Strategies for Immunomonitoring after Vaccination and during Infection

Graded expression of the chemokine receptor CX3CR1 marks differentiation states of human and murine T cells and enables cross-species interpretation

T cells differentiate into functionally distinct states upon antigen encounter. These states are delineated by different cell surface markers for murine and human T cells, which hamper cross-species translation of T cell properties. We aimed to identify surface markers that reflect the graded nature of CD8+ T cell differentiation and delineate functionally comparable states in mice and humans. CITEseq analyses revealed that graded expression of CX3CR1, encoding the chemokine receptor CX3CR1, correlated with the CD8+ T cell differentiation gradient. CX3CR1 expression distinguished human and murine CD8+ and CD4+ T cell states, as defined by migratory and functional properties. Graded CX3CR1 expression, refined with CD62L, accurately captured the high-dimensional T cell differentiation continuum. Furthermore, the CX3CR1 expression gradient delineated states with comparable properties in humans and mice in steady state and on longitudinally tracked virus-specific CD8+ T cells in both species. Thus, graded CX3CR1 expression provides a strategy to translate the behavior of distinct T cell differentiation states across species.

Impaired Humoral Immunity Identified in Inactivated SARS-CoV-2 Vaccine Recipients without Anti-Spike RBD Antibodies

Inactivated SARS-CoV-2 vaccines have been deployed in a significant portion of the world population, who have widely varied responses to vaccination. Understanding this differential response would help the development of new vaccines for non-responders. Here, we conducted surveillance of anti-Spike receptor-binding domain (RBD) antibody levels in a large cohort of 534 healthy Chinese subjects vaccinated with two doses of inactivated SARS-CoV-2 vaccines. We show that the positive rate of antibodies among vaccinated subjects rapidly wanes as the interval between antibody testing and vaccination increases (14 to 119 days: 81.03%, 363 of 448 subjects; 120 to 149 days: 46.43%, 13 of 28 subjects; more than 150 days: 20%, 1 of 5 subjects). However, the antibodies were maintained at high levels in 16 convalescent COVID-19 patients at more than 150 days after recovery. We also found that increased age and body mass index are associated with decreased antibody levels. Vaccinated subjects who fail to produce antibodies display impaired B-cell activating humoral immunity, which was confirmed in COVID-19 patients without antibodies detected at 4 to 18 days after diagnosis. IMPORTANCE Our study illustrates the immune responses engaged by encountering antigen, highlighting the critical roles of B-cell activating humoral immunity in the body's antibody production.

"Sinopharm", "Oxford-AstraZeneca", and "Pfizer-BioNTech" COVID-19 vaccinations: testing efficacy using lung CT-volumetry with comparative analysis of variance (ANOVA)

Background

Several clinical studies tested the efficacy of the different COVID-19 vaccinations while very few radiological researches targeted this issue before.

Aim of the work

To verify the additive role of lung CT-Volumetry in testing the efficacy of three widely distributed COVID-19 vaccinations; namely the "Sinopharm", "Oxford-AstraZeneca", and "Pfizer-BioNTech" vaccinations, with comparative analysis of variance (ANOVA).

Results

This study was retrospectively conducted on 341 COVID-19 patients during the period between June/2021 and March/2022. Based on the immunization status, they were divided into four groups; group (A) included 156/341 (46%) patients who did not receive any vaccination (control group), group (B) included 92/341 (27%) patients who received "Sinopharm" vaccine, group (C) included 55/341 (16%) patients who received "Oxford-AstraZeneca" vaccine, group (D) included 38/341 (11%) patients who received "Pfizer-BioNTech" vaccine. Every group was subdivided based on the medical history into three groups; group (1) patients without comorbidities, group (2) patients with comorbidities, and group (3) immunocompromised patients. Automated CT volumetry was calculated for the pathological lung parenchyma. Five CT-severity scores were provided (score 0 = 0%, score 1 = 1–25%, score 2 = 25–50%, score 3 = 51–75%, and score 4 = 76–100%). Analysis of variance (ANOVA) including Tukey HSD testing was utilized in comparison to the non-immunized patients. The "Phizer-Biontech" vaccine succeeded to eliminate severity in patients without and with comorbidity, and also decreased severity in immunocompromised patients (from 79 to 17%). The "Oxford-AstraZeneca" vaccine and to a lesser extent "Sinopharm" vaccine also decreased the clinical severity in patients with comorbidities and immunocompromised patients (from 15 to 9% & 10% as well as from 79 to 20% & 50% respectively). Significant variance was proved regarding the use of "Sinopharm", "Oxford-AstraZeneca", and "Phizer-Biontech" vaccines in patients without comorbidities (f-ratio averaged 4.0282, 10.8049, and 8.4404 respectively, also p-value averaged 0.04632, 0.001268, and 0.004294). Significant variance was proved regarding the use of "Oxford-AstraZeneca", and "Phizer-Biontech" vaccines in patients with comorbidities and immunocompromised patients (f-ratio averaged 4.7521, and 4.1682 as well as 11.7811, and 15.6 respectively, also p-value averaged 0.03492, and 0.04857, as well as both 0.003177, and 0.0009394 respectively, all < 0.05). No significant variance was proved regarding the use of the "Sinopharm" vaccine.

Conclusions

In addition to the decline of clinical severity rates & CT severity scores, a significant variance was proved regarding the use of the "Sinopharm", "Oxford-AstraZeneca", and "Phizer-Biontech" vaccines in patients without comorbidities. Significant variance was also proved regarding the use of the "Oxford-AstraZeneca" and "Phizer-Biontech" vaccines in patients with comorbidities and immunocompromised patients. Despite that, no significant variance could be proved regarding the use of the "Sinopharm" vaccine in these patients, it decreases the percentage of clinical severity and CT severity scores.

The immunogenicity of an inactivated vaccine against SARS-CoV-2 in healthy individuals: A systematic review and meta-analysis

OBJECTIVE

Inactivated (killed) vaccines against COVID-19 have been widely used for the control of the pandemic condition. We performed a systematic and meta-analysis review of randomized, double-blind, placebo-controlled trials of the immunogenicity of inactivated vaccines against SARS-CoV-2 in healthy individuals.

METHODS

In the present study, all research and evidence were extracted from the available online databases. Two researchers randomly evaluated the assessment of the research sensitivity. Finally, after quality assessment and regarding the specific inclusion and exclusion criteria, the eligible articles were entered for meta-analysis. The heterogeneity between the results of the studies was measured using test statistics (Cochran's Q) and the I² index. The forest plots illustrated the point and pooled estimates with 95% confidence intervals (crossed lines). All statistical analyses were performed using Comprehensive meta-Analysis V.2 software.

RESULTS

This meta-analysis included six primary studies investigating the immunogenicity of inactivated vaccines against SARS-CoV-2 in healthy individuals. According to the pooled prevalence (95% confidence interval), neutralizing antibody responses 28 days after receiving the second dose regarding different ages and micrograms per dose was 95.50% (CI: 93.2-97.1%). Our results showed that antibody levels were higher in the 6 μg group than in other groups. 98.3% (CI: 94.2-99.5%).

CONCLUSION

Since the rapid development of vaccinations has sparked widespread public anxiety regarding vaccine efficacy. Governments and unvaccinated individuals, particularly those with vaccination reluctance, will be interested in and benefit from the findings of this systematic study.

Antibody response after two doses of homologous or heterologous SARS-CoV-2 vaccines in healthcare workers at health promotion centers: A prospective observational study

Assaying of anti-spike-protein receptor-binding domain (S-RBD) antibodies are used to aid evaluations of the immune statuses of individuals. The aim of this study was to determine the antibody response after two doses of homologous or heterologous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and to identify the factors affecting this response among healthcare workers (HCWs) at health promotion centers. In this prospective observational study, 1095 consenting HCWs were recruited from 16 health checkup centers and were tested at T0 (day of first dose), T1-1 (1 month after first dose), T2-0 (day of second dose), T2-1 (1 month after second dose), and T2-3 (3 months after second dose). SARS-CoV-2 antibodies were measured using a chemiluminescence microparticle immunoassay with SARS-CoV-2 IgG II Quant in the ARCHITECT system (Abbott Diagnostics). At T1-1, anti-SARS-CoV-2 S-RBD IgG levels were significantly higher in participants who received messenger RNA (mRNA) vaccines than in those who received viral vector vaccines (p < 0.001). At T2-1, anti-SARS-CoV-2 S-RBD IgG levels were about 10 times higher than at T1-1 in participants who received homologous mRNA vaccines, which decreased to a third of those at T2-3. Anti-SARS-CoV-2 S-RBD IgG levels were highest among those who received homologous mRNA vaccines, followed by heterologous mRNA viral vector vaccines and homologous viral vector vaccines at T2-3 (p < 0.001). In a multivariable linear regression analysis, being female, taking at least one mRNA vaccine, and having a history of recovery from coronavirus disease 2019 (COVID-19) were significantly associated with anti-S-RBD levels. Anti-SARS-CoV-2 S-RBD IgG levels were decreased at 3 months after two-dose vaccinations and were associated with sex, vaccine type, and COVID-19 history.

The Effect of Age, Gender and Comorbidities Upon SARS-CoV-2 Spike Antibody Induction After Two Doses of Sinopharm Vaccine and the Effect of a Pfizer/BioNtech Booster Vaccine

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2 emerged in China in 2019 and has since travelled the world infecting millions. SARS-CoV-2 causes Corona Virus Disease (COVID-19), that has to date taken over 4 million lives. The Kingdom of Bahrain’s vaccine roll-out has consisted of Sinopharm’s BBIBP-CorV (Sinopharm) and Pfizer/BioNtech’s BNT162b2 (Pfizer/BioNtech). Testing for SARS-CoV-2 anti-Spike (S) antibodies is a useful technique in estimating an individual’s immune protection against the infection. In this study we evaluated S antibody levels by electro-chemiluminescence immunoassay in 379 individuals double vaccinated with Sinopharm and 15 of whom were given a booster with the Pfizer/BioNtech vaccine. Among our double vaccinated cohort, we found a spectrum of S antibody levels. Indeed, we found that a significant proportion of individuals with low S antibody levels had clinical conditions, which were mainly immune-related disorders. Furthermore, a significant proportion of individuals with low S antibody levels were above 50 years of age. Finally, we observed a significant increase in S antibody levels after the Pfizer/BioNtech booster was administered. These findings reveal that while a large proportion of Sinopharm vaccinated individuals did not develop high levels of antibodies against the S protein, a booster dose of the Pfizer/BioNtech vaccine significantly enhances S antibody levels, revealing this “triple dose” vaccination strategy as a useful method of ensuring protective immunity against SARS-CoV-2.

Serological Response to SARS-CoV-2 Messenger RNA Vaccine: Real-World Evidence from Italian Adult Population

BACKGROUND

This study aims to investigate the extent of the BNT162b2 mRNA vaccine-induced antibodies against SARS-CoV-2 in a large cohort of Italian subjects belonging to the early vaccinated cohort in Italy.

METHODS

A prospective study was conducted between December 2020 and May 2021. Three blood samples were collected for each participant: one at the time of the first vaccine dose (T0), one at the time of the second vaccine dose, (T1) and the third 30 days after this last dose (T2).

RESULTS

We enrolled 2591 fully vaccinated subjects; 16.5% were frail subjects, and 9.8% were over 80 years old. Overall, 98.1% of subjects were seropositive when tested at T2, and 76.3% developed an anti-S IgG titer ≥4160 AU/mL, which is adequate to develop viral neutralizing antibodies. Seronegative subjects at T1 were more likely to remain seronegative at T2 or to develop a low-intermediate anti-S IgG titer (51-4159 AU/mL).

CONCLUSIONS

In summary, vaccination leads to detectable anti-S IgG titer in nearly all vaccine recipients. Stratification of the seroconversion level could be useful to promptly identify high-risk groups who may not develop a viral neutralizing response, even in the presence of seroconversion, and therefore may remain at higher risk of infection, despite vaccination.

Pfizer-BioNTech and Sinopharm: A Comparative Study on Post-Vaccination Antibody Titers

COVID-19 (coronavirus disease 2019) vaccines induce immunity through different mechanisms. The aim of this study is to compare the titers of specific antibodies in subjects vaccinated with either the Pfizer-BioNTech COVID-19 vaccine or the Sinopharm vaccine. This prospective observational cohort included Jordanian adults vaccinated with two doses, 21 days apart, of either of the two aforementioned vaccines. Titers were collected 6 weeks after the administration of the second dose. Overall, 288 participants were included, of which 141 were administered the Pfizer-BioNTech vaccine, while 147 were administered the Sinopharm vaccine. Remarkably, 140 (99.3%) of the Pfizer-BioNTech vaccine recipients had positive IgG titers, while 126 (85.7%) of Sinopharm recipients had positive IgG (p < 0.001). The mean titer for IgG among Pfizer-BioNTech recipients was 515.5 ± 1143.5 BAU/mL, compared to 170.0 ± 230.0 BAU/mL among Sinopharm subjects (p < 0.001). Multivariable regression analysis showed that the Pfizer-BioNTech vaccine positively correlated with positive IgG titers (OR: 25.25; 95% CI: 3.25-196.15; p = 0.002), compared with a negative effect of cardiovascular diseases (OR: 0.33; 95% CI: 0.11-0.99; p = 0.48) on IgG titers. In conclusion, fully vaccinated recipients of the Pfizer-BioNTech vaccine had superior quantitative efficiency compared to Sinopharm recipients. A booster dose is supported for Sinopharm recipients, or those with chronic immunosuppressive diseases.

Evaluation of Anti-SARS-Cov-2 S-RBD IgG Antibodies after COVID-19 mRNA BNT162b2 Vaccine

(1) Background: The evaluation of anti-spike protein receptor-binding domain (S-RBD) antibodies represents a useful tool to estimate the individual protection against Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection; (2) Methods: We evaluated anti S-RBD IgG levels by indirect chemiluminescence immunoassay on Maglumi 800 (SNIBE, California) in 2248 vaccinated subjects without previous SARS-CoV-2 infection, 91 vaccinated individuals recovered from COVID-19, and 268 individuals recovered from COVID-19 who had not been vaccinated. Among those who were healthy and vaccinated, 352 subjects performed a re-dosing after about 72 days from the first measurement. (3) Results: Anti S-RBD IgG levels were lower in subjects with previous infection than vaccinated subjects, with or without previous infection (p < 0.001). No difference was observed between vaccinated subjects, with and without previous SARS-CoV-2 infection. Overall, anti-RBD IgG levels were higher in females than males (2110 vs. 1341 BAU/mL; p < 0.001) as well as in subjects with symptoms after vaccination than asymptomatic ones (2085 vs. 1332 BAU/mL; p = 0.001) and lower in older than younger subjects. Finally, a significant decrease in anti-RBD IgG levels was observed within a short period from a complete two-dose cycle vaccination. (4) Conclusions: Our results show an efficacy antibody response after vaccination with age-, time- and sex-related differences.