Thread by @guerreroespejo

#OutBreak of acute #hepatitis among #children
650 probable cases of acute hepatitis of unknown
aetiology in children have been reported to WHO from 33 countries in 5 WHO Regions between 5 April and 26 May 2022.
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who.int/emergencies/di…

- Three quarters (75.4%) of cases are 5 years of age.

- Of 156 cases with information on hospital admission, 22 (14.1%) were admitted to an intensive care unit.

Of the 117 cases for which this information was available, 14 (12%) have received a liver #transplant.
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- Overall, 181 cases were tested for #adenovirus by any specimen type, of which 110 (60.8%) tested positive. The positivity rate was the highest in whole blood specimens (69.5%).
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Table. Classification of reported probable cases per country

- Of the 188 cases PCR tested for #SARSCoV2, 23 (12.2%) tested positive. Serology results for SARS-CoV-2 were only available for 26 cases, of which 19 (73.1%) had a positive finding.

- Of the 63 cases with data on COVID-19 vaccination, 53 (84.1%) were unvaccinated
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While #adenovirus is a plausible hypothesis as part of the pathogenesis mechanism, further investigations are ongoing for the causative agent

Adenovirus infection does not fully explain the more severe clinical picture observed with these cases.
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Factors such as increased susceptibility amongst young children following a lower level of circulation of #adenovirus during the COVID-19 pandemic, the potential emergence of a novel adenovirus, #SARSCoV2 co-infection or a complication of previous SARS-CoV-2
infection,...
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... leading to superantigen-mediated immune cell activation, proposed a causal mechanism of multisystem inflammatory syndrome in children need to be further investigated.
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