Unvaccinated Adults Research Articles

Аналіз захворюваності на кір в Україні та стану популяційного імунітету

Since 2001, due to the effectiveness of vaccines, the Measles Elimination Initiative was introduced. However, there are periodic increases in its incidence. In terms of intensity, the measles epidemic process in Ukraine in 2017-2019 can be considered as an epidemic. In 2022, 205,153 cases of measles were reported worldwide (67% more than in 2021). In 2023, this indicator in the European Region of the World Health Organization increased 30 times compared to 2022. Thus, measles remains a pressing problem. Aim - to analyze the incidence of measles, particularly among vaccinated individuals, the state of specific population immunity, as well as to assess of the current epidemic situation. Materials and methods. An analysis was carried out: the incidence of measles in Ukraine (2017-11/30/2023), its level among vaccinated people (2017-2022), the rates of vaccination against measles, mumps and rubella (MMR) (2016-2023), the state of specific population immunity of the population (2019-2022). Descriptive-evaluative and analytical approaches of the epidemiological method, as well as methods of mathematical statistics were used. Results and conclusions. The previous rise in the incidence of measles in Ukraine (2017-2019) and the beginning of the current one (2023) occurred against the background of unsatisfactory coverage of the first and second doses of the MMR vaccinations (2016 - 45.5% and 30.2%; 2022 - 74.1% and 69.1%, respectively). The population of all age groups is involved in the intensification of the measles epidemic process (with the exception of patients who were ill in the pre-vaccination period). The high effectiveness of MMR-1 for children aged 1 to 4 years has been shown, with its decrease with increasing age and gaps in the coverage of MMR-2 for children aged 6 years. Unvaccinated adults remain at risk. In 2019-2021, the proportion of individuals with a protective level of specific antibodies was 89-91%, and by age groups - 83-91%. A significant decrease of this indicator was observed in 2022 compared to 2021 in all age groups, with the exception of children aged 1-4 years. Ensuring proper vaccine prevention in Ukraine is one of the primary tasks for reducing the cyclical outbreaks of measles and achieving its elimination. No conflict of interests was declared by the authors.

Rational attenuation of canine distemper virus (CDV) to develop a morbillivirus animal model that mimics measles in humans.

Morbilliviruses are members of the family Paramyxoviridae and are known for their ability to cause systemic disease in a variety of mammalian hosts. The prototypic morbillivirus, measles virus (MeV), infects humans and still causes morbidity and mortality in unvaccinated children and young adults. Experimental infection studies in non-human primates have contributed to the understanding of measles pathogenesis. However, ethical restrictions call for the development of new animal models. Canine distemper virus (CDV) infects a wide range of animals, including ferrets, and its pathogenesis shares many features with measles. However, wild-type CDV infection is almost always lethal, while MeV infection is usually self-limiting. Here, we made five recombinant CDVs, predicted to be attenuated, and compared their pathogenesis to the non-attenuated recombinant CDV in a ferret model. Three viruses were insufficiently attenuated based on clinical signs, fatality, and systemic infection, while one virus was too attenuated. The last candidate virus caused a self-limiting infection associated with transient viremia and viral dissemination to all lymphoid tissues, was shed transiently from the upper respiratory tract, and did not result in acute neurological signs. Additionally, an in-depth phenotyping of the infected white blood cells showed lower infection percentages in all lymphocyte subsets when compared to the non-attenuated CDV. In conclusion, infection models using this candidate virus mimic measles and can be used to study pathogenesis-related questions and to test interventions for morbilliviruses in a natural host species.IMPORTANCEMorbilliviruses are transmitted via the respiratory route but cause systemic disease. The viruses use two cellular receptors to infect myeloid, lymphoid, and epithelial cells. Measles virus (MeV) remains an important cause of morbidity and mortality in humans, requiring animal models to study pathogenesis or intervention strategies. Experimental MeV infections in non-human primates are restricted by ethical and practical constraints, and animal morbillivirus infections in natural host species have been considered as alternatives. Inoculation of ferrets with wild-type canine distemper virus (CDV) has been used for this purpose, but in most cases, the virus overwhelms the immune system and causes highly lethal disease. Introduction of an additional transcription unit and an additional attenuating point mutation in the polymerase yielded a candidate virus that caused self-limiting disease with transient viremia and virus shedding. This rationally attenuated CDV strain can be used for experimental morbillivirus infections in ferrets that reflect measles in humans.

Seroprevalence of IgM/IgG and Neutralizing Antibodies against SARS-CoV-2 in Unvaccinated Young Adults from Mexico Who Reported Not Having Had a Previous COVID-19 Infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes coronavirus disease 2019 (COVID-19). It is estimated that more than half of new infections are transmitted by asymptomatic people; therefore, the isolation of symptomatic people is not enough to control the spread of the disease. A total of 171 unvaccinated young adults (18-35 years) from Sonora, Mexico, who underwent a structured survey to identify prior COVID-19 infections, were included in this study. A qualitative determination of anti-SARS-CoV-2 antibodies in serum was performed by lateral flow immunoassay (Certum IgG/IgM Rapid Test™ cassette kit) and neutralizing antibodies were also determined (GenScript cPass assay). A total of 36 people reported a history of COVID-19 infection, and 135 reported no history of COVID-19. In contrast, 49.6% (67/135) of individuals who had not reported a previous SARS-CoV-2 infection were seropositive to the rapid anti-SARS-CoV-2 antibody test, and 48.1% (65/135) of them had neutralizing antibodies. These results suggest that in young adults, SARS-CoV-2 infections could be asymptomatic in a high percentage of individuals, which could contribute in part to the slow control of the current pandemic due to the large number of asymptomatic cases that are contagious and that could be a silent spread of the virus.

Risk factors for human papillomavirus infection and disease: A targeted literature summary.

Adolescents are the primary cohort for routine human papillomavirus (HPV) vaccination, but unvaccinated adults may also benefit. A lack of consensus on which adults to target and the presence of reimbursement barriers likely contribute to the lag in adult vaccinations, highlighting missed prevention opportunities. Understanding factors contributing to risk of HPV infection and disease could help in decision making on vaccination. This review summarizes existing literature on risk factors for HPV infection and disease and includes 153 studies reporting relative risks or odds ratios for factors associated with HPV infection or disease in adults, published between 2009 and 2020. Despite inconsistent design and reporting of risk factors across studies, this review confirmed several risk factors associated with adult infection, including human immunodeficiency virus positivity, number of sex partners, and smoking. These findings can support policymaking, guideline development, and clinical decision making for HPV vaccination and screening of high-risk adult groups.

Using the Health Belief Model to Predict Vaccination Intention in Unvaccinated Adults in Latvia During the COVID-19 Pandemic

Abstract Vaccination is a global health development success story that saves millions of lives every year and reduces the risk of getting various infectious diseases, including COVID-19. At the end of 2021, a rapid increase in the size of the population infected with COVID-19 and a low vaccination coverage were observed in Latvia (Centre for Disease Prevention and Control, 2021). Also, despite the available vaccines, by the beginning of May 2022, only 60.6% of the population of Latvia had completed the full course of vaccination against COVID-19. According to the Ministry of Health, the vaccination process is characterised by variability and flexibility, and in general, vacci-nation rates have declined in recent years. Therefore, the aim of the study was to investigate the vaccination predicting factors of unvaccinated adults in Latvia using the Health Belief Model (HBM) during the COVID-19 pandemic. The study sample consisted of 539 respondents aged 18 to 75 years (M = 45.35, SD = 15.70), who were not vaccinated against COVID-19 and who had to make a decision to vaccinate or not, and who were part of a representative sample of Latvian residents (n = 1017). The data was collected in September and were analysed using Spearman’s rank correlation coefficient and multivariate linear regression analysis. A statistically significant moderate strong positive correlation was shown between vaccination intention and all six vaccination motives as perceived benefits (r = 0.40–0.44, p < 0.01); statistically significant but weak positive correlation between vaccination intention and risk appraisal as perceived threat (r = 0.20, p < 0.01) and COVID-19 experience as cues to action (r = 0.20, p < 0.01); and statistically significant negative but weak correlation for vaccination intention and fear of vaccination as perceived barriers (r = –0.21, p < 0.01). The results revealed a statistically significant positive association of vaccination intention and the components of HBM: perceived threats, perceived benefits and cues to action, as well as a statistically significant negative association with perceived barriers. The results revealed several factors that predict vaccination intention, explaining 32% of the variation in vaccination intention: education level, perceived threats, perceived benefits, perceived barriers, and cues to action. Higher levels of education, higher perceived threat of contracting COVID-19, many different social motives for vaccination (e.g., to be able travel), confidence that the vaccine will not cause significant side effects and long-term consequences, and experience with COVID-19 are factors that predicts an individual’s intention to vaccinate against COVID-19.

COVID-19 vaccine hesitancy in KwaZulu-Natal, South Africa: A survey of unvaccinated adults.

Concerns and misconceptions surrounding coronavirus disease 2019 (COVID-19) vaccines may account for vaccine hesitancy and low uptake. To determine prevalence of COVID-19 vaccine hesitancy, vaccine-related misconceptions, and predictors of vaccine hesitancy among South Africans. Community setting in five districts in KwaZulu- Natal province. Between August 20, 2021, and September 27, 2021, we conducted a cross-sectional survey, interviewing 300 unvaccinated adults amid the national vaccination campaign. Predictors of hesitancy were identified through multivariable logistic regression analysis. Participants had a median age of 29 years (IQR: 23-39), 86.7% were Black African, 63.2% were male, 53.3% resided in rural communities, and 59.3% (95% CI: 53.8% - 64.9%) were classified as vaccine hesitant. The primary reason for not vaccinating was a lack of trust in the vaccine (62.1%). Factors associated with reduced vaccine hesitancy included age (participants aged 35-49 years: OR: 0.28, 95% CI: 0.18-0.64, p = 0.003; participants over 50 years: OR: 0.18, 95% CI: 0.07-0.47, p = 0.0004), previous COVID-19 infection (OR: 0.31, 95% CI: 0.11-0.87, p = 0.03), and receiving vaccine information from healthcare workers (OR: 0.32, 95% CI: 0.10-1.0, p = 0.05). Unemployed (OR: 2.14, 95% CI: 1.1-4.2, p = 0.03) and self-employed individuals (OR: 2.98, 95% CI: 1.27-7.02, p = 0.01) were more likely to be vaccine hesitant. COVID-19 vaccine hesitancy rates are high in KwaZulu-Natal. Uptake could be enhanced by healthcare workers leading information campaigns with messages targeting younger individuals, the unemployed, and the self-employed. This survey provides evidence to improve COVID-19 vaccination uptake in South Africa.

Does vaccination make a difference? Understanding the role of vaccination in consumers’ in-restaurant dining intentions during a pandemic

ABSTRACT This study investigated temporal differences in the relationships among consumers’ perceived protection of the COVID-19 vaccination, their threat and coping appraisal, subsequent in-restaurant dining decisions, and the moderating role of vaccination status. Data was collected at times during the post-vaccine availability era of the COVID-19 pandemic: Phase 1 in March 2021 (N = 282), Phase 2 in September 2021 (N = 320), and Phase 3 in March 2022 (N = 342). PLS-SEM and multi-group analysis were employed to test the hypotheses. Results revealed temporal differences in the relationships between perceived vaccine protection, threat appraisal, and in-restaurant dining intention with variation between vaccinated and unvaccinated adults. However, neither temporal differences were found regarding the coping appraisal nor related variances regarding vaccination status. This study empirically examined the impact of COVID-19 vaccination on consumers’ protection motivation appraisals and consequent dine-in decisions. Furthermore, the temporal changes along various pandemic stages were investigated.

Reduction in Long COVID Symptoms and Symptom Severity in Vaccinated Compared to Unvaccinated Adults.

The impact of vaccination prior to infection on postacute sequelae of coronavirus disease 2019 (COVID-19, PASC), also known as long COVID, remains unclear. Here we assess the protective effect of vaccination on long COVID in a community-based setting. The Immunity Associated with SARS-CoV-2 (IASO) study is an ongoing prospective cohort of working adults that began in October 2020. Participants are actively followed for severe acute respiratory syndrome coronavirus 2 infection. We compared the prevalence of symptoms and symptom severity in vaccinated compared to unvaccinated cases. Our primary definition of long COVID was the presence of symptoms at 90 days postinfection; 30 days postinfection was also examined. Overall, by 90 days postinfection, 13% of cases had long COVID, with 27% of unvaccinated cases and 8% of vaccinated cases reporting long COVID (relative risk [RR], 0.31 [95% confidence interval {CI}, .22-.42]). Vaccination was also associated with significantly lower average severity scores at all timepoints (eg, relative severity at 90 days postinfection: -2.70 [95% CI, -1.68 to -3.73]). In the pre-Omicron era, 28% of unvaccinated cases and 18% of vaccinated cases reported long COVID (P = .07), and vaccinated cases reported less severe symptoms including less difficulty breathing (P = .01; 90-day RR, 0.07). Vaccinated cases had lower prevalence of long COVID and reduced symptom severity.

Prevalence and Factors Associated with Long COVID Symptoms among U.S. Adults, 2022.

Long COVID and its symptoms have not been examined in different subpopulations of U.S. adults. Using the 2022 BRFSS (n = 445,132), we assessed long COVID and each symptom by sociodemographic characteristics and health-related variables. Multivariable logistic regression was conducted to examine factors associated with long COVID and the individual symptoms. Prevalence differences were conducted to examine differences in long COVID by vaccination status. Overall, more than one in five adults who ever had COVID-19 reported symptoms consistent with long COVID (21.8%). The most common symptom was tiredness or fatigue (26.2%), followed by difficulty breathing or shortness of breath (18.9%), and loss of taste or smell (17.0%). Long COVID was more common among adults under 65 years, women, American Indian or Alaska Native or other/multi race group, smokers, and people with a disability, depression, overweight or obesity compared to their respective counterparts. The prevalence of long COVID was higher among unvaccinated adults (25.6%) than vaccinated adults (21.6%) overall, and for 20 of 32 subgroups assessed. These findings underscore the benefits of vaccination, the importance of early treatment, and the need to better inform health care resource allocation and support services for those experiencing long COVID.

Factors associated with SARS-CoV-2 infection in unvaccinated children and young adults

Background and objectivesPediatric COVID-19 cases are often mild or asymptomatic, which has complicated estimations of disease burden using existing testing practices. We aimed to determine the age-specific population seropositivity and risk factors of SARS-CoV-2 seropositivity among children and young adults during the pandemic in British Columbia (BC).MethodsWe conducted two cross-sectional serosurveys: phase 1 enrolled children and adults < 25 years between November 2020-May 2021 and phase 2 enrolled children < 10 years between June 2021-May 2022 in BC. Participants completed electronic surveys and self-collected finger-prick dried blood spot (DBS) samples. Samples were tested for immunoglobulin G antibodies against ancestral spike protein (S). Descriptive statistics from survey data were reported and two multivariable analyses were conducted to evaluate factors associated with seropositivity.ResultsA total of 2864 participants were enrolled, of which 95/2167 (4.4%) participants were S-seropositive in phase 1 across all ages, and 61/697 (8.8%) unvaccinated children aged under ten years were S-seropositive in phase 2. Overall, South Asian participants had a higher seropositivity than other ethnicities (13.5% vs. 5.2%). Of 156 seropositive participants in both phases, 120 had no prior positive SARS-CoV-2 test. Young infants and young adults had the highest reported seropositivity rates (7.0% and 7.2% respectively vs. 3.0-5.6% across other age groups).ConclusionsSARS-CoV-2 seropositivity among unvaccinated children and young adults was low in May 2022, and South Asians were disproportionately infected. This work demonstrates the need for improved diagnostics and reporting strategies that account for age-specific differences in pandemic dynamics and acceptability of testing mechanisms.

Real-World Effectiveness Study of Nirmatrelvir-Ritonavir or Molnupiravir in Hospitalized Unvaccinated Patients with Chronic Respiratory Diseases and Moderate COVID-19 at Presentation.

Nirmatrelvir-ritonavir (NMV-r) and molnupiravir (MOL) were developed as out-patient anti-viral for mild COVID-19. There was limited data on their role in treating COVID-19 for hospitalized patients, especially among adult patients who are unvaccinated and had chronic respiratory diseases. A territory-wide retrospective study was conducted in Hong Kong to compare the efficacy of NMV-r and MOL against COVID-19 in unvaccinated adult patients with asthma, chronic obstructive pulmonary disease, bronchiectasis and interstitial lung diseases presenting with moderate COVID-19 from 16th February 2022 to 15th March 2023. A total of 1354 patients were included, 738 received NMV-r and 616 received MOL. NMV-r was more effective in reducing 90-day mortality with adjusted hazard ratios (aHR) of 0.508 (95% confidence interval [CI] = 0.314-0.822, p = 0.006). Patients who received NMV-r also had significantly shorter length of stay (LOS) than those receiving MOL, with median LOS of 4 (Interquartile range [IQR] = 2-7) for NMV-r and 6 (IQR = 3-10) for MOL (p-value < 0.001). There was no statistically significant difference in the development of respiratory failure and severe respiratory failure in the two groups. NMV-r was more effective than MOL among unvaccinated adults with chronic respiratory diseases who were hospitalized for moderate COVID-19 without hypoxaemia on admission.

Cost-effectiveness of 20-valent pneumococcal conjugate vaccine in US infants

BackgroundAs of June 2023, two pneumococcal conjugate vaccines, 20- (PCV20) and 15- (PCV15) valent formulations, are recommended for US infants under a 3 + 1 schedule. This study evaluated the health and economic impact of vaccinating US infants with a new expanded valency PCV20 formulation. MethodsA population-based, multi cohort, decision-analytic Markov model was developed to estimate the public health impact and cost-effectiveness of PCV20 from both societal and healthcare system perspectives over 10 years. Epidemiological data were based on published studies and unpublished Active Bacterial Core Surveillance System (ABCs) data. Vaccine effectiveness was based on PCV13 effectiveness and PCV7 efficacy studies. Indirect impact was based on observational studies. Costs and disutilities were based on published data. PCV20 was compared to both PCV13 and PCV15 in separate scenarios. ResultsReplacing PCV13 with PCV20 in infants has the potential to avert over 55,000 invasive pneumococcal disease (IPD) cases, 2.5 million pneumonia cases, 5.4 million otitis media (OM) cases, and 19,000 deaths across all ages over a 10-year time horizon, corresponding to net gains of 515,000 life years and 271,000 QALYs. Acquisition costs of PCV20 were offset by monetary savings from averted cases resulting in net savings of $20.6 billion. The same trend was observed when comparing PCV20 versus PCV15, with a net gain of 146,000 QALYs and $9.9 billion in net savings. A large proportion of the avoided costs and cases were attributable to indirect effects in unvaccinated adults and elderly. From a health-care perspective, PCV20 was also the dominant strategy compared to both PCV13 and PCV15. ConclusionsInfant vaccination with PCV20 is estimated to further reduce pneumococcal disease and associated healthcare system and societal costs compared to both PCV13 and PCV15.

Bolstering the willingness to uptake covid-19 vaccination through multidisciplinary health communication intervention: a cue for reaching herd immunity in Nigeria.

The prevailing unwillingness to accept COVID-19 vaccination among the eligible population has been a serious setback in Nigeria's bid to reach herd immunity against the pandemic. We assessed the impact of a multidisciplinary health communication intervention (MHCI) on willingness to accept COVID-19 vaccination among eligible unvaccinated community dwellers (EUCD) in Nsukka Urban, Enugu State, Nigeria. Through a quasi-experiment that adopted a pre-test, post-test, non-control group design, we studied a total of 85 eligible unvaccinated adults. A researcher-designed "Willingness to Accept COVID-19 Vaccination Questionnaire" was the instrument used for data collection. The data gathered was analysed by means of Statistical Package for Social Sciences (SPSS) version 23.0. Specifically, descriptive and inferential statistics were used to test the formulated research questions and the hypothesis at 0.05 level of significance. We found that the mean scores of willingness to accept COVID-19 vaccination increased significantly after the treatment. There was no significant interaction effect of gender, level of education, and age on the mean of willingness to accept COVID-19 vaccination scores of EUCD after MHCI. The study established that MHCI is impactful in bolstering the willingness to accept COVID-19 vaccination. The Nigerian government should adopt and implement this intervention in schools, communities, and other institutions in order to attain herd immunity in Nigeria.

A pilot study of the acceptability, efficacy, and iatrogenic effects of a brief dynamic norms intervention for reducing young adult alcohol use.

Alcohol use and its related consequences are a public health problem among young adults. Building upon efficacious personalized normative feedback interventions, dynamic norms can be used to highlight the decreasing prevalence of alcohol use over time among young adults' peers, thereby increasing their motivation to change drinking consistent with the trend. Because limited research has examined dynamic norms feedback interventions for alcohol use, we examined the acceptability and initial efficacy of such an intervention, and potential iatrogenic effects of showing norms feedback about drinking to light drinkers and nondrinkers. Participants were 546 unvaccinated young adults ages 18-24 who completed a baseline survey, intervention, and 1-month follow-up assessment. Participants were block randomized to receive a brief web-based dynamic norms intervention, with feedback content focused on either (a) alcohol-related behaviors (intervention) or (b) COVID-19 vaccine behaviors (the attention-matched control for the present study). On average, participants who received the alcohol intervention rated it as generally engaging, helpful, and acceptable, with the majority (90.8%) indicating that they would recommend it to a friend. Supporting initial efficacy, in generalized linear models controlling for demographics and baseline alcohol outcomes, at 1-month follow-up the alcohol intervention was associated with statistically and clinically significant reductions in all indices of perceived drinking norms, drinking quantity, drinking frequency, and driving after drinking occasions. Lighter drinkers showed no adverse iatrogenic effects. Presenting alcohol-related personalized normative feedback using dynamic trends is a promising intervention for reducing alcohol use in a community sample of young adults. Further research clarifying the optimal presentation of dynamic norms is needed.

Vaccination Status and In-hospital Mortality Among Adults With COVID-19 in Jakarta, Indonesia: A Retrospective Hospital-based Cohort Study.

Prospective studies on vaccination status and mortality related to coronavirus disease 2019 (COVID-19) in low-resource settings are still limited. We assessed the association between vaccination status (full, partial, or none) and in-hospital mortality among COVID-19 patients at most hospitals in Jakarta, Indonesia during the Delta predomination wave. We conducted a retrospective cohort study among hospitalized COVID-19 patients who met the study criteria (>18 years old and admitted for inpatient treatment because of laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection). We linked individual-level data in the hospital admission database with vaccination records. Several socio-demographic and clinical characteristics were also analyzed. A Cox proportional hazards regression model was used to explore the association between vaccination status and in-hospital mortality in this patient group. In total, 40 827 patients were included in this study. Of these, 70% were unvaccinated (n=28 543) and 19.3% (n=7882) died during hospitalization. The mean age of the patients was 49 years (range, 35-59), 53.2% were female, 22.0% had hypertension, and 14.2% were treated in the intensive care unit, and the median hospital length of stay across the group was 9 days. Our study showed that the risk of in-hospital mortality among fully and partially vaccinated patients was lower than among unvaccinated adults (adjusted hazard ratio [aHR], 0.43; 95% confidence interval [CI], 0.40 to 0.47 and aHR, 0.70; 95% CI, 0.64 to 0.77, respectively). Vaccinated patients had fewer severe outcomes among hospitalized adults during the Delta wave in Jakarta. These features should be carefully considered by healthcare professionals in treating adults within this patient group.

COVID-19 Vaccine Hesitancy among Unvaccinated Adults: A Cross-Sectional Exploratory Analysis of Vaccination Intentions in Italy Related to Fear of Infection.

From the initial COVID-19 outbreak, Italy was the first Western country to be seriously affected by the pandemic. Understanding vaccine hesitancy can help efforts to achieve broad vaccination coverage. The objectives of this research were to determine the extent of vaccine hesitancy in Italy and to understand the characteristics of those segments of the population with some hesitancy. Between January and February 2021, 41,473 subjects answered the second questionnaire delivered in phase II of the web-based EPICOVID19 survey. Among the included adult volunteers living in Italy, 4653 (11.2%) reported having previously received at least one dose of the COVID-19 vaccine. In the sample of 36,820 respondents, all not vaccinated (age 51.1 ± 13.5; 59.7% female; 63.6% high level of education), the comparison between hesitant and inclined participants was accompanied by percentages and odds ratios. A total of 2449 individuals were hesitant (6.7% of the unvaccinated ones). Hesitancy was higher among women (OR = 1.48; 95%CI: 1.36-1.62); it was highest in the 50-59 and 40-49 age groups and among those with a lower educational level. A higher level of education was associated with a lower proportion of hesitancy (5.54%) compared with 9.44% among respondents with a low level of education (OR = 0.56; 95%CI: 0.46-0.68). Hesitancy was most common in subjects who did not report fear of infection (12.4%, OR = 4.0; 95%CI: 3.46-4.61). The results can guide the design of tailored information and communication campaigns through considering objective and subjective characteristics.

COVID-19 Related Mortality Does Not Correlate with Vaccine Availability in Leukemia Patients: 2020-2023 Analysis in the United States

Introduction: Leukemia patients have abnormal immune function due to both the innate characteristics of their disease and the treatments, which are almost invariably immunosuppressive in nature. Treatment modalities may lead to both temporary and long term immunosuppression. For these reasons, the coronavirus disease 2019 (COVID-19) pandemic has posed challenges to the management of patients with leukemia.With the approval of several types of COVID-19 vaccines, the first of which became available in December 2020, there has been a significant decrease in morality from COVID-19 among vaccinated adults compared to unvaccinated adults. It is unclear if the same trend applies to adults with leukemia who may have an impaired immune response to vaccination. To further elucidate the efficacy of COVID-19 vaccination in this inherently immunocompromised group of patients, we performed a nationwide analysis of COVID-19 mortality trends in adults over 25 years old with leukemia. Methods: Using the CDC Wonder Database, we reviewed death certificates for COVID-19 related mortality trends from March 2020 to June 2023 for all subtypes of leukemia in the United States in adults above 25 years old. We included respective ICD codes: C91 lymphoid leukemia, C92 myeloid leukemia, C93 monocytic leukemia, C94 other leukemias of specified cell types, and C95 leukemia of unspecified cell types. Age-adjusted mortality rates (AAMRs) were calculated per 100,000 people. Data was stratified by reported sex, race/ethnicity, and census region. Results: Deaths from COVID-19 in people with leukemia were reported as 1800 in 2020, 2813 in 2021, 2445 in 2022, and 481 as of June 2023 (Figure 1). There were fluctuations of COVID-19 AAMR per 100,000 people with all subtypes of leukemia from 2020 to 2023 (Table 1). The provisional and incomplete data in 2023 showed a sudden decrease of AAMR within all groups. In 2020 the overall AAMR in all groups was 0.7 which increased to 1.1 in 2021, decreased to 0.9 in 2022, and 0.2 as of June 2023. There is a difference in mortality rates between sex with male AAMR being greater than female in all 3 years. For example in 2021 the AAMR for males was 1.4 while for females it was 0.6. Analysis of racial and ethnic groups showed Asians with the lowest AAMR (0.3 AAMR, 2020) compared to Whites (1.5 AAMR, 2020), Blacks (0.9 AAMR, 2020), and Hispanics (0.6 AAMR, 2020). The trends between the census regions were also comparable. Conclusion: The data demonstrates variations in AAMRs from each year to the next. These variations can be affected by infection rates, public health measures, healthcare access, and socioeconomic factors. The 2023 data is still provisional and incomplete, however, they do offer a glimpse of the 2023 trends. The multiple subtypes of leukemia have different degrees of immunosuppression, thus not all leukemia patients have the same risk profile. Despite the type of Leukemia, it is widely accepted that these patients are in an immunocompromised state and at a higher risk to develop complications from COVID-19. It is recommended for all patients with leukemia to receive non-live, attenuated viral vaccines. Although considered safe and recommended, there is very limited data regarding efficacy of the COVID-19 vaccine in immunocompromised patients. One study showed patients with CLL about 36% of patients were seronegative after vaccination (Chatzikonstantinou et al., 2021) and seronegativity rates may be even higher in patients with acute leukemias. Certainly the absence of steady downward trend in mortality following the availability of vaccination suggests either that leukemia patients are not complying with vaccination recommendations or that vaccination is often ineffective in the setting of their inherent immunocompromise. Certainly a limitation of this analysis is the lack of data regarding COVID-related mortality in vaccinated versus unvaccinated individuals. Given the lack of improvement in AAMR among leukemic patients following the availability of a COVID 19 vaccination, it seems appropriate that physicians still recommend using additional preventative measures from COVID-19 including social distancing and mask wearing. It is important to continue studying the relationship between serology positivity, immunity, and overall outcomes.

2384. Exploring COVID-19 Vaccine Hesitancy in Unvaccinated Adults within a Semi-Urban Population of South India: A Qualitative Investigation

Abstract Background This qualitative study examines COVID-19 vaccine hesitancy among unvaccinated adults in a semi-urban region of South India. Despite broad vaccination coverage in India, vaccine hesitancy persists, contributing to the ongoing transmission. By conducting region-specific in-depth qualitative research, we aim to identify barriers to vaccination, to address this public health menace. Methods This grounded theory-based qualitative study explores COVID-19 vaccine hesitancy among unvaccinated adults in semi-urban regions of Ernakulam, Kerala, India. Conducted from April to May 2022, the study used purposive sampling to enrol participants with the help of ASHA workers. Semi-structured face-to-face interviews were carried out, utilizing an open-ended questionnaire-based interview guide. Audio files of the interviews were transcribed verbatim, and the data underwent a multistage thematic analysis using the constant comparative method. Results In our study with 35 unvaccinated individuals, vaccine hesitancy factors were categorized into three themes: vaccine-related (33.33%), social/environmental (31.67%), and individual factors (35%). Individual factors included medical conditions (26.67%) and attitudes towards vaccines (8.33%). Vaccine-related factors involved safety concerns (15%), efficacy (6.67%), and administration mode (5%). Social/environmental factors covered accessibility/availability (16.67%) and influencers like healthcare workers, friends, and family (15%). Table 1, Figure 1, and Figure 2 provide further details on themes, subthemes, and their overlap. Figure 1 Representation of identified themes and subthemes among the vaccine hesitant individuals Figure 2 Schematic representation of identified themes and its overlap among the vaccine hesitant individuals. Table 1 Excerpts of 35 study participants outlining the factors for Covid-19 vaccine hesitancy exploring themes and sub-themes of quotes Conclusion Our study finds three main factors contributing to COVID-19 vaccine hesitancy: vaccine-related concerns, social/environmental influences, and individual factors. To tackle hesitancy, it's crucial to address safety concerns, engage with various medical systems, and leverage community influencers. Focusing on vaccine equity and addressing the needs of vulnerable populations is essential for the success of vaccination programs. Targeted communication strategies and behaviour change interventions should be employed to promote vaccine acceptance, and public health authorities must provide accurate, transparent information on vaccine safety and efficacy. Disclosures All Authors: No reported disclosures

Fading SARS-CoV-2 humoral VOC cross-reactivity and sustained cellular immunity in convalescent children and adolescents

Cross-reactive cellular and humoral immunity can substantially contribute to antiviral defense against SARS-CoV-2 variants of concern (VOC). While the adult SARS-CoV-2 cellular and humoral immunity and its cross-recognition potential against VOC is broadly analyzed, similar data regarding the pediatric population are missing. In this study, we perform an analysis of the humoral and cellular SARS-CoV-2 response immune of 32 convalescent COVID-19 children (children), 27 convalescent vaccinated adults(C + V+) and 7 unvaccinated convalescent adults (C + V-). Similarly to adults, a significant reduction of cross-reactive neutralizing capacity against delta and omicron VOC was observed 6 months after SARS-CoV-2 infection. While SAR-CoV-2 neutralizing capacity was comparable among children and C + V- against all VOC, children demonstrated as expected an inferior humoral response when compared to C + V+. Nevertheless, children generated SARS-CoV-2 reactive T cells with broad cross-recognition potential. When compared to V + C+, children presented even comparable frequencies of WT-reactive CD4 + and CD8 + T cells with high avidity and functionality. Taking into consideration the limitations of study - unknown disease onset for 53% of the asymptomatic pediatric subjects, serological detection of SARS-CoV-2 infection-, our results suggest that following SARS-CoV-2 infection children generate a humoral SARS-CoV-2 response with neutralizing potential comparable to unvaccinated COVID-19 convalescent adults as well a sustained SARS-CoV-2 cellular response cross-reactive to VOC.

Establishing clinically meaningful ranges of metal hypersensitivity in orthopaedic patients using COVID-19 vaccine-induced adaptive immune responses from fully vaccinated adults

BackgroundThis study aimed to assess metal sensitization ranges among orthopaedic patients by comparing adaptive immune responses in all-comer pre- and post-operative orthopaedic adults who were COVID-19 unvaccinated or vaccinated vs patients with a painful aseptic implant by lymphocyte transformation test (LTT) to SARS-CoV-2-Spike-Protein (SP) and implant metal(s), respectively. MethodsData were retrospectively reviewed from three independent groups: unvaccinated COVID-19 adults (n = 23); fully COVID-19 vaccinated adults (n = 35); unvaccinated, painful aseptic implant patients with history of metal allergy (n = 98). Standard in vitro LTT for SP and implant metal(s) (nickel, cobalt) were performed and rated as negative (stimulation index [SI]<2), mild (SI ≥ 2), positive (SI ≥ 4–15), and high sensitization (SI > 15) adaptive immune responses to tested antigen. ResultsOverall, 17/23 (74%) of unvaccinated adults showed negative to mild LTT ranges, and 35/35 (100%) of vaccinated showed mild to positive LTT ranges to SP. Vaccinated individuals showed significantly higher median SI (16.1) to SP than unvaccinated (median SI, 1.7; P < 0.0001). Most vaccinated adults (94%) showed a lymphocyte SI > 4 to SP, establishing LTT SI ≥ 4 with >90% sensitivity for diagnosing effective COVID-19 adaptive immune responses. Significantly fewer painful orthopaedic patients (41%) showed comparable elevated levels of lymphocyte metal sensitivity at SI ≥ 4 compared to vaccinated group (P < 0.0001). ConclusionsVaccinated adults showed significantly higher lymphocyte SI to SP than unvaccinated indicating that SI ranges ≥4 should be set as unequivocally diagnostic of LTT-positive adaptive immune responses to tested antigen. This analysis supports using higher LTT SI ranges (SI ≥ 4) in diagnosing clinical orthopaedic-related Type IV metal-hypersensitivity responses among orthopaedic patients.