Genomic Investigations of Acute Hepatitis of Unknown Aetiology in Children (preprint)

Since the first reports of hepatitis of unknown aetiology occurring in UK children, over 1000 cases have been reported worldwide, including 268 cases in the UK, with the majority younger than 6 years old. Using genomic, proteomic and immunohistochemical methods, we undertook extensive investigation of 28 cases and 136 control subjects. In five cases who underwent liver transplantation, we detected high levels of adeno-associated virus 2 (AAV2) in the explanted livers. AAV2 was also detected at high levels in blood from 10/11 non-transplanted cases. Low levels of Adenovirus (HAdV) and Human Herpesvirus 6B (HHV-6B), both of which enable AAV2 lytic replication, were also found in the five explanted livers and blood from 15/17 and 6/9 respectively, of the 23 non-transplant cases tested. In contrast, AAV2 was detected at low titre in 6/100 whole bloods from child controls from cohorts with presence or absence of hepatitis and/or adenovirus infection. Our data show an association of AAV2 at high titre in blood or liver tissue, with unexplained hepatitis in children infected in the recent HAdV-F41 outbreak. We were unable to find evidence by electron microscopy, immunohistochemistry or proteomics of HAdV or AAV2 viral particles or proteins in explanted livers, suggesting that hepatic pathology is not due to direct lytic infection by either virus. The potential that AAV2, although not previously associated with disease, may, together with HAdV-F41 and/or HHV-6, be causally implicated in the outbreak of unexplained hepatitis, requires further investigation.

Comparing lateral flow testing with a rapid RT-PCR method for SARS-CoV-2 detection in the UK (preprint)

In late 2019, SARS-CoV-2 emerged in the Wuhan province of China. Rapid global spread led to the Covid-19 pandemic. Rapid and accurate detection of SARS-CoV-2 has become a vitally important tool in controlling the spread of the virus. Lateral flow devices (LFDs) offer the potential advantage of speed and on-site testing. The sensitivity of these devices compared to the gold standard RT-PCR has been questioned. We compared the performance of the Innova lateral flow kit, recommended by the UK government, with our rapid in-house RT-PCR protocol using stored positive patient samples. The LFD device was found to be 6,000-10,000 times less sensitive than RT-PCR for the detection of SARS-CoV-2. Overall, the LFD detected 46.2% of the positives detected by RT-PCR. 50% of the LFD results were observed to be weak positives, only visible after careful examination by experienced laboratory staff. At lower viral loads, such as 10,000-100,000 RNA copies/ml, the LFD detected 22.2% of positives. In addition, two strong positives (3 and 1.5 million RNA copies/ml) were not detected by the LFD. The argument for use of LFD kits, despite their lack of sensitivity, is that they detect infectious virus and hence contagious individuals. At present, there is a lack of scientific evidence supporting this claim. The LFD used in the UK fails to identify individuals with considerable viral loads and has been subject to a class I recall by the US FDA but is still approved and recommended for use by the UK government. We believe that using LFD testing for assessing SARS-CoV-2 infection risk is a strategy which has risks that outweigh any benefits.