Vaccine Deployment Research Articles

Monovalent SARS-COV-2 mRNA vaccine using optimal UTRs and LNPs is highly immunogenic and broadly protective against Omicron variants.

The emergence of highly transmissible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that are resistant to the current COVID-19 vaccines highlights the need for continued development of broadly protective vaccines for the future. Here, we developed two messenger RNA (mRNA)-lipid nanoparticle (LNP) vaccines, TU88mCSA and ALCmCSA, using the ancestral SARS-CoV-2 spike sequence, optimized 5' and 3' untranslated regions (UTRs), and LNP combinations. Our data showed that these nanocomplexes effectively activate CD4+ and CD8+ T cell responses and humoral immune response and provide complete protection against WA1/2020, Omicron BA.1 and BQ.1 infection in hamsters. Critically, in Omicron BQ.1 challenge hamster models, TU88mCSA and ALCmCSA not only induced robust control of virus load in the lungs but also enhanced protective efficacy in the upper respiratory airways. Antigen-specific immune analysis in mice revealed that the observed cross-protection is associated with superior UTRs [Carboxylesterase 1d (Ces1d)/adaptor protein-3β (AP3B1)] and LNP formulations that elicit robust lung tissue-resident memory T cells. Strong protective effects of TU88mCSA or ALCmCSA against both WA1/2020 and VOCs suggest that this mRNA-LNP combination can be a broadly protective vaccine platform in which mRNA cargo uses the ancestral antigen sequence regardless of the antigenic drift. This approach could be rapidly adapted for clinical use and timely deployment of vaccines against emerging and reemerging VOCs.

Achieving COVID-19 and Routine Immunization Data Systems Integration on the Electronic Management of Immunization Data System in Nigeria.

In 2021, Nigeria developed a novel Electronic Management of Immunization Data (EMID) system to address COVID-19 data management challenges and ensure the successful implementation of its COVID-19 vaccine deployment plan. The EMID system was envisioned to be interoperable with the DHIS2 national data management system and serve as a gateway into the integration of other primary health care (PHC) service data management. However, the EMID system faced challenges, including inability to filter reports, missing or loss of data, and difficulties with data synchronization, which curtailed its potential to meet the country's needs for COVID-19 data management and negatively impacted system scalability to enable integration with other PHC data systems. Multilayered stakeholder interviews were conducted to determine the optimal functionality requirements for the EMID system. Based on these findings, an optimization plan was designed and implemented to address identified gaps and create a more stable and scalable system to enable further system integrations. Following optimization, a routine immunization module was developed and integrated with the EMID system as a first step to achieving an integrated data management system for PHC services in Nigeria. The integrated system currently provides an opportunity to address data fragmentation and strengthen PHC service delivery in Nigeria. By allowing 1 health care worker to deliver both vaccinations, there is also potential for reduction in cost and redundancies, informing redistribution of the health workforce and overall system strengthening. The journey from the initial challenges faced by the EMID system to the development of an integrated system for PHC services in Nigeria has been a transformative one. Through a thorough optimization process, training and capacity-building, stakeholder-driven improvements, and an elicitation exercise, the EMID system has evolved into a powerful tool for addressing data fragmentation and enhancing public health service delivery in the country.

Awareness, Coverage, and Barriers to COVID-19 Vaccination Among Undergraduate Students in Nigeria

BACKGROUND: With the resumption of physical learning activities across Nigeria's higher education institutions, tertiary-level students, a prioritized group according to the WHO SAGE in the deployment of the COVID-19 vaccines, face circumstances that necessitate widespread vaccination coverage among them. This is critical in view of vaccine hesitancy attitude and low vaccination coverage that has been reported among this subpopulation and the larger Nigerian populace. Surmounting these barriers is necessary to achieving a successful national vaccination program and for future pandemic preparedness and response. To this end, this study aimed to assess Nigerian undergraduate students' knowledge, coverage, and barriers to COVID-19 vaccination. METHODS: A cross-sectional survey of Nigerian undergraduates was conducted in October 2021, using an online questionnaire and a non-probability convenient sampling technique. The questionnaire included sections on respondents' demographic characteristics, COVID-19 vaccine awareness, coverage, barriers, and recommendations. A total of 326 respondents electronically completed and returned the informed consent form along with the questionnaire. Microsoft Excel spreadsheet and statistical package for the social sciences (SPSS) version 25 were used to code and analyze the data, respectively. RESULTS: The overall awareness of COVID-19 vaccines among the sampled students were high, with 62.3% having good knowledge, 20.9% having average knowledge, and 16.9% having poor knowledge. However, the majority of the respondents (81.3%) had not received the vaccines. The most prominent barrier to vaccination was misinformation about vaccine safety (23.6%). Opening vaccination centers on campuses (18.6%), demonstrating vaccine effectiveness and safety (18.7%), and organizing awareness campaigns (17.2%) were the most frequently recommended actions. CONCLUSION: Most respondents were aware of the availability and potential benefits of COVID-19 vaccines; however, coverage remained extremely low. Our findings emphasize the importance of addressing vaccination barriers by public health stakeholders to achieve optimal COVID-19 vaccine coverage.

The genomic epidemiology of Neisseria meningitidis carriage from a randomised controlled trial of 4CMenB vaccination in an asymptomatic adolescent population

Oropharyngeal carriage of Neisseria meningitidis is frequent during adolescence, representing a major source of invasive meningococcal disease. This study examined the impact of a serogroup B vaccination (Bexsero, GSK 4CMenB) programme on adolescent N.meningitidis carriage using genomic data. A total 34,489 oropharyngeal samples were collected as part of a state-wide cluster randomised-controlled trial in South Australia during 2017 and 2018 (NCT03089086). Samples were screened for the presence of N.meningitidis DNA by porA PCR prior to culture. Whole genome sequencing was performed on all 1772N.meningitidis culture isolates and their genomes were analysed. Unencapsulated meningococci were predominant at baseline (36.3% of isolates), followed by MenB (31.0%), and MenY (20.5%). Most MenB were ST-6058 from hyperinvasive cc41/44, or ST-32 and ST-2870 from cc32. For MenY, ST-23 and ST-1655 from cc23 were prevalent. Meningococcal carriage was mostly unchanged due to the vaccination programme; however, a significant reduction in ST-53 capsule-null meningococci prevalence was observed in 2018 compared to 2017 (OR=0.52; 95% CI: 0.30-0.87, p=0.0106). This effect was larger in the vaccinated compared to the control group (OR=0.37; 95% CI: 0.12-0.98, p=0.0368). While deployment of the 4CMenB vaccination did not alter the carriage of hyperinvasive MenB in the vaccinated population, it altered the carriage of other N.meningitidis sequence types following the vaccination program. Our findings suggest 4CMenB vaccination is unlikely to reduce transmission of hyperinvasive N.meningitidis strains and therefore ongoing targeted vaccination is likely a more effective public health intervention. This work was funded by GlaxoSmithKline Biologicals SA.

Awareness, Coverage, and Barriers to COVID-19 Vaccination among Undergraduate Students in Nigeria

Background: With the resumption of physical learning activities across Nigeria's higher education institutions, tertiary-level students, a priority group in the deployment of the COVID-19 vaccines according to the WHO SAGE, face circumstances that necessitate widespread vaccination coverage among them. This study aimed to assess Nigerian undergraduate students' knowledge, coverage, and barriers to COVID-19 vaccination. Method: A cross-sectional survey of Nigerian undergraduates was conducted in October 2021, using an online questionnaire and a combined simple random and snowballing sampling technique. The questionnaire included sections on respondents' demographic characteristics, COVID-19 vaccine awareness, coverage, barriers, and recommendations. A total of 326 respondents electronically completed and returned the informed consent form along with the questionnaire. The data obtained were analyzed using the statistical package for the social sciences (SPSS) version 25. Results: The overall awareness of COVID-19 vaccines among the sampled students was high; with 62.3%, 20.9%, and 16.9% having good, average, and poor levels of knowledge respectively. However, a majority of the respondents (81.3%) had not received the vaccines. The most prominent barrier to vaccination was misinformation about vaccine safety (23.6%). Opening vaccination centers on campuses (18.6%), demonstrating vaccine effectiveness and safety (18.7%), and organizing awareness campaigns (17.2%) were the most frequently recommended actions. Conclusion: Most respondents were aware of the availability and potential benefits of COVID-19 vaccines; however, coverage remained extremely low. Our findings emphasize the importance of addressing vaccination barriers by public health stakeholders to achieve optimal COVID-19 vaccine coverage.

COVID-19 vaccination implementation in 52 African countries: trajectory and implications for future pandemic preparedness

IntroductionTo end the COVID-19 pandemic, the WHO set a goal in 2021 to fully vaccinate 70% of the global population by mid-2022. We projected the COVID-19 vaccination trajectory in 52...

Breakthrough infections and acceptance of COVID-19 vaccine boosters: A survey analysis.

This Short Communication explores the effect of COVID-19 breakthrough infections (defined as a COVID-19 diagnosis after vaccination) on the willingness of previously vaccinated individuals to receive ongoing vaccine boosters. Specifically, we examine unique effects for three different breakthrough infection experiences, including the participant themselves, a close member of their family, and a friend/coworker. A representative, web-based survey of 600 adults in the state of Florida was fielded in March/April of 2022. Among the respondents, 455 had been vaccinated against COVID-19. Their responses were analyzed for this study using both descriptive and inferential statistical methods. Individuals who have experienced a personal breakthrough infection are two times less likely to receive annual vaccine boosters, ceteris paribus. However, there is not a statistically significant relationship between vaccine acceptance and breakthrough infections among close family members or friends/coworkers. We also found a very strong relationship between vaccine decisions and confidence in public health guidance. Our findings show that confidence in public health guidelines is the most compelling determinant of vaccine acceptance, but breakthrough infections also have a significant impact on individual decision making when it comes to ongoing vaccination. Going forward, public health messaging should directly account for this correlation in order to effectively maintain vaccination levels. The COVID-19 pandemic marked a turning point in the development and deployment of mRNA vaccines. This study contributes to innovation in health communication research by examining how breakthrough infections in these vaccinated individuals impacts ongoing booster shot acceptance. The findings of this study contribute to the nascent and ongoing development of baseline research in this area.

Behavioural and social drivers of COVID-19 vaccination in Vietnam: a scoping review

BackgroundUnderstanding of the behavioural and social drivers (BeSD) of vaccination is key to addressing vaccine hesitancy and accessibility issues. Vietnam’s national COVID-19 vaccination programme resulted in high uptake of primary...

Cellular Mechanisms Associated with Suboptimal Immune Responses to Sars-Cov-2 Bivalent Booster Vaccination in Patients with Multiple Myeloma

Background: In response to the ever-evolving challenges posed by the antigenically diverse Omicron variants, the deployment of bivalent mRNA booster vaccines encompassing both the ancestral (WA1) and Omicron BA.5 spike components was initiated in fall of 2022. The real-world impact of these bivalent vaccines is largely unknown in patients with Multiple Myeloma (MM). We characterize the humoral and cellular immune responses in patients with MM before and after receiving the bivalent booster implementing cutting edge methodologies to identify patterns associated with continuing vulnerability in the current post-pandemic era. Methods: We studied the humoral and cellular immune responses before and after bivalent booster immunization in 48 MM patients. Spike binding IgG antibody levels were measured by SARS-CoV-2 spike binding ELISA and neutralization capacity was assessed by a SARS-CoV-2 multi-cycle microneutralization assay. We measured spike specific T cell function using the QuantiFERON SARS-CoV-2 (Qiagen) assay as well as flow cytometry-based T cell assays quantifying interferon-gamma (IFNg) production. In a subset of 38 patients, immune profiling was performed using high-dimensional flow cytometry. The frequencies of dendritic cells (DCs), B cells, Natural Killer (NK) cells and T follicular helper cells (TFH) were compared between responders and non-responders. Results: The serological effect of the bivalent vaccination in MM patients is nuanced with the overall cohort not demonstrating a significant increase post bivalent vaccination (median 196 AU/mL prior to bivalent to median 276 post bivalent p=0.11). The lack of antibody response was driven by patients undergoing anti-CD38 and anti-BCMA antibody therapy as compared to MM patients undergoing other therapies who demonstrated a significant increase in antibody levels post vaccination (p=0.021). Patients on anti-CD38 and anti-BCMA antibody therapy also did not significantly increase neutralizing capacity to WA1 (p=0.42) or BA.5 omicron strain (p=0.48) while MM patients on other therapies benefitted significantly, as illustrated by the increased neutralizing capacity of WA1 (p=0.024) and BA.5 (p=0.0055 Figure 1A). In addition to quantifying antibody responses, we profiled T cell responses using our published flow cytometry method using WA1 anti-S peptides as well as the QuantiFERON SARS-CoV-2 RUO assay (Qiagen). Spike reactive T cell responses significantly correlated with anti-Spike IgG levels in MM patients (r 2=0.49, p<0.001), WA1 neutralizing ID50 (R 2 = 0.6, p<0.01) and BA.5 neutralizing ID50 (R 2= 0.54, p=0.01) reinforcing the fact that T cell compensation is lacking in MM patients. We separated the lowest quantile (patients with Anti-S IgG <156 AU/mL) to delineate suboptimal producing patients compared to the remaining MM anti-S producing patients. Non-responders exhibited deficiencies in immune populations involved in robust antibody production including lower frequency of CD1c+ DCs (p=0.02 Figure 1B), B Cells (p<0.01 Figure 1B) and circulating CXCR3-CCR4+TFH cells (p<0.01 Figure 1B). Furthermore, immature NK cells were the predominant population in non-responders, while responders had more cytotoxic mature NK phenotype (p<0.01 Figure 1B) after bivalent vaccination. Conclusions: Our study highlights the varying immune responses observed in MM patients after receiving bivalent COVID-19 vaccination. Specifically, a subgroup of MM patients undergoing anti-CD38 and anti-BCMA therapy experience impairments in immune cells such DCs, B cells, NK cells and TFH cells, leading to an inability to generate adequate antibody and T cell responses to vaccinations. Our results indicate that the QuantiFERON SARS-CoV-2 assay could be deployed for clinical use bridging the need for suitable laboratory tests to measure SARS-CoV-2 specific T cell responses. Ongoing research will further investigate whether the compromised immune machinery and diminished T cell activity identified in this study can serve as discriminators for identifying MM patients at high risk of infectious complications stemming from anti-BCMA therapies. Such insights will aid in developing targeted strategies to address these challenges and improve patient outcomes.

Erythromycin, retapamulin, pyridoxine, folic acid, and ivermectin inhibit cytopathic effect, papain-like protease, and MPRO enzymes of SARS-CoV-2.

Although tremendous success has been achieved in the development and deployment of effective COVID-19 vaccines, developing effective therapeutics for the treatment of those who do come down with the disease has been with limited success. To repurpose existing drugs for COVID-19, we previously showed, qualitatively, that erythromycin, retapamulin, pyridoxine, folic acid, and ivermectin inhibit SARS-COV-2-induced cytopathic effect (CPE) in Vero cells. This study aimed to quantitatively explore the inhibition of SARS-CoV-2-induced CPE by erythromycin, retapamulin, pyridoxine, folic acid, and ivermectin and to determine the effect of these drugs on SARS-CoV-2 papain-like protease and 3CL protease (MPRO) enzymes. Neutral red (3-amino-7-dimethylamino-2-methyl-phenazine hydrochloride) cell viability assay was used to quantify CPE after infecting pre-treated Vero cells with clinical SARS-Cov-2 isolates. Furthermore, SensoLyte® 520 SARS-CoV-2 papain-like protease and SensoLyte® 520 SARS-CoV-2 MPRO activity assay kits were used to evaluate the inhibitory activity of the drugs on the respective enzymes. Erythromycin, retapamulin, pyridoxine, folic acid, and ivermectin dose-dependently inhibit SARS-CoV-2-induced CPE in Vero cells, with inhibitory concentration-50 (IC50) values of 3.27 µM, 4.23 µM, 9.29 µM, 3.19 µM, and 84.31 µM, respectively. Furthermore, erythromycin, retapamulin, pyridoxine, folic acid, and ivermectin dose-dependently inhibited SARS-CoV-2 papain-like protease with IC50 values of 0.94 µM, 0.88 µM, 1.14 µM, 1.07 µM, and 1.51 µM, respectively, and inhibited the main protease (MPRO) with IC50 values of 1.35 µM, 1.25 µM, 7.36 µM, 1.15 µM, and 2.44 µM, respectively. The IC50 for all the drugs, except ivermectin, was at the clinically achievable plasma concentration in humans, which supports a possible role for the drugs in the management of COVID-19. The lack of inhibition of CPE by ivermectin at clinical concentrations could be part of the explanation for its lack of effectiveness in clinical trials.

A longitudinal study of Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels

BackgroundMiddle East respiratory syndrome coronavirus (MERS-CoV) was identified in humans in 2012. Since then, 2605 cases and 937 associated deaths have been reported globally. Camels are the natural host for MERS-CoV and camel to human transmission has been documented. The relationship between MERS-CoV shedding and presence of neutralizing antibodies in camels is critical to inform surveillance and control, including future deployment of camel vaccines. However, it remains poorly understood. The longitudinal study conducted in a closed camel herd in Egypt between December 2019 and March 2020 helped to characterize the kinetics of MERS-CoV neutralizing antibodies and its relation with viral shedding.ResultsDuring the 100-day longitudinal study, 27 out of 54 camels (50%) consistently tested negative for presence of antibodies against MERS-CoV, 19 (35.2%) tested positive and 8 (14.8%) had both, positive and negative test results. Fourteen events that could be interpreted as serological indication of probable infection (two seroconversions and twelve instances of positive camels more than doubling their optical density ratio (OD ratio) in consecutive samples) were identified. Observed times between the identified events provided strong evidence (p = 0.002) against the null hypothesis that they occurred with constant rate during the study, as opposed to clustering at certain points in time. A generalized additive model showed that optical density ratio (OD ratio) is positively associated with being an adult and varies across individual camels and days, peaking at around days 20 and 90 of the study. Despite serological indication of probable virus circulation and intense repeated sampling, none of the tested nasal swab samples were positive for MERS-CoV RNA, suggesting that, if the identified serological responses are the result of virus circulation, the virus may be present in nasal tissue of infected camels during a very narrow time window.ConclusionsLongitudinal testing of a closed camel herd with past history of MERS-CoV infection is compatible with the virus continuing to circulate in the herd despite lack of contact with other camels. It is likely that episodes of MERS-CoV infection in camels can take place with minimal presence of the virus in their nasal tissues, which has important implications for future surveillance and control of MERS-CoV in camel herds and prevention of its zoonotic transmission.

Recent advance in the development of tuberculosis vaccines in clinical trials and virus-like particle-based vaccine candidates.

Tuberculosis (TB) remains a serious public health threat around the world. An effective vaccine is urgently required for cost-effective, long-term control of TB. However, the only licensed vaccine Bacillus Calmette-Guerin (BCG) is limited to prevent TB for its highly variable efficacy. Substantial progress has been made in research and development (R&D) of TB vaccines in the past decades, and a dozen vaccine candidates, including live attenuated mycobacterial vaccines, killed mycobacterial vaccines, adjuvanted subunit vaccines, viral vector vaccines, and messenger RNA (mRNA) vaccines were developed in clinical trials to date. Nevertheless, many challenges to the successful authorization for the use and deployment of an effective tuberculosis vaccine remain. Therefore, it is still necessary and urgent to continue exploring new vaccine construction approaches. Virus-like particles (VLPs) present excellent prospects in the field of vaccine development because of their helpful immunological features such as being safe templates without containing viral nucleic acid, repetitive surface geometry, conformational epitopes similar to natural viruses, and enhancing both innate and adaptive immune responses. The marketization process of VLP vaccines has never stopped despite VLP vaccines face several shortcomings such as their complex and slow development process and high production cost, and several VLP-based vaccines, including vaccines against Human papillomavirus (HPV), Hepatitis B Virus (HBV) and malaria, are successfully licensed for use at the market. In this review, we provide an update on the current progress regarding the development of TB vaccines in clinical trials and seek to give an overview of VLP-based TB vaccine candidates.

Healthcare provider perspectives on COVID-19 vaccination for children in India

BackgroundThe rapid development and deployment of effective COVID-19 vaccines have been critical to halt the spread of the pandemic. India started vaccinating children in early 2022, however, vaccine uptake has...

Beyond Information Provision: Analysis of the Roles of Structure and Agency in COVID-19 Vaccine Confidence in Ethnic Minority Communities.

People from Black and Asian backgrounds are more likely to die from COVID-19 but less likely to be vaccinated, threatening to exacerbate health inequalities already experienced by ethnic minority groups. The literature suggests that mistrust rooted in structural inequality (including socioeconomic position and experience of racism) may be a key barrier to COVID-19 vaccine uptake. Understanding and addressing structural inequality is likely to lead to longer-term impacts than information alone. The aim of this study is to draw on health and sociological theories of structure and agency to inform our understanding of how structural factors influence vaccine confidence. We conducted qualitative interviews and focus groups with 22 people from London and the surrounding areas from December 2021 to March 2022. Fourteen participants were members of the public from ethnic minority backgrounds, and seven were professionals working with the public to address concerns and encourage vaccine uptake. Our findings suggest that people from ethnic minority backgrounds make decisions regarding COVID-19 vaccination based on a combination of how they experience external social structures (including lack of credibility and clarity from political authority, neglect by health services, and structural racism) and internal processes (weighing up COVID-19 vaccine harms and benefits and concerns about vaccine development and deployment). We may be able to support knowledge accumulation through the provision of reliable and accessible information, particularly through primary and community care, but we recommend a number of changes to research, policy and practice that address structural inequalities. These include working with communities to improve ethnicity data collection, increasing funding allocation to health conditions where ethnic minority communities experience poorer outcomes, greater transparency and public engagement in the vaccine development process, and culturally adapted research recruitment processes.

COVID-19 Vaccines for Optimizing Immunity in the Upper Respiratory Tract.

Rapid development and deployment of vaccines greatly reduced mortality and morbidity during the COVID-19 pandemic. The most widely used COVID-19 vaccines approved by national regulatory authorities require intramuscular administration. SARS-CoV-2 initially infects the upper respiratory tract, where the infection can be eliminated with little or no symptoms by an effective immune response. Failure to eliminate SARS-CoV-2 in the upper respiratory tract results in lower respiratory tract infections that can lead to severe disease and death. Presently used intramuscularly administered COVID-19 vaccines are effective in reducing severe disease and mortality, but are not entirely able to prevent asymptomatic and mild infections as well as person-to-person transmission of the virus. Individual and population differences also influence susceptibility to infection and the propensity to develop severe disease. This article provides a perspective on the nature and the mode of delivery of COVID-19 vaccines that can optimize protective immunity in the upper respiratory tract to reduce infections and virus transmission as well as severe disease.

Optimal vaccination strategies for a heterogeneous population using multiple objectives: The case of [formula omitted] and [formula omitted]formulations

The choice of the objective functional in optimization problems coming from biomedical and epidemiological applications plays a key role in optimal control outcomes. In this study, we investigate the role of the objective functional on the structure of the optimal control solution for an epidemic model for sexually transmitted infections that includes a core group with higher sexual activity levels than the rest of the population. An optimal control problem is formulated to find a targeted vaccination program able to control the spread of the infection with minimum vaccine deployment. Both L1− and L2−objectives are considered as an attempt to explore the trade-offs between control dynamics and the functional form characterizing optimality. The results show that the optimal vaccination policies for both the L1− and the L2−formulation share one important qualitative property, that is, immunization of the core group should be prioritized by policymakers to achieve a fast reduction of the epidemic. However, quantitative aspects of this result can be significantly affected depending on the choice of the control weights between formulations. Overall, the results suggest that with appropriate weight constants, the optimal control outcomes are reasonably robust with respect to the L1− or L2−formulation. This is particularly true when the monetary cost of the control policy is substantially lower than the cost associated with the disease burden. Under these conditions, even if the L1−formulation is more realistic from a modeling perspective, the L2−formulation can be used as an approximation and yield qualitatively comparable outcomes.

Identifying target areas for risk-based surveillance and control of transboundary animal diseases: a seasonal analysis of slaughter and live-trade cattle movements in Uganda

Animal movements are a major driver for the spread of Transboundary Animal Diseases (TADs). These movements link populations that would otherwise be isolated and hence create opportunities for susceptible and infected individuals to meet. We used social network analysis to describe the seasonal network structure of cattle movements in Uganda and unravel critical network features that identify districts or sub-regions for targeted risk-based surveillance and intervention. We constructed weighted, directed networks based on 2019 between-district cattle movements using official livestock mobility data; the purpose of the movement (‘slaughter’ vs. ‘live trade’) was used to subset the network and capture the risks more reliably. Our results show that cattle trade can result in local and long-distance disease spread in Uganda. Seasonal variability appears to impact the structure of the network, with high heterogeneity of node and edge activity identified throughout the seasons. These observations mean that the structure of the live trade network can be exploited to target influential district hubs within the cattle corridor and peripheral areas in the south and west, which would result in rapid network fragmentation, reducing the contact structure-related trade risks. Similar exploitable features were observed for the slaughter network, where cattle traffic serves mainly slaughter hubs close to urban centres along the cattle corridor. Critically, analyses that target the complex livestock supply value chain offer a unique framework for understanding and quantifying risks for TADs such as Foot-and-Mouth disease in a land-locked country like Uganda. These findings can be used to inform the development of risk-based surveillance strategies and decision making on resource allocation. For instance, vaccine deployment, biosecurity enforcement and capacity building for stakeholders at the local community and across animal health services with the potential to limit the socio-economic impact of outbreaks, or indeed reduce their frequency.

Modeling of malaria vaccine effectiveness on disease burden and drug resistance in 42 African countries

BackgroundThe emergence of antimalarial drug resistance poses a major threat to effective malaria treatment and control. This study aims to inform policymakers and vaccine developers on the potential of an effective malaria vaccine in reducing drug-resistant infections.MethodsA compartmental model estimating cases, drug-resistant cases, and deaths averted from 2021 to 2030 with a vaccine against Plasmodium falciparum infection administered yearly to 1-year-olds in 42 African countries. Three vaccine efficacy (VE) scenarios and one scenario of rapidly increasing drug resistance are modeled.ResultsWhen VE is constant at 40% for 4 years and then drops to 0%, 235.7 (Uncertainty Interval [UI] 187.8–305.9) cases per 1000 children, 0.6 (UI 0.4–1.0) resistant cases per 1000, and 0.6 (UI 0.5–0.9) deaths per 1000 are averted. When VE begins at 80% and drops 20 percentage points each year, 313.9 (UI 249.8–406.6) cases per 1000, 0.9 (UI 0.6–1.3) resistant cases per 1000, and 0.9 (UI 0.6–1.2) deaths per 1000 are averted. When VE remains 40% for 10 years, 384.7 (UI 311.7–496.5) cases per 1000, 1.0 (0.7–1.6) resistant cases per 1000, and 1.1 (UI 0.8–1.5) deaths per 1000 are averted. Assuming an effective vaccine and an increase in current levels of drug resistance to 80% by 2030, 10.4 (UI 7.3–15.8) resistant cases per 1000 children are averted.ConclusionsWidespread deployment of a malaria vaccine could substantially reduce health burden in Africa. Maintaining VE longer may be more impactful than a higher initial VE that falls rapidly.

Highest Risk Groups and the Distribution of COVID-19 Vaccine in Milwaukee County, Wisconsin: A Census Tract Level Evaluation

Introduction: COVID-19 vaccinations are the most effective approach to COVID-19 control. The vaccine deployment was designed to support the at-risk individuals and reduce COVID-19 mortality. This study asked, “Were vaccine doses successfully administered to Milwaukee County Wisconsin census tracts with the highest at-risk populations?”

SARS-CoV-2 incidence, seroprevalence, and COVID-19 vaccination coverage in the homeless population: a systematic review and meta-analysis.

SARS-CoV-2 infection and COVID-19 vaccination of homeless people are a serious public health concern during COVID-19 pandemic. We aimed to systematically assess SARS-CoV-2 incidence, seroprevalence, and COVID-19 vaccination coverage in homeless people, which are important to inform resource allocation and policy adjustment for the prevention and control of COVID-19. We searched PubMed, Web of Science, and the World Health Organization COVID-19 database for the studies of SARS-CoV-2 incidence, seroprevalence, and COVID-19 vaccination coverage in the homeless population. Subgroup analyses were conducted to pool SARS-CoV-2 incidence and seroprevalence in sheltered homeless, unsheltered homeless, and mixed population, respectively. Potential sources of heterogeneity in the estimates were explored by meta-regression analysis. Forty-nine eligible studies with a total of 75,402 homeless individuals and 5,000 shelter staff were included in the meta-analysis. The pooled incidence of SARS-CoV-2 infection was 10% (95% CI: 7 to 12%) in the homeless population and 8% (5 to 12%) for shelter staff. In addition, the overall estimated SARS-CoV-2 specific seroprevalence was 19% (8 to 33%) for homeless populations and 22% (3 to 52%) for shelter staff, respectively. Moreover, for the homeless subjects, the pooled incidence was 10% (4 to 23%) for asymptomatic SARS-CoV-2 infections, 6% (1 to 12%) for symptomatic SARS-CoV-2 infections, 3% (1 to 4%) for hospitalization for COVID-19, and 1% (0 to 2%) for severe COVID-19 cases, respectively while no COVID-19-related death was reported. Furthermore, the data derived from 12 included studies involving 225,448 homeless individuals revealed that the pooled proportion of one dose COVID-19 vaccination was 41% (35 to 47%), which was significantly lower than those in the general population. Our study results indicate that the homeless people remain highly susceptible to SARS-CoV-2 infection, but COVID-19 vaccination coverage was lower than the general population, underscoring the need for prioritizing vaccine deployment and implementing enhanced preventive measures targeting this vulnerable group.