ABSTRACT
Since April 2022, the world has been witnessing a rapidly spreading outbreak of acute hepatitis of unknown origin in children < 16 years old that has affected several countries around the world. Most of the cases have presented with the clinical picture of severe hepatitis that has led to resorting to liver transplantation in several cases. Despite the numerous theories that have been suggested on the possible underlying etiologies of the outbreak, an association with hepatitis A-E viruses and a link to COVID-19 vaccines have been excluded. Adenovirus serotype 41 has been detected in numerous cases, which makes it the most likely underlying cause of the disease. Nevertheless, other hypotheses are being investigated to justify the severity of the clinical picture, which is not typical of this type of virus. This review aims to summarize the current knowledge about the outbreak, highlight the suggested working hypotheses, and report the public health measures undertaken to tackle the outbreak.
ABSTRACT
The emergence of the SARS-CoV-2 Omicron variant (B.1.1.529) has created great global distress. This variant of concern shows multiple sublineages, importantly B.1.1.529.1 (BA.1), BA.1 + R346K (BA.1.1), and B.1.1.529.2 (BA.2), each with unique properties. However, little is known about this new variant, specifically its sub-variants. A narrative review was conducted to summarise the latest findings on transmissibility, clinical manifestations, diagnosis, and efficacy of current vaccines and treatments. Omicron has shown two times higher transmission rates than Delta and above ten times more infectious than other variants over a similar period. With more than 30 mutations in the spike protein's receptor-binding domain, there is reduced detection by conventional RT-PCR and rapid antigen tests. Moreover, the two-dose vaccine effectiveness against Delta and Omicron variants was found to be approximately 21%, suggesting an urgent need for a booster dose to prevent the possibility of breakthrough infections. However, the current vaccines remain highly efficacious against severe disease, hospitalisation, and mortality. Japanese preliminary lab data elucidated that the Omicron sublineage BA.2 shows a higher illness severity than BA.1. To date, the clinical management of Omicron remains unchanged, except for monoclonal antibodies. Thus far, only Bebtelovimab could sufficiently treat all three sub-variants of Omicron. Further studies are warranted to understand the complexity of Omicron and its sub-variants. Such research is necessary to improve the management and prevention of Omicron infection.