Booster Dose Of Vaccine Research Articles

Effect of RTS,S/AS01E vaccine booster dose on cellular immune responses in African infants and children

RTS,S/AS01E, the first approved malaria vaccine, demonstrated moderate efficacy during the phase 3 pediatric trial. We previously investigated cell-mediated immune (CMI) responses following the primary 3-dose immunization and now report responses to the booster dose given 18 months later. Thirty CMI markers were measured by Luminex in supernatants of peripheral blood mononuclear cells from 709 children and infants after RTS,S/AS01E antigen stimulation, and their associations with malaria risk and antibodies one month post-booster and one year later were assessed. IL-2, IFN-γ, IL-17, IL-5, and IL-13 were associated with RTS,S/AS01E booster vaccination, and IL-2 responses to the circumsporozoite protein (CSP) remained higher after one year. IL-2 was associated with reduced malaria risk in one site, and IL-10 was associated with increased risk in infants. Anti-CSP IgG and IL-2 were moderately correlated one year after booster. This study highlights the moderate cell-mediated immunogenicity of the RTS,S/AS01E booster dose that aligns with partial recovery of RTS,S/AS01E vaccine efficacy.

Humoral Response to SARS-CoV-2 Vaccine-Boost in Cancer Patients: A Case Series from a Southern European Cancer Center

Background: Cancer patients face a greater risk of complications and death after contracting the SARS-CoV-2 virus. Booster doses of the COVID-19 vaccine were suggested to provide additional protection. This study aimed to assess how cancer patients’ immune systems respond to the booster shots and categorize their responses. Methods: We analyzed 735 samples from 422 individuals, including patients followed at the Portuguese Oncology Institute of Porto (IPO-Porto). Three cohorts were recruited, and blood samples were collected 3- and 6-months post-booster dose: cohort 1 cancer patients (also collected before the booster); cohort 2 cancer patients; and cohort 3 (healthy individuals). Humoral immune response was evaluated by analyzing IgG levels against the SARS-CoV-2 Spike (S) protein. IgG levels against the SARS-CoV-2 Nucleocapsid(N) protein was also analyzed in order to address previous contact with the virus. Results: Among Cohort 1 patients with solid tumors, when compared to pre-boost, IgG S levels increased 3 months after the boost and remained high after 6 months. Patients with hematologic tumors demonstrated lower IgG S levels at both timepoints. Comparing the IgG S levels among hematological tumors, solid tumors, and healthy individuals in both timepoints we observed that the healthy individuals had the strongest IgG S response, followed by the solid, and, lastly, the hematologic tumors. Solid tumor patients undergoing chemotherapy had reduced IgG S levels, especially those on high febrile neutropenia risk regimens. Conclusions: In conclusion, cancer patients have a weaker immune response to the SARS-CoV-2 vaccine, especially those with hematological cancers. Chemotherapy and febrile neutropenia risk further reduce booster effectiveness. Further research is needed to optimize vaccine timing for cancer patients undergoing chemotherapy.

Risk of major adverse cerebro-cardiovascular events following BNT162b2, CoronaVac, and ChAdOx1 vaccination and SARS-CoV-2 infection: A self-controlled case-series study

ObjectiveTo assess the potential risk of major adverse cerebro-cardiovascular events (MACCE) associated with COVID-19 vaccination and SARS-CoV-2 infection. MethodsThis self-controlled case series study used nationwide health database from Malaysia. The study included individuals aged ≥18 years who were hospitalised between 24 February 2021 and 30 June 2022. Outcomes were composite of MACCE: stroke, acute ischaemic heart disease, and cardiovascular death. Exposures were COVID-19 vaccination and SARS-CoV-2 infection. The risk period was day 1 to day 21 following exposure. Conditional Poisson regression model was used to estimate the incidence rate ratios (IRRs) and 95 % confidence interval (CI) comparing the outcomes in the risk and control periods. ResultsThe risk of MACCE within 21 days after vaccination per 100,000 doses administered were 12.0 (95% CI 11.9–12.1) (BNT162b2), 9.2 (95% CI 9.1–9.3) (CoronaVac), and 6.8 (95% CI 6.6–7.0) (ChAdOx1). The incidence rate ratios showed no increased risk of MACCE associated with the first, second, or third doses of BNT162b2, CoronaVac, and ChAdOx1 vaccines for individuals without prior cardiovascular disease (CVD). This finding was consistent for individuals with CVD. Vaccine booster dose, whether in a homologous or heterologous schedule, did not show increased risk of MACCE. Analysis by ethnic groups detected a slightly elevated risk of MACCE in Indian after the first dose of ChAdOx1 (IRR 1.64; 95% CI 1.08–2.48) in those without CVD. No significant association were observed in other subgroup analyses. SARS-CoV-2 infection was associated with significantly increased risk of MACCE in individuals without CVD (IRR 3.54; 95% CI 3.32–3.76) and with CVD (IRR 1.98; 95% CI 1.61–2.34). ConclusionsOur findings support the favourable safety profile of these COVID-19 vaccines and indicate that the overall benefit-risk ratio of the COVID-19 vaccines remains positive.

Safety and immunogenicity of a modified mRNA-lipid nanoparticle vaccine candidate against COVID-19: Results from a phase 1, dose-escalation study

ABSTRACT This phase 1, open-label, dose-escalation, multi-center study (NCT05477186) assessed the safety and immunogenicity of a booster dose of an mRNA COVID-19 vaccine (CV0501) encoding the SARS-CoV-2 Omicron BA.1 spike protein. Participants aged ≥ 18 years previously vaccinated with ≥ 2 doses of an mRNA COVID-19 vaccine received CV0501 doses ranging from 12 to 200 μg. After assessment of safety and immunogenicity of the 12 μg dose in 30 adults, 30 adults ≤ 64 years were randomized to receive either a 3 or 6 μg dose. Solicited adverse events (AEs) were collected for 7 days, unsolicited AEs for 28 days, and serious AEs (SAEs), medically attended AEs (MAAEs), and AEs of special interest (AESIs) until day (D) 181 post-vaccination. Serum neutralizing titers specific to SARS-CoV-2 BA.1, wild-type, Delta, and additional Omicron subvariants were assessed at D1, D15, D29, D91, and D181. Of 180 vaccinated participants (mean age: 49.3 years; 57.8% women), 70.6% had prior SARS-CoV-2 infection. Most solicited local (98.1%) and systemic (96.7%) AEs were of mild-to-moderate severity; the most common were injection site pain (57.5%; 33.3–73.3% across groups) and myalgia (36.9%; 13.3–56.7%). Unsolicited AEs were reported by 14.4% (6.7–26.7%) of participants (mild-to-moderate severity in 88.5% of the participants). Three participants (1.7%) reported SAEs, 16.7% (6.7–30.0%) reported MAAEs, and 8.3% (0.0–13.3%) reported AESIs (15 COVID-19 cases), none related to vaccination. Geometric means of serum neutralizing titers increased from baseline to D15 and D29 (dose-dependent), and then decreased over time. The safety and immunogenicity results supported advancement to a phase 2 trial.

BNT162b2 vaccine booster dose did not influence the activity of the exudative form of age-related macular degeneration during anti-vascular endothelial growth factor therapy.

Due to safety concerns, patients were hesitant to receive a booster dose of COVID-19 vaccine. In this study, we investigated whether neovascular age-related macular degeneration activity deteriorated after receiving the booster dose of the BNT162b2 vaccine. Optical coherence tomography (OCT) of the macula, best-corrected visual acuity (BCVA), and slit-lamp examination data were collected from 89 patients. All these individuals were diagnosed with neovascular age-related macular degeneration (AMD) and treated with intravitreal injections of aflibercept or ranibizumab. During the process of treatment, patients received a booster dose of the BNT162b2 vaccine. Time points included two visits before (marked as "-2", "-1") and two visits after (marked as "1", "2") the uptake of the booster dose. There were significant differences in the average thickness and total volume of the macula during follow-up. Moreover, a decreased average thickness, total volume, total thickness of the macula, subretinal fluid thickness, and subretinal complex thickness was observed between the time points "-2" and "2", but only in the aflibercept group. There were no significant differences in the frequency of occurring intraretinal cysts, subretinal fluid, serous retinal pigment epithelial detachments retinal hemorrhage, subretinal hyperreflective material, complete RPE and outer retinal atrophy, and BCVA before and after the booster dose. These results demonstrate that the BNT162b2 vaccine booster dose did not deteriorate the course of neovascular AMD.

Protection conferred by booster vaccine doses in hospitalized patients with COVID-19 during the SARS-CoV-2 Omicron BA.2 and BA.5 epidemics from 2022 to 2023 in Greece

BackgroundTo estimate the protection that coronavirus disease 2019 (COVID-19) vaccine doses conferred to hospitalized patients with COVID-19 against adverse outcomes and longer length of stay during the Omicron BA.2 and BA.5 subvariant epidemics in Greece. MethodsThe study was conducted from November 2022 to May 2023. Multivariable logistic and negative binomial regression models were applied to estimate the association between any adverse outcomes and length of stay with the number of COVID-19 vaccine doses. ResultsWe studied 962 patients (median age: 78 years; mean length of stay: 9.2 days), of whom 847 (88.0%) had ≥ 1 comorbidity. Of these, 39 (4.0%) were admitted to the intensive care unit, 44 (4.6%) received invasive mechanical ventilation, and 110 (11.4%) died in hospital. There were 184 (19.1%) unvaccinated patients, 125 (13.0%) with one or two vaccine doses, and 653 (67.9%) with ≥ 3 doses. In multivariable analyses, patients with ≥ 3 doses had lower odds of experiencing any adverse outcomes (adjusted odds ratio: 0.57; 95% confidence interval [CI]: 0.37–0.86) compared with unvaccinated patients. On average, patients with one or two doses and those with ≥ 3 had decreased length of hospital stay (−1.5 days [95% CIs: −2.6 to −0.4] and −2.8 days [95% CIs: −4.1 to −1.4], respectively] compared with unvaccinated patients. Other characteristics consistently associated with adverse outcomes and longer length of stay included older age, having three or more comorbidities compared with none, and being admitted to the hospital two or more weeks post-diagnosis. ConclusionsA history of ≥ 3 vaccine doses conferred significant protection against any adverse outcome and longer length of stay in hospitalized patients with COVID-19.

Assessing vaccinated persons’ intention to take the COVID-19 boosters using a combined theoretical framework: an online survey in Egypt

Vaccines, like the Corona Virus Disease-2019 (COVID-19) vaccines, can control diseases, but vaccine hesitancy reduces their use. It is important to assess the intention to use COVID-19 vaccines boosters and the determinants of this intention to help in developing programs to promote the uptake of boosters. An online survey collected data from adults in Egypt between March and June 2022 using a questionnaire that assessed demographic characteristics, and constructs of the Theory of Planned Behaviour (TPB) and the Health Belief Model (HBM). The survey was uploaded to SurveyMonkey and the links were posted on social media platforms. Binary regression analysis was used and the dependent variable was intention to use boosters of COVID-19 vaccines. The independent variables were indicators of the HBM including perceived susceptibility to COVID-19 infection (medical history) and possibility of disease prevention (awareness of the availability of types of COVID-19 vaccines); and indicators of the TPB including attitude toward COVID-19 vaccines (that they are harmful, that they may lead to death and confidence in locally and foreign manufactured vaccines), perceived norms (the percentage of vaccinated persons in one’s circle) and perceived control over booster uptake (presence of government mandates for COVID-19 vaccination). The confounders were sociodemographic factors (age, sex, education, and place of residence). Complete responses were available from 1113 out of 1401 participants (79.4%), with mean (SD) age = 25 (9.5) years, of whom, 66.7% (n = 742) were females and 68.6% (n = 764) were university students. About 39.4% and 31.2% indicated that they would get or would definitely get the booster dose of the COVID-19 vaccines. In multiple regression, intention to use a booster dose was significantly related to not agreeing (AOR = 4.87, P < 0.001) or not agreeing at all (AOR = 8.46, P = 0.001) that vaccines are harmful and to having no confidence (AOR = 0.21, P < 0.001) or no confidence at all (AOR = 0.14, P < 0.001) in foreign-manufactured vaccines. Most university-educated Egyptians in the study intended to take the COVID-19 vaccine booster dose and this intention was associated with attitude toward the harm of the vaccine and confidence in foreign-manufactured vaccines. Awareness campaigns are needed to counteract misinformation and promote booster dose uptake.

Evidence brief on facilitators, barriers and hesitancy of COVID-19 booster doses in Canada.

Understanding the facilitators, barriers and hesitancy to accepting COVID-19 booster doses is important for encouraging recommended vaccination. This evidence brief summarizes literature on the intention to accept or reject COVID-19 vaccine booster doses and the factors associated with intention/uptake among individuals in Canada. A database of COVID-19 literature established at the Public Health Agency of Canada was searched for articles referencing vaccination and knowledge, attitudes and behaviours towards COVID-19 boosters. A grey literature search of Canadian governmental and academic institutions was also conducted. Primary research conducted in Canada (n=21) and relevant systematic reviews of the global literature (n=8) were included in this evidence brief. Intentions to get a booster dose in the general population have decreased between 2021-2023, with intentions varying across subpopulations. In Canada and within the global systematic reviews, facilitators, barriers and hesitancy were similar. Older age was the most common factor positively associated with intention/uptake of a booster, and the most common motivators were government/healthcare provider recommendations and helping to protect others. The main reasons for hesitancy were concerns about vaccine side effects and a lack of belief in the vaccine's efficacy. Intentions to get a booster dose have decreased in Canada. Understanding the reasons for vaccine hesitancy and motivators for obtaining a booster can help guide future public health COVID-19 booster vaccination programs.

Investigating Covid-19 Vaccine Booster Dose Policy Acceptance among Pregnant Women

Investigating Covid-19 Vaccine Booster Dose Policy Acceptance among Pregnant Women

Acceptance of COVID-19 vaccine booster doses among the Adult Population in Ghana: a cross-sectional study using the Health Belief Model.

The Health Belief Model (HBM) is a widely utilised framework for understanding vaccination behaviour against COVID-19. This study assessed the acceptance of COVID-19 vaccine booster doses in Ghana and identified predictors using HBM domains, including perceived susceptibility, severity, benefits, barriers, self-efficacy, and cues to action. Additionally, it examined the sources of information about COVID-19 vaccines. We employed a cross-sectional quantitative design, using convenient and snowball sampling methods to recruit participants. Between March 20 and May 10, 2023, 822 Ghanaians completed a predesigned self-administered online survey via commonly used social media platforms (WhatsApp, Facebook, X (Twitter), and LinkedIn). The study used a binary logistic regression to predict COVID-19 booster dose acceptance. The respondents had a mean age of 29.3 ± 6.2, with 55.5 being males, 53.0% being single/never married, 93.7% having tertiary education, 83.0% being Christians, 59.1% were healthcare workers, 57.8% residing in urban areas, 95.5% having no chronic disease, 90.6% reporting negative COVID-19 history, and 78.3% reporting no reported relative/friend infected with COVID-19. The study showed that 81.1% [95% confidence interval (CI) = 78.4 - 83.8%] of respondents received the COVID-19 vaccine, and 58.3% [95% CI = 54.2 - 62.5%] of respondents were willing to accept the COVID-19 booster dose. The main reasons for non-acceptance of COVID-19 vaccine booster doses were personal reasons (41.7%) and experienced side effects or fear of side effects (32.4%). Regression analysis revealed that perceived benefits and perceived barriers (specifically worrying about serious risk factors) were the significant predictors of accepting COVID-19 booster doses in Ghana. Many respondents were willing to receive the COVID-19 booster dose. Personal reasons, fear of side effects, and experienced side effects were the main reasons for refusing COVID-19 booster doses. Perceived benefits and perceived barriers predicted COVID-19 booster dose acceptance in Ghana. Policymakers should consider these factors in designing public health interventions to increase the patronage of COVID-19 booster doses.

Three doses of Sars-CoV-2 mRNA vaccine in older adults result in similar antibody responses but reduced cellular cytokine responses relative to younger adults

ObjectivesBooster COVID-19 vaccinations are used to protect the elderly, a group vulnerable to severe disease. We compared humoral and cellular immunity in older versus younger adults up to eight months after administering a BNT16b2 booster vaccine dose. Next, we analyzed the plasma levels of soluble T cell activation/exhaustion markers. MethodsHome-dwelling older adults (n = 68, median age 86) and younger healthcare workers (n = 35, median age 39), previously vaccinated with two doses of BNT162b2, were given a booster dose at ten months after the initial dose. Our analysis consisted of spike-specific IgG, neutralizing antibodies, memory B cells, IFN-γ and IL-2 secreting T cells and soluble T cell exhaustion/activation markers. ResultsFollowing the initial two doses, the elderly cohort exhibited lower humoral and IFN-γ responses compared to younger adults. The booster dose increased the humoral responses in both older and younger adults. At two months after the booster dose, older and younger vaccinees had comparable levels of antibodies and the responses were maintained up to 18 months. The younger cohort elicited an increase in the cellular response, while no increase was detected in the elderly. The elderly had higher plasma levels of soluble forms of the T cell activation/exhaustion markers CD25 and TIM-3, which inversely correlated with age and T-cell cytokine responses. This suggests that these markers may be related to the observed dysfunctional cellular cytokine response in older adults. However, both elderly and younger adults who experienced breakthrough infections after booster vaccination, elicited more robust humoral and IFN-γ responses. ConclusionsThe booster dose elicited neutralizing and spike-specific antibody responses in the elderly that were comparable with that of the younger cohort. However, the lack of a strong cellular cytokine response to the third dose in the elderly may explain their vulnerability to severe infection and may be a consequence of exhausted or senescent T cell responses. (https://clinicaltrials.gov/study/NCT04706390).

Use of Haemophilus influenzae Type b-Containing Vaccines Among American Indian and Alaska Native Infants: Updated Recommendations of the Advisory Committee on Immunization Practices - United States, 2024.

Invasive Haemophilus influenzae type b (Hib) disease is a serious bacterial infection that disproportionally affects American Indian and Alaska Native (AI/AN) populations. Hib vaccination with a monovalent Hib conjugate vaccine consisting of Hib capsular polysaccharide (polyribosylribitol phosphate [PRP]) conjugated to outer membrane protein complex of Neisseria meningitidis serogroup B, PRP-OMP (PedvaxHIB, Merck and Co., Inc.) has historically been preferred for AI/AN infants, who are at increased risk for invasive Hib disease, because it provides substantial protection after the first dose. On June 26, 2024, CDC's Advisory Committee on Immunization Practices (ACIP) recommended that a hexavalent, combined diphtheria and tetanus toxoids and acellular pertussis (DTaP), inactivated poliovirus (IPV), Hib conjugate, and hepatitis B (HepB) vaccine, DTaP-IPV-Hib-HepB (Vaxelis, MSP Vaccine Company) should be included with monovalent PRP-OMP in the preferential recommendation for AI/AN infants because of the PRP-OMP Hib component. A primary Hib vaccination series consisting of either 1) monovalent PRP-OMP (2-dose series at ages 2 and 4 months) or 2) DTaP-IPV-Hib-HepB (3-dose series at ages 2, 4, and 6 months) is preferred for AI/AN infants. DTaP-IPV-Hib-HepB is only indicated for use in infants at ages 2, 4, and 6 months and should not be used for the booster doses of Hib, DTaP, or IPV vaccines. For the booster dose of Hib vaccine, no vaccine formulation is preferred for AI/AN children; any Hib vaccine (except DTaP-IPV-Hib-HepB) should be used. This report summarizes evidence considered for these recommendations and provides clinical guidance for the use of Hib-containing vaccines among AI/AN infants and children.

A Preliminary Study to Evaluate the Immune Response to a Booster Dose of the Adult Tetanus-Diphtheria Vaccine (Td) Available in Iran

A Preliminary Study to Evaluate the Immune Response to a Booster Dose of the Adult Tetanus-Diphtheria Vaccine (Td) Available in Iran

Neutralizing Antibodies against 10 SARS-CoV-2 Variants at Two Years Post-COVISHIELD Vaccination with Special Reference to Omicron Subvariants and Booster Administration.

To study the durability of neutralizing antibodies (NAbs) against ten SARS-CoV-2 variants among COVISHIELD vaccine recipients from Pune, India, 184 vaccinee samples with (pre-positives) or without (pre-negatives) prior antibody positivity were evaluated. To estimate NAb levels, a validated ten-plex MSD ACE2 neutralization assay was used. NAbs against Alpha, Beta, Delta, and Omicron/subvariants were assessed at 1 month (PD2-1) and 6 months (PD2-6) post-vaccination, post-booster dose, and 2 years (2Y) post-vaccination. In pre-negatives, the seropositivity declined from PD2-1 to PD2-6 for all variants (Omicron variants: 14-54% to 0%; non-Omicron variants: 66-100% to 8-44%). In pre-positives, the decline in seropositivity from PD2-1 to PD2-6 was seen only for Omicron variants (14-39%). At PD2-6, a significant reduction in NAb levels was observed in all vaccinees against all the variants. Irrespective of prior exposure, the diminished anti-variant antibody levels at PD2-6 increased significantly following the administration of the booster. In conclusion, the COVISHIELD vaccine booster dose did provide cross-neutralizing antibodies against broad-range SARS-CoV-2 variants with improved durability up to [16 (15-18)] months post-booster dose and two years post-vaccination.

COVID-19 Vaccine Uptake among People with Spinal Cord Injury and Dysfunction in Ontario, Canada: A Population-Based Retrospective Cohort Study.

Persons with disabilities experience numerous barriers to healthcare access including vaccine accessibility. The purpose of this study was to determine COVID-19 vaccine uptake in the spinal cord injury and disease (SCI/D) population of Ontario and identify potential factors influencing C OVID-19 vaccine uptake. This was a retrospective closed-cohort study using administrative health data on individuals with SCI/D of traumatic and non-traumatic causes to examine the monthly number of COVID-19 vaccine doses received between December 2020 and December 2023. Logistic regression analysis was used to examine the potential association between socio-demographic, clinical, and neighbourhood characteristics with initial COVID-19 vaccine receipt and booster dose uptake. By the end of the observation period in December 2023, 82.9% received the full two-dose coverage and 65.6% received at least one additional booster dose in a cohort of 3574 individuals with SCI/D. SCI/D individuals showed a comparable COVID-19 vaccine uptake percentage to the general population. Sociodemographic, clinical, and neighbourhood characteristics were associated with COVID-19 vaccine uptake in the SCI/D population, including age, type of injury, number of comorbidities, mental health history, and neighbourhood characteristics such as income. Further investigation is necessary to determine the causation effects of these relationships with vaccine uptake to address health equity concerns.

Delirium Incidence and Predictors in SARS-CoV-2 Vaccinated Residents in Long-Term Care Facilities (LTCF): Insights from the GeroCovid Vax Study

ObjectiveSARS-CoV-2 vaccination can bring an important benefit for older people in terms of reduction of mortality and hospitalization; however, reports of rare adverse effects like altered consciousness and delirium among this demographic have raised concerns. This study aimed to assess delirium incidence post-SARS-CoV-2 vaccination and its predictors in older residents across 60 Italian long-term care facilities (LTCFs). DesignThis is a prospective cohort study considering data from GeroCovid Vax, a multicenter cohort study jointly performed by the Italian Society of Gerontology and Geriatrics (SIGG) (Florence, Italy) and the Italian National Institute of Health (Istituto Superiore di Sanità—ISS, Rome, Italy), and sponsored by the Italian Medicines Agency (Agenzia Italiana del Farmaco—AIFA). Setting and ParticipantsGeroCovid Vax enrolled LTCFs residents aged ≥60 who received at least 1 anti–SARS-CoV-2 vaccine dose. MethodsBaseline data covered sociodemographic details, chronic diseases, medications, nutritional status, cognitive and functional assessments, mobility, and frailty. Delirium was assessed post-first, second, and booster vaccine doses using DSM-5 criteria. Data analysis involved descriptive statistics, multivariate logistic regression, and network analysis. ResultsA total of 2521 participants (mean age 83.10 ± 9.21 years, 70.7% female) were analyzed. Delirium incidence post-first, second, and booster doses was 3.5%, 1.6%, and 1.5%, respectively. Age, preexisting cognitive disorders, and frailty were significant predictors of delirium, with odds ratios (ORs) of 1.70 (95% CI, 1.08–2.77), 2.05 (95% CI, 1.40–2.97), and 1.77 (95% CI, 1.25–2.52), respectively. Prior use of antipsychotics (OR, 1.75; 95% CI, 1.22–2.51) and antidepressants (OR, 1.77; 95% CI, 1.25–2.52) correlated significantly with delirium. Network analysis indicated a strong association between anorexia and delirium. Conclusion and ImplicationsPost-vaccination delirium is infrequent and decreases with subsequent doses. Timely assessments for frailty and cognitive impairment could aid in stratifying delirium risk among LTCF residents, facilitating enhanced prevention measures and close monitoring for delirium indicators.

Factors influencing the third COVID-19 vaccine booster dose acceptance among older adults in northern Thailand

BackgroundCoronavirus disease 2019 (COVID-19) causes more deaths in older adults than in younger adults. Older adults are a vulnerable group with a high need for coronavirus vaccines to decrease the severity of the disease. The aim of this analytical cross-sectional study was to determine the factors influencing third COVID-19 vaccine booster dose acceptance among older adults in northern Thailand.MethodsThe study samples were composed of 2,155 older adults living in Kamphaeng Phet Province, northern Thailand. They were randomly selected by multistage random sampling. Data were collected in a self-administered questionnaire consisting of 7 parts: (1) personal factors, (2) knowledge about COVID-19, (3) perceived susceptibility to COVID-19 infection, (4) perceived severity of COVID-19, (5) perceived benefits of the third COVID-19 vaccine booster dose, (6) perceived barriers to the third COVID-19 vaccine booster dose vaccination, and (7) the third COVID-19 vaccine booster dose acceptance. Data were analyzed via frequency, percentage, mean, standard deviation, and binary logistic regression. All the significance levels were set to 0.05.ResultsThe results indicated that only 28.5% of older adults accepted the third COVID-19 vaccine booster dose. The factors influencing third COVID-19 vaccine booster dose acceptance among older adults included 5 variables. The participants aged ≥ 70 years was 1.37 times (95%CI = 1.12–1.69) greater than those aged < 70 years who accepted the vaccine. Participants who were married were more likely to accept the vaccine by 1.39 times (95%CI = 1.09–1.79) compared with single individuals. Those with underlying diseases tended to accept the vaccine by 1.56 times (95%CI = 1.26–1.92) more than those without underlying diseases. Those who had high perceived benefit from the COVID-19 vaccine possibly accepted the vaccine by 1.50 times (95%CI = 1.10–2.04) more than those with low perceived benefit, and those who had a low perceived barrier to the third COVID-19 booster dose vaccination seemed to accept the vaccine by 1.29 times (95%CI = 1.01–1.52) more than those with a high perceived benefit.ConclusionOlder adults should receive health education regarding the perceived benefit of the COVID-19 vaccine and the perceived barrier to COVID-19 vaccination, especially older adults aged < 70 years, those who are single, and those who are free of underlying diseases.

Comparative analysis of COVID-19 vaccine booster dose (VBD) acceptance among trainees and students of health professions in Bangladesh

BackgroundDespite the proven therapeutic potential of bivalent vaccine primer doses against COVID-19, acceptance of vaccine booster doses (VBD) varies among various subgroups of the global population. This study investigated the acceptance of COVID-19 VBD among trainees and students of health professions in Bangladesh and compared the potential factors influencing their VBD decisions. MethodsThe questionnaire was deployed in an online-enabled layout and conveniently sent to encounters between 10th June 2023 and 10th September 2023. Data from 501 trainees and 501 students were compared (response rate 80.8% vs.78.3%) to explore the study objectives. ResultsThe pooled COVID-19 VBD acceptance rates were 90.2% (95% Confidence Interval [CI]:87.6─92.8) vs. 93.2% (95% [CI]: 91.2─95.2) between trainees and students. The binary logistic analysis revealed that out of twelve factors “equal safety” (Adjusted odds ratio [aOR]: 4.476 vs. 6.459), “efficacy” ([aOR]:3.673 vs. 2.913), “repeated immunity” ([aOR]: 1.729 vs. 2.247), and “self-priority” ([aOR]:3.108 vs. 4.645) had a significant positive association (p<0.01 and p<0.05) with VBD acceptance in both groups. There were varied effects on several predictors. Among trainee professionals, "communication" and "booster mandate" were associated significantly ([aOR]:1.534 and 1.748, respectively; p<0.05) with VBD acceptance, whereas "information source" and "culture" were associated ([aOR]:3.692 and 3.151, respectively; p<0.05) significantly with VBD acceptance in the student cohort. ConclusionsThere was a satisfactory acceptance level of COVID-19 VBD among healthcare participants, and several multidimensional factors influenced their VBD decisions in different ways. For enhancing public booster immunization decisions against COVID-19, individual health expectations must be linked to wider societal influences.

Comparative effectiveness of bivalent BA.4–5 or BA.1 mRNA booster vaccines among immunocompromised individuals across three Nordic countries: A nationwide cohort study

ObjectivesTo estimate the effectiveness and waning of the bivalent BA.4-5 or BA.1 mRNA booster vaccine against Covid-19-related hospitalization and death in immunocompromised individuals. MethodsNationwide analyses across Nordic countries from 1 September 2022 to 31 October 2023 using a matched cohort design. Individuals boosted with a BA.4-5 or BA.1 vaccine were matched 1:1 with unboosted individuals. The outcomes of interest were country-combined vaccine effectiveness (VE) estimates against Covid-19-related hospitalization and death at day 270 of follow-up. Waning was assessed in 45-day intervals. ResultsA total of 352,762 BA.4-5 and 191,070 BA.1 booster vaccine doses were included. At day 270, the comparative VE against Covid-19-related hospitalization was 34.2% (95% CI, 7.1% to 61.3%) for the bivalent BA.4-5 vaccine and 42.6% (95% CI, 31.3% to 53.9%) for the BA.1 vaccine compared with matched unboosted. The comparative VE against Covid-19-related death was 53.9% (95% CI, 38.6% to 69.3%) for the bivalent BA.4-5 vaccine and 57.9% (95% CI, 48.5% to 67.4%) for the BA.1 vaccine. ConclusionsIn immunocompromised individuals, vaccination with bivalent BA.4-5 or BA.1 booster lowered the risk of Covid-19-related hospitalization and death over a follow-up period of 9 months. The effectiveness was highest during the first months since vaccination with subsequent gradual waning.

The Major Role of T Regulatory Cells in the Efficiency of Vaccination in General and Immunocompromised Populations: A Review.

Since their conception with the smallpox vaccine, vaccines used worldwide have mitigated multiple pandemics, including the recent COVID-19 outbreak. Insightful studies have uncovered the complexities of different functional networks of CD4 T cells (T helper 1 (Th1); Th2, Th17) and CD8 T cells (T cytotoxic; Tc), as well as B cell (BIgM, BIgG, BIgA and BIgE) subsets, during the response to vaccination. Both T and B cell subsets form central, peripheral, and tissue-resident subsets during vaccination. It has also become apparent that each vaccination forms a network of T regulatory subsets, namely CD4+ CD25+ Foxp3+ T regulatory (Treg) cells and interleukin-10 (IL-10)-producing CD4+ Foxp3- T regulatory 1 (Tr1), as well as many others, which shape the quality/quantity of vaccine-specific IgM, IgG, and IgA antibody production. These components are especially critical for immunocompromised patients, such as older individuals and allograft recipients, as their vaccination may be ineffective or less effective. This review focuses on considering how the pre- and post-vaccination Treg/Tr1 levels influence the vaccination efficacy. Experimental and clinical work has revealed that Treg/Tr1 involvement evokes different immune mechanisms in diminishing vaccine-induced cellular/humoral responses. Alternative steps may be considered to improve the vaccination response, such as increasing the dose, changing the delivery route, and/or repeated booster doses of vaccines. Vaccination may be combined with anti-CD25 (IL-2Rα chain) or anti-programmed cell death protein 1 (PD-1) monoclonal antibodies (mAb) to decrease the Tregs and boost the T/B cell immune response. All of these data and strategies for immunizations are presented and discussed, aiming to improve the efficacy of vaccination in humans and especially in immunocompromised and older individuals, as well as organ transplant patients.