Prevention and Control of Nosocomial Varicella During the United States Varicella Vaccination Program Era.

The United States varicella vaccination program has successfully reduced varicella incidence and hospitalizations by ≥90%, consequently reducing the risk of nosocomial exposures. However, patients and healthcare personnel (HCP) continue to introduce varicella zoster virus (VZV) into healthcare settings. Herpes zoster (HZ) is less contagious than varicella, but it can also result in exposures. Unrecognized varicella and HZ may lead to extensive contact investigations, control efforts, and HCP furloughs that result in significant disruption of healthcare activities as well as substantial costs. Robust occupational health and infection prevention programs that ensure healthcare personnel immunity and prompt recognition and isolation of patients with varicella or HZ will lower the risk of VZV transmission and reduce or eliminate the need to furlough exposed HCP and associated costs.

Economic Evaluation of Vaccination Programs: A Guide for Selecting Modeling Approaches.

OBJECTIVES: Illustrate 3 economic evaluation methods whose value measures may be useful to decision makers considering vaccination programs. METHODS: Keyword searches identified example publications of cost-effectiveness analysis (CEA), fiscal health modeling (FHM), and constrained optimization (CO) for economic evaluation of a vaccination program in countries where at least 2 of the methods had been used. We examined the extent to which different value measures may be useful for decision makers considering adoption of a new vaccination program. With these findings, we created a guide for selecting modeling approaches illustrating the decision-maker contexts and policy objectives for which each method may be useful. RESULTS: We identified 8 countries with published evaluations for vaccination programs using >1 method for 4 infections: influenza, human papilloma virus, rotavirus, and malaria. CEA studies targeted health system decision makers using a threshold to determine the efficiency of a new vaccination program. FHM studies targeted public sector spending decision makers estimating lifetime changes in government tax revenue net of transfer payments. CO studies targeted decision makers selecting from a mix of options for preventing an infectious disease within budget and feasibility constraints. Cost and utility inputs, epidemiologic models, comparators, and constraints varied by modeling method. CONCLUSIONS: Although CEAs measures of incremental cost-effectiveness ratios are critical for understanding vaccination program efficiency for all decision makers determining access and reimbursement, FHMs provide measures of the program's impact on public spending for government officials, and COs provide measures of the optimal mix of all prevention interventions for public health officials.

Considerations for Establishing Successful Coronavirus Disease Vaccination Programs in Africa.

The accelerated development of coronavirus disease (COVID-19) candidate vaccines is intended to achieve worldwide immunity. Ensuring COVID-19 vaccination is crucial to stemming the pandemic, reclaiming everyday life, and helping restore economies. However, challenges exist to deploying these vaccines, especially in resource-limited sub-Saharan Africa. In this article, we highlight lessons learned from previous efforts to scale up vaccine distribution and offer considerations for policymakers and key stakeholders to use for successful COVID-19 vaccination rollout in Africa. These considerations range from improving weak infrastructure for managing data and identifying adverse events after immunization to considering financing options for overcoming the logistical challenges of vaccination campaigns and generating demand for vaccine uptake. In addition, providing COVID-19 vaccination can be used to promote the adoption of universal healthcare, especially in sub-Saharan Africa countries.

Chronic hepatitis B virus infection in Italy during the twenty-first century: an updated survey in 2019.

The aim of this study is to provide updates on the characteristics of chronic HBsAg carriers in Italy before the advent of new drugs eliminating or functionally inactivating the genome HBV reservoirs. HBV endemicity has greatly decreased in Italy over the past decades. A not negligible number of chronic HBsAg carriers are still alive in the country. Chronic HBsAg carriers consecutively referring to 9 units in Italy were prospectively enrolled for a 6-month period in 2019. Multiple logistic regression analysis was performed to identify independent predictors of treatment. A total of 894 cases was recruited (sex ratio 1.6; mean age 53.7 ± 13.5 years). The proportion of subjects born abroad was 19.0%; only 1% of cases reported current heavy alcohol intake (> 4 units/day). Chronic HBV infection, chronic HBV hepatitis, and subjects with liver cirrhosis and/or HCC represented 24.8%, 55%, and 19.3% of cases, respectively. After exclusion of the 222 subjects with chronic HBV infection, the proportion of subjects under therapy was as high as 89.3%. A more severe liver disease (OR 2.52; 95% CI = 1.25-5.14) resulted an independent predictor of the likelihood of treatment; male sex was marginally associated (OR 1.67; 95% CI = 1.02-2.76) to the chance of treatment. People born abroad had same chance than Italians native to be treated (OR 2.12; 95% CI = 0.9-4.97). The high proportion of subjects under treatment and the absence of gender and ethnic barrier against treatment sound good news. These updated figures may represent reference data for evaluating the potential impact of forthcoming new therapy against HBV-related disease.

Evaluating Vaccination Programs That Prevent Diseases With Potentially Catastrophic Health Outcomes: How Can We Capture the Value of Risk Reduction?

In the last 5 years, guidelines have been developed for performing cost-effectiveness analyses (CEAs) for the economic evaluation of vaccination programs against infectious diseases. However, these cost-effectiveness guidelines do not provide specific guidance for including the value of reducing the risk of rare but potentially catastrophic health outcomes, such as mortality or long-term sequelae. Alternative economic evaluation methods, including extended CEA, the impact inventory, cost-benefit analyses, willingness to pay or the value of a statistical life, to capture the value of this risk reduction could provide more complete estimates of the value of vaccination programs for diseases with potentially catastrophic health and nonhealth outcomes. In this commentary, using invasive meningococcal disease as an example, we describe these alternative approaches along with examples to illustrate how the benefits of vaccination in reducing risk of catastrophic health outcomes can be valued. These benefits are not usually captured in CEAs that only include population benefits estimated as the quality-adjusted life-years gained and reduced costs from avoided cases.

Estimated number of deaths directly averted in people 60 years and older as a result of COVID-19 vaccination in the WHO European Region, December 2020 to November 2021.

Since December 2019, over 1.5 million SARS-CoV-2-related fatalities have been recorded in the World Health Organization European Region - 90.2% in people ≥ 60 years. We calculated lives saved in this age group by COVID-19 vaccination in 33 countries from December 2020 to November 2021, using weekly reported deaths and vaccination coverage. We estimated that vaccination averted 469,186 deaths (51% of 911,302 expected deaths; sensitivity range: 129,851-733,744; 23-62%). Impact by country ranged 6-93%, largest when implementation was early.

Individual and Population Trajectories of Influenza Antibody Titers Over Multiple Seasons in a Tropical Country.

Seasonal influenza epidemics occur year-round in the tropics, complicating the planning of vaccination programs. We built an individual-level longitudinal model of baseline antibody levels, time of infection, and the subsequent rise and decay of antibodies postinfection using influenza A(H1N1)pdm09 data from 2 sources in Singapore: 1) a noncommunity cohort with real-time polymerase chain reaction-confirmed infections and at least 1 serological sample collected from each participant between May and October 2009 (n = 118) and 2) a community cohort with up to 6 serological samples collected between May 2009 and October 2010 (n = 760). The model was hierarchical, to account for interval censoring and interindividual variation. Model parameters were estimated via a reversible jump Markov chain Monte Carlo algorithm using custom-designed R (https://www.r-project.org/) and C++ (https://isocpp.org/) code. After infection, antibody levels peaked at 4-7 weeks, with a half-life of 26.5 weeks, followed by a slower decrease up to 1 year to approximately preinfection levels. After the third wave, the seropositivity rate and the population-level antibody titer dropped to the same level as they were at the end of the first pandemic wave. The results of this analysis are consistent with the hypothesis that the population-level effect of individuals' waxing and waning antibodies influences influenza seasonality in the tropics.

Cost-Effectiveness Analysis of Universal Human Papillomavirus Vaccination Using a Dynamic Bayesian Methodology: The BEST II Study.

BACKGROUND: Human papillomavirus (HPV) plays a role in the development of benign and malign neoplasms in both sexes. The Italian recommendations for HPV vaccines consider only females. The BEST II study (Bayesian modelling to assess the Effectiveness of a vaccination Strategy to prevent HPV-related diseases) evaluates 1) the cost-effectiveness of immunization strategies targeting universal vaccination compared with cervical cancer screening and female-only vaccination and 2) the economic impact of immunization on various HPV-induced diseases. OBJECTIVE: The objective of this study was to evaluate whether female-only vaccination or universal vaccination is the most cost-effective intervention against HPV. METHODS: We present a dynamic Bayesian Markov model to investigate transmission dynamics in cohorts of females and males in a follow-up period of 55 years. We assumed that quadrivalent vaccination (against HPV 16, 18, 6, and 11) is available for 12-year-old individuals. The model accounts for the progression of subjects across HPV-induced health states (cervical, vaginal, vulvar, anal, penile, and head/neck cancer as well as anogenital warts). The sexual mixing is modeled on the basis of age-, sex-, and sexual behavioral-specific matrices to obtain the dynamic force of infection. RESULTS: In comparison to cervical cancer screening, universal vaccination results in an incremental cost-effectiveness ratio of €1,500. When universal immunization is compared with female-only vaccination, it is cost-effective with an incremental cost-effectiveness ratio of €11,600. Probabilistic sensitivity analysis shows a relatively large amount of parameter uncertainty, which interestingly has, however, no substantial impact on the decision-making process. The intervention being assessed seems to be associated with an attractive cost-effectiveness profile. CONCLUSIONS: Universal HPV vaccination is found to be a cost-effective choice when compared with either cervical cancer screening or female-only vaccination within the Italian context.

Adult vaccination coverage in the United States: A database analysis and literature review of improvement strategies.

Despite vaccines being instrumental in reducing vaccine-preventable disease, adult vaccination rates in the United States (US) are below optimal levels. To better understand factors affecting vaccination rates, we analyzed trends in adult vaccination coverage using data from the Behavioral Risk Factor Surveillance System (BRFSS) and conducted a targeted literature review (TLR) on interventions to improve adult vaccination rates in the US. Both the BRFSS analysis and the TLR focused on influenza; pneumococcal disease; tetanus and diphtheria or tetanus, diphtheria, and acellular pertussis; herpes zoster; and human papillomavirus vaccination for US adults aged 18-64 years. The TLR additionally included hepatitis A and hepatitis B vaccination. Vaccination coverage rates (VCRs) and changes in VCRs were calculated using the 2011-2019 BRFSS survey data. For the TLR, the MEDLINE and MEDLINE In-Process databases were searched for articles on vaccination interventions published between January 2015 and June 2021. The BRFSS analysis showed that changes in VCRs were generally modest and positive for most states over the study period. The TLR included 32 articles that met the eligibility criteria; intervention strategies that improved adult vaccination outcomes incorporated an educational component, vaccination reminders or reinforcement at the point of care, or authorized non-clinician members of the healthcare team to vaccinate. Furthermore, interventions combining more than one approach appeared to enhance effectiveness. The strategies identified in this TLR will be valuable for policymakers and stakeholders to inform the development and implementation of evidence-based policies and practices to improve adult vaccination coverage.

Clinical Profile of Hospitalized Varicella Cases From Pediatric Emergency Consultations: A Retrospective Cohort Study.

BACKGROUND: Varicella is a very common childhood infectious disease. It is generally benign, but it can lead to fatal complications. Our study aimed to describe the clinical and therapeutic profile of varicella based on consultations in the pediatric emergency department, to determine the incidence of hospitalized varicella cases in the pediatric department for complementary management, and to specify the incidence of varicella complications in hospitalized patients. MATERIALS AND METHODS: We conducted a retrospective descriptive cohort study over 12 months. It took place in the pediatrics and pediatric emergency departments of the Mother-Child Hospital of the Mohammed VI University Hospital, Mohammed I University, in Oujda, Morocco. RESULTS: We collected 120 cases of varicella. The mean age of patients was 4.5 years. The most common age range was 4-6 years (69%). Males predominated. The reason for consulting the pediatric emergency department was a febrile rash in 65% of cases. Treatment in pediatric emergencies was mostly symptomatic. Antibiotic treatment for superinfection of lesions was used in 11% of cases. The number of hospitalizations due to complicated and/or severe varicella was 17 cases. The median age was 6.3 years. Most of the children (82%) were immunodeficient and 18% were immunocompetent. Sixteen patients had underlying risk factors. Infectious skin and soft tissue complications were noted in most hospitalized patients (47%). They were mainly presented by cutaneous reinfections with alteration of general health (41%). Neurological complications ranked second (23%). The majority were febrile convulsions (17%). One case of bronchopulmonary complication was noted. No hematological, digestive, renal, or cardiac complications were noted. Intravenous antiviral treatment was used in 88% of hospitalized cases. The drug of choice was acyclovir. Antibiotic therapy was used in 53% of cases. No patient received corticosteroid therapy. The median length of hospitalization for our patients was 14 days. The evolution was favorable in 100% of cases. CONCLUSION: Varicella remains a benign disease in children, rarely leading to hospitalization. However, complications may develop in cases of comorbidity or children with risk factors. The introduction of the varicella vaccine into the national immunization program could considerably reduce the number of children hospitalized in the near future.

Evolving Epidemiology and Antibiotic Resistance in Enteric Fever: A Comprehensive Review.

Enteric fever, predominantly caused by Salmonella enterica serovar Typhi and Salmonella enterica serovar Paratyphi, remains a significant global health challenge. This comprehensive review examines the evolving epidemiology and antibiotic resistance associated with enteric fever. We provide an overview of the disease's definition and historical context, highlighting the substantial impact of antibiotic resistance on treatment efficacy. The review details the global burden, incidence trends, and risk factors of enteric fever while elucidating the pathogenesis and clinical manifestations of the disease. A critical analysis of antibiotic resistance mechanisms reveals the alarming rise of multi-drug resistant (MDR) and extensively drug-resistant (XDR) strains, complicating treatment regimens and underscoring the need for novel therapeutic strategies. Current treatment protocols, the role of empirical therapy, and the rational use of antibiotics are discussed in depth. Additionally, we explore prevention and control strategies, emphasizing the importance of vaccination programs, sanitation improvements, and effective public health interventions. The review concludes with recommendations for future actions, including enhanced surveillance, research and development of new antibiotics, expansion of vaccination efforts, and improved public health infrastructure. The findings highlight the necessity for updated clinical guidelines and sustained global efforts to address the challenges of enteric fever and its evolving antibiotic resistance patterns. Through coordinated action and continued innovation, it is possible to mitigate the impact of this enduring public health threat.

Vaccines for the Elderly and Vaccination Programs in Europe and the United States.

The share of the elderly population is growing worldwide as life expectancy increases. Immunosenescence and comorbidities increase infectious diseases' morbidity and mortality in older adults. Here, we aimed to summarize the latest findings on vaccines for the elderly against herpes zoster, influenza, respiratory syncytial virus (RSV), COVID-19, and pneumococcal disease and to examine vaccine recommendation differences for this age group in Europe and the United States. PubMed was searched using the keywords "elders" and "vaccine" alongside the disease/pathogen in question and paraphrased or synonymous terms. Vaccine recommendations were also sought in the European and US Centers for Disease Control and Prevention databases. Improved vaccines, tailored for the elderly, mainly by using novel adjuvants or by increasing antigen concentration, are now available. Significant differences exist between immunization policies, especially between European countries, in terms of the recipient's age, number of doses, vaccination schedule, and implementation (mandatory or recommended). Understanding the factors that influence the immune response to vaccination in the elderly may help to design vaccines that offer long-term protection for this vulnerable age group. A consensus-based strategy in Europe could help to fill the gaps in immunization policy in the elderly, particularly regarding vaccination against RSV and pneumococcus.

Landscape connectivity for predicting the spread of ASF in the European wild boar population.

African swine fever (ASF) is an infectious and highly fatal disease affecting wild and domestic swine, which is unstoppably spreading worldwide. In Europe, wild boars are one of the main drivers of spread, transmission, and maintenance of the disease. Landscape connectivity studies are the main discipline to analyze wild-species dispersal networks, and it can be an essential tool to predict dispersal-wild boar movement routes and probabilities and therefore the associated potential ASF spread through the suitable habitat. We aimed to integrate wild boar habitat connectivity predictions with their occurrence, population abundance, and ASF notifications to calculate the impact (i.e., the capacity of a landscape feature to favor ASF spread) and the risk (i.e., the likelihood of a habitat patch becoming infected) of wild boar infection across Europe. Furthermore, we tested the accuracy of the risk of infection by comparing the results with the temporal distribution of ASF cases. Our findings identified the areas with the highest impact and risk factors within Europe's central and Eastern regions where ASF is currently distributed. Additionally, the impact factor was 31 times higher on habitat patches that were infected vs non-infected, proving the utility of the proposed approach and the key role of wild boar movements in ASF-spread. All data and resulting maps are openly accessible and usable.

Molecular characterization of measles viruses in Turkey (2010-2011): first report of genotype D9 involved in an outbreak in 2011.

Genetic characterization of measles viruses (MVs) combined with acquisition of epidemiologic information is essential for measles surveillance programs used in determining transmission pathways. This study describes the molecular characterization of 26 MV strains (3 from 2010, 23 from 2011) obtained from urine or throat swabs harvested from patients in Turkey. MV RNA samples (n = 26) were subjected to sequence analysis of 450 nucleotides comprising the most variable C-terminal region of the nucleoprotein (N) gene. Phylogenetic analysis revealed 20 strains from 2011 belonged to genotype D9, 3 to D4, 2 strains from 2010 to genotype D4 and 1 to genotype B3. This study represents the first report describing the involvement of MV genotype D9 in an outbreak in Turkey. The sequence of the majority of genotype D9 strains was identical to those identified in Russia, Malaysia, Japan, and the UK. Despite lack of sufficient epidemiologic information, the presence of variants observed following phylogenetic analysis suggested that exposure to genotype D9 might have occurred due to importation more than once. Phylogenetic analysis of five genotype D4 strains revealed the presence of four variants. Epidemiological information and phylogenetic analysis suggested that three genotype D4 strains and one genotype B3 strain were associated with importation. This study suggests the presence of pockets of unimmunized individuals making Turkey susceptible to outbreaks. Continuing molecular surveillance of measles strains in Turkey is essential as a means of acquiring epidemiologic information to define viral transmission patterns and determine the effectiveness of measles vaccination programs designed to eliminate this virus.

Inequities in Screening and HPV Vaccination Programs and Their Impact on Cervical Cancer Statistics in Romania.

(1) Introduction: A Romanian woman is diagnosed with cervical cancer every two hours; the country ranks second in Europe in terms of the mortality and incidence rate of this disease. This paper aims to identify the main reasons that have led to this situation, focusing on the measures taken by the Romanian Ministry of Health for the prevention of this type of cancer-national programs for cervical cancer screening and HPV vaccination. (2) Materials and methods: We performed a study based on the available secondary data from the National Statistics Institute, World Health Organization and Bucharest Institute of Oncology in order to assess the burden associated with cervical cancer and place it in the context of known global and European incidence and mortality rates, thus evaluating the importance of this health issue in Romania. The second component of our study was a cross-sectional study. Here, we used a 14-question questionnaire applied to the women participating in the National Screening Program for Cervical Cancer and aimed to evaluate the women's level of knowledge about screening and HPV vaccination and their access cervical-cancer-specific healthcare services. (3) Results: The results of this research show that a high percentage of women postpone routine checks due to a lack of time and financial resources and indicate that a low level of knowledge about the disease and the specific preventive methods determines the low participation in screening and HPV vaccination programs implemented in Romania, contributing to the country's cervical cancer situation. (4) Conclusions: The national programs have complicated procedures, are underfunded and do not motivate healthcare workers enough. This, combined with the lack of information for the eligible population, adds up to an extremely low number of women screened and vaccinated. Our conclusion is that the Romanian Ministry of Health must take immediate action by conducting major awareness campaigns, implementing measures to make the programs functional and ensuring coherent funding.

COVID-19 Vaccine Hesitancy in Denmark and Russia: A qualitative typology at the nexus of agency and health capital.

Vaccination of the world population is being embraced by 184 countries as the main strategy to end the COVID-19 pandemic; vaccination rates are stalling even in countries with high vaccine availability, though. This article investigates the phenomenon of vaccine hesitancy in two such countries, the Kingdom of Denmark and the Russian Federation, through a qualitative study of the different types of hesitancy to COVID-19 vaccination programs and their underlying mechanisms. The analysis reveals a typology along the dimensions of agency and health capital: resisting hesitancy based on mistrust of authority, paralyzed hesitancy based on personal fear, informed hesitancy based on informed choice, and empowered hesitancy based on empowered choice. While the mechanisms underlying vaccine hesitancy are to a great extent comparable between the two countries, differences in population size, societal cohesion, and political culture seem to impact the prevalence and severity of types and, thereby, the outcomes of national COVID-19 vaccination programs and national campaigns for mitigating COVID-19 vaccine hesitancy. The implications of these findings extend beyond the particular context of COVID-19 and the countries studied, supporting and nuancing existing models for vaccine hesitancy, as well as providing a starting point for tailored campaigns for mitigating vaccine hesitancy.

Adolescent girls' recommendations for the design of a human papillomavirus vaccination program in Sindh, Pakistan: a qualitative study.

PURPOSE: Vaccination of adolescent girls against human papillomavirus (HPV) significantly reduces the incidence of cervical cancer. HPV vaccines are available in Pakistan but plans to develop HPV vaccination program are at a nascent stage. We conducted a formative study to explore adolescent girls' knowledge and perspectives on HPV and cervical cancer and collect their recommendations for implementing an HPV vaccination program in their community. METHODS: Using qualitative exploratory study design, we conducted four focus group discussions (FGDs) with 12 adolescent girls per group in District West, Karachi. We recruited unmarried girls aged 16-19 years from schools and community settings between May-December 2020. Data analysis was done using NVivo. RESULTS: Overall, participants displayed a positive attitude toward HPV vaccine. However, they were unfamiliar with basic concepts related to female reproductive health. Female relatives were indicated as girls' preferred point of contact for discussions on HPV and cervical cancer, but fathers were portrayed as decision-making authority on vaccination. Participants indicated vaccine hesitancy among parents may affect HPV vaccination uptake. Girls suggested individual household visits and community-based camps as strategies for successful implementation of HPV vaccination program. A solid foundation of trust between girls' families, program managers, and other stakeholders emerged as a key asset for the program's success. CONCLUSION: Adolescent girls' suggestions of informing key decision-makers in the family (particularly fathers) of the benefits of HPV vaccination, establishing trust with vaccine providers, and increasing accessibility of vaccinations should be explored for successful implementation of an HPV vaccination program in Pakistan.

Resumption of active recommendation of the human papillomavirus vaccine in Japan and future challenges for the National Immunization Program.

Japan's immunization program resumed proactively recommending the use of the human papillomavirus (HPV) vaccine nationwide in April 2022, after suspending this recommendation in June 2013. The promotion of catch-up vaccinations is an urgent issue to reduce the increase in cervical cancer and other cancers caused by low vaccination rates. In addition, the National Immunization Program still has issues to be considered, such as the adoption of the 9-valent vaccine, establishment of an appropriate number of vaccinations according to age, and routine immunization of males. There is a history of eliminating the use of the measles, mumps, and rubella vaccine and the mouse brain-derived, purified inactivated Japanese encephalitis vaccine, as well as suspending the HPV vaccine recommendation in Japan. These decisions have led to the current preventable infectious disease burden. In order to make the right policy decisions based on science-based assessments, it is necessary to establish a safety assessment platform to evaluate the causal relationship between vaccines and adverse events following immunization. Information technology, which has been promoted with the coronavirus disease 2019 vaccine in the current pandemic, may assist in providing more detailed vaccine safety evaluations for other vaccines.

Beyond Influenza Vaccination: Expanding Infrastructure for Hospital-based Pediatric COVID-19 Vaccine Delivery.

Controlling the spread of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), will rely on vaccination at increasing rates and in an equitable manner. The main reasons for under-vaccination are varied among different segments of the population and include vaccine hesitancy and lack of access. While vaccine hesitancy is complicated and requires long-term solutions, access can be enhanced through evidence-based delivery strategies that augment conventional approaches. Hospital-based COVID-19 vaccination programs hold particular promise in reaching populations with decreased vaccine access and those at higher risk for adverse outcomes from SARS-CoV-2 infection. Hospitals have the necessary equipment and storage capabilities to maintain cold chain requirements-a common challenge in the primary care setting-and can serve as a central distribution point for delivering vaccines to patients in diverse hospital locations, including inpatient units, emergency departments, urgent care centers, perioperative areas, and subspecialty clinics. They also have the capacity for mass-vaccination programs and other targeted outreach efforts. Hospital-based programs that have been successful in implementing influenza and other routine vaccinations can leverage existing infrastructure, such as electronic health record-related tools. With the possibility of COVID-19 becoming endemic, much like seasonal influenza, these programs will require flexibility as well as planning for long-term sustainability. This commentary highlights existing vaccine delivery to children in hospital-based settings, including key advantages and important challenges, and outlines how these systems could be expanded to include the COVID-19 vaccine delivery.

Effect of vaccination against Covid-19 one year after its introduction in Brazil.

BACKGROUND: Worldwide, several efforts have been made to develop, distribute and administer safe and effective vaccines to reduce morbidity and mortality and control the Covid-19 pandemic. This study aimed to analyze the effect of vaccination against Covid-19, one year after its introduction in Brazil. METHODS: An ecological study that analyzed the general effect of vaccination against Covid-19 on disease morbidity and mortality indicators among the Brazilian population aged 18 years or older per epidemiological week (EW), comparing the pre and postvaccination period. Morbidity and mortality indicators were calculated from secondary databases (hospitalization rate, severity, case fatality rate and mortality) and vaccination coverage by age groups (18 to 59 years and 60 years or older). Morbimortality trends were estimated using the JoinPoint model and their association with vaccine coverage using the Poisson model. RESULTS: The average weekly percentage change (AWPC) of morbidity and mortality indicators reduced after the introduction of Covid-19 vaccination: hospitalization rate (from 15.3% to -6.0%), severity (from 0.4% to -0.2%), case fatality rate (from 0.3% to -0.2%) and mortality (from 20.5% to -4.3%). The following indicators were inversely associated with the increase in vaccine coverage against Covid-19: hospitalization (IRR: 0.974), mortality (IRR: 0.975) and lethality for people aged 60 years or older (IRR: 0.997). CONCLUSIONS: In spite of the three epidemic waves and the circulation of variants of concern, the general effect of vaccination against Covid-19 in reducing the trend of morbidity and mortality from the disease in Brazil was demonstrated. These findings contribute to a better understanding of the mass vaccination program against Covid-19 and may inform future public health policies.