Live, attenuated, tetravalent Butantan- Dengue vaccine in children and adults

BACKGROUND Butantan–Dengue Vaccine (Butantan-DV) is an investigational, single-dose, live, attenuated, tetravalent vaccine against dengue disease, but data on its overall efficacy are needed. METHODS In an ongoing phase 3, double-blind trial in Brazil, we randomly assigned participants to receive Butantan-DV or placebo, with stratification according to age (2 to 6 years, 7 to 17 years, and 18 to 59 years); 5 years of follow-up is planned. The objectives of the trial were to evaluate overall vaccine efficacy against symptomatic, virologically con firmed dengue of any serotype occurring more than 28 days after vaccination (the primary efficacy end point), regardless of serostatus at baseline, and to describe safety up to day 21 (the primary safety end point). Here, vaccine efficacy was assessed on the basis of 2 years of follow-up for each participant, and safety as solicited vaccine-related adverse events reported up to day 21 after injection. Key secondary objectives were to assess vaccine efficacy among participants according to dengue serostatus at baseline and according to the dengue viral serotype; efficacy according to age was also assessed. RESULTS Over a 3-year enrollment period, 16,235 participants received either Butantan-DV (10,259 participants) or placebo (5976 participants). The overall 2-year vaccine effi cacy was 79.6% (95% confidence interval [CI], 70.0 to 86.3) — 73.6% (95% CI, 57.6 to 83.7) among participants with no evidence of previous dengue exposure and 89.2% (95% CI, 77.6 to 95.6) among those with a history of exposure. Vaccine effi cacy was 80.1% (95% CI, 66.0 to 88.4) among participants 2 to 6 years of age, 77.8% (95% CI, 55.6 to 89.6) among those 7 to 17 years of age, and 90.0% (95% CI, 68.2 to 97.5) among those 18 to 59 years of age. Efficacy against DENV-1 was 89.5% (95% CI, 78.7 to 95.0) and against DENV-2 was 69.6% (95% CI, 50.8 to 81.5). DENV-3 and DENV-4 were not detected during the follow-up period. Solicited systemic vaccine- or placebo-related adverse events within 21 days after injection were more common with Butantan-DV than with placebo (58.3% of participants, vs. 45.6%). CONCLUSIONS A single dose of Butantan-DV prevented symptomatic DENV-1 and DENV-2, regard less of dengue serostatus at baseline, through 2 years of follow-up. (Funded by Instituto Butantan and others; DEN-03-IB ClinicalTrials.gov number, NCT02406729, and WHO ICTRP number, U1111-1168-8679.)

The impact of an enhanced health surveillance system for COVID-19 management in Serrana - Brazil

Objective To describe the successful implementation of an enhanced public health surveillance system based on early detection, tracing contacts, and patient follow-up and support. Study design A prospective observational cohort study conducted in Serrana, São Paulo State, Brazil. Methods The implementation was based on four axes: increasing the access to SARS-CoV-2 testing; correct swab collection; testing patients with mild symptoms; and patient follow-up. Positivity rate, patient demographic and clinical characteristics, dynamics of disease severity, SARS-CoV-2 genome evolution, and the impact on COVID-19 research were assessed from August 23, 2020 to February 6, 2021 (between epidemiological week 35/2020 and 5/2021, a total of 24 weeks). Results The number of sites collecting rt-PCR for SARS-CoV-2 was increased from one to seven points and staff was trained in the correct use of personal protective equipment and in the swab collection technique. During the study period, 6728 samples were collected from 6155 participants vs. 2770 collections in a similar period before. SARS-CoV-2 RNA was detected in 1758 (26.1%) swabs vs. 1117 (36.7%) before the implementation of the surveillance system (p < 0.001). Positivity rates varied widely between epidemiological weeks 35/2020 and 5/2021 (IQR, 12.8%–31.3%). Out of COVID-19 patients, 91.1% were adults at a median age of 35 years (IQR, 25–50 years), 42.6% were men and 57.4% were women, with a SARS-CoV-2 positivity rate of 28.6% and 24.4% (p < 0.001), respectively. The most common symptoms were headache (72.6%), myalgia (65.0%), and cough (61.7%). Comorbidities were found in 20.8% of patients, the most common being hypertension and diabetes. According to the World Health Organization clinical progression scale, 93.5% of patients had mild disease, 1.6% were hospitalized with moderate disease, 3.2% were hospitalized with severe disease, and 1.4% died. The enhanced surveillance system led to the development of COVID-19 related research. Conclusions The enhanced surveillance system in Serrana improved COVID-19 understanding and management. By integrating community and academic institutions, it was possible to monitor SARS-CoV-2 positive cases and variants, follow the epidemic trend, guide patients, and develop relevant research projects.

Plasmablast expansion following the tetravalent, live-attenuated dengue vaccine Butantan-DV in DENV-Naïve and DENV-exposed individuals in a Brazilian cohort

An effective vaccine against the dengue virus (DENV) should induce a balanced, long-lasting antibody (Ab) response against all four viral serotypes. The burst of plasmablasts in the peripheral blood after vaccination may reflect enriched vaccine-specific Ab secreting cells. Here we characterize the acute plasmablast responses from naïve and DENV-exposed individuals following immunization with the live attenuated tetravalent (LAT) Butantan DENV vaccine (Butantan-DV). The frequency of circulating plasmablasts was determined by flow cytometric analysis of fresh whole blood specimens collected from 40 participants enrolled in the Phase II Butantan-DV clinical trial (NCT01696422) before and after (days 6, 12, 15 and 22) vaccination. We observed a peak in the number of circulating plasmablast at day 15 after vaccination in both the DENV naïve and the DENV-exposed vaccinees. DENV-exposed vaccinees experienced a significantly higher plasmablast expansion. In the DENV-naïve vaccinees, plasmablasts persisted for approximately three weeks longer than among DENV-exposed volunteers. Our findings indicate that the Butantan-DV can induce plasmablast responses in both DENV-naïve and DENV-exposed individuals and demonstrate the influence of pre-existing DENV immunity on Butantan DV-induced B-cell responses.

An open-label randomized controlled parallel-group pilot study comparing the immunogenicity of a standard-, double- and booster-dose regimens of the 2014 seasonal trivalent inactivated influenza vaccine in kidney transplant recipients

Background: Immunogenicity of influenza vaccine in transplant recipients is suboptimal and alternative vaccination regimens are necessary. Methods: We compared the immunogenicity of a standard-dose trivalent inactivated influenza vaccination (SDTIIV), double-dose trivalent inactivated influenza vaccination (DDTIIV) and booster-dose trivalent inactivated influenza vaccination (BDTIIV) of the 2014 seasonal trivalent inactivated influenza vaccine in kidney transplant recipients. We randomized 176 participants to SDTIIV (59), DDTIIV (59) and BDTIIV regimens (58). Antibody titres were determined by hemagglutination inhibition at enrollment and 21 days post-vaccination. Seroprotection rates (SPR), seroconversion rates (SCR) and geometric mean ratios (GMR) were analyzed separately for participants with low (<1:40) and high (≥1:40) pre-vaccination antibody titres. Results: Vaccination was confirmed for 172 participants. Immunogenicity analysis was done for 149 participants who provided post-vaccination blood samples. In the subgroup with high pre-vaccination antibody titres, all vaccination regimens induced SPR >70% to all antigens, but SCR and GMR were below the recommendations. In the subgroup with low pre-vaccination antibody titres, DDTIIV and BDTIIV regimens induced adequate SCR >40% and GMR >2,5 for all antigens, while SDTIIV achieved the same outcomes only for influenza B. SPR were >70% only after DDTIIV (A/H1N1 - 77.8%) and BDTIIV (A/H3N2 - 77.8%). BDTIIV regimen independently increased seroprotection to A/H1N1 (PR=2.58; p=0.021) and A/H3N2 (PR=2.21; p=0.004), while DDTIIV independently increased seroprotection to A/H1N1 (PR=2.59; p=0.021). Conclusion: Our results suggest that DDTIIV and BDTIIV regimens are more immunogenic than SDTIIV, indicating the need for head-to-head multicenter clinical trials to further evaluate their efficacy.

Learning from combination HIV prevention programmes to face COVID-19 emerging pandemic / Aprender de los programas combinados de prevención del VIH para enfrentar la pandemia emergente COVID-19

Abstract Before a vaccine against SARS-CoV-2 became available, several measures to control COVID-19 pandemic are necessary. Analogously, in the absence of an available vaccine, Combination HIV Prevention Programmes have consolidated a large experience of biomedical, behavioral and structural interventions suitable for several epidemiological settings. Adaptation of such experiences can organize mid-term and long-term responses to face COVID-19.

Resumen Antes de que se disponga de una vacuna contra el SARS-CoV-2, son necesarias varias medidas para controlar la pandemia de COVID-19. En forma análoga, en ausencia de una vacuna disponible, los Programas de Prevención del VIH combinados han consolidado una gran experiencia de intervenciones biomédicas, conductuales y estructurales adecuadas para varios entornos epidemiológicos. La adaptación de estas experiencias puede organizar respuestas a mediano y largo plazo para hacer frente a la epidemia de COVID-19.

Learning from combination HIV prevention programmes to face COVID-19 emerging pandemic / Aprender de los programas combinados de prevención del VIH para enfrentar la pandemia emergente COVID-19

Before a vaccine against SARS-CoV-2 became available, several measures to control COVID-19 pandemic are necessary. Analogously, in the absence of an available vaccine, Combination HIV Prevention Programmes have consolidated a large experience of biomedical, behavioral and structural interventions suitable for several epidemiological settings. Adaptation of such experiences can organize mid-term and long-term responses to face COVID-19.

Informed consent for controlled human infection studies in low‐ and middle‐income countries: ethical challenges and proposed solutions

In controlled human infection studies (CHIs), participants are deliberately exposed to infectious agents in order to better understand the mechanism of infection or disease and test therapies or vaccines. While most CHIs have been conducted in high‐income countries, CHIs have recently been expanding into low‐ and middle‐income countries (LMICs). One potential ethical concern about this expansion is the challenge of obtaining the voluntary informed consent of participants, especially those who may not be literate or have limited education. In some CHIs in LMICs, researchers have attempted to address this potential concern by limiting access to literate or educated populations. In this paper, we argue that this practice is unjustified, as it does not increase the chances of obtaining valid informed consent and therefore unfairly excludes illiterate populations and populations with lower education. Instead, we recommend that investigators improve the informed consent process by drawing on existing data on obtaining informed consent in these populations and interventions aimed at improving their understanding. Based on a literature review, we provide concrete suggestions for how to follow this recommendation and ensure that populations with lower literacy or education are given a fair opportunity to protect their rights and interests in the informed consent process.

When could human challenge trials be deployed to combat emerging infectious diseases? Lessons from the case of a Zika virus human challenge trial

Human challenge trials (HCTs) deliberately infect participants in order to test vaccines and treatments in a controlled setting, rather than enrolling individuals with natural exposure to a disease. HCTs are therefore potentially powerful tools to prepare for future outbreaks of emerging infectious diseases. Yet when an infectious disease is emerging, there is often substantial risk and uncertainty about its complications, and few available interventions, making an HCT ethically complex. In light of the need to consider ethical issues proactively as a part of epidemic preparedness, we use the case of a Zika virus HCT to explore whether and when HCTs might be ethically justified to combat emerging infectious diseases. We conclude that emerging infectious diseases could be appropriate candidates for HCTs and we identify relevant considerations and provide a case example to illustrate when they might be ethically acceptable.

When could human challenge trials be deployed to combat emerging infectious diseases? Lessons from the case of a Zika virus human challenge trial

Human challenge trials (HCTs) deliberately infect participants in order to test vaccines and treatments in a controlled setting, rather than enrolling individuals with natural exposure to a disease. HCTs are therefore potentially powerful tools to prepare for future outbreaks of emerging infectious diseases. Yet when an infectious disease is emerging, there is often substantial risk and uncertainty about its complications, and few available interventions, making an HCT ethically complex. In light of the need to consider ethical issues proactively as a part of epidemic preparedness, we use the case of a Zika virus HCT to explore whether and when HCTs might be ethically justified to combat emerging infectious diseases. We conclude that emerging infectious diseases could be appropriate candidates for HCTs and we identify relevant considerations and provide a case example to illustrate when they might be ethically acceptable.

Development of vaccines against Zika virus

Zika virus is an emerging pathogen of substantial public health concern to human beings. Although most infections are asymptomatic or present with benign, self-limited symptoms, a small percentage of patients have complications, such as congenital anomalies in the developing fetus of pregnant women infected with the virus and neurological complications (eg, Guillain-Barre syndrome). To date, there is no vaccine, antiviral drug, or other modality available to prevent or treat Zika virus infection. In this Review, we examine vaccine development efforts for Zika virus to date and research gaps in the development of candidate vaccines against Zika virus. Top research priorities should include development of a better understanding of immunity to Zika virus to establish clear correlates of protection; determination of what effect, if any, Zika vaccine-induced immune responses will have on subsequent dengue virus infection; evaluation of vaccine immunogenicity and efficacy in healthy adults and in the various subpopulations affected by Zika virus infection (children, pregnant women, women of childbearing age, and eldery people); and identification of the molecular mechanisms that underlie birth defects and neurological sequelae related to Zika virus.

Development of vaccines against Zika virus

Zika virus is an emerging pathogen of substantial public health concern to human beings. Although most infections are asymptomatic or present with benign, self-limited symptoms, a small percentage of patients have complications, such as congenital anomalies in the developing fetus of pregnant women infected with the virus and neurological complications (eg, Guillain-Barre syndrome). To date, there is no vaccine, antiviral drug, or other modality available to prevent or treat Zika virus infection. In this Review, we examine vaccine development efforts for Zika virus to date and research gaps in the development of candidate vaccines against Zika virus. Top research priorities should include development of a better understanding of immunity to Zika virus to establish clear correlates of protection; determination of what effect, if any, Zika vaccine-induced immune responses will have on subsequent dengue virus infection; evaluation of vaccine immunogenicity and efficacy in healthy adults and in the various subpopulations affected by Zika virus infection (children, pregnant women, women of childbearing age, and eldery people); and identification of the molecular mechanisms that underlie birth defects and neurological sequelae related to Zika virus.