A head-to-head comparison of humoral and cellular immune responses of five COVID-19 vaccines in adults in China.

Introduction: Various COVID-19 vaccine trials have shown that vaccines can successfully prevent symptomatic cases of COVID-19 and death. Head-to-head comparisons help to better understand the immune response characteristics of different COVID-19 vaccines in humans. Methods: We randomly selected 20 participants from each of five ongoing Phase II trials of COVID-19 vaccines. Here, SARS-CoV 2-specific immune responses to DNA vaccine (INO-4800), mRNA vaccine (BNT162b2), Adenovirus-vectored vaccine (CONVIDECIA), Protein subunit vaccine (Recombinant COVID- 19 Vaccine (Sf9 Cells)), Inactivated Vaccine (KCONVAC) were examined longitudinally in healthy adults between Jan 15, 2021 and July 5, 2021 for 6 months. RBD-IgG titres were detected by ELISA, neutralising antibody titer were detected by pseudoviral neutralization and immune cell response were detected by flow cytometry. Results: At the first visit (V1), 100% of individuals who received the BNT162b2, CONVIDECIA, or KCONVAC vaccines experienced seroconversion of neutralizing and binding antibodies in the serum. Except for the Recombinant COVID-19 Vaccine (Sf9 Cells) vaccine having the highest neutralizing antibody GMT at the second visit (although there was no statistically significant difference in geometric mean titers between V1 and V2), the rest of the vaccines had the highest levels of binding antibodies and neutralizing antibodies at V1. The neutralizing antibodies GMT of all vaccines showed a significant decrease at V3 compared to V1. The neutralizing antibody GMT against the omicron variant of all vaccines at V1 showed a significant decrease compared to the wild strain. We observed statistically significant differences in Tcm cells and RBD-specific memory B cells among various vaccines. Discussion: BNT162b2 (mRNA vaccine) exhibits the highest antibody levels among the five vaccines evaluated, regardless of whether the target is the wild-type virus or its variants. However, its cellular immune response may be weaker compared to CONVIDECIA (adenovirus type 5 vector vaccine).

Effect of COVID 19 pandemic on the neurology department hospitalization with analysis of the neurological complications secondary to COVID 19 and vaccination against COVID 19.

Objective: We investigated the effect of the pandemic on neurological hospitalizations and complications associated with severe acute respiratory syndrome coronavirus 2 infection or vaccinations. Methods: We retrospectively analyzed data of patients hospitalized in our neurology division from 1 April 2019 to 31 March 2022 as the opt-out study. We classified the neurological diseases into nine subgroups, evaluated changes of neurological disease characteristics, and analyzed patients hospitalized with the complications from severe acute respiratory syndrome coronavirus 2 infection or after the coronavirus disease 2019 vaccination over three eras based on the pandemic stages: (1) pre-pandemic, (2) during the pandemic but before vaccines, and (3) during the pandemic with vaccines. Results: Overall, 1756 patients were included in the analyses. The patient characteristics significantly changed throughout the pandemic (p < 0.01). Although the number of autoimmune cases did not change throughout the pandemic (p = 0.53), that of psychological cases and that of unknown cases were significantly changed (p < 0.05, p < 0.01). There were four infectious cases and 11 cases following vaccination from 1 April 2020 to 31 March 2022. The 11 postvaccination cases involved 10 kinds of neurological diseases. Conclusions: The neurological characteristics significantly changed throughout the pandemic and there were diverse neurological complications following vaccinations.

COVID-19 vaccines are not associated with axonal injury in patients with multiple sclerosis.

Objective: To evaluate the safety of COVID-19 vaccines in patients with multiple sclerosis (MS) by assessing their impact on serum neurofilament light chain (sNfL) levels as a marker of neuroaxonal damage. Methods: Single-center observational longitudinal study including patients with MS who consecutively received their initial vaccination against SARS-CoV-2 at Hospital Universitario Ramón y Cajal, following the first national immunization program in Spain. Serum samples were collected at baseline and after receiving the second dose of the vaccine. sNfL levels were quantified using the single molecule array (SIMOA) technique. Adverse events, including clinical or radiological reactivation of the disease, were recorded. Results: Fifty-two patients were included (median age, 39.7 years [range, 22.5-63.3]; 71.2% female). After SARS-CoV-2 vaccination, no increased inflammatory activity, either determined by the presence of relapses and/or new MRI lesions and/or high sNfL levels, was detected. Accordingly, there was no difference between median sNfL levels before and after vaccination (5.39 vs. 5.76 pg/ml, p=0.6). Despite this, when looking at baseline patient characteristics before vaccination, younger age associated with disease activity after vaccination (OR 0.87, 95% CI: 0.77-0.98, p=0.022). Larger studies are needed to validate these results. Conclusion: COVID-19 vaccines did not cause reactivation of disease at a clinical, radiological or molecular level, thus suggesting that they are safe in MS patients.

Knowledge and practices of South African oral.

Background: Severe Acute Respiratory Syndrome Coronavirus 2 is a recently discovered virus responsible for causing coronavirus disease 19 (COVID-19). No study has been carried out on South African oral healthcare workers (OHCWs) regarding their knowledge and practices with regard to COVID-19 and its vaccine. Aim: This study aimed to determine the knowledge, attitudes and practices of South African OHCWs regarding COVID-19 and its vaccine. Method: This was a cross-sectional study, which utilised an online questionnaire. The link to the questionnaire was sent via email and social media platforms. There was a total of 8056 OHCWs, and a minimum sample size of 367 was required. All information was confidential and anonymous. Results: A total of 327 OHCWs participated with a mean age of 43 years (±12.23) and the majority (60%) being general dentists. Less than half (42%) had obtained additional postgraduate qualifications while 57% were employed in the private and 24% in the academic sectors. Almost two-thirds (60%) obtained a 'good' knowledge score. Overall, OHCWs displayed positive attitudes towards COVID-19 and the majority implemented appropriate infection control protocols at their place of work. The majority (87%) reported to be vaccinated and of those who did not vaccinate, 34% cited concerns about possible side effects as a reason for not vaccinating. Conclusion: Respondents displayed gaps in their knowledge. There was a positive attitude towards the prevention of COVID-19, and almost all participants reported to have implemented the necessary infection control methods. Contributions: This study's contribution to research was to identify gaps in the knowledge and practices of OHCWs with regards to COVID 19 and its vaccine. Once these gaps have been identified, measures will be put in place to address them.

Rate of recurrence after discontinuing anticoagulation in patients with venous thromboembolism within 30 days after COVID-19 vaccine.

This study generated evidence to guide anticoagulation in patients with VTE after vaccination for COVID-19. We provided data on the low recurrence rate after cessation of anticoagulant therapy and the findings for this study offer timely insights into the management of a potentially vaccine-related adverse event.

Comparison of healthcare resource use and cost between influenza and COVID-19 vaccine coadministration and influenza vaccination only.

OBJECTIVE: To compare healthcare resource utilization (HCRU) and all-cause medical costs among individuals aged ≥50 years who received influenza and COVID-19 vaccines on the same day and those who received influenza vaccine only. METHODS: We conducted a retrospective cohort study leveraging Optum's de-identified Clinformatics DataMart from 8/31/2021 to 7/31/2023. Individuals aged ≥50 years continuously enrolled in health plans for 1 year prior and until 7/31/2023 were included. Two cohorts were formed based on vaccination status between 8/31/2022 and 1/31/2023: co-administered influenza and COVID-19 vaccines (co-admin cohort) and influenza vaccine only (influenza cohort). Associations between vaccination status and all-cause, influenza-related, COVID-related, pneumonia-related, and cardiorespiratory-related hospitalization, outpatient or emergency room visits and all-cause medical costs were estimated by weighted generalized linear models, adjusting for confounding by stabilized inverse probability of treatment weighting. RESULTS: 613,156 (mean age: 71) and 1,340,011 (mean age: 72) individuals were included in the co-admin and influenza cohorts, respectively. After weighting, the baseline characteristics were balanced between cohorts. The co-admin cohort was at statistically significant lower risk of all-cause (RR: 0.95, 95% CI: 0.93-0.96), COVID-19-related (RR: 0.59, 95% CI: 0.56-0.63), cardiorespiratory-related (RR: 0.94, 95% CI: 0.93-0.96) and pneumonia-related (RR: 0.86, 95% CI: 0.83-0.90) hospitalization but not influenza-related hospitalizations (RR: 0.91, 95% CI: 0.81, 1.04) compared with the influenza cohort. Co-administration was associated with 3% lower all-cause medical cost (cost ratio: 0.974, 95% CI: 0.968, 0.979) during the follow-up period compared to receiving influenza vaccine only. LIMITATIONS: Limitations include the potential residual confounding bias in observational data, measurement errors from claims data, and that the cohort was followed for a single season. CONCLUSION: Receiving co-administered COVID-19 and influenza vaccines versus only receiving influenza vaccination reduced the risk of HCRU, especially COVID-19-related hospitalization and all-cause medical costs. Increasing vaccine coverage, particularly for COVID-19, might have public health and economic benefits.

Vaccine pharmacovigilance in South Africa: successes and limitations of current approaches.

INTRODUCTION: Despite the public health success of vaccination, there is an ongoing need to build public confidence in vaccines and improve systems to monitor safety while maintaining data security and patient privacy. African countries face multiple challenges in establishing systems for vaccine pharmacovigilance as was demonstrated during COVID-19 mass vaccination. We provide a framework for the development of pharmacovigilance using the COVID-19 vaccination roll-out as an exemplar. AREAS COVERED: We describe the pre-COVID-19 vaccine pharmacovigilance systems in Southern Africa and propose improvements based on our experience of COVID-19 vaccine roll-out in South Africa where we implemented systems to evaluate real-world safety and effectiveness of COVID-19 vaccinations. By conducting a pubmed review of the literature on pharmacovigilance with a focus on Africa and from guidance emanating from the World Health Organisation (WHO), we evaluate challenges and opportunities to improve pharmacovigilance in our setting. EXPERT OPINION: There are ongoing efforts to improve pharmacovigilance on the African continent with improved coordination at a national level with the support of WHO, the national regulatory authorities, and national departments of health. COVID-19 vaccine roll-out provided an opportunity to improve pharmacovigilance by integrating national vaccine platforms with active and passive surveillance including hospital and death registries.

A health equity science approach to assessing drivers of COVID-19 vaccination coverage disparities over the course of the COVID-19 pandemic, United States, December 2020-December 2022.

INTRODUCTION: Health equity science examines underlying social determinants, or drivers, of health inequities by building an evidence base to guide action across programs, public health surveillance, policy, and communications efforts. A Social Vulnerability Index (SVI) was utilized during the COVID-19 response to identify areas where inequities exist and support communities with vaccination. We set out to assess COVID-19 vaccination coverage by two SVI themes, Racial and Ethnicity Minority Status and Housing Type and Transportation to examine disparities. METHODS: US county-level COVID-19 vaccine administration data among persons aged 5 years and older reported to the Centers for Disease Control and Prevention from December 14, 2020 to December 14, 2022, were analyzed. Counties were categorized 1) into tertiles (low, moderate, high) according to each SVI theme's level of vulnerability or 2) dichotomized by urban or rural classification. Primary series vaccination coverage per age group were assessed for SVI social factors by SVI theme tertiles or urbanicity. RESULTS: Older adults aged 65 years and older had the highest vaccination coverage across all vulnerability factors compared with children aged 5-17 years and adults aged 18-64 years. Overall, children and adults had higher vaccination coverage in counties of high vulnerability. Greater vaccination coverage differences were observed by urbanicity as rural counties had some of the lowest vaccination coverage for children and adults. CONCLUSION: COVID-19 vaccination efforts narrowed gaps in coverage for adults aged 65 years and older but larger vaccination coverage differences remained among younger populations. Moreover, greater disparities in coverage existed in rural counties. Health equity science approaches to analyses should extend beyond identifying differences by basic demographics such as race and ethnicity and include factors that provide context (housing, transportation, age, and geography) to assist with prioritization of vaccination efforts where true disparities in vaccination coverage exist.

Immunogenicity, clinical efficacy, and safety of the sinopharm (BBIBP-CorV) SARS-CoV-2 vaccine among people with multiple sclerosis receiving disease-modifying therapies: a prospective cohort study.

BACKGROUND: To investigate the safety (adverse events [AEs] and post-vaccination multiple sclerosis [MS] activity within 6 weeks), clinical efficacy (protection against coronavirus disease 2019 [COVID-19]), and vaccine-induced humoral immunogenicity (SARS-CoV-2 neutralizing antibody, anti-nucleocapsid IgG, and anti-spike IgG) of the Sinopharm (BBIBP-CorV) vaccine among people with MS (PwMS) receiving different disease-modifying therapies (DMTs). METHODS: This prospective cohort study was conducted between November 2021 and May 2022. PwMS were followed for six months after the 2nd dose of vaccination. Antibody responses were measured 2-16 weeks after the 2nd dose injection. Multivariate logistic regression was employed to assess the impact of each DMT on dichotomous antibody responses, adjusting for age, sex, MS phenotype, expanded disability status scale, disease duration, and vaccination-antibody titration interval. RESULTS: Among the 261 screened PwMS, 209 (aged 38.23 ± 9.73 years, female: 70.8%; relapsing-remitting MS: 80.4%) were included. The frequencies of experiencing non-serious AEs and post-vaccination MS activity were 66.0% and 4.8%, respectively. Breakthrough COVID-19 infection was observed in 14.8% of the PwMS. A subcohort of 125 PwMS was assessed for antibody responses. Positive neutralizing antibodies, anti-nucleocapsid IgG, and anti-spike IgG were detected in 36.8%, 35.2%, and 52.0% of the PwMS, respectively. Multivariate regression indicated a 96% (OR: 0.04 [95% CI: 0.00, 0.51], P = 0.013), 93% (OR: 0.07 [0.01, 0.64], P = 0.019), and 89% (OR: 0.11 [0.01, 0.96], P = 0.045) reduced odds of positive neutralizing antibody, anti-nucleocapsid IgG, and anti-spike IgG, respectively, among fingolimod-receivers. Additionally, anti-CD20s-receivers had 88% (OR: 0.12 [0.02, 0.85], P = 0.034) lower odds of being positive for anti-nucleocapsid IgG. CONCLUSIONS: BBIBP-CorV appeared to be well tolerated in PwMS, with promising clinical efficacy. However, a suboptimal humoral response was observed in PwMS receiving fingolimod and anti-CD20s. Future research should investigate the relationship between humoral responses and the frequency and severity of COVID-19 infection across various DMTs.

Patient-reported outcomes of adverse events after COVID-19 vaccination in Nigeria: A mixed methods study.

BACKGROUND: Adverse events following immunization (AEFIs), especially if serious, may impact vaccine recipients' quality of life and financial well-being and fuel vaccine hesitancy. Nigeria rolled out COVID-19 vaccination in 2021 with little known about the impact of AEFIs on an individual's quality of life. No study in Africa has explored the health and financial impact of AEFIs. We explored patient-reported outcomes (PROs) of adverse events after COVID-19 vaccination and documented the lived experiences of those with serious AEFIs to understand the effect on their health, financial well-being, and attitude to future vaccinations. METHODS: We conducted a convergent mixed-methods study using the RAND 36-item health survey and in-depth interviews to collect PROs on vaccine recipients in Nigeria. Eight health scale scores and two summary composite scores were used to measure the health-related quality of life outcomes from the survey and inductive analysis was used to identify themes from the interview scripts. The results of both studies were integrated in a joint display to highlight areas of concordance. RESULTS: In total, 785 survey responses were analyzed (53% females, 68% aged 18-30 years). Responders reporting an AEFI were 58%, of whom 62% received the first dose only. Younger age and first vaccine dose (p < .001 respectively) were associated with experiencing an AEFI. Not reporting an AEFI was associated with better quality of life, measured as higher scores on all eight SF-36 Health scales and the physical and mental component summary scores. All six interviewees with serious AEFIs experienced physical, mental, and financial distress. Some expressed a strong negative attitude toward future COVID-19 vaccinations but not toward vaccines for routine immunization. CONCLUSION: AEFIs negatively impact the health and financial well-being of affected individuals and their attitude to future vaccinations, especially if serious. Understanding the impact of AEFIs on people is important and should inform future policies and interventions. The results of our study can inform policy and planning for future mass vaccination campaigns in LMICs.

4th booster-dose SARS-CoV-2 heterologous and homologous vaccination in rheumatological patients.

Objective: to evaluate the immune response to the SARS-CoV-2 vaccines in adults with immune-mediated rheumatic diseases (IMRDs) in comparison to healthy individuals, observed 1-20 weeks following the fourth vaccine dose. Additionally, to evaluate the impact of immunosuppressive therapies, vaccination schedules, the time interval between vaccination and sample collection on the vaccine's immune response. Methods: We designed a longitudinal observational study conducted at the rheumatology department of Hospital de Copiapó. Neutralizing antibodies (Nabs) titers against the Wuhan and Omicron variant were analyzed between 1-20 weeks after administration of the fourth dose of the SARS-CoV-2 vaccine to 341 participants (218 IMRD patients and 123 healthy controls). 218 IMRD patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS), systemic lupus erythematosus (SLE), systemic vasculitis (VS) and systemic scleroderma (SS) were analyzed. Results: Performing a comparison between the variants, Wuhan vs Omicron, we noticed that there were significant differences (p<0.05) in the level of the ID50, both for healthy controls and for patients with IMRDs. The humoral response of patients with IMRDs is significantly lower compared to healthy controls for the Omicron variant of SARS-CoV-2 (p = 0.0015). The humoral response of patients with IMRDs decreases significantly when the time interval between vaccination and sample collection is greater than 35 days. This difference was observed in the response, both for the Wuhan variant and for the Omicron variant. Conclusion: The IMRDs patients, the humoral response variation in the SARS-CoV-2 vaccine depends on doses and type of vaccine administered, the humoral response times and the treatment that these patients are receiving.

Incidence of narcolepsy symptoms after taking COVID-19 vaccines: a Jordanian cross-sectional study.

Purpose: Sleeping disorders were reported in many patients who took vaccines during previous pandemics. We aim to investigate the relationship between coronavirus disease 2019 (COVID-19) vaccines and the incidence of narcolepsy symptoms in the Jordanian population. Materials and Methods: We used a descriptive, cross-sectional, online self-administered survey conducted between December 2022 and May 2023. The survey targeted males and females above the age of 18 years who took any type of COVID-19 vaccine, had no chronic diseases, and had no sleep disorders prior to taking the vaccine. The survey was distributed via social media platforms. Results: A total of 873 participants were included in this study, consisting of 44.4% males and 55.6% females, with the majority being in the 18-29 age group. Most participants (79.8%) received two vaccine doses, with the Pfizer vaccine being the most common. Nearly half of the participants reported excessive daytime sleepiness. Sleep paralysis and hypnagogic hallucinations were reported by a notable proportion of participants, but no significant differences were found among the vaccine types. Sleep attacks and fragmented nighttime sleep were associated with the number of vaccine doses received, suggesting a possible influence of the dose count on these symptoms. The presence of excessive daytime sleepiness, sudden loss of muscle tone, sleep paralysis, and hypnagogic hallucinations showed no significant association with the number of doses taken. Conclusion: We hypothesize a possible link between COVID-19 vaccination and the emergence of narcolepsy symptoms in Jordanian individuals. Additional investigations and continuous monitoring to determine the extent of the risk and uncover potential mechanisms behind this connection should be performed.

Effectiveness of COVID-19 Vaccination against Severe Symptoms and Death Among Geriatric Inpatients: A Retrospective Cohort Study in Macao.

Monitoring the effectiveness of COVID-19 vaccination is critical for understanding if the vaccinated population, especially the elderly, is adequately protected from the emergence of new SARS-CoV-2 variants. This study aimed to investigate the effects of COVID-19 vaccination on the severity of symptoms and mortality in hospitalized geriatric patients during the Omicron BF.7 surge in Macao. Data from electronic health records and vaccination registry of inpatients aged 60 years or above admitted to Kiang Wu Hospital from 12 December 2022 to 12 March 2023 were retrospectively analyzed. The study involved 848 people, including 426 vaccinated and 422 unvaccinated individuals. The mean CXR scores (8.95 ± 9.49 vs. 11.41 ± 10.81, p < 0.001) and the mean MEWS scores (0.96 ± 2.01 vs. 1.49 ± 2.45, p < 0.001) were lower in the vaccinated group. By comparing the dose counts, no significant difference was seen in the odds of death. Based on the time of the last vaccination, 128 people were categorized as complete and 298 as incomplete vaccination. The complete vaccination group showed a 54% (95% CI 0.23-0.91) reduction in mortality risk (p = 0.026). The study findings not only reconfirm the effectiveness of COVID-19 vaccination but, more importantly, highlight the importance of vaccination timing to maximize vaccines' protective effect.

Impact of recruitment strategies on individual participation practices in the Canadian National Vaccine Safety Network: prospective cohort study.

Background: The Canadian National Vaccine Safety (CANVAS) network conducted a multi-center, prospective vaccine safety study to collect safety data after dose 1 and 2 of COVID-19 vaccines and follow up safety information 7 months after dose 1. Objective: This study aimed to describe and evaluate the recruitment methods used by CANVAS and the retention of participants by each modality. Methods: CANVAS deployed a multi-pronged recruitment approach to reach a larger sample, without in-person recruitment. Three primary recruitment strategies were used: passive recruitment, technology-assisted electronic invitation through the vaccine booking system (auto-invitation), or auto-registration through the vaccine registries (auto-enrollment). Results: Between December 2020 and April 2022, approximately 1.3 million vaccinated adults either self-enrolled or were auto-enrolled in CANVAS, representing about 5% of the vaccinated adult Canadian population. Approximately 1 million participants were auto-enrolled, 300,000 were recruited by auto-invitation, and 5,000 via passive recruitment. Overall survey completion rates for dose 1, dose 2 and the 7-month follow-up surveys were 51.7% (681,198 of 1,318,838), 54.3% (369,552 of 681,198), and 66.4% (452,076 of 681,198), respectively. Completion rates were lower among auto-enrolled participants compared to passively recruited or auto-invited participants who self-enrolled. However, auto-enrolled samples were much larger, which offset the lower completion rates. Conclusion: Our data suggest that auto-enrollment provided an opportunity to reach and retain a larger number of individuals in the study compared to other recruitment modalities.

Acceptance of a third COVID-19 vaccine dose, vaccine interchangeability, and clinical trial enrolment among parents of children 12-17 years in Lima, Perú.

Objectives: To characterize factors associated with parental willingness for their children participation in a COVID-19 vaccine trial, use of different COVID-19 vaccines and acceptance of a third vaccine dose. Methods: Parents of children aged 12-17 years in Lima, Perú were asked to complete an online questionnaire via social networks, from November 9, 2021, to April 23, 2022. We calculated crude and adjusted prevalence ratios with 95% confidence intervals to compare factors with the mentioned outcomes. Results: From 523 parents responding, 374 completed the survey. 90.4% would give their children a third vaccine dose, 36.6% would allow their children participation in a COVID-19 vaccine clinical trial, and 33.2% would accept different vaccine brands between doses. Parental belief that COVID-19 vaccine studies met quality standards was associated with acceptance of a third booster dose (adjusted PR 3.25; 95% CI1.57-6.74; p = 0.002), enrolment in a COVID-19 clinical trial (adjusted PR 4.49; 95% CI1.25-16.06; p = 0.02), and acceptance of different COVID-19 vaccine brands between doses (adjusted PR 10.02; 95% CI1.40-71.95; p = 0.02). Conclusion: Most parents would accept a third vaccine booster dose, approximately a third would participate in COVID-19 vaccine trials. Believing COVID-19 vaccines studies fulfilled quality standards was associated with the study outcomes. It is necessary to inform about the rigorous processes for the development of COVID-19 vaccines to generate confidence in parents to accept these vaccine-related outcomes.

COVID-19 vaccine hesitancy: Meaning relations between responses in an epidemiological study and twitter messages.

BACKGROUND: Vaccine hesitancy is a concerning public health issue, further amplified during the COVID-19 pandemic. Social media is an important player in this context, promoting the dissemination of both information and misinformation. Qualitative studies analyzing the meaning of social media contents in correlation with epidemiological data are scarce, and could aid our understanding of social media's impact on vaccine hesitancy. METHODS: In this study, we identified open-ended responses on reasons to refuse the COVID-19 vaccine collected in an epidemiologic study, and analyzed meaning relations with Twitter posts according to theme categories using a qualitative approach. RESULTS: Among responses to open-ended questions on motivations for refusing the COVID-19 vaccine, we identified and analyzed five theme categories: 1. individuality; 2. fear of adverse events/distrust in vaccine safety; 3. political ideologies/aversion to recommendations issued by the State; 4. skepticism about vaccine efficacy; and 5. refusal of non-natural products or interventions. We observed a close correspondence between open-ended responses in the epidemiological study and Twitter posts in all 5 theme categories. The highest outreach of Twitter posts was observed for those in the "individuality" and "fear of adverse the events/distrust in vaccine safety" theme categories. CONCLUSIONS: Our study suggests that social media interactions can perpetuate misinformation and hesitant attitudes about vaccines. Social media algorithms can intensify ideologic isolation, and strategies to promote the dissemination of tailored health information among social media users should be implemented to promote an overall understanding of health, particularly those concerning the collective wellbeing.

Lessons for Future Vaccination Policies: COVID-19 Vaccination Intention in People With and Without Chronic Diseases.

PURPOSE: This study compared COVID-19 vaccination intentions in those with and without chronic diseases (CDs and non-CDs) in South Korea. We hypothesized that the factors associated with COVID-19 vaccination intentions would differ between CDs and non-CDs in South Korea. METHODS: Using survey data collected through a Korean online panel in June 2021, we conducted a cross-sectional secondary data analysis. Of the 2292 participants, 411 had at least one chronic disease. To construct a comparable dataset, we selected non-CDs via a 1:1 case-control matching for age and gender. We then utilized a multivariable binary logistic regression model to explore the factors contributing to COVID-19 vaccination intentions in CDs and non-CDs. RESULTS: All told, over 75% of participants in both groups indicated that they intended to vaccinate against COVID-19. In both groups, those who mistrusted general vaccine benefits reported significantly lower COVID-19 vaccination intentions. Regarding factors associated with vaccination intentions, CDs identified anxiety regarding coronavirus and exposure to COVID-19 vaccination promotions at the community level, while non-CDs highlighted hesitancy regarding vaccines and confidence in government/health services. CONCLUSION: Improving vaccination acceptance will require the development and implementation of tailored approaches for CDs and non-CDs and efforts to minimize general vaccine mistrust.

Creating a Culturally Safe Online Data Collection Instrument to Measure Vaccine Confidence Among Indigenous Youth: Indigenous Consensus Method.

BACKGROUND:  Participating in surveys can shape the perception of participants related to the study topic. Administering a vaccine hesitancy questionnaire can have negative impacts on participants' vaccine confidence. This is particularly true for online and cross-cultural data collection because culturally safe health education to correct misinformation is typically not provided after the administration of an electronic survey. OBJECTIVE:  To create a culturally safe, online, COVID-19 vaccine confidence survey for Indigenous youth designed to collect authentic, culturally relevant data of their vaccine experiences, with a low risk of contributing to further vaccine confusion among participants. METHODS:  Using the Aboriginal Telehealth Knowledge Circle consensus method, a team of academics, health care providers, policy makers, and community partners reviewed COVID-19 vaccine hesitancy surveys used in public health research, analyzed potential risks, and created a framework for electronic Indigenous vaccine confidence surveys as well as survey items. RESULTS:  The framework for safer online survey items is based on 2 principles, a first do-no-harm approach and applying a strengths-based lens. Relevant survey domains identified in the process include sociodemographic information, participants' connection to their community, preferred sources for health information, vaccination uptake among family members and peers, as well as personal attitudes toward vaccines. A total of 44 survey items were developed, including 5 open-ended items to improve the authenticity of the data and the analysis of the experiences of Indigenous youth. CONCLUSIONS:  Using an Indigenous consensus method, we have developed an online COVID-19 vaccine confidence survey with culturally relevant domains and reduced the risk of amplifying misinformation and negative impacts on vaccine confidence among Indigenous participants. Our approach can be adapted to other online survey development in collaboration with Indigenous communities.

Relative vaccine effectiveness of ChAdOx1/AZD1222 vaccines as booster dose via intradermal injection with a one-fifth dose compared with the intramuscular injection in the prevention of SAR-CoV-2 infections in Phuket: A retrospective cohort study.

OBJECTIVES: This study assessed the real-world relative vaccine effectiveness of the ChAdOx1/AZD1222 vaccine given intradermally at one-fifth dose compared to the standard intramuscular injection, following the completion of 2 doses of CoronaVac, due to limited vaccine availability in Thailand during the Coronavirus disease 2019 (COVID-19) pandemic. METHOD: This retrospective cohort study used 138,264 records from Vachira Phuket Hospital, Phuket, Thailand. The records were divided into 2 groups: 49,387 recipients received one-fifth doses via intradermal injections, and 88,877 recipients received standard-dose intramuscular injections from September 14 to October 3, 2021, with follow-up until December 31, 2021. Relative vaccine effectiveness for the cohorts was estimated using Cox regression, adjusting for demographic and clinical risk factors. RESULTS: The adjusted hazard ratio between the intradermal and intramuscular groups was 0.88 (95% Confidence Interval 0.76-1.02, P = 0.09), indicating a nonsignificant protective factor for the intradermal group. Further stratified analysis revealed no significant difference between the 2 groups. The 21 and 28-day postvaccination periods minimized the possibility of confounding due to differences in the cohorts' timeframes. CONCLUSION: A booster dose of ChAdOx1/AZD1222 given intradermally at one-fifth dose did not show a significant difference compared to the standard intramuscular injection.