Third Dose of SARS-CoV-2 Vaccine: A Systematic Review of 30 Published Studies

Immunologic responses to the third and fourth doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in cell therapy recipients: a systematic review and meta-analysis

BACKGROUND

Multiple studies have provided evidence of suboptimal or poor immune responses to SARS-CoV-2 vaccines in recipients of hematopoietic stem cell transplantation (HSCT) and chimeric antigen receptor-T (CAR-T) cell therapy compared to healthy individuals. Given the dynamic nature of SARS-CoV2, characterized by the emergence of many viral variations throughout the general population, there is ongoing discussion regarding the optimal quantity and frequency of additional doses required to sustain protection against SARS-CoV2 especially in this susceptible population. This systematic review and meta-analysis investigated the immune responses of HSCT and CAR-T cell therapy recipients to additional doses of the SARS-CoV-2 vaccines.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the study involved a comprehensive search across PubMed, Scopus, Web of Science Core Collection, Embase, and Cochrane Biorxiv and medRxiv, focusing on the serological responses to the third and fourth vaccine doses in HSCT and CAR-T cell patients.

RESULTS

This study included 32 papers, with 31 qualifying for the meta-analysis. Results showed that after the third dose, the seroconversion rate in HSCT and CAR-T cell therapy recipients who didn't respond to the second dose was 46.10 and 17.26%, respectively. Following the fourth dose, HSCT patients had a seroconversion rate of 27.23%. Moreover, post-third-dose seropositivity rates were 87.14% for HSCT and 32.96% for CAR-T cell therapy recipients. Additionally, the seropositive response to the fourth dose in the HSCT group was 90.04%.

CONCLUSION

While a significant portion of HSCT recipients developed antibodies after additional vaccinations, only a minority of CAR-T cell therapy patients showed a similar response. This suggests that alternative vaccination strategies are needed to protect these vulnerable groups effectively. Moreover, few studies have reported cellular responses to additional SARS-CoV-2 vaccinations in these patients. Further studies evaluating cellular responses are required to determine a more precise assessment of immunogenicity strength against SARS-CoV-2 after additional doses.

Unravelling humoral immunity in SARS-CoV-2: Insights from infection and vaccination

Following infection and vaccination against SARS-CoV-2, humoral components of the adaptive immune system play a key role in protecting the host. Specifically, B cells generate high-affinity antibodies against various antigens of the virus. In this review, we discuss the mechanisms of immunity initiation through both natural infection and vaccination, shedding light on the activation of B cell subsets in response to SARS-CoV-2 infection and vaccination. The innate immune system serves as the initial line of primary and nonspecific defence against viruses. However, within several days following infection or a vaccine dose, a virus-specific immune response is initiated, primarily by B cells that produce antibodies. These antibodies contribute to the resolution of the disease. Subsequently, these B cells transition into memory B cells, which play a crucial role in providing long-term immunity against the virus. CD4+ T helper cells initiate a cascade, leading to B cell somatic hypermutation, germinal center memory B cells, and the production of neutralizing antibodies. B-cell dysfunction can worsen disease severity and reduce vaccine efficacy. Notably, individuals with B cell immunodeficiency show lower IL-6 production. Furthermore, this review delves into several aspects of immune responses, such as hybrid immunity, which has shown promise in boosting broad-spectrum protection. Cross-reactive immunity is under scrutiny as well, as pre-existing antibodies can offer protection against the disease. We also decipher breakthrough infection mechanisms, especially with the novel variants of the virus. Finally, we discuss some potential therapeutic solutions regarding B cells including convalescent plasma therapy, B-1 cells, B regulatory cell (Breg) modulation, and the use of neutralizing monoclonal antibodies in combating the infection. Ongoing research is crucial to grasp population immunity trends and assess the potential need for booster doses in maintaining effective immune responses against potential viral threats.

Study of the cellular and humoral immune responses to SARS-CoV-2 vaccination

Our understanding of cellular immunity in response to COVID-19 infection or vaccination is limited because of less commonly used techniques. We investigated both the cellular and humoral immune responses before and after the administration of a third dose of the SARS-CoV-2 vaccine among a group of healthcare workers. Cellular immunity was evaluated using the VIDAS interferon-gamma (IFNγ) RUO test, which enables automated measurement of IFNγ levels after stimulating peripheral blood lymphocytes. Booster doses significantly enhanced both cellular and humoral immunity. Concerning cellular response, the booster dose increased the percentage of positive IFNγ release assay (IGRA) results but no difference in IFNγ release was found. The cellular response was not associated with protection against SARS-CoV-2 infection. Interestingly, vaccinated and infected healthcare workers exhibited the highest levels of anti-spike and neutralizing antibodies. In conclusion, the IGRA is a simple method for measuring cellular immune responses after vaccination. However, its usefulness as a complement to the study of humoral responses is yet to be demonstrated in future research.

Immunogenicity and Safety of the Three-Dose COVID-19 Vaccine Regimen in Patients Receiving Renal Replacement Therapy: A Systematic Review and Meta-Analysis

Background

A three-dose regimen is the current standard for COVID-19 vaccination, but systematic data on immunogenicity and safety in chronic kidney disease patients remains limited.

Objectives

We conducted a meta-analysis on the immunogenicity and safety of three-dose COVID-19 vaccination in patients on renal replacement therapy (RRT).

Methods

Systematic literature search in four electronic databases yielded twenty eligible studies (2,117 patients, 94% of whom received mRNA vaccines) for meta-analysis.

Results

The overall seropositivity rate of anti-SARS-CoV-2 was 74.2% (95% CI: 65.0-83.4%) after three-dose COVID-19 vaccination. The seropositivity rate of anti-SARS-CoV-2 in kidney transplant recipients (KTRs) was 64.6% (95% CI: 58.7-70.5%), and 43.5% (95% CI: 38.5-48.6%) of non-responders after second dose became seropositive after third dose. The seropositivity rate of anti-SARS-CoV-2 was 92.9% (95% CI: 89.5-96.2%) in dialysis patients, and 64.6% (95% CI: 46.8-82.3%) of non-responders after second dose became seropositive after third dose. In KTRs, each year increase in transplant vintage was associated with 35.6% increase in anti-SARS-CoV-2 seropositivity (95% CI: 15.9-55.4%, p = 0.01). There were no serious adverse events attributed to vaccination in KTRs, and the commonest local and systemic adverse events were injection site pain and fatigue, respectively.

Conclusion

Three-dose COVID-19 vaccination regimen in patients on RRT is associated with reduced immunogenicity, especially in KTRs. There are no adverse events associated with third-dose COVID-19 vaccine in KTRs.

Reactivity of anti-SARS-CoV-2 antibodies in Serbian voluntary blood donors

BACKGROUND

The COVID-19 pandemic has major implications on the entire blood supply system worldwide. Seroepidemiological studies are certainly necessary for better understanding the global burden that the COVID-19 pandemic represents.

OBJECTIVES

In this study, we analysed the association between demographic factors, COVID-19 severity, vaccination status and the reactivity of anti-SARS-CoV-2 IgG antibodies in Serbian blood donors.

MATERIALS AND METHODS

In a prospective study, demographic data and data related to previous SARS-CoV-2 infection, COVID-19 severity and vaccination status among whole blood donors were analysed, from February 10 to August 10, 2022, at the Blood Transfusion Institute of Vojvodina, Serbia. The detection and determination of the level of anti-SARS-CoV-2 IgG antibodies were performed using LIAISON® SARS-CoV-2 TrimericS IgG immunoassay.

RESULTS

A total of 1190 blood donors were included, 24.5% were female and 75.5% were male while their average age was 41 years. Anti-SARS-CoV-2 antibody values ranged from 2.40 to 3120 BAU/ml with a mean value of 1354.56 BAU/ml. Statistical analysis showed that COVID-19 severity and vaccination status are linked with reactivity of anti-SARS-CoV-2 antibodies, while gender and age of voluntary blood donors are not related to the values of anti-SARS-CoV-2 antibodies.

CONCLUSION

The values of anti-SARS-CoV-2 antibodies in voluntary blood donors in Serbia are kept relatively high, especially in blood donors who have overcome the severe COVID-19, as well as in donors who have been vaccinated against COVID-19. Further SARS-CoV-2 seroprevalence studies in our country are certainly still necessary so global strategies to fight against COVID-19 would be adequately evaluated.

Immunogenicity and Safety of Half-Dose Heterologous mRNA-1273 Booster Vaccination for Adults Primed with the CoronaVac® and ChAdOx1-S Vaccines for SARS-CoV-2

Coronavirus disease 2019 (COVID-19) has been extensively researched, particularly with regard to COVID-19 vaccines. However, issues with logistics and availability might cause delays in vaccination programs. Thus, the efficacy and safety of half-dose heterologous mRNA should be explored. This was an open-label observational study to evaluate the immunogenicity and safety of half-dose mRNA-1273 as a booster vaccine among adults aged >18 years who underwent a complete primary SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) vaccination regimen with CoronaVac® and ChAdOx1-S. Adverse events (AEs), seropositivity rate, seroconversion, geometric mean titer (GMT) of SARS-CoV-2 antibodies, neutralizing antibodies, and T cells (CD4+ and CD8+) specific for SARS-CoV-2 were analyzed. Two hundred subjects were included in the final analysis, with 100 subjects in each priming vaccine group. Most of the AEs were mild, with systemic manifestations occurring between 1 and 7 days following vaccination. A significant difference was observed in the GMT and seropositivity rate following booster dose administration between the two groups. CD8+/CD3+, IFN (interferon)-producing CD8+, and TNF (tumor necrosis factor)-producing CD8+ cells showed significant increases in both groups. The administration of the half-dose mRNA-1273 booster is safe and effective in increasing protection against SARS-CoV-2 infection.

Comparing reactogenicity of COVID-19 vaccine boosters: a systematic review and meta-analysis

INTRODUCTION

Different COVID-19 vaccines are being utilized as boosters. This systematic review and meta-analysis aims to evaluate the reactogenicity of COVID-19 vaccines given as booster doses, according to vaccine type, dose, timing, participant characteristics and primary immunization regimen received.

METHODS

Four databases (MEDLINE, Embase, Web of Science and CENTRAL) were searched for randomized controlled trials between 1 January 2020 and 1 January 2023 according to predetermined criteria.

RESULTS

Twenty-eight studies describing 19 vaccines of four different types (viral vector, inactivated, mRNA and protein sub-unit) were identified. BNT162b2 vaccine (Pfizer-BioNTech) was selected as the control as it was most often compared with other vaccines. Fever, fatigue, headache, injection-site pain, redness, and swelling were the most frequently reported solicited events. mRNA vaccines were the most reactogenic, followed by viral vector vaccines and protein sub-unit vaccines, while inactivated vaccines were the least reactogenic. Full-dose vaccines were more reactogenic than half-dose vaccines. Heterologous BNT162b2 boosters were more reactogenic than boosters with the same vaccine used for primary immunization.

CONCLUSIONS

COVID-19 vaccine booster schedules have distinct reactogenicity profiles, dependent on dose and vaccine type, which may allow targeted recommendations and provide choice for specific populations. Greater standardization of adverse event reporting will aid future studies.

Longitudinal anti-SARS-CoV-2 antibody immune response in acute and convalescent patients

Despite global efforts to assess the early response and persistence of SARS-CoV-2 antibodies in patients infected with or recovered from COVID-19, our understanding of the factors affecting its dynamics remains limited. This work aimed to evaluate the early and convalescent immunity of outpatients infected with SARS-CoV-2 and to determine the factors that affect the dynamics and persistence of the IgM and IgG antibody response. Seropositivity of volunteers from Mexico City and the State of Mexico, Mexico, was evaluated by ELISA using the recombinant receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein for 90 days, at different time points (1, 15, 45, 60, and 90 days) after molecular diagnosis (RT-qPCR). Gender, age range, body mass index (BMI), comorbidities, and clinical spectrum of disease were analyzed to determine associations with the dynamics of anti-SARS-CoV-2 antibodies. On 90 days post-infection, individuals with moderate and asymptomatic disease presented the lowest levels of IgM, while for IgG, at the same time, the highest levels occurred with mild and moderate disease. The IgM and IgG levels were related to the clinical spectrum of disease, BMI, and the presence/absence of comorbidities through regression trees. The results suggest that the dynamics of anti-SARS-CoV-2 IgM and IgG antibodies in outpatients could be influenced by the clinical spectrum of the disease. In addition, the persistence of antibodies against SARS-CoV-2 could be related to the clinical spectrum of the disease, BMI, and the presence/absence of comorbidities.

Evaluation of Covid-19 anti-spike IgG antibody five months after the second Covid-19 vaccination

Background

Studies in different communities have shown significant differences in IgG antibody titers in the time period after the first and second doses of the vaccines. This study aimed to serologically evaluate the IgG anti-spike antibody titer five months after injection of the second COVID-19 vaccine in healthcare workers.

Materials and method

This study was performed in healthcare personnel for whom five months had passed since their second anti-Covid-19 vaccination. The level of IgG antibody against SARS-CoV-2 spike protein was measured by ELISA. Healthcare workers in Mofid Children's hospital received three brands of vaccines: Sputnik V, Sinopharm, and AstraZeneca.

Results

The mean titer of anti-spike IgG was 4.3±2.29 units. The percentage of positive cases of the antibody was estimated to be 96.4%. The titer of anti-spike IgG antibody was dependent on both the occupational area and a positive history of Covid-19 disease.

Conclusion

About 96.4% of the staff vaccinated against Covid-19 had a high titer of anti-spike IgG antibody even five months after inoculation of the second dose. The field of occupational can affect the level of antibody present.

Predictors of SARS-CoV-2 Infection and Severe and Lethal COVID-19 after Three Years of Follow-Up: A Population-Wide Study

In this cohort study, the general population of an Italian Province was followed for three years after the start of the pandemic, in order to identify the predictors of SARS-CoV-2 infection and severe or lethal COVID-19. All the National Healthcare System information on biographical records, vaccinations, SARS-CoV-2 swabs, COVID-19 cases, hospitalizations and co-pay exemptions were extracted from 25 February 2020 to 15 February 2023. Cox proportional hazard analysis was used to compute the relative hazards of infection and severe or lethal COVID-19, adjusting for age, gender, vaccine status, hypertension, diabetes, major cardiovascular diseases (CVD), chronic obstructive pulmonary disease (COPD), kidney disease or cancer. Among the 300,079 residents or domiciled citizens, 41.5% had ≥1 positive swabs during the follow-up (which lasted a mean of 932 days). A total of 3.67% of the infected individuals experienced severe COVID-19 (n = 4574) and 1.76% died (n = 2190). Females, the elderly and subjects with diabetes, CVD, COPD, kidney disease and cancer showed a significantly higher risk of SARS-CoV-2 infection. The likelihood of severe or lethal COVID-19 was >90% lower among the youngest, and all comorbidities were independently associated with a higher risk (ranging from +28% to +214%) of both outcomes. Two years after the start of the immunization campaign, the individuals who received ≥2 doses of COVID-19 vaccines still showed a significantly lower likelihood of severe or lethal disease, with the lowest risk observed among subjects who received at least one booster dose.

Prior cycles of anti-CD20 antibodies affect antibody responses after repeated SARS-CoV-2 mRNA vaccination

BACKGROUNDWhile B cell depletion is associated with attenuated antibody responses to SARS-CoV-2 mRNA vaccination, responses vary among individuals. Thus, elucidating the factors that affect immune responses after repeated vaccination is an important clinical need.METHODSWe evaluated the quality and magnitude of the T cell, B cell, antibody, and cytokine responses to a third dose of BNT162b2 or mRNA-1273 mRNA vaccine in patients with B cell depletion.RESULTSIn contrast with control individuals (n = 10), most patients on anti-CD20 therapy (n = 48) did not demonstrate an increase in spike-specific B cells or antibodies after a third dose of vaccine. A third vaccine elicited significantly increased frequencies of spike-specific non-naive T cells. A small subset of B cell-depleted individuals effectively produced spike-specific antibodies, and logistic regression models identified time since last anti-CD20 treatment and lower cumulative exposure to anti-CD20 mAbs as predictors of those having a serologic response. B cell-depleted patients who mounted an antibody response to 3 vaccine doses had persistent humoral immunity 6 months later.CONCLUSIONThese results demonstrate that serial vaccination strategies can be effective for a subset of B cell-depleted patients.FUNDINGThe NIH (R25 NS079193, P01 AI073748, U24 AI11867, R01 AI22220, UM 1HG009390, P01 AI039671, P50 CA121974, R01 CA227473, U01CA260507, 75N93019C00065, K24 AG042489), NIH HIPC Consortium (U19 AI089992), the National Multiple Sclerosis Society (CA 1061-A-18, RG-1802-30153), the Nancy Taylor Foundation for Chronic Diseases, Erase MS, and the Claude D. Pepper Older Americans Independence Center at Yale (P30 AG21342).

Safety and immunogenicity of the third (booster) dose of inactivated and recombinant protein SARS-CoV-2 vaccine for patients with endocrine-related cancer

Background

Our study aimed to evaluate the safety and immunogenicity of the third (booster) dose of the COVID-19 vaccine for patients with endocrine-related cancers.

Methods

This observational study involved 94 breast cancer patients, 92 thyroid cancer patients, and 123 healthy individuals who had received the third (booster) dose of the COVID-19 vaccine. Data on the adverse effects, serum anti-receptor binding domain (RBD)-immunoglobulin (Ig) G, and neutralizing antibodies (NAbs) were collected prospectively.

Results

The serum anti-RBD-IgG and NAb titers were significantly lower for the patients with endocrine-related malignancies than for the healthy controls (3.01 [IQR: 1.11-6.70] vs. 4.19 [1.95-9.11], p = 0.001; 0.23 [0.11-0.52] vs. 0.41 [0.22-0.78], p = 0.001), and the seroconversion rates of anti-RBD-IgG and NAbs showed similar results. The serum antibody titers and seroconversion rates were significantly lower for patients aged ≥65 years with endocrine-related cancers, but there were no significant differences related to gender, vaccine type, or cancer type. Subgroup analysis showed that the antibody titers and seroconversion rates were significantly lower for patients with intermediate to advanced breast cancer, HR-/Her2+ breast cancer, and breast cancer undergoing treatment than for healthy controls. In contrast, breast cancer patients who completed their treatment and those who received endocrine therapy after completing their treatment were not significantly different from healthy controls. The NAbs titers and seroconversion rates were significantly lower for patients with primary thyroid cancer (0.19 [IQR: 0.10-0.46] vs. 0.41 [0.22-0.78], p = 0.003; 55.9 vs. 84.9%, p < 0.001); the seroconversion rates were significantly higher for the patients with combined Hashimoto's thyroiditis than for those without it. Multiple linear regression showed that patients aged ≥65 years who were receiving treatment were at risk of having lower antibody levels.

Conclusion

The third (booster) dose of the COVID-19 vaccine is safe and well-tolerated. Our data support a third (booster) dose of the SARS-CoV-2 vaccine for breast and thyroid cancer patients. Breast cancer patients aged ≥65 years who are receiving treatment should be more protected, while thyroid cancer and breast cancer patients who have completed their treatment can be vaccinated like the general population.

Differences in BNT126b2 and ChAdOx1 Homologous Vaccination Antibody Response among Teachers in Poznan, Poland

Children are among the best vectors to spread respiratory viruses, including emerging variants of SARS-CoV-2 due to the asymptomatic or relatively mild course of infection and simultaneously high titres of pathogens in the respiratory tract. Therefore, individuals who have constant contact with children, e.g., teachers should be vaccinated against COVID-19 as essential workers within the first phases of a vaccination campaign. In Poland, primary and secondary school teachers were vaccinated with ChAdOx1 from February 2021 with a three month interval between the two doses, while lecturers at medical universities, who are simultaneously healthcare workers, received the BNT126b2 vaccine from December 2020 with three weeks between the first and second doses. The aim of this study was to compare the antibody responses at two weeks and three months after vaccination and to estimate the vaccine effectiveness against COVID-19 among infection-naïve teachers vaccinated with mRNA and a vector vaccine. We found that the anti-SARS-CoV-2 spike protein antibodies were significantly higher among the lecturers but antibody waning was slower among the schoolteachers. However, those vaccinated with ChAdOx1 complained significantly more often of vaccine side effects. In addition, during the three months after the second vaccine dose no study participants were infected with SARS-CoV-2. The BNT126b2 vaccine gave higher antibody titres in comparison with ChAdOx1 but protection against COVID-19 in both cases was similar. Moreover, we did not find any anti-SARS-CoV-2 nucleoprotein antibodies at two weeks as well as at three months after vaccination among the study participants, which shows a very high vaccine effectiveness in the occupational group with a high SARS-CoV-2-infection risk.

In-depth analysis of T cell immunity and antibody responses in heterologous prime-boost-boost vaccine regimens against SARS-CoV-2 and Omicron variant

With the emergence of novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) Variants of Concern (VOCs), vaccination studies that elucidate the efficiency and effectiveness of a vaccination campaign are critical to assess the durability and the protective immunity provided by vaccines. SARS-CoV-2 vaccines have been found to induce robust humoral and cell-mediated immunity in individuals vaccinated with homologous vaccination regimens. Recent studies also suggest improved immune response against SARS-CoV-2 when heterologous vaccination strategies are employed. Yet, few data exist on the extent to which heterologous prime-boost-boost vaccinations with two different vaccine platforms have an impact on the T cell-mediated immune responses with a special emphasis on the currently dominantly circulating Omicron strain. In this study, we collected serum and peripheral blood mononuclear cells (PBMCs) from 57 study participants of median 35-year old's working in the health care field, who have received different vaccination regimens. Neutralization assays revealed robust but decreased neutralization of Omicron VOC, including BA.1 and BA.4/5, compared to WT SARS-CoV-2 in all vaccine groups and increased WT SARS-CoV-2 binding and neutralizing antibodies titers in homologous mRNA prime-boost-boost study participants. By investigating cytokine production, we found that homologous and heterologous prime-boost-boost-vaccination induces a robust cytokine response of CD4⁺ and CD8⁺ T cells. Collectively, our results indicate robust humoral and T cell mediated immunity against Omicron in homologous and heterologous prime-boost-boost vaccinated study participants, which might serve as a guide for policy decisions.

Need of booster vaccine doses to counteract the emergence of SARS-CoV-2 variants in the context of the Omicron variant and increasing COVID-19 cases: An update

The emergence of different variants of SARS-CoV-2, including the Omicron (B.1.1.529) variant in November 2021, has resulted in a continuous major health concern at a global scale. Presently, the Omicron variant has spread very rapidly worldwide within a short time period. As the most mutated variant of SARS-CoV-2, Omicron has instilled serious uncertainties on the effectiveness of humoral adaptive immunity generated by COVID-19 vaccination or an active viral infection as well as the protection provided by antibody-based immunotherapies. Amidst such high public health concerns, the need to carry out booster vaccination has been emphasized. Current evidence reveals the importance of incorporating booster vaccination using several vaccine platforms, such as viral vector- and mRNA-based vaccines, as well as other platforms that are under explorative investigations. Further research is being conducted to assess the effectiveness and durability of protection provided by booster COVID-19 vaccination against Omicron and other SARS-CoV-2 variants.

Anti-spike T-cell and Antibody Responses to SARS-CoV-2 mRNA Vaccines in Patients with Hematologic Malignancies

The anti-spike T-cell and antibody responses to SARS-CoV-2 mRNA vaccines in patients with B-cell malignancies were examined in a real-world setting. A next-generation sequencing (NGS)-based molecular assay was used to assess SARS-CoV-2-specific T-cell responses. After the second dose, 58% (166/284) of seropositive and 45% (99/221) of seronegative patients display anti-spike T cells. The percentage of patients who displayed T-cell response was higher among patients receiving mRNA-1273 vaccines compared with those receiving BNT162b2 vaccines. After the third vaccination, 40% (137/342) of patients seroconverted, although only 22% displayed sufficient antibody levels associated with the production of neutralizing antibodies. 97% (717/738) of patients who were seropositive before the third dose had markedly elevated anti-spike antibody levels. Anti-spike antibody levels, but not T-cell responses, were depressed by B cell-directed therapies. Vaccinated patients with B-cell malignancies with a poor response to SARS-CoV-2 vaccines may remain vulnerable to COVID-19 infections.

SIGNIFICANCE

This study represents the first investigation of SARS-CoV-2-specific immune responses to vaccination in a patient registry using an NGS-based method for T-cell receptor repertoire-based analysis combined with anti-spike antibody assessments. Vaccinated patients with B cell-derived hematologic malignancies are likely at higher risk of infection or severe COVID-19. This article is highlighted in the In This Issue feature, p. 476.

Assessing T-Cell Immunity in Kidney Transplant Recipients with Absent Antibody Production after a 3rd Dose of the mRNA-1273 Vaccine

The vulnerable population of kidney transplant recipients (KTRs) are low responders to COVID-19 vaccines, so specific immune surveillance is needed. The interferon-gamma (IFN-γ) release assay (IGRA) is effective in assessing T cell-mediated immunity. We assessed SARS-CoV-2-directed T cell responses in KTRs with absent antibody production after a third dose of the mRNA-1273 vaccine, using two different IGRAs. A cohort of 57 KTRs, who were actively followed up, received a third dose of the mRNA-1273 vaccine. After the evaluation of humoral immunity to SARS-CoV-2, 14 seronegative patients were tested with two commercial IGRAs (SD Biosensor and Euroimmun). Out of 14 patients, one and three samples were positive by IGRAs with Euroimmun and SD Biosensor, respectively. The overall agreement between the two assays was 85.7% (κ = 0.444). In addition, multivariate linear regression analysis showed no statistically significant association between the IFN-γ concentration, and the independent variables analyzed (age, gender, years since transplant, total lymphocytes cells/mcl, CD3+ cells/mcl, CD3+ CD4+ cells/mcl, CD3+ CD8+ cells/mcl, CD19+ cells/mcl, CD3-CD16+CD56+ cells/mcl) (p > 0.01). In a vulnerable setting, assessing cellular immune response to complement the humoral response may be advantageous. Since the two commercial IGRAs showed a good agreement on negative samples, the three discordant samples highlight the need for further investigations.

Cost-Effectiveness of COVID-19 Sequential Vaccination Strategies in Inactivated Vaccinated Individuals in China

To effectively prevent and control the COVID-19 pandemic, countries have adopted a booster vaccination strategy. This study aimed to estimate the cost-effectiveness of sequential booster COVID-19 vaccination compared to two-dose inactivated vaccination in China from a societal perspective. A Markov model was developed to estimate the cost-effectiveness of sequential vaccination, including two doses of an inactivated vaccine followed by a booster shot of an inactivated vaccine, adenovirus vectored vaccine, protein subunit vaccine, or mRNA vaccine. The incremental effects of a booster shot with an inactivated vaccine, protein subunit vaccine, adenovirus vectored vaccine, and mRNA vaccine were 0.0075, 0.0110, 0.0208, and 0.0249 QALYs and saved costs of US$163.96, US$261.73, US$583.21, and US$724.49, respectively. Under the Omicron virus pandemic, the sequential vaccination among adults and the elderly (aged 60-69, 70-79, over 80) was consistently cost-saving, and a booster shot of the mRNA vaccine was more cost-saving. The results indicate that the sequential vaccination strategy is cost-effective in addressing the COVID-19 pandemic, and improving vaccination coverage among the elderly is of great importance in avoiding severe cases and deaths.

SARS-CoV-2 spike protein antibody titers 6 months after SARS-CoV-2 mRNA vaccination among patients undergoing hemodialysis in Japan

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is shown to prevent severe illness and death in hemodialysis (HD) patients, but the immune response to vaccines is reduced in this population. This study compared SARS-CoV-2 spike protein antibody titers between HD patients and healthy controls in Japan for up to 6 months following vaccination.

METHODS

A multi-institutional retrospective study at five clinics in Japan was conducted using 412 HD patients and 156 healthy controls who received two doses of the BNT162b2 (Pfizer-BioNTech) mRNA vaccine. Anti-SARS-CoV-2 spike protein S1 IgG antibody titers were measured at 1, 3, and 6 months after the second dose. The attenuation speed was calculated as slope (i.e., -β) using a linear mixed-effects model toward the log-transformed antibody titers.

RESULTS

The HD group had significantly lower month 1 antibody titers (Ab-titer-1) than the controls, and these remained lower through month 6 (95% CI: 2617.1 (1296.7, 5240.8) vs. 7285.4 (4403.9, 11,000.0) AU/mL at Ab-titer-1, and 353.4 (178.4, 656.3) vs. 812.0 (498.3, 1342.7) AU/mL at Ab-titer-6 (p < 0.001, respectively)). Lower log Ab-titer-1 levels in the HD group were significantly associated with a lower log Ab-titer-6 (0.90 [0.83, 0.97], p < 0.001). The -β values in the HD patients and healthy controls were -4.7 ± 1.1 and -4.7 ± 1.4 (year-1), respectively.

CONCLUSION

SARS-CoV-2 spike protein antibody titers were significantly lower in HD patients than in healthy controls at 1 (peak) and 6 months after the second vaccination. Low peak antibody titers contributed to low 6-month antibody titers.

The third dose of mRNA SARS-CoV-2 vaccines enhances the spike-specific antibody and memory B cell response in myelofibrosis patients

Vaccination against SARS-CoV-2 using mRNA-based vaccines has been highly recommended for fragile subjects, including myelofibrosis patients (MF). Available data on the immune responsiveness of MF patients to mRNA SARS-CoV-2 vaccination, and the impact of the therapy with the JAK inhibitor ruxolitinib, are still fragmented. Here, we profile the spike-specific IgG and memory B-cell response in MF patients, treated or not with ruxolitinib, after the second and the third dose of SARS-CoV-2 BNT162b2 (BioNTech) and mRNA-1273 (Moderna) vaccines. Plasma and peripheral blood mononuclear cells samples were collected before vaccination, post the second and the third doses and tested for spike-specific antibodies, ACE2/RBD antibody inhibition binding activity and spike-specific B cells. The third vaccine dose significantly increased the spike-specific IgG titers in both ruxolitinib-treated and untreated patients, and strongly enhanced the percentage of subjects with antibodies capable of in vitro blocking ACE2/RBD interaction, from 50% up to 80%. While a very low frequency of spike-specific B cells was measured in blood 7 days after the second vaccination dose, a strong and significant increase was elicited by the third dose administration, generating a B cell response similar to the one detected in healthy controls. Despite the overall positive impact of the third dose in MF patients, two patients that were under active concomitant immunosuppressive treatment at the time of vaccination, and a patient that received lymphodepleting therapies in the past, remained low responders. The third mRNA vaccine dose strongly increases the SARS-CoV-2 specific humoral and B cell responses in MF patients, promoting a reactivation of the immune response similar to the one observed in healthy controls.

Ongoing Mycophenolate Treatment Impairs Anti-SARS-CoV-2 Vaccination Response in Patients Affected by Chronic Inflammatory Autoimmune Diseases or Liver Transplantation Recipients: Results of the RIVALSA Prospective Cohort

Vaccines are the most effective means to prevent the potentially deadly effects of SARS-CoV-2 infection, but not all vaccinated individuals gain the same degree of protection. Patients undergoing chronic immunosuppressive therapy due to autoimmune diseases or liver transplants, for example, may show impaired anti-SARS-CoV-2 antibody response after vaccination. We performed a prospective observational study with parallel arms, aiming to (a) evaluate seroconversion after anti-SARS-CoV-2 mRNA vaccine administration in different subgroups of patients receiving immunosuppressive treatment for rheumatological or autoimmune diseases or to prevent organ rejection after liver transplantation and (b) identify negative predictors of IgG anti-SARS-CoV-2 development. Out of 437 eligible patients, 183 individuals were enrolled at the Rheumatology and Hepatology Tertiary Units of “Maggiore della Carità” University Hospital in Novara: of those, 52 were healthy subjects, while among the remaining 131 patients, 30 had a diagnosis of spondyloarthritis, 25 had autoimmune hepatitis, 10 were liver transplantation recipients, 23 suffered from connective tissue diseases (including 10 cases that overlapped with other diseases), 40 were treated for rheumatoid arthritis, and 5 had vasculitis. Moreover, all patients were receiving chronic immunosuppressive therapy. The immunogenicity of mRNA COVID-19 vaccines was evaluated by measuring IgG anti-SARS-CoV-2 antibody titers before vaccination and after 10, 30, and 90 days since the first dose administration. Of the selected cohort of patients, 24.0% did not develop any detectable anti-SARS-CoV-2 IgG after a complete mRNA-based two doses primary vaccination cycle. At univariate analysis, independent predictors of an absent antibody response to vaccine were a history of liver transplantation (OR 11.5, 95% CI 2.5−53.7, p = 0.0018), the presence of a comorbid active neoplasia (OR 26.4, 95% CI 2.8−252.4, p = 0.0045), and an ongoing immunosuppressive treatment with mycophenolate (MMF) (OR 14.0, 95% CI 3.6−54.9, p = 0.0002) or with calcineurin inhibitors (OR 17.5, 95% CI 3.1−99.0, p = 0.0012). At multivariate analysis, only treatment with MMF (OR 24.8, 95% CI 5.9−103.2, p < 0.0001) and active neoplasia (OR 33.2, 95% CI 5.4−204.1, p = 0.0002) were independent predictors of seroconversion failure. These findings suggest that MMF dose reduction or suspension may be required to optimize vaccine response in these patients.

Long-Term Longitudinal Analysis of Neutralizing Antibody Response to Three Vaccine Doses in a Real-Life Setting of Previously SARS-CoV-2 Infected Healthcare Workers: A Model for Predicting Response to Further Vaccine Doses

We report the time course of neutralizing antibody (NtAb) response, as measured by authentic virus neutralization, in healthcare workers (HCWs) with a mild or asymptomatic SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection diagnosed at the onset of the pandemic, with no reinfection throughout and after a three-dose schedule of the BNT162b2 mRNA vaccine with an overall follow-up of almost two years since infection. Forty-eight HCWs (median age 47 years, all immunocompetent) were evaluated: 29 (60.4%) were asymptomatic. NtAb serum was titrated at eight subsequent time points: T1 and T2 were after natural infection, T3 on the day of the first vaccine dose, T4 on the day of the second dose, T5, T6, and T7 were between the second and third dose, and T8 followed the third dose by a median of 34 days. NtAb titers at all postvaccination time points (T4 to T8) were significantly higher than all those at prevaccination time points (T1 to T3). The highest NtAb increase was following the first vaccine dose while subsequent doses did not further boost NtAb titers. However, the third vaccine dose appeared to revive waning immunity. NtAb levels were positively correlated at most time points suggesting an important role for immunogenetics.

Reactogenicity to the mRNA-1273 Booster According to Previous mRNA COVID-19 Vaccination

The objective of this study was to assess the local and systemic adverse reactions after the administration of a COVID-19 mRNA-1273 booster between December 2021 and February 2022 by comparing the type of mRNA vaccine used as primary series (mRNA-1273 or BNT162b2) and homologous versus heterologous booster in health care workers (HCW). A cross-sectional study was performed in HCW at a tertiary hospital in Barcelona, Spain. A total of 17% of booster recipients responded to the questionnaire. The frequency of reactogenicity after the mRNA-1273 booster (88.5%) was similar to the mRNA-1273 primary doses (85.8%), and higher than the BNT162b2 primary doses (71.1%). The reactogenicity was similar after receiving a heterologous booster compared to a homologous booster (88.0% vs. 90.2%, p = 0.3), and no statistically significant differences were identified in any local or systemic reactions. A higher frequency of medical leave was identified in the homologous booster dose group vs. the heterologous booster dose group (AOR 1.45; 95% CI: 1.00-2.07; p = 0.045). Our findings could be helpful in improving vaccine confidence toward heterologous combinations in the general population and in health care workers.

Will People Accept a Third Booster Dose of the COVID-19 Vaccine? A Cross-Sectional Study in China

Objective

The coronavirus disease 2019 (COVID-19) vaccines are considered to be an effective way to prevent the spread of the infection. Our previous study has shown that about 75% of healthcare workers (HCWs) in China were willing to receive the vaccine when it became available. Here, we examined the acceptance of a third booster dose among Chinese people and identified the influencing factors.

Methods

A cross-sectional online survey was conducted and the snowball sampling method was utilized. An online questionnaire was provided to all the participants in the form of a quick response (QR) code. The questionnaire included general demographic information, views on vaccines, the General Health Questionnaire-12 (GHQ-12), and the Depression, Anxiety, and Stress Scale-21 (DASS-21). The univariate analysis was done between all the variables and our dependent variable. Then, we used the multivariate logistic regression model to examine the influencing factors of the third booster dose acceptance.

Results

We collected 1,062 complete answers. Of these, 90.39% (n = 960) declared that they would accept the booster dose. Knowing more about the vaccine and recognizing the efficacy of vaccines were significantly associated with greater acceptance of the booster dose. People willing to take the booster dose had better psychological health. A belief that the booster dose could prevent severe infection caused by COVID-19 and enhance the effectiveness of the first two doses were the main contributing factors to vaccine acceptance. Vaccine hesitancy was mainly due to a low perceived risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and rapid mutation of SARS-CoV-2.

Conclusion

This study revealed that Chinese people were very receptive to the third booster dose, which is an inspiring result. More positive attitudes regarding COVID-19 vaccination were supported by its efficacy and few side effects.

SARS-CoV-2 Spike S1-specific IgG kinetic profiles following mRNA or vector-based vaccination in the general Dutch population show distinct kinetics

mRNA- and vector-based vaccines are used at a large scale to prevent COVID-19. We compared Spike S1-specific (S1) IgG antibodies after vaccination with mRNA-based (Comirnaty, Spikevax) or vector-based (Janssen, Vaxzevria) vaccines, using samples from a Dutch nationwide cohort. In adults 18-64 years old (n = 2412), the median vaccination interval between the two doses was 77 days for Vaxzevria (interquartile range, IQR: 69-77), 35 days (28-35) for Comirnaty and 33 days (28-35) for Spikevax. mRNA vaccines induced faster inclines and higher S1 antibodies compared to vector-based vaccines. For all vaccines, one dose resulted in boosting of S1 antibodies in adults with a history of SARS-CoV-2 infection. For Comirnaty, two to four months following the second dose (n = 196), S1 antibodies in adults aged 18-64 years old (436 BAU/mL, IQR: 328-891) were less variable and median concentrations higher compared to those in persons ≥ 80 years old (366, 177-743), but differences were not statistically significant (p > 0.100). Nearly all participants seroconverted following COVID-19 vaccination, including the aging population. These data confirm results from controlled vaccine trials in a general population, including vulnerable groups.