High Vaccination Rates Research Articles

Medical and dental student knowledge about COVID-19 and influenza vaccines impact opinions about vaccine advocacy and future practice.

The World Health Organization has identified vaccine hesitancy as a global public health challenge. Healthcare providers are among the most influential and trusted figures for vaccine counseling. This article focuses on COVID-19 and influenza personal immunization behaviors, vaccine knowledge and opinions, and vaccine counseling confidence among future healthcare providers - dental and medical students. A cross-sectional anonymous online survey was conducted at four dental schools and one allopathic medical school in the United States. Items included personal vaccination status for the COVID-19 and influenza vaccines and vaccine-specific items developed based on past research to assess knowledge, opinions, and behaviors. Two hundred and thirty-two medical and 221 dental students completed the survey. 68 and 55% scored average/above-average knowledge on COVID-19 and influenza vaccine items, respectively. There were significant differences between those with average/above-average and below-average knowledge scores regarding learning about, recommending, and advocating for vaccines and counseling vaccine-hesitant patients for both vaccines (p < 0.0001). Although higher-knowledge students had higher vaccination rates (p < 0.0001), many had insufficient knowledge about vaccines. Healthcare providers play a crucial role in vaccine advocacy. The identified knowledge gaps are significant as they impact quality of patient care. And opinions about future vaccination practice such as recommending, providing, and counseling about vaccines. Equipping students with knowledge and communication skills will enable them to be strong vaccine advocates to improve overall public health.

Knowledge, Attitudes and Practices of Pediatricians About COVID-19 Vaccination to Children.

Achieving high vaccination rates is very important in the prevention of the coronavirus disease 2019 (COVID-19) as in other infectious diseases. This study aimed to evaluate pediatricians' knowledge, attitudes and behaviours about COVID-19 vaccination of children. Our single-center, descriptive, cross-sectional, prospective study was conducted between September 20, 2022 and November 30, 2022. The sample consisted of 350 physicians who agreed to fill out the questionnaire voluntarily. Participants were asked 21 questions about their sociodemographic data, knowledge about COVID-19 vaccination of children, attitudes and behaviours via Google Forms. A total of 350 pediatricians, 72.6% of whom were women, participated in our study. 51.4% of the participants were working in a Training and Research Hospital, and 99.1% had received COVID-19 vaccination themselves. While 65.7% (n=230) of pediatricians recommended COVID-19 vaccination for all children, 27.7% (n=97) recommended it only for children in the risk group, and 6.6% (n=23) did not recommend COVID-19 vaccination for children. The most common reasons why pediatricians did not recommend the vaccine to all children were; 56.7% lack of sufficient clinical research on vaccination in children, 50% concerns about the long-term effects of the vaccine, 27.5% vaccine-related side effects. The most risk groups for which participants recommended vaccination were asthma (chronic lung disease) 84.6%, diabetes mellitus 72%, and immunodeficiency 69.7%. 68.9% of pediatricians knew that COVID-19 vaccine was used for children aged 12 years and older in Türkiye, and 60.9% thought that COVID-19 vaccine was safe for children. Those who thought that COVID-19 vaccine was safe for children were more likely to recommend the vaccine to children (p<0.001). When the answers given to the knowledge questions were analyzed, it was found that the knowledge level of those who did not recommend vaccination to children was lower than the others (p<0.001). In the present study, pediatricians mostly recommend COVID-19 vaccine to children. The vaccine safety and the level of knowledge about COVID-19 vaccine are effective factors in recommending the vaccine. Therefore, we conclude that trainings to be organized for pediatricians about COVID-19 vaccine will increase the rate of recommending COVID-19 vaccine to children.

A protocol for modeling the factors influencing the deployment of the COVID-19 vaccine across African countries.

Evidence fails to capture disparities amongst African countries in terms of the measure of administered COVID-19 vaccine doses per 100 people. Assessment of data on doses secured, administered, and supplied was undertaken to investigate quantitative measures that impacted COVID-19 vaccine deployment, thereby emphasizing distribution and supply indicators. We employ a full linear regression to identify independent variables that have an impact on vaccination rates, including macroeconomic indicators such as World Bank Income Classification, Gross Domestic Product (GDP) per capita and various indices such as Health Access and Quality Index, Human Development Index, Global Peace Index, Education Index, Political Stability Index and Government Effectiveness. This analysis aims to construct a statistical model utilizing regression analysis to identify key drivers of COVID-19 vaccine deployment in Africa and offer insights into vaccination disparities in the continent. Recognizing the global importance of achieving high vaccination rates, the study sheds light on specific challenges faced by individual countries within Africa, thereby emphasizing the need for tailored efforts. Beyond COVID-19, the research contributes to understanding the relationship between vaccination rates and social indicators that, potentially impact broader public health concerns and global vaccination programs. This study provides a foundation for informed policymaking to enhance vaccine accessibility, inform targeted programs, and improve individual health systems, thereby addressing broader implications for global health.

A Dynamic Model of Information‐Vaccination‐Disease That Accounts for Emerging Viral Variants: Model Development and a Case Study for COVID‐19 in Iceland

Pathogens mutate as diseases spread, and variants that become epidemic or pandemic strains have higher transmission rates and a greater capacity to escape vaccine protection. Considering different vaccine efficacy and vaccination rates is of great significance for the prevention and control of infectious diseases. The spread of vaccination information and the level of trust in vaccinations determine whether people will choose to be vaccinated. To analyze these factors, we developed mean‐field equations for system dynamics to model the complex system of vaccine information dissemination and vaccination, calculated the basic reproduction rate number, and used the Icelandic COVID‐19 outbreak (Omicron variant) as a case study. We found that in the face of emerging variants, increasing vaccine efficacy is more effective than increasing vaccination rates. If vaccine efficacy increases from 40% to 90%, infections can be decreased by 98.5%. However, even a 100% vaccination rate cannot stop the spread of a mutated virus if vaccine efficacy falls below a certain level. High vaccination rates decrease the virus transmission rate. If the efficacy of the vaccine diminishes, the infection will spread rapidly, leading to a greater number of individuals becoming infected with the infectious disease. Due to the high vaccine efficacy against major illnesses and fatalities, improving vaccination rates can lower deaths. Iceland could decrease deaths by 44.8% by raising the vaccination rate from 75.9% to 95.0%. To combat emerging virus variants, it is therefore necessary to both create more effective vaccines and raise awareness of the benefits of vaccination to increase vaccination rates.

Public values to guide childhood vaccination mandates: A report on four Australian community juries.

Governments use vaccination mandates, of different degrees of coerciveness, to encourage or require childhood vaccination. We elicited the views of well-informed community members on the public acceptability of using childhood vaccination mandates in Australia. Four community juries were conducted in Canberra, Launceston, Cairns and Melbourne, Australia between 2021 and 2022. We recruited 51 participants from diverse backgrounds, genders and ages through random digit dialling and social media. Two juries were held in metropolitan areas, and two in regional/rural settings. Outcome measures included jury verdicts and reasons in response to structured questions. All juries were concerned about collective protection and individual rights but prioritised the former over the latter. A majority in all juries supported mandates but juries disagreed with respect to the appropriate mandate types. All juries endorsed using the least restrictive or coercive means to encourage vaccination (providing incentives or education, e.g.) before imposing penalties such as financial losses and school exclusions. The overriding view was that it is fairer to place a direct burden on parents rather than children and that mandates should be designed to avoid inequitable impacts on less advantaged groups in society. Many jurors found conscientious objection acceptable as a controlled option for resolute refusers, provided that overall vaccination coverage remains high. This paper gives policymakers access to the reasons that Australians have for supporting or opposing different mandates under conditions of high knowledge, understanding and deliberation regarding policy options. Sustaining high rates of vaccination requires high levels of co-operation between governments, public health actors and the public. Our findings highlight the importance of considering public values in the design and implementation of vaccination mandates. We sought input from individuals who did and did not vaccinate during the study design. The views and perspectives of nonvaccinating parents were presented in the evidence to juries. We deliberately excluded nonvaccinating individuals from participating, as the divisive and often hostile nature of the topic, and their minority status, made it difficult to ensure they would feel safe as members of the jury without overrepresenting their perspective in the sample. Two related projects engaged directly with these parents.

Exploring spatiotemporal pattern in the association between short-term exposure to fine particulate matter and COVID-19 incidence in the continental United States: a Leroux-conditional-autoregression-based strategy.

Numerous studies have demonstrated that fine particulate matter (PM2.5) is adversely associated with COVID-19 incidence. However, few studies have explored the spatiotemporal heterogeneity in this association, which is critical for developing cost-effective pollution-related policies for a specific location and epidemic stage, as well as, understanding the temporal change of association between PM2.5 and an emerging infectious disease like COVID-19. The outcome was state-level daily COVID-19 cases in 49 native United States between April 1, 2020 and December 31, 2021. The exposure variable was the moving average of PM2.5 with a lag range of 0-14 days. A latest proposed strategy was used to investigate the spatial distribution of PM2.5-COVID-19 association in state level. First, generalized additive models were independently constructed for each state to obtain the rough association estimations, which then were smoothed using a Leroux-prior-based conditional autoregression. Finally, a modified time-varying approach was used to analyze the temporal change of association and explore the potential causes spatiotemporal heterogeneity. In all states, a positive association between PM2.5 and COVID-19 incidence was observed. Nearly one-third of these states, mainly located in the northeastern and middle-northern United States, exhibited statistically significant. On average, a 1 μg/m3 increase in PM2.5 concentration led to an increase in COVID-19 incidence by 0.92% (95%CI: 0.63-1.23%). A U-shaped temporal change of association was examined, with the strongest association occurring in the end of 2021 and the weakest association occurring in September 1, 2020 and July 1, 2021. Vaccination rate was identified as a significant cause for the association heterogeneity, with a stronger association occurring at a higher vaccination rate. Short-term exposure to PM2.5 and COVID-19 incidence presented positive association in the United States, which exhibited a significant spatiotemporal heterogeneity with strong association in the eastern and middle regions and with a U-shaped temporal change.

The Knowledge, Attitude, and Perception of Needlestick Injuries Among Dental Students in Riyadh, Kingdom of Saudi Arabia: A Cross-Sectional Survey.

Needlestick injuries (NSIs) represent a significant source of bloodborne viruses in the healthcare sector, particularly in dentistry. Developing effective infection control programs necessitates access to surveillance data. A comprehensive evaluation, encompassing human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and serological testing, is crucial due to the potential lack of immediate symptoms in infected patients. It is essential to verify hepatitis B and tetanus immunization statuses and seek guidance from infectious disease experts for post-exposure prophylaxis. Aimand objective: This study aims to assess the knowledge, attitudes, and perceptions of NSIs among dentistry students in Riyadh, Saudi Arabia. Conducted during the 2023-2024 academic year in Riyadh, Saudi Arabia, this cross-sectional study evaluated the knowledge, attitudes, and perceptions of undergraduate dental medicine students regarding NSIs. Ethical approval was obtained, and informed consent was meticulously collected. Before participation, potential subjects were furnished with a comprehensive information sheet outlining the study's purpose, the survey's nature, expected duration, and potential risks or benefits. The document emphasized their unequivocal right to withdraw from the study at any point without any adverse consequences. Data collection relied on an online survey administered to third and final-year dental students selected from specific universities. This selection criterion ensured that participants were directly relevant to the dental education context under investigation. Careful exclusions were made to minimize potential bias, particularly by excluding students from academic years other than the third and final years, thus maintaining a specific focus on this subgroup. Data analysis primarily compared NSI occurrences and awareness based on dental college and academic year. Detailed findings are presented in the results section. The study unveiled high vaccination rates (95.23%) and significant levels of education regarding bloodborne infections (81.38%) among participants. However, it was noteworthy that 72.72% believed their vaccinations offered complete protection. Only 47.18% believed that wearing surgical gloves reduced the risk of NSIs, while a substantial majority (93.07%) opposed the practice of needle recapping. Moreover, 76.19% demonstrated knowledge of post-exposure prophylaxis, indicating room for improvement in healthcare safety practices. Statistical analysis identified significant associations between the Dental College attended and both NSI occurrence (χ²=12.164, p=0.058) and awareness (χ²=14.629, p=0.023). Conversely, the academic year exhibited no significant relationship with either NSI occurrence (χ²=1.2, p=0.55) or awareness (χ²=0.44, p=0.8). Additionally, the study revealed non-normal distributions for both NSI occurrence (p<0.001) and awareness (p<0.001) among participants. In conclusion, this study underscores the pivotal role of awareness in mitigating NSI occurrences among dental students. Irrespective of their academic year, heightened awareness significantly correlated with reduced NSI incidence. These findings bear significant implications for dental education and practice, emphasizing the imperative need for comprehensive education and awareness initiatives to bolster healthcare safety among dental professionals.

SOURCES OF VACCINE INFORMATION: MISGIVINGS AND TRUST ISSUES AMONG OLDER ADULTS IN NORTH DAKOTA

Abstract Older adults consistently have relatively high vaccination rates. What is not fully understood is how trust in immunization information sources impacts vaccine decision-making among older adults. This study examines older adults’ perceptions and decision-making processes for vaccines such as influenza, pneumonia, shingles, and COVID-19. Older adults (65+) in North Dakota (N=51) who participated in a larger survey study on vaccine behaviors voluntarily agreed to participate in a follow-up phone interview (November 2022-January 2023). Qualitative, semi-structured phone interviews focused on access, knowledge, and decision about vaccines. Interview transcripts were inductively coded for emergent themes related to trust. Three themes were identified: implicit trust in information sources, uncertainty who to trust for vaccine information, and regaining trust in information sources. Implicit trust focused on familiarity with sources of information (such as inherently trusting family members), source expertise (such as doctor recommendations), and reliability of sources (including if the source always provides accurate information). The second theme, uncertainty who to trust, stressed confusion over source inconsistency, such as changing positions on vaccines, or having opposing sources that both seem to be trustworthy. The final theme, regaining trust in information sources, highlighted if and how trust in a source of vaccine information could be recovered, including transparency, sincerity, and verifying immunization information through obtaining a second opinion. These findings contribute to the understanding of vaccine decision-making among older adults and provide focus areas for interventions to address lack of trust in information sources and improve immunization rates for this population.

Prevention of influenza complications in patients with liver disease: a retrospective cohort study.

Patients with chronic liver disease are highly prone to acquiring influenza infection diseases and experiencing associated complications. National and international guidelines recommend the influenza vaccine for patients with liver disorders to reduce the risk of influenza complications. Our study aims to evaluate the risk of flu complications faced by patients with liver disease and assess influenza vaccination coverage. The archive of hospital discharge forms was used to define the list of Apulian patients with liver disease, considering data from 2017 through 2022. The vaccination status of these patients was assessed via data collected from the Regional Immunization Database. We focused on influenza vaccine shots administered during the 2020/21, 2021/22, and 2022/23 flu seasons. A declining trend across the flu seasons was observed, with a VC of 49.5% in the 2020/21 flu season, 48.1% in the 2021/22 season, and 45.0% in the 2022/23 season. Subjects with multiple comorbidities have higher vaccination rates. Additionally, the multivariate models demonstrate that vaccination compliance increases with age and is strongly associated with having received a previous influenza vaccine shot. The VC rates reported in our study are unsatisfactory and did not reach the minimum achievable goal (75%) the Italian Ministry of Health set. A multifactorial approach is required to raise the immunization rates and therefore protect the patients from the influenza-associated risk of collateral liver damage; the role of gastroenterologists and hepatologists is crucial, as their responsibilities should extend beyond patient care to the prevention of complications after infectious diseases.

Effect of Covid19 Pandemic on Preventive Vaccinations Among Patients with The End Stage Kidney Disease At New York Harbor VA Medical Center

Background: The COVID-19 pandemic revealed challenges and barriers in achieving high preventive vaccination rates. This study aimed to explore the effects of the pandemic on vaccination rates in patients with end stage kidney disease (kidney dialysis) patients in New York City. These patients compose a challenging cohort as their transplant optimization includes routine vaccinations including pneumococcal, flu, Hepatitis A and B, meningococcal, H flu, HPV, Tdap, RZV, and Covid. Materials and Methods: This study population consisted of 142 participants from two Veteran Affairs hospitals in New York City. Vaccination and demographic information were compiled via EMR and compared to long term US vaccination rates using exact binomial tests. Secondary analysis using generalized estimating equations was used to compare vaccination rates pre- and post-pandemic within the Brooklyn VA population controlling for demographic variables. Results: The combined vaccination rate for the post-pandemic period was found to be significantly lower than the pre-pandemic rate in the general US population for several vaccines, including Hepatitis A (CI: 0.088, 0.098; p&lt;0.001), Influenza (CI: 0.68, 0.69, p&lt;0.001), Meningococcal (CI: 0.34, 0.35; p&lt;0.001), MMR (, CI: 0.51, 0.52; p=0.001), and TDAP (CI: 0.18, 0.20; p&lt;0.001). Secondary analysis using generalized estimating equations controlling for age, race, and time on dialysis within the Brooklyn VA population revealed increases in post-pandemic vaccination rates for Shingles (subunit; B=1.03; 95% Wald CI: .178, 1.87; p=.018) and Hepatitis B (B=-.739; 95% Wald CI: .084, 1.39; p=.027), while a significant decrease was observed for Hep A (B=-2.65; 95% Wald CI: -4.4, -.90; p=.003). Conclusion: This data demonstrates that post-pandemic vaccination rates in VA dialysis patients is lower than the past 10-year US average for several vaccines including Hepatitis A, Influenza, Meningococcal, MMR, and TDAP. Mixed effects of pre- and post-pandemic vaccination rates within the Brooklyn VA were also found with a decreased vaccination rate for Hepatitis A, and increased rates for Shingles and Hepatitis B. Further study is needed to evaluate pandemic’s effect on these rates, disease prevention, and identify the reasons contributing to vaccine hesitancy vs. acceptance.

Looking beyond vaccines: Cultural tightness-looseness moderates the relationship between immunization coverage and disease prevention vigilance.

Advancements in vaccination technologies mitigate disease transmission risks but may inadvertently suppress the behavioral immune system, an evolved disease avoidance mechanism. Applying behavioral immune system theory and utilizing robust big data analytics, we examined associations between rising vaccination coverage and government policies, public mobility, and online information seeking regarding disease precautions. We tested whether cultural tightness-looseness moderates the relationship between mass immunization and disease prevention vigilance. Comprehensive time series analyses were conducted using American data (Study 1) and international data (Study 2), employing transfer function modeling, cross-correlation function analysis, and meta-regression analysis. Across both the US and global analyses, as vaccination rates rose over time, government COVID-19 restrictions significantly relaxed, community mobility increased, and online searches for prevention information declined. The relationship between higher vaccination rates and lower disease prevention vigilance was stronger in culturally looser contexts. Results provide initial evidence that mass immunization may be associated with attenuated sensitivity and enhanced flexibility of disease avoidance psychology and actions. However, cultural tightness-looseness significantly moderates this relationship, with tighter cultures displaying sustained vigilance amidst immunization upticks. These findings offer valuable perspectives to inform nuanced policymaking and public health strategies that balance prudent precautions against undue alarm when expanding vaccine coverage worldwide.

The Western Australian experience of COVID-19 after the borders reopened: evaluation of public health modelling predictions.

Western Australia (WA) serves as a unique global case study on the impact of coronavirus disease 2019 (COVID-19) on an isolated, prepared and highly vaccinated population. This study builds upon the study performed by House et al. through an extended data set. To examine the impact of COVID-19 at the only quaternary hospital in WA following the border opening from 3 March to 17 July 2022. A total of 257 adults were admitted with COVID-19 under either respiratory or the intensive care unit (ICU). Admission numbers, disease severity, ICU admission, prevalence of COVID-19 deterioration risk factors, length of stay and mortality. A total of 257 patients were admitted with COVID-19, under respiratory (81.7%) and ICU (18.3%). COVID-19 was the primary reason for admission for 67.7%. Ten patients died during the study, with seven deaths attributed to COVID pneumonitis. COVID-19 severity was 37.4% mild, 37.0% moderate, 18.3% severe and 7.4% critical. Risk factors for requiring ICU included incomplete immunisation status (P = 0.011), chronic kidney disease (P = 0.008) and Aboriginal and Torres Strait Islander (ATSI) ethnicity. The WA Department of Health predicted that the number of hospitalisations and ICU cases were significantly higher than the actual number of cases. The number of hospitalisations and ICU COVID-19 cases were significantly less than predicted, likely due to high population vaccination rates prior to border opening. The main risk factors for COVID-19 severity were incomplete immunisation and ATSI ethnicity.

Healthcare system efficiency and drivers: Re-evaluation of OECD countries for COVID-19

The Covid-19 pandemic has raised concerns about the resilience of health systems. The aim of this study is twofold: i) to measure and compare the resilience of health system efficiency of OECD countries before and during Covid-19 and ii) to determine the healthcare efficiency drivers (e.g., socio-economic) of health system performance. Using a dataset of 31 OECD countries for 2018 and 2020, we first estimate bias-adjusted efficiency scores, followed by a double bootstrap truncated regression procedure to study the drivers associated with health system efficiency. We find that the health system efficiency overall score decreased among OECD countries during the Covid-19 pandemic compared to before Covid-19. Estonia and Japan retained their full efficiency scoreduring Covid-19. We find a negative association between health system efficiency and unemployment rate, share of health expenditure in GDP, and share of population over 65. Conversely, high vaccination rates contribute positively to health system efficiency during the Covid-19 period.

Motivations for Adolescent COVID-19 Vaccination: A Comparative Study of Adolescent and Caregiver Perspectives in Germany.

Given the crucial role of vaccination in halting the COVID-19 pandemic, it is imperative to understand the factors that motivate adolescents to get vaccinated. We surveyed adolescents and their accompanying guardians scheduled to receive a COVID-19 vaccination (Comirnaty) in an urban region in Germany in mid-2021 regarding their motivation for getting vaccinated and collected data on their sociodemographic characteristics, medical history, vaccination status, and any history of COVID-19 infection in the family. We also queried information strategies related to the SARS-CoV-2 pandemic. Motivations for getting vaccinated were similar among adolescents and their parents. The primary reasons for vaccination were protection against SARS-CoV-2-related illness and gaining access to leisure facilities. This was not influenced by gender, health status, migration background, or the presence of chronic or acute diseases. The percentage of parents who had received SARS-CoV-2 immunization and the proportion of parents with a high level of education were higher among study participants than in the general population. Adolescents were especially willing to be vaccinated if they came from a better educational environment and had a high vaccination rate in the family. Emphasizing the importance of vaccination among all segments of the population and removing barriers to vaccines may lead to an ameliorated acceptance of COVID-19 vaccines.

Evolution of neutralizing antibodies through vaccination and breakthrough infections in the era of COVID-19 endemicity.

Despite a high vaccination rate, the COVID-19pandemic continues with immune-evading Omicron variants. The success of additional antigenic stimulation through breakthrough infection (BI)and updated vaccination in overcoming antigenic imprinting needs to be determined. Participants in a long-term follow-up cohort of healthcare worker (HCW)vaccinee were categorized according to their infection/vaccination status. Anti-SARS-CoV-2spike/nucleocapsid protein antibodies were measured, and plaque reduction neutralization tests (PRNTs)against wild-type (WT),BA.5,BN.1,and XBB.1.5were conducted. The neutralization activity of intravenous immunoglobulin (IVIG)products was evaluated to assess the immune status of the general population. Ninety-fiveHCWs were evaluated and categorized into seven groups. The WT PRNT ND50 value was highest regardless of infection/vaccination status, and groups with recent antigenic stimulation showed high PRNT titers overall. Groups with double Omicron stimulation, either by BI plus BA.4/5bivalent vaccination or repeated BI, exhibited significantly higher BA.5and BN.1 PRNT to WT PRNT ratios than those with single Omicron stimulation. Overall group immunity was estimated to be boosted in January 2023, reflecting the effect of the BA.4/5bivalent booster and additional BIs, but slightly declined in June 2023. A substantial increase in the antibody concentrations of IVIG products was noticed in 2022, and recently produced IVIG products exhibited a substantial level of cross-reactive neutralizing activity against emerging variants. Neutralizing activity against emerging variants could be enhanced by repeated antigenic stimulation via BI and/or updated vaccination. Overall group immunity was elevated accordingly, and IVIG products showed substantial activity against circulating strains.

Control Strategies for the COVID-19 Infection Wave in India: A Mathematical Model Incorporating Vaccine Effectiveness

The waning effectiveness of the coronavirus disease-2019 (COVID-19) vaccines and the emergence of new variants have given rise to the possibility of future outbreaks of the infection. COVID-19 has caused more than 43 million reported cases and 526,000 deaths in India so far, and the disease spread is active again despite mass vaccinations. In this article, we present a compartmental epidemiological model incorporating vaccinations with dose-dependent effectiveness. We study a possible sudden outbreak of SARS-CoV2 variants in India, bring out the associated predictions for various vaccination rates, and point out optimum control measures. Our model simulation numbers for the total infected are close to the seroprevalance data in August 2021, and our results show that second dose vaccine effectiveness is the most sensitive parameter in the future evolution of the disease. A combination of vaccination and social distancing is the key to tackling the current situation and for the coming few months. Our simulation shows that social distancing measures show better control over disease spread than higher vaccination rates, and disease spread does not appear to rise sharply in the near future unless a new variant emerges.

Healthcare Systems and COVID-19 Mortality in Selected OECD Countries: A Panel Quantile Regression Analysis.

The pandemic caused by coronavirus disease 2019 (COVID-19) has exerted an unprecedented impact on the health of populations worldwide. However, the adverse health consequences of the pandemic in terms of infection and mortality rates have varied across countries. In this study, we investigate whether COVID-19 mortality rates across a group of developed nations are associated with characteristics of their healthcare systems, beyond the differential policy responses in those countries. To achieve the study objective, we distinguished healthcare systems based on the extent of healthcare decommodification. Using available daily data from 2020, 2021, and 2022, we applied quantile regression with non-additive fixed effects to estimate mortality rates across quantiles. Our analysis began prior to vaccine development (in 2020) and continued after the vaccines were introduced (throughout 2021 and part of 2022). The findings indicate that higher testing rates, coupled with more stringent containment and public health measures, had a significant negative impact on the death rate in both pre-vaccination and post-vaccination models. The data from the post-vaccination model demonstrate that higher vaccination rates were associated with significant decreases in fatalities. Additionally, our research indicates that countries with healthcare systems characterized by high and medium levels of decommodification experienced lower mortality rates than those with healthcare systems involving low decommodification. The results of this study indicate that stronger public health infrastructure and more inclusive social protections have mitigated the severity of the pandemic's adverse health impacts, more so than emergency containment measures and social restrictions.

Vaccination, immunity, and the changing impact of COVID-19 on infant health

In utero exposure to COVID-19 infection may lead to large intergenerational health effects. The impact of infection exposure has likely evolved since the onset of the pandemic as new variants emerge, immunity from prior infection increases, vaccines become available, and vaccine hesitancy persists, such that when infection is experienced is as important as whether it is experienced. We examine the changing impact of COVID-19 infection on preterm birth and the moderating role of vaccination. We offer the first plausibly causal estimate of the impact of maternal COVID-19 infection by using population data with no selectivity, universal information on maternal COVID-19 infection, and linked sibling data. We then assess change in this impact from 2020 to 2023 and evaluate the protective role of COVID-19 vaccination on infant health. We find a substantial adverse effect of prenatal COVID-19 infection on the probability of preterm birth. The impact was large during the first 2 y of the pandemic but had fully disappeared by 2022. The harmful impact of COVID-19 infection disappeared almost a year earlier in zip codes with high vaccination rates, suggesting that vaccines might have prevented thousands of preterm births. The findings highlight the need to monitor the changing consequences of emerging infectious diseases over time and the importance of mitigation strategies to reduce the burden of infection on vulnerable populations.

2393. Factors Associated with Time to COVID-19 Vaccination among People with HIV

Abstract Background The COVID-19 pandemic has significantly impacted at-risk populations, including people with HIV/AIDS (PWHA). Several reports indicate a higher risk of SARS-CoV-2 infection and mortality in PWHA compared to the general population. Despite an effective vaccine, PWHA with low CD4 count develop a weak immune response and are at risk of severe breakthrough infections. Vaccination gaps have been identified amongst PWHA, but factors associated with time to mRNA COVID-19 vaccine initiation and first booster have not been studied. Methods PWHA age ≥ 18 years, in HIV care at an urban clinic, and who completed the primary series of COVID-19 vaccines were invited to complete an online survey. Socio-demographic and clinical characteristics and COVID-19 vaccination motivators were assessed and complemented by a review of medical records. Statements on motivators to vaccination were rated on a 5-point Likert scale treated as ordinal data (minimum score 19, maximum 95). Factors associated with time to first COVID-19 vaccine and first booster were analyzed by the Kaplan-Meier method. Results A total of 129 patients enrolled; 83% (108/129) received the COVID-19 booster. Mean age was 50.3 (±10.9) years; 26.4% were female; 54.3% were Black, and 34.1% were White; 91.5% were non-Hispanic. The mean nadir CD4 count throughout their care was 309.4 (±245.6) cells/mm3. The mean time to first COVID-19 vaccine dose was 2.8 (±1.8) months from December 2020 (Pfizer-BioNTech vaccine approval), and time to first booster was 9.9 (±3.8) months from the date of the first vaccine. Factors associated with quicker uptake of the first dose included being ≥ 51 years of age (p=0.001), White race (p=0.027), male sex (p=0.023), and gay/lesbian identity (p=0.014) (Fig 1). Factors associated with quicker uptake of the first booster included being ≥ 51 years of age (p &amp;lt; 0.000) and a COVID-19 motivators’ survey score &amp;gt; 69 (p=0.017) (Fig 2). Figure 1. Kaplan-Meier Curves for Time to COVID-19 First Dose Vaccination Among People Living with HIV/AIDS Receiving HIV Care through Penn Medicine. Figure 2. Kaplan-Meier Curves for Time to COVID-19 First Booster Vaccination Among People Living with HIV/AIDS Receiving HIV Care through Penn Medicine. Conclusion We found high rates of COVID-19 booster vaccination among PWHA. White and male patients got vaccinated quicker in the early phase of the pandemic; however, race and age-based inequities resolved in the later phase of the pandemic. Motivation to vaccination emerged as a facilitator for uptake of booster vaccines. Disclosures All Authors: No reported disclosures

1168. Cost-effectiveness of high-dose quadrivalent influenza vaccine versus standard-dose quadrivalent influenza vaccine for older people in a country with high influenza vaccination rate

Abstract Background The high-dose quadrivalent formulation (QIV-HD) has shown improved protection against influenza and its complications in older adults. We aimed to evaluate the cost-effectiveness of QIV-HD compared with QIV-SD among Korean adults aged ≥ 65 years in reducing influenza-related disease burden. Methods We evaluated the 2016/2017 and 2017/2018 seasons and their average values using a static decision tree model. For the main analysis, hospitalization was defined as cardiorespiratory disease-related. The difference in efficacy between standard-dose (SD) and high-dose (HD) was calculated based on the results of a clinical trial comparing Fluzone® High-Dose Vaccine and Fluzone® Vaccine in older adults. Incremental cost-effectiveness ratios (ICERs) were assessed from the healthcare system perspective. A discount rate of 4.5% was applied to life-year-gained (LYG) values and utilities. We performed deterministic and probabilistic sensitivity analyses to account for both epidemiological and economic sources of uncertainty. Results In the analysis of the 2017/2018 season, the QIV-HD strategy generated an excess of 0.003953 quality-adjusted life-years (QALYs) compared with QIV-SD. The ICER was 6,467.56 USD/QALY. For the 2016/2017 season, QIV-HD caused an excess of 0.003272 QALYs and ICER was 7,902.46 USD /QALY. From the average data of the two seasons, an excess of 0.003561 QALYs were generated and the ICER was 7,190.44 USD/QALY. In the one-way sensitivity analysis, the parameters with the greatest impact on the results were the relative VE of QIV-HD vs. QIV-SD against influenza-associated hospitalization. PSAs were conducted for the 2016/2017 and 2017/2018 seasons, with the cost of the QIV-HD vaccine fixed at 50,000 KRW (40.48 USD) or 65,000 KRW (52.62 USD). The results showed that for a WTP threshold of 24,692.36 USD/QALY, the probability that QIV-HD is a cost-effective option for the Korean health system is 100% in all seasons and QIV-HD vaccine costs considered. Conclusion From the healthcare system perspective, QIV-HD was a more cost-effective vaccination option in reducing influenza-related disease burden and healthcare costs in Koreans aged ≥ 65 years compared with QIV-SD. Disclosures Hee Jin Cheong, M.D., Ph.D., Sequiris: Advisor/Consultant Jung-Min Lee, n/a, Sanofi Korea: Stocks/Bonds