Effects of Antibody Response after Booster Vaccination on SARS-CoV-2 Breakthrough Infections and Disease Outcomes in Advanced Cancer Patients: A Prospective Analysis of the Vax-on-Third Study.

(1) Background: The clinical implications of COVID-19 outbreaks following SARS-CoV-2 vaccination in immunocompromised recipients are a worldwide concern. Cancer patients on active treatment remain at an increased risk of developing breakthrough infections because of waning immunity and the emergence of SARS-CoV-2 variants. There is a paucity of data on the effects of COVID-19 outbreaks on long-term survival outcomes in this population. (2) Methods: We enrolled 230 cancer patients who were on active treatment for advanced disease and had received booster dosing of an mRNA-BNT162b2 vaccine as part of the Vax-On-Third trial between September 2021 and October 2021. Four weeks after the third immunization, IgG antibodies against the spike receptor domain of SARS-CoV-2 were tested in all patients. We prospectively evaluated the incidence of breakthrough infections and disease outcomes. The coprimary endpoints were the effects of antibody titers on the development of breakthrough infections and the impact of COVID-19 outbreaks on cancer treatment failure. (3) Results: At a median follow-up of 16.3 months (95% CI 14.5-17.0), 85 (37%) patients developed SARS-CoV-2 infection. Hospitalization was required in 11 patients (12.9%) and only 2 (2.3%) deaths related to COVID-19 outbreaks were observed. Median antibody titers were significantly lower in breakthrough cases than in non-cases (291 BAU/mL (95% CI 210-505) vs. 2798 BAU/mL (95% CI 2323-3613), p < 0.001). A serological titer cut-off below 803 BAU/mL was predictive of breakthrough infection. In multivariate testing, antibody titers and cytotoxic chemotherapy were independently associated with an increased risk of outbreaks. Time-to-treatment failure after booster dosing was significantly shorter in patients who contracted SARS-CoV-2 infection (3.1 months (95% CI 2.3-3.6) vs. 16.2 months (95% CI 14.3-17.0), p < 0.001) and had an antibody level below the cut-off (3.6 months (95% CI 3.0-4.5) vs. 14.6 months (95% CI 11.9-16.3), p < 0.001). A multivariate Cox regression model confirmed that both covariates independently had a worsening effect on time-to-treatment failure. (4) Conclusions: These data support the role of vaccine boosters in preventing the incidence and severity of COVID-19 outbreaks. Enhanced humoral immunity after the third vaccination significantly correlates with protection against breakthrough infections. Strategies aimed at restraining SARS-CoV-2 transmission in advanced cancer patients undergoing active treatment should be prioritized to mitigate the impact on disease outcomes.

Antibody response to the third dose of inactivated COVID-19 vaccine in people living with HIV (PLWH): A longitudinal cohort.

The immunogenicity induced by the third dose of inactivated coronavirus disease 2019 (COVID-19) vaccines in people living with HIV (PLWH) is unclear, and relevant literature is extremely scarce. It is important to add evidence on the humoral immune response induced by the third dose of inactivated COVID-19 vaccine in PLWH. We collected peripheral venous blood for spike receptor binding domain-protein specific immunoglobulin G (S-RBD-IgG) antibody tests at 28 days after the second dose (T1 ), 180 days after the second dose (T2 ) and 35 days after the third dose (T3 ) of inactivated COVID-19 vaccines in PLWH. The differences in S-RBD-IgG antibody levels and specific seroprevalence among T1 , T2 , and T3 time periods were analyzed, and the effects of age, vaccine brand, and CD4+ T cell count on the levels and specific seroprevalence of S-RBD-IgG antibody induced by the third dose in PLWH were examined. The third dose of inactivated COVID-19 vaccines induced strong S-RBD-IgG antibody responses in PLWH. The levels and specific seroprevalence of S-RBD-IgG antibody were significantly higher than those at 28 and 180 days after the second dose and were not affected by vaccine brand or CD4+ T cell count. Younger PLWH produced higher levels of S-RBD-IgG antibody. The third dose of inactivated COVID-19 vaccine showed good immunogenicity in PLWH. It is necessary to popularize the third dose in the PLWH population, especially PLWH who do not respond to two doses of inactivated COVID-19 vaccines. Meanwhile, the durability of the protection provided by the third dose in PLWH must be continuously monitored.

Persistence of Immune Response Elicited by Three Doses of mRNA Vaccine against SARS-CoV-2 in a Cohort of Patients with Solid Tumors: A One-Year Follow-Up.

The role and durability of the immunogenicity of the BNT162b2 mRNA vaccine against severe acute respiratory virus 2 (SARS-CoV-2), in cancer patients one year after receiving the third dose have to be elucidated. We have prospectively evaluated the long-term immunogenicity of the third dose of the SARS-CoV-2 BNT162b2 mRNA vaccine in 55 patients undergoing active treatment. Neutralizing antibody (NT Ab) titers against Omicron variants and total anti-trimeric S IgG levels were measured one year after the third dose. Heparinized whole-blood samples were used for the assessment of the SARS-CoV-2 interferon-γ release assay (IGRA). Thirty-seven patients (67.3%) showed positive total anti-trimeric S IgG one year after the third dose. Looking at the T-cell response against the spike protein, the frequency of responder patients did not decrease significantly between six and twelve months after the third dose. Finally, less than 20% of cancer patients showed an undetectable NT Ab titer against BA.1 and BA.5 variants of concern (VOCs). Underlying therapies seem to not affect the magnitude or frequency of the immune response. Our work underlines the persistence of humoral and cellular immune responses against BNT162b2 in a cohort of cancer patients one year after receiving the third dose, regardless of the type of underlying therapy.

SARS-CoV-2 Neutralizing Antibodies to B.1 and to BA.5 Variant after Booster Dose of BNT162b2 Vaccine in HIV Patients COVID-Naïve and on Successful Antiretroviral Therapy.

Live virus neutralization is the gold standard to investigate immunity. This prospective observational study aimed to determine the magnitude of response against the original B.1 lineage and against the BA.5 lineage six months after the third BNT162b2 mRNA vaccine dose in patients with HIV infection on successful antiretroviral treatment and no previous SARS-CoV-2 infection. A total of 100 subjects (M/F 83/17, median age 54 years) were included in the analysis: 95 had plasma HIV RNA <40 copies/mL, the median CD4+ T cell count at the administration of the third dose was 580 cells/mm3, and the median nadir CD4+ T cell count was 258 cells/mm3. Neutralizing antibodies (NtAb) against B.1 were detectable in all the subjects, but those to BA.5 were only detected in 88 (p < 0.001). The median NtAb titer to B.1 was significantly higher than that to BA.5 (393 vs. 60, p < 0.0001), and there was a strong positive correlation between the paired measurements (p < 0.0001). Linear regression on a subset of 87 patients excluding outlier NtAb titers showed that 48% of the changes in NtAb titers to BA.5 are related to the changes in value titers to B.1. SARS-CoV-2 variants evolve rapidly, challenging the efficacy of vaccines, and data on comparative NtAb responses may help in tailoring intervals between vaccine doses and in predicting vaccine efficacy.

Immunogenicity of a Third Dose of BNT162b2 Vaccine among Lung Transplant Recipients-A Prospective Cohort Study.

Two doses of mRNA SARS-CoV-2 vaccines elicit an attenuated humoral immune response among immunocompromised patients. Our study aimed to assess the immunogenicity of a third dose of the BNT162b2 vaccine among lung transplant recipients (LTRs). We prospectively evaluated the humoral response by measuring anti-spike SARS-CoV-2 and neutralizing antibodies in 139 vaccinated LTRs ~4-6 weeks following the third vaccine dose. The t-cell response was evaluated by IFNγ assay. The primary outcome was the seropositivity rate following the third vaccine dose. Secondary outcomes included: positive neutralizing antibody and cellular immune response rate, adverse events, and COVID-19 infections. Results were compared to a control group of 41 healthcare workers. Among LTRs, 42.4% had a seropositive antibody titer, and 17.2% had a positive t-cell response. Seropositivity was associated with younger age (t = 3.736, p < 0.001), higher GFR (t = 2.355, p = 0.011), and longer duration from transplantation (t = -1.992, p = 0.024). Antibody titer positively correlated with neutralizing antibodies (r = 0.955, p < 0.001). The current study may suggest the enhancement of immunogenicity by using booster doses. Since monoclonal antibodies have limited effectiveness against prevalent sub-variants and LTRs are prone to severe COVID-19 morbidity, vaccination remains crucial for this vulnerable population.

People with HIV receiving suppressive antiretroviral therapy show typical antibody durability after dual COVID-19 vaccination, and strong third dose responses.

BACKGROUND: Longer-term humoral responses to two-dose COVID-19 vaccines remain incompletely characterized in people living with HIV (PLWH), as do initial responses to a third dose. METHODS: We measured antibodies against the SARS-CoV-2 spike protein receptor-binding domain, ACE2 displacement and viral neutralization against wild-type and Omicron strains up to six months following two-dose vaccination, and one month following the third dose, in 99 PLWH receiving suppressive antiretroviral therapy, and 152 controls. RESULTS: Though humoral responses naturally decline following two-dose vaccination, we found no evidence of lower antibody concentrations nor faster rates of antibody decline in PLWH compared to controls after accounting for sociodemographic, health and vaccine-related factors. We also found no evidence of poorer viral neutralization in PLWH after two doses, nor evidence that a low nadir CD4+ T-cell count compromised responses. Post-third-dose humoral responses substantially exceeded post-second-dose levels, though Omicron-specific responses were consistently weaker than against wild-type. Nevertheless, post-third-dose responses in PLWH were comparable to or higher than controls. An mRNA-1273 third dose was the strongest consistent correlate of higher post-third-dose responses. CONCLUSION: PLWH receiving suppressive antiretroviral therapy mount strong antibody responses after two- and three-dose COVID-19 vaccination. Results underscore the immune benefits of third doses in light of Omicron.

OPTIMAL CONTROL OF A NEW CORONA VIRUS MODEL

This study proposes a corona pandemic model that incorporates both reported and unreported cases of virus to be more realistic. In addition, it is advised to employ both preventive measures: vaccination and treatment and applied them at the simultaneously. The optimal controls were characterized with the maximum Pontryagin principle. Finally, the results of the numerical simulations demonstrate the utility of the proposed control mechanisms and this modeling. © 2023, SCIK Publishing Corporation. All rights reserved.

Comparison of the efficacy of one, two, and third doses of BNT162b2 in patients suffering from cardiovascular diseases, respiratory diseases, and diabetes against COVID-19

The COVID-19 pandemic has had a major impact on human health around the world. Given the speed of the spread of the disease and its impact on people's lives, different countries including Jordan issued approval for the emergency use of the mRNA vaccine BNT162b2 for COVID-19. This respiratory disease has led to an increased risk of complications and significant mortality in patients with pre-existing medical conditions such as respiratory disease, cardiovascular disease, and diabetes. Vaccination against COVID-19 is recommended for people with chronic diseases to reduce the risk of infection, hospitalization, and death. The BNT162b2 vaccine has shown high efficacy in healthy adults. The results of our study suggest a high efficacy of the BNT162b2 vaccine in patients with diabetes and cardiovascular after the second and third doses compared to the first dose of the vaccine. Vaccine efficacy for the third dose was similar to that for the third dose while the effectiveness did not change between the first, second, and third doses in respiratory diseases. In conclusion, receiving second and third doses of the COVID-19 vaccine was associated with a decreased risk of mortality and hospitalization compared with the first dose. Unfortunately, the efficacy of the first, second, and third doses was similar in respiratory patients.Copyright © Jaber SA, Saadh M

The effect of the third dose of the BNT162b2 vaccine on anti-SARS-CoV-2 spike antibody levels in healthcare workers with and without COVID-19 infection.

AIM: A third (booster) dose of the anti-SARS-CoV-2 vaccine became necessary due to the observed decrease in anti-SARS-CoV-2S antibody levels over time, new mutations, and low global vaccination rates. In this study, anti-SARS-CoV-2S antibody levels were measured (ECLIA assay) in 50 healthcare workers with and without a history of COVID-19 infection to determine the humoral immune response to the third dose of the BNT162b2 vaccine. METHODS: Antibody levels were determined in the blood serum, and blood was sampled for analysis 20-40 days after the administration of the booster dose. RESULTS: A greater increase in anti-SARS-CoV-2S antibody titers was noted in persons without a history of infection, but antibody levels continued to be higher in previously infected individuals when the results were adjusted for age, gender, BMI, type of work, and presence of comorbidities. CONCLUSION: The results of this study can be used to improve the vaccination strategy for the general population.KEY MESSAGESThree doses of the vaccine BNT162b2 strongly stimulate the immune system to produce anti-SARS-CoV-2s antibodies, especially in people with a previous infection COVID-19.Age, gender, and BMI may be associated with different humoral immune response to the BNT162b2 vaccine.

Evolution of antibody profiles against SARS-CoV-2 in experienced and naïve vaccinated elderly people.

Introduction: The third dose of the COVID-19 vaccine is especially necessary in people over 65 years of age due to their lower immune response. Methods: We designed a multicentre, prospective observational study including 98 people ≤65 years old who lived in two nursing homes in Valladolid, Spain. One of the groups had previous experience with SARS-CoV-2 (n=68;69.4%) and the other was naïve (n=30;30.6%). We evaluated the response to the three doses of the Comirnaty vaccine and the dynamics of antibodies during 5 consecutive serum samplings: 2 after the first two doses of vaccination, one three months after the first dose, another at 6 months and the last one month after the third dose. IgG antibodies against SARS-CoV-2 S1, RBD and N antigens were analysed. Results: Both groups increased the level of Abs against S1 and RBD, but the experienced group showed a 130-fold higher humoral response due to hybrid immunisation (infection+vaccination). The response to vaccination with Comirnaty against COVID-19 was higher in those ≤65 years with previous experience than those who were naïve. However, the amount of antibodies against S1 and RBD equalised at 6 months. After the third dose, both groups raised the amount of antibodies to a similar level. The reinfections suggested by the analysis of antibodies against N were frequent in both groups. Discussion: The third dose showed a clear benefit for elderly people, with the reinforcement of the antibody levels after the decline suffered after six months of the first two doses.

Could Prior COVID-19 Affect the Neutralizing Antibody after the Third BNT162b2 Booster Dose: A Longitudinal Study.

Vaccination is an essential public health measure for preventing the spread of illness during this continuing COVID-19 epidemic. The immune response developed by the host or the continuation of the immunological response caused by vaccination is crucial since it might alter the epidemic's prognosis. In our study, we aimed to determine the titers of anti-S-RBD antibody and surrogate neutralizing antibody (snAb) formed before and after the third dose of the BNT162b2 vaccination (on the 15th, 60th, and 90th days) in healthy adults who did not have any comorbidity either with or without prior SARS-CoV-2 infection. In this longitudinal prospective study, 300 healthy persons were randomly included between January and February 2022, following two doses of BNT162b2 immunization and before a third dosage. Blood was drawn from the peripheral veins. SARS-CoV-2 NCP IgG and anti-S-RBD IgG levels were detected by the CMIA method, and a surrogate neutralizing antibody was seen by the ELISA method. Our study included 154 (51.3%) female and 146 (48.7%) male (total 300) participants. The participants' median age was 32.5 (IQR:24-38). It was discovered that 208 individuals (69.3%) had never been infected with SARS-CoV-2, whereas 92 participants (30.7%) had SARS-CoV-2 infections in the past. Anti-S-RBD IgG and nAb IH% levels increased 5.94- and 1.26-fold on day 15, 3.63- and 1.22-fold on day 60, and 2.33- and 1.26-fold on day 90 after the third BNT162b2 vaccine dosage compared to pre-vaccination values (Day 0). In addition, the decrease in anti-S-RBD IgG levels on the 60th and 90th days was significantly different in the group without prior SARS-CoV-2 infection compared to the group with past SARS-CoV-2 infection (p < 0.05). In conclusion, it was observed that prior SARS-CoV-2 infection and the third BNT162b2 vaccine dose led to a lower decrease in both nAb and anti-S-RBD IgG levels. To evaluate the vaccine's effectiveness and update immunization programs, however, it is necessary to perform multicenter, longer-term, and comprehensive investigations on healthy individuals without immune response issues, as there are still circulating variants.

SARS-CoV-2 Antibody Response and Sustainability after a Third Dose of BNT162b2 in Healthcare Workers at Health Promotion Centers.

The aim of this study was to determine the antibody response and the sustainability of immunogenicity after a third dose of BNT162b2 (BNT) in homologous [ChAdOx1 (ChAd)/ChAd, BNT/BNT, and mRNA-1273 (Moderna)/Moderna] and heterologous (ChAd/BNT) vaccinations of two primary doses with different schemes. This prospective observational study recruited consenting healthcare workers from 16 health checkup centers in 13 Korean cities. Three-point blood tests were analyzed as the antibody response after the third vaccination: T3-1 (1 month after the third dose), T3-3 (3 months after the third dose), and T3-4-10 (4-10 months after the third 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). The antibody levels were significantly higher in the Moderna /Moderna and BNT/BNT groups than in the ChAd/ ChAd and ChAd/BNT groups (p < 0.05) at T3-1. At T3-3, antibody levels had decreased by 29.1% in the BNT/BNT group and by 45.3% in the ChAd/ChAd group compared with the antibody levels at T3-1. The anti-SARS-CoV-2 S-RBD IgG levels at T3-1 were significantly associated with having received mRNA vaccines as the two primary doses (p < 0.001). The third dose of BNT induced an increased humoral immune response in various vaccination schemes, which was more prominent for the two primary doses of homologous mRNA vaccines. However, this immunogenicity decreased within 3-10 months after the third dose. These results suggest that another booster dose (a fourth dose), which would be able to counteract SARS-CoV-2 variants, is needed.

Improved immunogenicity following the third dose of BNT162b2 mRNA vaccine in heart transplant recipients.

OBJECTIVES: The immunogenicity of two-dose severe acute respiratory syndrome coronavirus 2 vaccine is lower among heart transplant (HTx) recipients, compared with the general population. Our aim was to assess the immunogenicity of a third-dose vaccine in HTx recipients. METHODS: This is a prospective cohort study of HTx recipients who received a third dose of the BNT162b2 vaccine. Immunogenicity was assessed by serum levels of anti-spike immunoglobulin G (S-IgG), taken at baseline and 14-28 days after the third dose. Titres above 50 U/ml were interpreted positive. RESULTS: We Included 42 HTx recipients at a median age of 65 years [interquartile range (IQR) 58-70]. At baseline, the median of 27 days (IQR 13-42) before the third dose and the median titre of the whole group was 18 U/ml (IQR 4-130). Only 14 patients (33%) were S-IgG seropositive. After the third dose, the proportion of seropositive patients increased significantly to 57% (P = 0.05) and the median titre increased significantly to 633 U/ml (IQR 7-6104, P < 0.0001). Younger age at HTx (OR per 1-year decrease 1.07, P = 0.05), low tacrolimus serum level (OR per 1-unit decrease 2.28, P = 0.02), mammalian target of rapamycin use (OR 13.3, P = 0.003), lack of oral steroids use (OR 4.17, P = 0.04) and lack of calcineurin inhibitor use (71% of responders vs 100% non-responders received calcineurin inhibitors, P = 0.01) were predictors of seropositive result after the third dose. However, no significant association was detected following adjustment for baseline S-IgG titre. CONCLUSIONS: Third-dose booster of BNT162b2 vaccine significantly increased immunogenicity among HTx recipients who previously received a two-dose vaccine.

Humoral Response to the Third Dose of BNT162b2 COVID-19 Vaccine among Hemodialysis Patients.

BACKGROUND: Hemodialysis patients are at high risk for severe COVID-19 disease. Despite a high early seropositivity rate, dialysis patients mount a dampened immune response following two doses of an mRNA vaccine. This study aimed to evaluate the serologic response to a booster dose of BNT162b2 vaccine, 6 months after the second dose, among hemodialysis patients. METHODS: This prospective study included 80 hemodialysis patients and 56 healthcare workers serving as controls. Serologic samples were evaluated before and ∼3 weeks after the third vaccine dose. The primary outcomes were the seropositivity rate and the log-transformed anti-SARS-COV-2 S1 (RBD) IgG as a continuous variable after the third dose. Secondary outcomes were the proportion of participants with "high response," defined as antibody levels >1,000 AU/mL, and "robust response," defined as antibody levels >4,160 AU/mL, according to prespecified cutoff values associated with neutralizing antibodies. Univariate and multivariate analyses were conducted to identify predictors of antibody response. RESULTS: Among 80 hemodialysis patients, seropositivity rates improved from 78% (62/80) before the third dose, up to 96% (77/80) after the booster dose. The S1-RBD log-transformed antibody level increased significantly following the third dose from 2.15 ± 0.75 to 3.99 ± 0.83 compared with 2.65 ± 0.4 to 4.31 ± 0.42 in the control group. Among the hemodialysis patients, 88% (70/80) became "high responders" (>1,000 AU/mL), and of these, 79% (63/80) mounted a "robust response" (>4,160 AU/mL). Baseline antibody level, dialysis therapy, and hypoalbuminemia were independent predictors of impaired antibody response. CONCLUSIONS: A third dose of BNT162b2 COVID-19 vaccine, 6 months after the standard two-dose vaccination regimen, substantially improved humoral response in hemodialysis patients.

Anti-SARS-CoV-2 spike IgG following injection of the third dose vaccine: A systematic review with meta-analysis of heterologous versus homologous vaccination.

Background: The mass vaccination is a key strategy to prevent and control the coronavirus disease 2019 (COVID-19) pandemic. Today, several different types of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed worldwide. These vaccines are usually administered in a two-dose schedule, and the third dose is currently being administered in most countries. This study aimed to systematically review and meta-analyze the immunogenicity of heterologous vs. homologous vaccination after administration of the third dose of COVID-19 vaccines. Methods: Electronic databases and websites including Scopus, PubMed, Web of Science, and Google scholar were searched for relevant randomized clinical trial (RCT) studies. After applying the inclusion and exclusion criteria, a total of three RCTs were included in the study. These RCTs were included 2,613 healthy adults (18 years or older and without a history of laboratory-confirmed COVID-19) with 15 heterologous and five homologous prime-boost vaccination regimens. Anti-SARS-CoV-2-spike IgG levels at day 28 after administration of the third dose, were compared between the heterologous and homologous regimens. Results: The highest antibody responses had been reported for the homologous vaccination regimen of m1273/m1273/m1273 (Moderna), followed by the heterologous regimen of BNT/BNT/m1273. In addition, the immunogenicity of viral vector and inactivated vaccines was remarkably enhanced when they had been boosted by a heterologous vaccine, especially mRNA vaccines. Conclusion: This systematic review suggests that mRNA vaccines in a homologous regimen induce strong antibody responses to SARS-CoV-2 compared to other vaccine platforms. In contrast, viral vector and inactivated vaccines show a satisfactory immunogenicity in a heterologous regimen, especially in combination with mRNA vaccines.

Humoral Response after Two Doses of BNT162b2 mRNA Vaccine Has a Role in Predicting Response after Three Doses That Is Related to Plasma HIV Viremia and Nadir CD4+ Cell Count in HIV-Positive Patients.

We investigated the spike IgG levels of HIV+ patients on antiretroviral therapy six months after they received their second dose (T2) and six months after the third dose (T3) of the BNT162b2 mRNA vaccine, as well as the influence of different levels of plasma HIV viremia of overall CD4+ cell count and nadir value on the humoral time course. One hundred eighty-four patients were enrolled. The median age was 55 years, the median CD4+ cell count was 639 cells/mm3 and the median nadir value was 258 cells/mm3. On the basis of all tests performed during the study period, persistently undetectable plasma HIV RNA (PUD) was found in 66 patients, low-level viremia (LLV) in 57 and ongoing viremia (OV) in 61. Serum levels of IgG antibodies against a trimeric S-protein antigen were tested with DiaSorin Liaison SARS-CoV-2 TrimericS IgG and the response was classified as optimal (>75th percentile), intermediate (50th−25th percentile) and low (<25th percentile). The frequencies of the three different patterns of plasma HIV viremia (PUD, LLV and OV) were comparable in patients with low, intermediate and optimal IgG response evaluated at T2, with no difference in overall CD4+ cell count or nadir count. At T3, 92.9% of patients achieved an optimal response: T2 response proved to be the most important factor in predicting T3 optimal response in patients with LLV and OV.A nadir value ≤ 330 cells/mm3 had 100% sensitivity in predicting a non-optimal response. In conclusion, we demonstrated the persistence of anti-spike IgG, with high serum levels occurring in most patients six months after the third dose of the BNT162b2 mRNA vaccine and a predictive role of humoral response at T2 in subjects with detectable plasma HIV viremia. Immunological alterations related to past immunodeficiency may persist despite immune reconstitution, and the nadir value could be a useful tool for elaborating personalized vaccine schedules.

Neutralizing antibodies after three doses of the BNT162b2 vaccine, breakthrough infection, and symptoms during the Omicron-predominant wave.

OBJECTIVES: To investigate the role of immunogenicity after the third vaccine dose against Omicron infection and COVID-19-compatible symptoms of infection. METHODS: First, we examined vaccine effectiveness (VE) of the third dose against the second dose during the Omicron wave among the staff at a tertiary hospital in Tokyo. In a case-control study of third vaccine recipients, we compared the preinfection live-virus neutralizing antibodies (NAb) against Omicron between breakthrough cases and their controls who had close contact with patients with COVID-19. Among these cases, we examined the association between NAb levels and the number of COVID-19-compatible symptoms. RESULTS: Among the 1456 participants for VE analysis, 60 breakthrough infections occurred during the Omicron wave. The third dose VE for infection was 54.6%. Among the third dose recipients, NAb levels against Omicron did not differ between the cases (n = 22) and controls (n = 21). Among the cases, those who experienced COVID-19-compatible symptoms had lower NAb levels against Omicron than those who did not. CONCLUSION: The third vaccine dose was effective in decreasing the risk of SARS-CoV-2 infection during Omicron wave compared with the second dose. Among third dose recipients, higher preinfection NAb levels may not be associated with a lower risk of Omicron infection. Contrarily, they may be associated with fewer symptoms of infection.

Humoral and cellular immune response dynamics in Japanese healthcare workers up to six months after receiving a third dose of BNT162b2 monovalent vaccine.

Longitudinal data on the immune response from the first dose to several months after the third dose of COVID-19 vaccine are limited. We analyzed the immune response in 406 Japanese healthcare workers who received at least three doses of vaccine. The geometric mean anti-receptor binding domain IgG antibody titers and antigen-stimulated T-cell interferon-gamma levels after 6 months after receiving a third dose were similar to those 8 weeks after receiving a second dose. Humoral and cellular immunity induced by the third dose was more durable than that induced by the second dose. UMIN Clinical Trials Registry ID: UMIN000043340.

Anti-SARS-CoV-2 cellular response after 2 and 3 doses of BNT162b2 mRNA vaccine in lymphoma patients receiving anti-CD20 antibodies.

Patients receiving anti-CD20 antibodies showed limited efficacy of a booster dose of BNT162b2. Patients with lymphomas combine such immunotherapies with cytotoxic chemotherapies that could result in an even greater alteration of the immune response to vaccination. We report here the impact of a third vaccine dose on T cell specific responses in a small cohort of patients treated in our center by anti-CD20 therapies and cytotoxic chemotherapies for lymphoid malignancies. Our results showed that a third dose in these severely immune suppressed patients could improve the expansion on CD4+Th1+T cell responses while the effect CD8 + T cell responses was marginal.

Humoral immune response following a third SARS-CoV-2 mRNA vaccine dose in solid organ transplant recipients compared with matched controls.

Background: Solid organ transplant (SOT) recipients have shown suboptimal antibody response following COVID-19 vaccination. Several risk factors for the diminished response have been identified including immunosuppression and older age, but the influence of different comorbidities is not fully elucidated. Method: This case-control study consisted of 420 Danish adult SOT recipients and 840 sex- and age-matched controls, all vaccinated with a third homologous dose of either BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) vaccine. The primary outcome was differences in humoral immune response. The secondary outcome was breakthrough infections. Additionally, we looked for factors that could predict possible differences between the two groups. Results: Response rate increased from 186/382 (49%) to 275/358 (77%) in SOT recipients and remained on 781/790 (99%) to 601/609 (99%) in controls following a third vaccine dose. SOT recipients had significantly lower median antibody concentrations after third dose compared to controls (332.6 BAU/ml vs 46,470.0 BAU/ml, p <0.001). Lowest median antibody concentrations were seen in SOT recipients with liver disease (10.3 BAU/ml, IQR 7.1-319) and diabetes (275.3 BAU/ml, IQR 7.3-957.4). Breakthrough infections occurred similarly frequent, 150 (40%) among cases and 301 (39%) among controls (p = 0.80). Conclusion: A third COVID-19 vaccine dose resulted in a significant increase in humoral immunogenicity in SOT recipients and maintained high response rate in controls. Furthermore, SOT recipients were less likely to produce antibodies with overall lower antibody concentrations and humoral immunity was highly influenced by the presence of liver disease and diabetes. The prevalence of breakthrough infections was similar in the two groups.