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Despite the availability of effective vaccines against COVID-19, booster vaccinations are needed to maintain vaccine-induced protection against variant strains and breakthrough infections. This study aimed to investigate the efficacy, safety, and immunogenicity of the Ad26.COV2.S vaccine (Janssen) as primary vaccination plus a booster dose.ENSEMBLE2 is a randomised, double-blind, placebo-controlled, phase 3 trial including crossover vaccination after emergency authorisation of COVID-19 vaccines. Adults aged at least 18 years without previous COVID-19 vaccination at public and private medical practices and hospitals in Belgium, Brazil, Colombia, France, Germany, the Philippines, South Africa, Spain, the UK, and the USA were randomly assigned 1:1 via a computer algorithm to receive intramuscularly administered Ad26.COV2.S as a primary dose plus a booster dose at 2 months or two placebo injections 2 months apart. The primary endpoint was vaccine efficacy against the first occurrence of molecularly confirmed moderate to severe-critical COVID-19 with onset at least 14 days after booster vaccination, which was assessed in participants who received two doses of vaccine or placebo, were negative for SARS-CoV-2 by PCR at baseline and on serology at baseline and day 71, had no major protocol deviations, and were at risk of COVID-19 (ie, had no PCR-positive result or discontinued the study before day 71). Safety was assessed in all participants; reactogenicity, in terms of solicited local and systemic adverse events, was assessed as a secondary endpoint in a safety subset (approximately 6000 randomly selected participants). The trial is registered with ClinicalTrials.gov, NCT04614948, and is ongoing.Enrolment began on Nov 16, 2020, and the primary analysis data cutoff was June 25, 2021. From 34 571 participants screened, the double-blind phase enrolled 31 300 participants, 14 492 of whom received two doses (7484 in the Ad26.COV2.S group and 7008 in the placebo group) and 11 639 of whom were eligible for inclusion in the assessment of the primary endpoint (6024 in the Ad26.COV2.S group and 5615 in the placebo group). The median (IQR) follow-up post-booster vaccination was 36·0 (15·0-62·0) days. Vaccine efficacy was 75·2% (adjusted 95% CI 54·6-87·3) against moderate to severe-critical COVID-19 (14 cases in the Ad26.COV2.S group and 52 cases in the placebo group). Most cases were due to the variants alpha (B.1.1.7) and mu (B.1.621); endpoints for the primary analysis accrued from Nov 16, 2020, to June 25, 2021, before the global dominance of delta (B.1.617.2) or omicron (B.1.1.529). The booster vaccine exhibited an acceptable safety profile. The overall frequencies of solicited local and systemic adverse events (evaluated in the safety subset, n=6067) were higher among vaccine recipients than placebo recipients after the primary and booster doses. The frequency of solicited adverse events in the Ad26.COV2.S group were similar following the primary and booster vaccinations (local adverse events, 1676 [55·6%] of 3015 vs 896 [57·5%] of 1559, respectively; systemic adverse events, 1764 [58·5%] of 3015 vs 821 [52·7%] of 1559, respectively). Solicited adverse events were transient and mostly grade 1-2 in severity.A homologous Ad26.COV2.S booster administered 2 months after primary single-dose vaccination in adults had an acceptable safety profile and was efficacious against moderate to severe-critical COVID-19. Studies assessing efficacy against newer variants and with longer follow-up are needed.Janssen ResearchDevelopment.

This article aims to analyse a fundamental issue in contemporary societies: the payment of taxes as a form of wealth distribution, with a particular emphasis for the tax evasion. In particular, this study deals with an African country, Mozambique. Here, from the one side, research on this subject is rare and, from the other side, the local government delegated to a Tax Authority the task to collect the taxes of the taxpayers. Through a qualitative approach, using an historical and sociological perspective, and starting from the analysis of the activity of the Tax Authority of Mozambique, this research shows, as its main conclusions, that the tax value collected by the Tax Authority is still far from what Mozambican government desired. This circumstance is due to structural factors, as the weak technical training of the employees of the Tax Authorities and the absence of a reliable database, as well as to subjective factors, first of all a pervasive corruption among the employees of that institution. Such elements make the work of the Tax Authority very difficult, and for these reasons it cannot accomplish with its own goals. Este artigo tenciona analisar uma questão de fundamental relevância nas sociedades contemporâneas: o pagamento dos impostos como forma de redistribuição da riqueza, com enfoque especial para a fuga ao fisco. De forma específica, o estudo debruça-se sobre a realidade de um país africano, Moçambique, em que, por um lado, as pesquisas sobre o tema são escassas, e por outro, o governo local confiou à Autoridade Tributária a tarefa de colectar os impostos dos contribuintes. Mediante uma abordagem qualitativa, de tipo histórico e sociológico, a partir da análise da actividade da Autoridade Tributária Moçambicana, o estudo conclui que o valor dos impostos arrecadado por parte da Autoridade Tributária ainda está aquém do desejado. Tal circunstância deve-se a factores estruturais, tais como escassa formação do pessoal técnico e ausência de uma base de dados fiável, assim como subjetivos, acima de tudo uma corrupção difusa entre os funcionários daquela instituição, que torna complicado o bom funcionamento da mesma, que não consegue cumprir com as suas próprias metas.