelled the need for a booster dose vaccine. We aim to evaluate B and T cell immunogenicity and reactogenicity of mRNA-1273 COVID-19 vaccine (100 µg) as a third booster dose after receiving either two doses of inactivated COVID-19 vaccine (CoronaVac) or two doses of viral vector vaccine (AZD1222) in adults not previously infected with COVID-19. The anti-receptor-binding-domain IgG (anti-RBD IgG), surrogate virus neutralization test (sVNT) against the Delta variant, and Interferon-Gamma (IFN-γ) level were measured at baseline, day (D)14 and D90 after vaccination. In D14 and D90, the geometric means of sVNT were significantly increased to 99.4% and 94.5% inhibition in CoronaVac, respectively, whereas AZD1222 showed inhibition of 99.1% and 93%, respectively. Anti-RBD IgG levels were 61,249 to 9235 AU/mL in CoronaVac and 38,777 to 5877 AU/mL in AZD1222 after D14 and D90 vaccination. Increasing median frequencies of S1-specific T cell response by IFN-γ concentration were also elevated in D14 and were not significantly different between CoronaVac (107.8–2035.4 mIU/mL) and AZD1222 (282.5–2001.2 mIU/mL). This study provides evidence for the high immunogenicity of the mRNA-1273 booster after two doses of CoronaVac or AZD1222 in the Thai population.

Background: To understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps. Methods: Antibodies to the SARS‐CoV‐2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2‐blocking antibodies (ACE2‐blocking Abs), antibodies to the receptor‐binding domain (RBD) of variants of concern (VOC), and ex vivo T cell responses were assessed in a subcohort. Results: All individuals (100%) had SARS‐CoV‐2‐specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2‐blocking Abs. There was no difference in antibody titers or positivity rates in different age groups in both cohorts. The ACE2‐blocking Abs (p <.0001) and antibodies to the RBD of the VOCs were significantly higher in cohort 2 compared to cohort 1. 41.2% to 65.8% of different age groups gave a positive response by the hemagglutination assay to the RBD of the ancestral virus and VOCs in cohort 1, while 53.6%–90% gave a positive response in cohort 2. 17/57 (29.8%) of cohort 1 and 17/29 (58.6%) of cohort 2 had ex vivo interferon (IFN)γ ELISpot responses above the positive threshold. The ACE2‐blocking antibodies (Spearman's r =.46, p =.008) and ex vivo IFNγ responses (Spearman's r =.71, p <.0001) at 12 weeks post first dose, significantly correlated with levels 12 weeks post second dose. Conclusions: Both dosing schedules resulted in high antibody and T cell responses post vaccination, although those with a longer dosing gap had a higher magnitude of responses, possibly as immune responses were measured 6 weeks post second dose compared to 12 weeks post second dose. [ABSTRACT FROM AUTHOR]

Background The kinetics of neutralizing antibodies against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) play an important role in evaluating vaccine efficacy and durability, herd immunity, additional vaccination, and prediction models of immune protection against coronavirus disease 2019. Materials and Methods Serum collection times were 4 and 8 weeks after 1st inoculation of AZD1222 (AstraZeneca, Cambridge, UK), and 2 and 16 weeks after 2nd inoculation with 12-week dosing intervals. Neutralizing antibody (Nab) titers were measured indirectly using commercially available R-FIND SARS-CoV-2 Neutralizing Antibody ELISA Kit (SG Medical Inc., Seoul, Korea). Possible influences of gender, age, and adverse events on neutralizing antibody titer were also investigated. Results Nab titers (median inhibition %) started to decrease shortly after reaching peaks. This decrease was more pronounced in the elderly group (≥56 years) than in the young group (≤39 years) at 8 weeks (49.5% vs. 55.4%, P = 0.021) and 16 weeks (40.6% vs. 53.9%, P = 0.006) after the 1st and 2nd inoculation. And Nab titers were inversely correlated with age in the 8-week (r = -0.2091, P = 0.0284) and the 28-week group (r = -0.2811, P = 0.0029). Seropositive conversion of Nab reached 89.1% and 100% following 1st and 2nd inoculation. This 100% seropositivity was dropped sharply to 74.5% after 16 weeks. Compared to subjects without adverse events (51.8%), median inhibition was higher in subjects with one or more systemic adverse events (74.2%, P = 0.0203) or those with one or more local and systemic adverse events (77.1%, P = 0.0003). Conclusion Nab induced by AZD1222 (AstraZeneca, UK) vaccination started to degrade shortly after the production period. Nab titers were lower in the elderly than in younger group during the degradation period. This seems to be because the degradation process of Nab is more pronounced in the elderly. This may explain why the frequency of breakthrough infections, disease severity, and mortality were higher in the elderly and may require revaccination to ensure robust immunity. [ABSTRACT FROM AUTHOR]

Abstract Background To understand the kinetics of immune responses with different dosing gaps of the AZD1222 vaccine, we compared antibody and T cell responses in two cohorts with two different dosing gaps. Methods Antibodies to the SARS‐CoV‐2 virus were assessed in 297 individuals with a dosing gap of 12 weeks, sampled 12 weeks post second dose (cohort 1) and in 77 individuals with a median dosing gap of 21.4 weeks (cohort 2) sampled 6 weeks post second dose. ACE2‐blocking antibodies (ACE2‐blocking Abs), antibodies to the receptor‐binding domain (RBD) of variants of concern (VOC), and ex vivo T cell responses were assessed in a subcohort. Results All individuals (100%) had SARS‐CoV‐2‐specific total antibodies and 94.2% of cohort 1 and 97.1% of cohort 2 had ACE2‐blocking Abs. There was no difference in antibody titers or positivity rates in different age groups in both cohorts. The ACE2‐blocking Abs (p

Background: While vaccination programs against the severe acute respiratory syndrome virus 2 (SARS-CoV-2) are globally ongoing, disparate strategies for the deployment of spike antigen show varying effectiveness.Methods: In order to explore this phenomenon, we sought to compare the early immune responses against AZD1222 and BNT162b2. SARS-CoV-2 seronegative participants received a single dose of either vaccine and were analyzed for immune cell, effector T cell, and antibody dynamics.Results: AZD1222 induced transient leukopenia and major changes among innate and adaptive subpopulations. Both vaccines induced spike protein-specific effector T cells which were dominated by type 1 helper T cell responses following AZD1222 vaccination. A significant reduction of anti-inflammatory T cells upon re-stimulation was also restricted to AZD1222 vaccinees. While IgM and IgG were the dominant isotypes elicited by AZD1222, BNT162b2 led to a significant production of IgG and IgA.Conclusions: Our results suggest that the strategy for spike protein delivery impacts on how and to what extent immune priming against the main SARS-CoV-2 antigen proceeds. [ABSTRACT FROM AUTHOR]

• All fully vaccinated participants had seroresponses to SARS-CoV-2 spike antigen. • The humoral immune response was comparable with other populations in previous studies. • AZD1222 was well tolerated in Japanese adult participants independent of age. • No apparent differences in safety profile were found compared with results of previous studies. Immunogenicity and safety of the AZD1222 (ChAdOx1 nCoV-19) vaccine was evaluated in Japanese adults in an ongoing phase 1/2, randomized, double-blind, parallel-group, placebo-controlled, multi-centre trial (NCT04568031). Adults (n =256, age ≥18 years) seronegative for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) were stratified by age into 18–55- (n =128), 56–69- (n =86) and ≥70-year-old cohorts (n =42), and randomized 3:1 to receive AZD1222 or placebo (two intramuscular injections 4 weeks apart). Immunogenicity and safety were coprimary endpoints. Data collected up to Day 57 are reported. Positive seroresponses to SARS-CoV-2 spike and receptor-binding domain antigens were seen in all 174 participants who received two doses of AZD1222. Neutralizing antibody seroresponses were seen in 67.5%, 60.3% and 50.0% of participants receiving AZD1222 aged 18–55, 56–69 and ≥70 years, respectively. Solicited adverse events (AEs) were typically mild/moderate in severity and included pain and tenderness at the injection site, malaise, fatigue, muscle pain and headache. Common unsolicited AEs included pain and tenderness at the injection site, fatigue and elevated body temperature. No vaccine-related serious AEs or deaths were reported. AZD1222 elicited a strong humoral immune response against SARS-CoV-2, and was well tolerated in Japanese participants, including elderly participants. [ABSTRACT FROM AUTHOR]

Introduction Due to the vaccine’s short supply and the efficacy of a single dose of the ChAdOx1 (AZD1222) vaccine, many governments delayed the interval between prime and boost dose from 4 to 8–12 weeks. However, the waning of immune response in this period is a concern. This study evaluated the durability, contributing factors of anti-RBD antibody concentration, and reactogenicities after the single dose of AZD1222 vaccine in the Thai population. Methods This was a single-center, prospective cohort study at Chulabhorn Hospital, Bangkok, Thailand. Individuals 18 years or older who were negative for anti-SARS-CoV-2 antibody were eligible. Anti- receptor-binding domain antibody concentrations were tested at least three weeks after the first vaccination and immediately before the second dose of vaccine. Information on reactogenicities was obtained via a questionnaire sent by a short message service. Results Anti-RBD Antibody concentration at 2 and 3 months post-vaccination were significantly higher than at 1 months post-vaccination (20.14 BAU/mL (95%CI; 16.37, 24.77) at 1 month, 48.08 BAU/mL (95%CI; 42.76, 54.08) at 2 month, and 65.01 BAU/mL (95%CI; 58.88,71.61) at 3 month). Adverse events occurred in approximately 60% of participants. Factors influencing vaccine immunogenicity include age, sex, the time elapsed from the first dose of vaccine, and underlying disease with diabetes and hematologic disease. Conclusion A single dose of AZD1222 could elicit immune responses that did not decline within three months in Thai individuals. These data support the public health strategy of a delay between the prime and boost dose of AZD1222 of 4 to 12 weeks.

Autoimmunity following COVID-19 vaccination has been reported. Herein, a 79-year-old man with clinical and immunological features of autoimmune hepatitis type 1 after ChAdOx1 nCoV-19 vaccination is presented. Clinical manifestations rapidly remitted after the instauration of immunomodulatory management. This case, together with a comprehensive review of the literature, illustrates the association between COVID-19 vaccines and the development of autoimmune conditions.