BACKGROUND: Understanding how SARS-CoV-2 breakthrough infections impacts the breadth of immune responses against existing and pre-emergent SARS-CoV-2 strains is needed to develop an evidence-based long-term immunisation strategy.
METHODS: We performed a randomised, controlled trial to assess the immunogenicity of homologous (BNT162b2) versus heterologous (mRNA-1273) booster vaccination in 100 BNT162b2-vaccinated infection-naïve individuals enrolled from October 2021. Post hoc analysis was performed to assess the impact of SARS-CoV-2 infection on humoral and cellular immune responses against wild-type SARS-CoV-2 and/or Omicron subvariants.
RESULTS: 93 participants completed the study at day 360. 71% (66/93) of participants reported first SARS-CoV-2 Omicron infection by the end of the study with similar proportions of infections between homologous and heterologous booster groups (72.3% [34/47] vs 69.6% [32/46]; p = 0.82). Mean wildtype SARS-CoV-2 anti-S-RBD antibody level was significantly higher in heterologous booster group compared with homologous group at day 180 (14,588 IU/mL; 95% CI, 10,186-20,893 vs 7447 IU/mL; 4646-11,912; p = 0.025). Participants who experienced breakthrough infections during the Omicron BA.1/2 wave had significantly higher anti-S-RBD antibody levels against wildtype SARS-CoV-2 and antibody neutralisation against BA.1 and pre-emergent BA.5 compared with infection-naïve participants. Regardless of hybrid immunity status, wildtype SARS-CoV-2 anti-S-RBD antibody level declined significantly after six months post-booster or post-SARS-CoV-2 infection.
CONCLUSIONS: Booster vaccination with mRNA-1273 was associated with significantly higher antibody levels compared with BNT162b2. Antibody responses are narrower and decline faster among uninfected, vaccinated individuals. Boosters may be more effective if administered shortly before infection outbreaks and at least six months after last infection or booster.
BACKGROUND: Singapore NMRC, USFDA, MRC.

Objective. We aimed to report the real-world use and outcomes over time in immunocompromised individuals receiving tixagevimab/cilgavimab (T/C) pre-exposure prophylaxis (PrEP). Methods. This observational study included participants who received T/C PrEP, categorized into three groups: (i) No COVID-19 (NoC), i.e., participants who never had COVID-19; (ii) Hybrids (H), i.e., participants who had COVID-19 before PrEP; and (iii) Break-through Infections (BTIs), i.e., participants who had COVID-19 after PrEP. The study measured several immune markers at the administration of T/C (T0) at 3 (T1), 6 (T2), and 9 (T3) months afterward. These markers included: anti-receptor-binding domain (RBD) IgG antibodies; BA.5-neutralizing antibodies (nAbs); mucosal IgG; and T cell immunity. The incidence rate ratios for BTIs were analyzed using a Poisson regression model. Results. A total of 231 participants with a median age of 63 years (IQR 54.0-73.0). were included. Among these, 84% had hematological diseases and received a median of three vaccine doses. N = 72 participants belonged to the NoC group, N = 103 to the H group, and n = 56 to the BTI group (24%), with most BTIs being mild/moderate. The incidence rate (IR) of BTIs was 4.2 per 100 patient-months (95% CI 3.2-5.4), with no associated risk factors identified. There was a significant increase in anti-RBD IgG levels 3 months after the T/C administration in all groups, followed by a decline at 6 months, whereas at the same time points, geometric mean titers (GMTs) of anti-BA.5 nAbs were low for all groups and were around or below the detection threshold. No significant changes were observed in IFN-γ levels. The mucosal immune response was observed only 3 months after the PrEP administration. Conclusion. We provided a real-world experience model on the clinical efficacy of T/C PrEP in preventing severe COVID-19 during the Omicron wave through a comprehensive virological and immunological study. While waiting for the arrival of new monoclonal antibodies that can effectively neutralize the most recent variants, T/C PrEP remains the only viable strategy in the available armamentarium today to prevent COVID-19 complications in an extremely fragile population with suboptimal immune responses to COVID-19 vaccines.

The incidence of prosthetic joint infection (PJI) following elective primary total knee arthroplasty (TKA) is very low but serious risk remains. To identify unknown risk factors, we completed a natural history study of IgG specific for Staphylococcus aureus antigens previously phenotyped as protective (anti-Atl) and pathogenic (anti-Isd). Twenty-five male and 25 female optimized patients 50-85 years of age and BMI 24-39 undergoing primary TKA were prospectively enrolled. Blood sampling was performed preoperatively, postoperative Day 1, and at 2, 6, and 12 weeks, to assess serum cytokine, anti-staphylococcal IgG levels and anti-tetanus toxoid IgG measured via custom Luminex assay. Clinical, demographic, and PROMIS-10 data were collected with outcomes to 2 years postop. All participants completed the study and 2-year follow-up. No patients were readmitted or noted to develop a surgical site infection or serious adverse event, and patient-reported outcomes were improved. Serology revealed a highly significant decrease in six out of eight antibody titers against specific S. aureus antigens on Day 1 (p < 0.0001), five of which normalized to preoperative levels within 2 weeks. These changes were commensurate with a decrease and recovery of anti-tetanus toxoid titers, and a 20% drop in hemoglobin 13.8 ± 1.7 at preop to 11.1 ± 1.8 mg/dL on Day 1 (p < 0.0001). After TKA, a significant decrease in humoral immunity commensurate with blood loss and hemodilution was recorded. This decrease in circulating anti-staphylococcal antibodies in the early postop period may represent a periprosthetic joint infection risk factor for patients.

BACKGROUND: To overcome supply issues of COVID-19 vaccines, this partially single blind, multi-centric, vaccine trial aimed to evaluate humoral immunogenicity using lower vaccine doses, intradermal vaccination, and heterologous vaccine schedules. Also, the immunity after a booster vaccination was assessed.
METHODS: 566 COVID-19-naïve healthy adults were randomized to 1 of 8 treatment arms consisting of combinations of BNT162b2, mRNA-1273, and ChAdOx1-S. Anti-Receptor-Binding Domain immunoglobulin G (RBD IgG) titers, neutralizing antibody titres, and avidity of the anti-RBD IgGs was assessed up to 1 year after study start.
RESULTS: Prolonging the interval between vaccinations from 28 to 84 days and the use of a heterologous BNT162b2 + mRNA-1273 vaccination schedule led to a non-inferior immune response, compared to the reference schedule. A low dose of mRNA-1273 was sufficient to induce non-inferior immunity. Non-inferiority could not be demonstrated for intradermal vaccination. For all adapted vaccination schedules, anti-RBD IgG titres measured after a first booster vaccination were non-inferior to their reference schedule.
CONCLUSIONS: This study suggests that reference vaccine schedules can be adapted without jeopardizing the development of an adequate immune response. Immunity after a booster vaccination did not depend on the dose or brand of the booster vaccine, which is relevant for future booster campaigns. The trial is registered in the European Union Clinical Trials Register (number 2021-001993-52) and on clinicaltrials.gov (NCT06189040).

UNASSIGNED: To determine the humoral immunity in advanced maternal-age women with recurrent spontaneous abortion (RSA).
UNASSIGNED: A retrospective study was performed between January 2022 and October 2023 in the Department of Reproductive Immunity of Shanghai First Maternity and Infant Hospital. Women with RSA were recruited and multiple autoantibodies were tested. Multivariate logistic regression was performed to compare the associations between different age groups (20 to 34 years old in the low maternal-age group and 35 to 45 years in the advanced maternal-age group) and multiple autoantibodies, while controlling for three confounding factors, including body mass index (BMI), previous history of live birth, and the number of spontaneous abortions. Then, we investigated the differences in the humoral immunity of advanced maternal-age RSA women and low maternal-age RSA women.
UNASSIGNED: A total of 4009 women with RSA were covered in the study. Among them, 1158 women were in the advanced maternal-age group and 2851 women were in the low maternal-age group. The prevalence of antiphospholipid syndrome, systemic lupus erythematosus, Sjogren\'s syndrome, rheumatoid arthritis, and undifferentiated connective tissue disease was 15.6% and 14.1%, 0.0% and 0.1%, 0.9% and 0.9%, 0.3% and 0.0%, and 23.7% and 22.6% in the advanced maternal-age group and low maternal-age group, respectively, showing no statistical difference between the two groups. The positive rates of antiphospholipid antibodies (aPLs), antinuclear antibody (ANA), extractable nuclear antigen (ENA) antibody, anti-double stranded DNA (dsDNA) antibody, anti single-stranded DNA (ssDAN) antibody, antibodies against alpha-fodrin (AAA), and thyroid autoimmunity (TAI) were 19.1% and 19.5%, 6.6% and 6.6%, 9.2% and 10.5%, 2.0% and 2.0%, 2.2% and 1.2%, 5.1% and 4.9%, and 17.8% and 16.8%, respectively. No differences were observed between the two groups. 1.6% of the women in the advanced maternal-age group tested positive for lupus anticoagulant (LA), while 2.7% of the women in the low maternal-age group were LA positive, with the differences being statistically significant (odds ratio=0.36, 95% confidence interval: 0.17-0.78). In the 4008 RSA patients, the cumulative cases tested positive for the three antibodies of the aPLs spectrum were 778, of which 520 cases were positive for anti-β2 glycoprotein Ⅰ antibodies (β2GPⅠ Ab)-IgG/IgM, 58 were positive for aCL-IgG/IgM, 73 were positive for LA, 105 were positive for both β2GPⅠ Ab-IgG/IgM and aCL-IgG/IgM, 17 were positive for both β2GPⅠ Ab-IgG/IgM and LA, 2 were positive for both aCL-IgG/IgM and LA, and 3 were positive for all three antibodies.
UNASSIGNED: Our study did not find a difference in humoral immunity between RSA women of advanced maternal age and those of low maternal age.

BACKGROUND: This study aimed to explore how genetic variations in individuals impact neutralization activity post-mRNA vaccination, recognizing the critical role vaccination plays in curbing COVID-19 spread and the necessity of ensuring vaccine efficacy amidst genetic diversity.
METHODS: In a 4-week clinical pilot study, 534 healthy subjects received their first COVID vaccine dose, followed by the second dose. Antibody levels were evaluated thrice. From this pool, 120 participants were selected and divided into high- and low-antibody groups based on their levels. Genomic DNA was isolated from peripheral blood mononuclear cells for pilot genome-wide association studies (GWAS) conducted on a single platform. Real-time PCR was used to confirm differences in gene expression identified via GWAS analysis.
RESULTS: Three SNPs exceeded the level of p < 1.0 × 10-3. The rs7795433 SNP of the HDAC9 gene (7q21.1) showed the strongest association with COVID-19 vaccination under the additive model (OR = 5.63; p = 3 × 10-5). In the PCR experiments, the AA genotype group showed that the gene expression level of HDAC9 was likely to be decreased in the low-antibody-formation group at the time of vaccination.
CONCLUSIONS: We found that AA genotype holders (rs7795433 SNP of the HDAC9 gene) have a high probability of having a higher antibody count when vaccinated, and GG type holders have a high probability of the opposite. These findings show that the genetic characteristics of vaccinated people may affect antibody production after COVID vaccination.

UNASSIGNED: The use of botanical medicine has been demonstrated as a potential strategy to manage or treat a variety of health issues. Terminalia chebula (Retz) fruit and Withania somnifera (L.) Dunal roots are important medicinal herbs described in Ayurveda and traditional therapy for diverse health benefits.
UNASSIGNED: This pilot study aimed to evaluate the immune function-enhancing potential of a unique blend of T. chebula fruit and W. somnifera root extracts, LN20189, in healthy men and women.
UNASSIGNED: Forty healthy volunteers (age: 35-60 years) were randomized into two groups receiving either LN20189 (500 mg per day) or a matched placebo over 28 consecutive days. The total T-cell population was the primary efficacy measure in this study. The secondary efficacy measures included counts of CD4, CD8, natural killer (NK) cells, serum levels of interleukin-2 (IL-2), interferon-gamma (IFN-γ), total immunoglobulin-G (IgG), and Immune Function Questionnaire (IFQ) scores. Safety parameter assessments were also conducted.
UNASSIGNED: Post-trial, in LN20189-supplemented subjects, T cells, CD4, NK cells count, and the CD4:CD8 ratio were increased by 9.32, 10.10, 19.91, and 17.43%, respectively, as compared to baseline. LN20189 supplementation increased serum IFN-γ and IgG levels by 14.57 and 27.09% from baseline and by 13.98 and 21.99%, compared to placebo, respectively. Also, the IFQ scores in the LN20189 group were 84.68% (vs. baseline) and 69.44% (vs. placebo) lower at the end of the trial. LN20189 improved the study volunteers\' cellular and humoral immune functions.
UNASSIGNED: In summary, LN20189 supplementation was found tolerable and improved the key cellular and humoral factors of the immune system and helped improve immune function of the trial volunteers.

Since May 2022, several countries outside of Africa experienced multiple clusters of monkeypox virus (MPXV)-associated disease. In the present study, anti-MPXV and anti-vaccinia virus (VACV) neutralizing antibody responses were evaluated in two cohorts of subjects from the general Italian population (one half born before the WHO-recommended end of smallpox vaccination in 1980, the other half born after). Higher titers (either against MPXV or VACV) were observed in the cohort of individuals born before the interruption of VACV vaccination. An association between VACV and MPXV antibody levels was observed, suggesting that the smallpox vaccination may confer some degree of cross-protection against MPXV infection. Results from this study highlight low levels of immunity toward the assessed Orthopoxviruses, especially in young adults, advocating the introduction of a VACV- or MPXV-specific vaccine in case of resurgence of monkeypox disease outbreaks.

COVID-19 breakthrough infection (BTI) can occur despite vaccination. Using a multi-centre, prospective, observational Canadian cohort of people with HIV (PWH) receiving ≥2 COVID-19 vaccines, we compared the SARS-CoV-2 spike (S) and receptor-binding domain (RBD)-specific IgG levels 3 and 6 months post second dose, as well as 1 month post third dose, in PWH with and without BTI. BTI was defined as positivity based on self-report measures (data up to last study visit) or IgG data (up to 1 month post dose 3). The self-report measures were based on their symptoms and either a positive PCR or rapid antigen test. The analysis was restricted to persons without previous COVID-19 infection. Persons without BTI remained COVID-19-naïve until ≥3 months following the third dose. Of 289 participants, 92 developed BTI (31.5 infections per 100 person-years). The median days between last vaccination and BTI was 128 (IQR 67, 176), with the most cases occurring between the third and fourth dose (n = 59), corresponding to the Omicron wave. In analyses adjusted for age, sex, race, multimorbidity, hypertension, chronic kidney disease, diabetes and obesity, a lower IgG S/RBD (log10 BAU/mL) at 1 month post dose 3 was significantly associated with BTI, suggesting that a lower IgG level at this time point may predict BTI in this cohort of PWH.

Our goal was to determine the cellular immune response (CIR) in a sample of the Borriana COVID-19 cohort (Spain) to identify associated factors and their relationship with infection, reinfection and sequelae. We conducted a nested case-control study using a randomly selected sample of 225 individuals aged 18 and older, including 36 individuals naïve to the SARS-CoV-2 infection and 189 infected patients. We employed flow-cytometry-based immunoassays for intracellular cytokine staining, using Wuhan and BA.2 antigens, and chemiluminescence microparticle immunoassay to detect SARS-CoV-2 antibodies. Logistic regression models were applied. A total of 215 (95.6%) participants exhibited T-cell response (TCR) to at least one antigen. Positive responses of CD4+ and CD8+ T cells were 89.8% and 85.3%, respectively. No difference in CIR was found between naïve and infected patients. Patients who experienced sequelae exhibited a higher CIR than those without. A positive correlation was observed between TCR and anti-spike IgG levels. Factors positively associated with the TCR included blood group A, number of SARS-CoV-2 vaccine doses received, and anti-N IgM; factors inversely related were the time elapsed since the last vaccine dose or infection, and blood group B. These findings contribute valuable insights into the nuanced immune landscape shaped by SARS-CoV-2 infection and vaccination.