Phase 4 clinical trials in the era of the Coronavirus Disease (COVID-19) pandemic and their importance to optimize the COVID-19 vaccination

Dengue outbreaks in Brazil and Latin America: the new and continuing challenges

OBJECTIVES

To compare the number of suspected cases, severe cases, and deaths of dengue in 2023 and 2024 in Brazil and Latin America; and to describe its epidemiological profile.

DESIGN

Observational study.

METHODS

The data regarding dengue was retrieved from the Brazilian Ministry of Health website. The Chi-square test was used to compare the proportion of dengue cases in 2023 and 2024 according to gender, race, and age range. The odds ratio and the 95% confidence intervals were used to describe the data. The Spearman correlation test was used to compare the number of suspected cases, severe cases, and deaths of dengue with the number of distributed vaccines against dengue.

RESULTS

Dengue is one of the most common zoonoses in Latin America. In 2023, Brazil registered a total of 1,658,814 suspected cases of dengue with 1094 deaths. For 2024, a total of 1,978,372 suspected cases of dengue were reported only until the 11th epidemiological week, with 656 deaths. When comparing dengue cases reported in 2024 and 2023, there is an increase in suspected cases, with 20% more cases reported during the first 11 epidemiological weeks of 2024 than in the entire 52 epidemiological weeks of 2023. At the same time, in 2024, the Pan American Health Organization reported suspected cases in 20 Latin American countries, with 3073 cases of severe dengue and 1187 deaths. In Brazil, a different racial profile for dengue was described since Black people [OR = 1.56 (95% CI = 1.54-1.57)], Mixed individuals [OR = 1.36 (95% CI = 1.35-1.37), and Indigenous peoples [OR = 1.77 (95% CI = 1.70-1.85)] were more likely to be suspected cases of dengue in 2024 compared to 2023. Also, a positive correlation between the distributed vaccines with deaths due to dengue and the number of severe cases was described.

CONCLUSION

Brazil was responsible for more than 50% of suspected cases and deaths from dengue compared to the other Latin American countries in 2024. Furthermore, there is a different racial profile for dengue in Brazil, as Black people, Mixed individuals, and Indigenous peoples were more likely to be suspected cases of dengue in 2024 compared to 2023.

Efficacy of Ivermectin, Chloroquine/Hydroxychloroquine, and Azithromycin in Managing COVID-19: A Systematic Review of Phase III Clinical Trials

Background: During the coronavirus disease (COVID)-19 pandemic several drugs were used to manage the patients mainly those with a severe phenotype. Potential drugs were used off-label and major concerns arose from their applicability to managing the health crisis highlighting the importance of clinical trials. In this context, we described the mechanisms of the three repurposed drugs [Ivermectin-antiparasitic drug, Chloroquine/Hydroxychloroquine-antimalarial drugs, and Azithromycin-antimicrobial drug]; and, based on this description, the study evaluated the clinical efficacy of those drugs published in clinical trials. The use of these drugs reflects the period of uncertainty that marked the beginning of the COVID-19 pandemic, which made them a possible treatment for COVID-19. Methods: In our review, we evaluated phase III randomized controlled clinical trials (RCTs) that analyzed the efficacy of these drugs published from the COVID-19 pandemic onset to 2023. We included eight RCTs published for Ivermectin, 11 RCTs for Chloroquine/Hydroxychloroquine, and three RCTs for Azithromycin. The research question (PICOT) accounted for P-hospitalized patients with confirmed or suspected COVID-19; I-use of oral or intravenous Ivermectin OR Chloroquine/Hydroxychloroquine OR Azithromycin; C-placebo or no placebo (standard of care); O-mortality OR hospitalization OR viral clearance OR need for mechanical ventilation OR clinical improvement; and T-phase III RCTs. Results: While studying these drugs' respective mechanisms of action, the reasons for which they were thought to be useful became apparent and are as follows: Ivermectin binds to insulin-like growth factor and prevents nuclear transportation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), therefore preventing cell entrance, induces apoptosis, and osmotic cell death and disrupts viral replication. Chloroquine/Hydroxychloroquine blocks the movement of SARS-CoV-2 from early endosomes to lysosomes inside the cell, also, this drug blocks the binding between SARS-CoV-2 and Angiotensin-Converting Enzyme (ACE)-2 inhibiting the interaction between the virus spike proteins and the cell membrane and this drug can also inhibit SARS-CoV-2 viral replication causing, ultimately, the reduction in viral infection as well as the potential to progression for a higher severity phenotype culminating with a higher chance of death. Azithromycin exerts a down-regulating effect on the inflammatory cascade, attenuating the excessive production of cytokines and inducing phagocytic activity, and acts interfering with the viral replication cycle. Ivermectin, when compared to standard care or placebo, did not reduce the disease severity, need for mechanical ventilation, need for intensive care unit, or in-hospital mortality. Only one study demonstrated that Ivermectin may improve viral clearance compared to placebo. Individuals who received Chloroquine/Hydroxychloroquine did not present a lower incidence of death, improved clinical status, or higher chance of respiratory deterioration compared to those who received usual care or placebo. Also, some studies demonstrated that Chloroquine/Hydroxychloroquine resulted in worse outcomes and side-effects included severe ones. Adding Azithromycin to a standard of care did not result in clinical improvement in hospitalized COVID-19 participants. In brief, COVID-19 was one of the deadliest pandemics in modern human history. Due to the potential health catastrophe caused by SARS-CoV-2, a global effort was made to evaluate treatments for COVID-19 to attenuate its impact on the human species. Unfortunately, several countries prematurely justified the emergency use of drugs that showed only in vitro effects against SARS-CoV-2, with a dearth of evidence supporting efficacy in humans. In this context, we reviewed the mechanisms of several drugs proposed to treat COVID-19, including Ivermectin, Chloroquine/Hydroxychloroquine, and Azithromycin, as well as the phase III clinical trials that evaluated the efficacy of these drugs for treating patients with this respiratory disease. Conclusions: As the main finding, although Ivermectin, Chloroquine/Hydroxychloroquine, and Azithromycin might have mechanistic effects against SARS-CoV-2 infection, most phase III clinical trials observed no treatment benefit in patients with COVID-19, underscoring the need for robust phase III clinical trials.

Viral vector-based therapeutic HPV vaccines

Replication-defective viral vector vaccines have several advantages over conventional subunit vaccines, including potent antibody responses, cellular responses critical for eliminating pathogen-infected cells, and the induction of highly immunogenic and durable immune responses without adjuvants. The Human papillomavirus (HPV), a microorganism with over 200 genotypes, plays a crucial role in inducing human tumors, with the majority of HPV-related malignancies expressing HPV proteins. Tumors associated with HPV infection, most of which result from HPV16 infection, include those affecting the cervix, anus, vagina, penis, vulva, and oropharynx. In recent years, the development of therapeutic HPV vaccines utilizing viral vectors for the treatment of premalignant lesions or tumors caused by HPV infection has experienced rapid growth, with numerous research pipelines currently underway. Simultaneously, screening for optimal antigens requires more basic research and more optimized methods. In terms of preclinical research, we present the various models used to assess vaccine efficacy, highlighting their respective advantages and disadvantages. Further, we present current research status of therapeutic vaccines using HPV viral vectors, especially the indications, initial efficacy, combination drugs, etc. In general, this paper summarizes current viral vector therapeutic HPV vaccines in terms of HPV infection, antigen selection, vectors, efficacy evaluation, and progress in clinical trials.

Overview of childhood vaccination coverage in Brazil and the impact of the COVID-19 pandemic: Is our children's health at risk? A review of pre-COVID-19 periods and during the COVID-19 pandemic

Introduction

The coronavirus disease (COVID)-19 has had a great impact on several aspects related to the population's health, including the vaccination adherence rate. This study describes how childhood vaccination coverage (CVC) in Brazil was affected by the pandemic in the period from 2020 to 2022 and explores the relationship between this data and the Human Development Index (HDI), and the number of votes received in the government with a right-wing political ideology.

Methods

An ecological analysis of CVC was carried out including 12 vaccines. The HDI was evaluated considering the HDI-General, HDI-Income, HDI-Longevity, and HDI-Education. The percentage of valid votes received by the former president (right-wing political ideology) was also obtained. Spearman correlation tests were applied to compare markers.

Results

During the period analyzed, it was observed a linear growth trend in CVC between 2015 and 2018 regarding all vaccines. However, from 2018 onwards, after the presidential elections in Brazil, the CVC reduced significantly, showing an even more pronounced decrease with the start of the COVID-19 pandemic. This reduction in CVC observed for some vaccines was related to the higher percentage of votes for the government with a right-wing political ideology, especially in relation to the BCG (bacillus Calmette and Guerin) and pentavalent (protecting against diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type b bacteria) vaccines. In addition, when analyzing the HDI, it was observed that the lowest values of this indicator were associated with a more expressive reduction in CVC, mainly related to yellow fever, pentavalent, 10-valent pneumococcal conjugate, Human rotavirus, and triple viral (protecting against measles, mumps, and rubella - MMR) vaccines.

Conclusion

Although Brazil has a successful and exemplary record in combating several diseases, mainly due to the high rate of CVC, the continuous reduction in this coverage must be thoroughly evaluated by health managers.

COVID-19 in Brazil: a 3-year update

Three years into the coronavirus disease (COVID)-19 pandemic and the world is still struggling with the aftermath of this global health crisis. In Brazil, we are witnessing serious economic, health, social, and political problems. The rapid spread of the virus in our country was the result of a shortage of vaccines and the lack of an effective national campaign to identify and report cases. This health crisis also intensified social inequalities, hitting Indigenous peoples hard due to the lack of access to health services. In addition, rising unemployment and overcrowding of the health system made contagion possible, especially among the most vulnerable, increasing the number of serious cases of the disease. It is important to highlight that emotional problems worsened, the educational system was severely affected, and domestic violence increased during the confinement period, in addition to the fact that the pandemic exposed the great disparities of regional inequalities that exist across the country, mainly concerning health management.

Vaccine development against tuberculosis before and after Covid-19

Coronavirus disease (Covid-19) has not only shaped awareness of the impact of infectious diseases on global health. It has also provided instructive lessons for better prevention strategies against new and current infectious diseases of major importance. Tuberculosis (TB) is a major current health threat caused by Mycobacterium tuberculosis (Mtb) which has claimed more lives than any other pathogen over the last few centuries. Hence, better intervention measures, notably novel vaccines, are urgently needed to accomplish the goal of the World Health Organization to end TB by 2030. This article describes how the research and development of TB vaccines can benefit from recent developments in the Covid-19 vaccine pipeline from research to clinical development and outlines how the field of TB research can pursue its own approaches. It begins with a brief discussion of major vaccine platforms in general terms followed by a short description of the most widely applied Covid-19 vaccines. Next, different vaccination regimes and particular hurdles for TB vaccine research and development are described. This specifically considers the complex immune mechanisms underlying protection and pathology in TB which involve innate as well as acquired immune mechanisms and strongly depend on fine tuning the response. A brief description of the TB vaccine candidates that have entered clinical trials follows. Finally, it discusses how experiences from Covid-19 vaccine research, development, and rollout can and have been applied to the TB vaccine pipeline, emphasizing similarities and dissimilarities.