Análise da vacinação contra Covid-19 na população privada de liberdade: estudo ecológico / Covid-19 vaccination analysis in the population deprived of liberty: an ecological study / Análisis de la vacunación contra el Covid-19 en la población privada de libertad: estudio ecológico

Objetivo: analisar o cenário de vacinação contra Covid-19 na população privada de liberdade em um estado do Nordeste brasileiro. Método: estudo do tipo observacional e ecológico, com os dados extraídos do Sistema de informações penitenciário brasileiro e dos boletins publicados pelo Conselho Nacional de Justiça, referentes a outubro de 2021 a junho de 2022, submetidos à análise estatística descritiva, por meio de frequências absolutas e relativas. Resultados: verificou-se que, entre 4.345 pessoas privadas de liberdade com a primeira dose de vacinação contra Covid-19, apenas 573 possuíam a segnda dose e nenhuma a terceira dose. Conclusão: evidenciou-se que, apesar da vacinação ser um benefício, ainda é um grande desafio para ser implementada para a população privada de liberdade, visto que, mesmo sendo considerados grupos prioritários, o acesso a esse direito foi prejudicado para esses indivíduos.

Objective: to analyze the Covid-19 vaccination scenario in the population deprived of liberty in a state in the Brazilian Northeast. Method: observational and ecological study, with data extracted from the Brazilian Penitentiary Information System and the bulletins published by the National Council of Justice, referring to October 2021 to June 2022, submitted to descriptive statistical analysis, using absolute and relative frequencies. Results: it was found that of the 4,345 people deprived of their liberty who had received the first dose of Covid-19 vaccination, only 573 had received the second dose and none had received the third dose. Conclusion: it was evident that, although vaccination is a benefit, it is still a major challenge to implement it for the population deprived of their liberty, since even though they are considered priority groups, access to this right has been hampered for these individuals.

Objetivo: analizar el escenario de vacunación contra el Covid-19 en la población privada de libertad en un estado del Nordeste brasileño. Método: estudio observacional y ecológico, con datos extraídos del Sistema de Información Penitenciaria de Brasil y boletines publicados por el Consejo Nacional de Justicia, correspondientes al periodo entre octubre de 2021 y junio de 2022, sometidos a análisis estadístico descriptivo, utilizando frecuencias absolutas y relativas. Resultados: se encontró que, de las 4.345 personas privadas de libertad con la primera dosis de la vacuna contra el Covid-19, solo 573 contaban con la segunda dosis y ninguna tenía la tercera dosis. Conclusión: se observó que, pese a que la vacunación es un beneficio, sigue siendo un gran desafío implementarla para la población privada de libertad, ya que, si bien se los consideran grupos prioritarios, el acceso a este derecho se vio afectado para estos individuos.

The Ethiopian National Immunization Technical Advisory Group (E-NITAG): Establishment, Achievements and the Future.

The National Immunization Program (NIP) was introduced in Ethiopia in 1980. The NIP has expanded the number of vaccines from six to more than 14 in 2023. However, decisions on new vaccine introduction and other vaccine-related matters were not systematically deliberated nationally. Thus, the need to establish a national body to deliberate on vaccine and vaccination matters, in addition to the global immunization advisory groups, has been emphasized in the last decade. This article presents the establishment and achievements of the Ethiopian NITAG. The E-NITAG was established in 2016 and maintained its active role in providing recommendations for new vaccine introduction and improving the delivery of routine vaccines. The external assessment indicated the E-NITAG was highly functional and played a critical role in enhancing the vaccination practice in Ethiopia, especially during the COVID-19 pandemic. The absence of a dedicated secretariat staff was the major bottleneck to expanding the role of the E-NITAG beyond responding to MOH requests. The E-NITAG must be strengthened by establishing a secretariat that can eventually grow as an independent institution to address complex vaccine-related issues the NIP needs to address.

Next-Generation Vaccine Development with Nanomaterials: Recent Advances, Possibilities, and Challenges.

Nanomaterials are becoming important tools for vaccine development owing to their tunable and adaptable nature. Unique properties of nanomaterials afford opportunities to modulate trafficking through various tissues, complement or augment adjuvant activities, and specify antigen valency and display. This versatility has enabled recent work designing nanomaterial vaccines for a broad range of diseases, including cancer, inflammatory diseases, and various infectious diseases. Recent successes of nanoparticle vaccines during the coronavirus disease 2019 (COVID-19) pandemic have fueled enthusiasm further. In this review, the most recent developments in nanovaccines for infectious disease, cancer, inflammatory diseases, allergic diseases, and nanoadjuvants are summarized. Additionally, challenges and opportunities for clinical translation of this unique class of materials are discussed.

Epidemiologic and clinical updates on viral infections in Saudi Arabia.

In the past two decades, the world has witnessed devastating pandemics affecting the global healthcare infrastructure and disrupting society and the economy worldwide. Among all pathogens, viruses play a critical role that is associated with outbreaks due to their wide range of species, involvement of animal hosts, easily transmitted to humans, and increased rates of infectivity. Viral disease outbreaks threaten public health globally due to the challenges associated with controlling and eradicating them. Implementing effective viral disease control programs starts with ongoing surveillance data collection and analyses to detect infectious disease trends and patterns, which is critical for maintaining public health. Viral disease control strategies include improved hygiene and sanitation facilities, eliminating arthropod vectors, vaccinations, and quarantine. The Saudi Ministry of Health (MOH) and the Public Health Authority (also known as Weqayah) in Saudi Arabia are responsible for public health surveillance to control and prevent infectious diseases. The notifiable viral diseases based on the Saudi MOH include hepatitis diseases, viral hemorrhagic fevers, respiratory viral diseases, exanthematous viral diseases, neurological viral diseases, and conjunctivitis. Monitoring trends and detecting changes in these viral diseases is essential to provide proper interventions, evaluate the established prevention programs, and develop better prevention strategies. Therefore, this review aims to highlight the epidemiological updates of the recently reported viral infections in Saudi Arabia and to provide insights into the recent clinical treatment and prevention strategies.

Challenging Pandemic Law: From Vaccine Mandates to Judicial Review of Vaccine Approvals.

Over recent years, dozens of legal challenges have been instituted in response to government action during the COVID-19 pandemic. While public health orders have been challenged on several grounds, few cases have succeeded. Fewer cases still have called into question decisions made by the Therapeutic Goods Administration (TGA) to approve the COVID-19 vaccines. This section provides a brief update on one recent, partially successful COVID-19 health directions case before examining two applications in the Federal Court of Australia seeking judicial review of the TGA's approval of the COVID-19 vaccines. The section argues that, while both TGA applications were dismissed for lack of standing, they illustrate how and why third parties will ordinarily not be entitled to challenge administrative decisions about therapeutic goods.

Vaccine Politics.

A vaccine law and policy expert reflects on the dangers of the influence of politics on public health decision making.

Enhancing affordability and profit in a non-cooperative, coordinated, hypothetical pediatric vaccine market via sequential optimization.

This study considers a hypothetical global pediatric vaccine market where multiple coordinating entities make optimal procurement decisions on behalf of countries with different purchasing power. Each entity aims to improve affordability for its countries while maintaining a profitable market for vaccine producers. This study analyzes the effect of several factors on affordability and profitability, including the number of non-cooperative coordinating entities making procuring decisions, the number of market segments in which countries are grouped for tiered pricing purposes, how producers recover fixed production costs, and the procuring order of the coordinating entities. The study relies on a framework where entities negotiate sequentially with vaccine producers using a three-stage optimization process that solves a MIP and two LP problems to determine the optimal procurement plans and prices per dose that maximize savings for the entities' countries and profit for the vaccine producers. The study's results challenge current vaccine market dynamics and contribute novel alternative strategies to orchestrate the interaction of buyers, producers, and coordinating entities for enhancing affordability in a non-cooperative market. Key results show that the order in which the coordinating entities negotiate with vaccine producers and how the latter recuperate their fixed cost investments can significantly affect profitability and affordability. Furthermore, low-income countries can meet their demands more affordably by procuring vaccines through tiered pricing via entities coordinating many market segments. In contrast, upper-middle and high-income countries increase their affordability by procuring through entities with fewer and more extensive market segments. A procurement order that prioritizes entities based on the descending income level of their countries offers higher opportunities to increase affordability and profit when producers offer volume discounts.

Potential of mRNA-based vaccines for the control of tick-borne pathogens in one health perspective.

The One Health approach, which integrates the health of humans, animals, plants, and ecosystems at various levels, is crucial for addressing interconnected health threats. This is complemented by the advent of mRNA vaccines, which have revolutionized disease prevention. They offer broad-spectrum effectiveness and can be rapidly customized to target specific pathogens. Their utility extends beyond human medicine, showing potential in veterinary practices to control diseases and reduce the risk of zoonotic transmissions. This review place mRNA vaccines and One Health in the context of tick-borne diseases. The potential of these vaccines to confer cross-species immunity is significant, potentially disrupting zoonotic disease transmission cycles and protecting the health of both humans and animals, while reducing tick populations, infestations and circulation of pathogens. The development and application of mRNA vaccines for tick and tick-borne pathogens represent a comprehensive strategy in global health, fostering a healthier ecosystem for all species in our interconnected world.

Vaccines for Streptococcus agalactiae: current status and future perspectives.

A maternal vaccine to protect newborns against invasive Streptococcus agalactiae infection is a developing medical need. The vaccine should be offered during the third trimester of pregnancy and induce strong immune responses and placental transfer of protective antibodies. Polysaccharide vaccines against S. agalactiae conjugated to protein carriers are in advanced stages of development. Additionally, protein-based vaccines are also in development, showing great promise as they can provide protection regardless of serotype. Furthermore, safety concerns regarding a new vaccine are the main barriers identified. Here, we present vaccines in development and identified safety, cost, and efficacy concerns, especially in high-need, low-income countries.

Service disruptions, trauma and burnout during the COVID-19 pandemic among healthcare providers delivering immunisation and maternal and child health services in Indonesia.

BACKGROUND: The COVID-19 pandemic resulted in extreme strain on health systems including the health workforce, essential health services and vaccination coverage. We examined disruptions to immunisation and maternal and child health (MCH) services, concerns of personal well-being and delivery of healthcare during the pandemic as well as factors associated with self-reported trauma or burnout among healthcare providers (HCPs). METHODS: In March-April 2022, we conducted a cross-sectional survey among HCPs in two provinces of Indonesia. HCPs involved in COVID-19 or routine immunisation and MCH services were randomly selected from district/city health office registration lists. We descriptively analysed service disruptions experienced by HCPs as well as trauma, burnout and concerns of personal well-being and delivery of healthcare during the pandemic. Multivariate logistic regression analyses were undertaken to identify factors associated with trauma or burnout. RESULTS: We recruited 604 HCPs. Mobilisation of staff from routine health services to COVID-19 response duties was a key reason for service disruptions (87.9%). Strategies such as community outreach and task shifting were implemented to overcome disruptions. Trauma or burnout during the pandemic was reported by 64.1% HCPs, with 23.5% reporting worse mental or emotional health.Factors associated with trauma or burnout included delivery of COVID-19 immunisation (adjusted OR (aOR) 2.54, 95% CI 1.08 to 5.94); and delivery of both COVID-19 immunisation and routine immunisation compared with no involvement in vaccination programmes (aOR 2.42, 95% CI 1.06 to 5.52); poor treatment in the workplace (aOR 2.26, 95% CI 1.51 to 3.38) and lower confidence to respond to patient queries on COVID-19 immunisation (aOR 1.51, 95% CI 1.03 to 2.22). CONCLUSION: HCPs experienced service disruptions, trauma and burnout and implemented strategies to minimise disruptions to service delivery and improve patient experiences. Our study highlights the need to ensure that workforce resilience and strategies to protect and support HCPs are considered for pandemic planning, preparedness and management.

Lack of documentation in animal bite cases and its impact on rabies biologicals utilization.

Introduction: Rabies has significant health and economic consequences for both humans and animals. Annually, India witnesses 17.4 million dog bites, yet only 3 million individuals receive post-exposure prophylaxis (PEP). There is a shortage of anti-rabies vaccine in India as quoted in many news reports. In India, lack of documentation of previous vaccination against animal bites is there, hence resulting in the re-administration of the anti-rabies vaccine, leading to a significant biological loss (anti-rabies vaccine). Material and Methods: A cross-sectional, retrospective study was conducted. Data was collected, and analyzed from June 2021 to June 2023 a period of 2 years. Results: Majority of the patients reported within the first 24 hours after being bitten while approximately one-third reported after 24 hours. Majority were Category 3 bites and unprovoked. Males, lower-middle class, and bites on lower extremities were common among 4291 patients attending the clinic. Out of 217 re-exposure cases, 185 did not have any documentation regarding their previous treatment of animal bites. Conclusion: Among 4291 patients attending the clinic, majority were Category 3 bites on the lower extremities. 85.25% of re-exposure cases had to be administered a full course of treatment due to a lack of documentation leading to rabies as a biological wastage. This avoidable wastage can be a resource for treating more patients.

Impact of COVID-19 pandemic on routine childhood vaccinations.

Routine pediatric vaccination is one of the most effective public health inter-ventions for the control of a number of fatal diseases. However, during the coronavirus disease 2019 pandemic, routine pediatric vaccination rates were severely affected by disruptions of health services and vaccine confidence issues. Governments and the United Nations have taken measures to re-establish routine pediatric vaccination, while additional efforts are needed to catch up and develop plans to ensure routine vaccination services for the future pandemics.

A novel costimulatory molecule gene-modified leukemia cell-derived exosome enhances the anti-leukemia efficacy of DC vaccine in mouse models.

OBJECTIVES: Leukemia cell-derived exosomes (LEXs), carrying leukemia cell-specific antigens, can serve as a source of antigen for dendritic cell (DC) vaccine loading. However, LEX-targeted DC-based vaccines have demonstrated limited antitumor immune effects in clinical trials, attributed to the low immunogenicity of LEXs and the scant levels of costimulatory molecules on DCs. The costimulatory molecules CD80 and CD86, which are crucial to DC function, play a significant role in enhancing immune efficacy. In this study, we explored the anti-leukemia immune response of costimulatory molecule gene-modified LEX-targeted DCs (LEX-8086) in vitro and in animal models. METHODS: DCs were incubated with LEX-8086 to produce LEX-8086-targeted DCs (DCsLEX-8086). ELISA, cytotoxicity assays and flow cytometry utilized to assess the antitumor efficacy of DCsLEX8086 in vitro. Flow cytometry was used to evaluate the immunomodulatory function of DCsLEX8086 in animal models. RESULTS: Our findings indicated that LEX-8086 enhanced the maturation and antigen-presenting ability of DCs. Immunization with DCsLEX8086 significantly activated CD8+ T cells and boosted the CTL response in vitro. More importantly, DCsLEX-8086 effectively suppressed tumor growth and exerted anti-leukemia effects in both prophylactic and therapeutic animal models. Furthermore, DCsLEX-8086 promoted the proportion of CD4+ T cells, CD8+ T cells and M1 macrophages in the tumor environments both prophylactically and therapeutically. Treatment with DCsLEX-8086 showed no significant difference in the levels of M2 macrophages but decreased the proportion of Tregs within the tumor bed during therapeutic experiments. CONCLUSION: The results suggested that DCsLEX-8086 induces a more effective anti-leukemia immunity compared to DCsLEX-null in vivo and in vitro. DCsLEX-8086 might achieve antitumor effects by elevating the numbers of CD4+ T cells, CD8+ T cells, and M1 macrophages in tumors. Our findings indicate that DCsLEX-8086 could be leveraged to develop a new, highly effective vaccine for anti-leukemia immunity.

Primary outcomes and characteristics of clinical trial registries (up to October 2021) on COVID-19 vaccines.

OBJECTIVES: To analyse the general and primary outcome-related characteristics of clinical trials protocols on COVID-19 vaccines. STUDY DESIGN AND SETTING: A meta-research study. A search for clinical trial protocols on COVID-19 vaccines was conducted on the ClinicalTrials.gov platform. We considered all protocols of comparative trials registered up to October 26, 2021. RESULTS: Two hundred and eighty-two trials were analysed. The median expected trial duration was 445 days (interquartile range [IQR] = 225), and the median target sample size was 420 participants (IQR = 1638). A retrospective registry (after the start date) was observed for 42.55% of the trials. Randomization procedures were planned by 84.75% and full-blinding procedures by 34.75% of the 282 trials. Most trials were labelled as active or still recruiting, and 14 trials (5%) were completed. None of the 14 trials labelled as completed on our search date had results available. Industry funding was reported by 198 trials (70.2%). Most studies declared more than one primary outcome, usually a safety or immunogenicity outcome, and 59 studies (20.9%) had at least one primary efficacy outcome. The description of the primary efficacy outcomes was limited in most cases, referred to as a non-specified 'efficacy' outcome (18.6%) or described as 'COVID-19 cases' (32.2%). CONCLUSION: the primary outcomes of clinical trials on COVID-19 vaccines are poorly described, and the registers provide insufficient information about them. The registry was retrospectively fulfilled for many trials, which may lead to bias and research waste. Outcomes were generically described and did not provide transparent information for replication in practice, further trials or meta-analyses.

The COVID-19 Vaccines Evaluation Program: Implementation, Management, and Experiences, 2021-2023.

In 2021, China's domestically produced coronavirus disease 2019 (COVID-19) vaccines received approval from regulatory bodies and were administered worldwide. Due to a low number of infections within China during that period, it became imperative to evaluate the vaccines' real-world effectiveness through international studies. To facilitate this, China CDC launched the COVID-19 Vaccines Evaluation Program (COVEP). This program formed research collaboration agreements with health institutes across five World Health Organization regions, addressing key questions about vaccine performance through ten cooperative agreements. The findings from COVEP projects reinforced confidence, both domestically and globally, in the effectiveness of the vaccines produced in China. Moreover, the outcomes observed internationally were frequently mirrored by later studies conducted within China. COVEP thus pioneered a novel approach for fostering cross-national research collaborations, addressing significant public health issues and exemplifying a framework for international cooperation. This approach is in line with the strategic objectives and other development efforts of China CDC's national disease control and prevention initiatives.

IL-10 inhibition during immunization improves vaccine-induced protection against Staphylococcus aureus infection.

Staphylococcus aureus is a major human pathogen. An effective anti-S. aureus vaccine remains elusive as the correlates of protection are ill-defined. Targeting specific T cell populations is an important strategy for improving anti-S. aureus vaccine efficacy. Potential bottlenecks that remain are S. aureus-induced immunosuppression and the impact this might have on vaccine-induced immunity. S. aureus induces IL-10, which impedes effector T cell responses, facilitating persistence during both colonization and infection. Thus, it was hypothesized that transient targeting of IL-10 might represent an innovative way to improve vaccine efficacy. In this study, IL-10 expression was elevated in the nares of persistent carriers of S. aureus, and this was associated with reduced systemic S. aureus-specific Th1 responses. This suggests that systemic responses are remodeled because of commensal exposure to S. aureus, which negatively implicates vaccine function. To provide proof of concept that targeting immunosuppressive responses during immunization may be a useful approach to improve vaccine efficacy, we immunized mice with T cell-activating vaccines in combination with IL-10-neutralizing antibodies. Blocking IL-10 during vaccination enhanced effector T cell responses and improved bacterial clearance during subsequent systemic and subcutaneous infection. Taken together, these results reveal a potentially novel strategy for improving anti-S. aureus vaccine efficacy.

Differences Between RSV A and RSV B Subgroups and Implications for Pharmaceutical Preventive Measures.

INTRODUCTION: Understanding the differences between respiratory syncytial virus (RSV) subgroups A and B provides insights for the development of prevention strategies and public health interventions. We aimed to describe the structural differences of RSV subgroups, their epidemiology, and genomic diversity. The associated immune response and differences in clinical severity were also investigated. METHODS: A literature review from PubMed and Google Scholar (1985-2023) was performed and extended using snowballing from references in captured publications. RESULTS: RSV has two major antigenic subgroups, A and B, defined by the G glycoprotein. The RSV F fusion glycoprotein in the prefusion conformation is a major target of virus neutralizing antibodies and differs in surface exposed regions between RSV A and RSV B. The subgroups co-circulate annually, but there is considerable debate as to whether clinical severity is impacted by the subgroup of the infecting RSV strain. Large variations between the studies reporting RSV subgroup impact on clinical severity were observed. A tendency for higher disease severity may be attributed to RSV A but no consensus could be reached as to whether infection by one of the subgroup caused more severe outcomes. RSV genotype diversity decreased over the last two decades, and ON and BA have become the sole lineages detected for RSV A and RSV B, since 2014. No studies with data obtained after 2014 reported a difference in disease severity between the two subgroups. RSV F is relatively well conserved and highly similar between RSV A and B, but changes in the amino acid sequence have been observed. Some of these changes led to differences in F antigenic sites compared to reference F sequences (e.g., RSV/A Long strain), which are more pronounced in antigenic sites of the prefusion conformation of RSV B. Initial results from the second season after vaccination suggest specific RSV B efficacy wanes more rapidly than RSV A for RSV PreF-based monovalent vaccines. CONCLUSIONS: RSV A and RSV B both contribute substantially to the global RSV burden. Both RSV subgroups cause severe disease and none of the available evidence to date suggests any differences in clinical severity between the subgroups. Therefore, it is important to implement measures effective at preventing disease due to both RSV A and RSV B to ensure impactful public health interventions. Monitoring overtime will be needed to assess the impact of waning antibody levels on subgroup-specific efficacy.

Alopecia areata following COVID-19 vaccine: a systematic review.

BACKGROUND: To date, multiple cases of adverse reactions to COVID-19 vaccines have been reported worldwide. Alopecia areata (AA) is an uncommon type of adverse reaction reported in some articles and has a significant social and psychological impact on patients. Our study aimed to review the AA and COVID-19 vaccine literature. METHODS: This systematic review was conducted by searching for articles on AA following COVID-19 vaccines in international databases such as Embase, MEDLINE, PubMed, Web of Knowledge, and Ovid from December 2019 to December 30, 2023. We included studies that provided data for AA patients following COVID-19 vaccination with at least one dose. Data on sex, age, country/region of origin, vaccine type, days between vaccination and symptom presentation, manifestations of AA, trichoscopy and histopathological findings, treatment, and outcomes were included. RESULTS: In total, 579 explored studies were identified and assessed, and 25 articles with a total of 51 patients were included in the review. Twenty-seven (52.9%) patients developed new-onset AA following receiving the COVID-19 vaccine, and AA recurrence or exacerbation occurred after receiving the COVID-19 vaccine in 24 (47.1%) patients with preexisting disease. Five vaccines were reported to cause AA in all cases. The Pfizer vaccine (45.1%) was the most frequently reported, followed by the ChAdOx1 nCoV-19 vaccine (27.5%), Moderna mRNA-1273 (19.6%), Sinopharm (3.9%) and SinoVac (3.9%). AA occurred most frequently within one month after the 1st dose, and then, the incidence decreased gradually with time. Topical or systemic corticosteroids were used in 38 patients. Eleven patients were treated with a Janus Kinase inhibitor (jakinib) inhibitor, eight with tofacitinib, and three with an unspecified jakinib. However, 3 of the 11 patients experienced exacerbations after treatment. CONCLUSION: AA after COVID-19 vaccination is rare, and physicians should be aware of this phenomenon to improve early diagnosis and appropriate treatment.

Reflections on The Advisory Committee on Immunization Practices during the COVID-19 Pandemic.

Pediatricians and primary care providers serve an important role in building trust with families and communities. To support the critical role of front-line providers, this perspective seeks to reflect on the work of the Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices to support COVID-19 pandemic response efforts. Although ACIP recommends vaccines for all age groups, this perspective focuses on the pediatric lens and is tailored to Academic Pediatrics. ACIP adapted from in-person meetings 3 times yearly to virtual meetings on an emergency basis to ensure a thorough review and presentation of all the components of Evidence to Recommendation framework, including explicit consideration of equity in the decision-making process. The need for diverse enrollment in clinical trials was highlighted as critical for supporting recommendations and enhancing trust. Near real-time vaccine safety surveillance was implemented at scale and emphasized the importance of collaboration between federal partners engaged in vaccine safety in the U.S. and extended to other countries with similar safety surveillance systems to enable early recognition and response to safety concerns. A key equity opportunity for future pandemics is to shorten the time between vaccine was available for adults and young children.

Influenza Virus-Derived CD8 T Cell Epitopes: Implications for the Development of Universal Influenza Vaccines.

The influenza virus poses a global health burden. Currently, an annual vaccine is used to reduce influenza virus-associated morbidity and mortality. Most influenza vaccines have been developed to elicit neutralizing Abs against influenza virus. These Abs primarily target immunodominant epitopes derived from hemagglutinin (HA) or neuraminidase (NA) of the influenza virus incorporated in vaccines. However, HA and NA are highly variable proteins that are prone to antigenic changes, which can reduce vaccine efficacy. Therefore, it is essential to develop universal vaccines that target immunodominant epitopes derived from conserved regions of the influenza virus, enabling cross-protection among different virus variants. The internal proteins of the influenza virus serve as ideal targets for universal vaccines. These internal proteins are presented by MHC class I molecules on Ag-presenting cells, such as dendritic cells, and recognized by CD8 T cells, which elicit CD8 T cell responses, reducing the likelihood of disease and influenza viral spread by inducing virus-infected cell apoptosis. In this review, we highlight the importance of CD8 T cell-mediated immunity against influenza viruses and that of viral epitopes for developing CD8 T cell-based influenza vaccines.