SARS-CoV-2

A US team has analysed the presence of beta-amyloid deposits – which are linked to Alzheimer's disease – in the post-mortem retinas of four people with covid-19 and found that they were larger than in four people without covid. In complementary experiments, the SARS-CoV-2 spike protein in retinal organoids produced an increase in deposits, while the use of a drug that blocks the virus from binding to neurons reduced their accumulation. The results are published in the journal Science Advances.

An Australian team has conducted a study involving mice and humans that suggests that vaccine boosters would be more effective if administered in the same arm as the previous dose, at least in the short term. However, other recent research has pointed in the opposite direction. The results are published in the journal Cell.

Any infection can lead to sequelae and SARS-CoV-2 is no exception. However, the lack of rigorous studies has meant that, in 2023, uncertainty about the number of people affected remains high and treatments are scarce.

A French researcher has found genetic data showing that raccoon dogs, civets and other mammals susceptible to the infection with SARS-CoV-2 in the early 2020s in the Wuhan market in China. The findings have been presented to the Scientific Advisory Group on the Origin of Emerging Pathogens (SAGO), an expert group convened last year by the World Health Organisation. The data, collected by a team of Chinese scientists, were held in a database called GISAID, but had not been publicly reported and have been withdrawn. SAGO explained the origin of this data and the history of this research in a statement on 18 March.

In an interview with US television FOX News, FBI Director Christopher Wray said that, according to his office's assessment, "it is likely that the origin of the coronavirus pandemic was a leak from a laboratory in Wuhan, China". These statements follow media reports of a US Department of Energy report, accessed by the Wall Street Journal, that would also support "with low confidence" the leak hypothesis. Even so, a spokesman for the US National Security Council told AP that there is "no consensus" among intelligence agencies on the issue.

The end of the zero covid policy in China is leading to an increase in the number of cases and has revived the question of whether the epidemiological situation in China could favour the emergence of new variants of the SARS-CoV-2 coronavirus.

An international team with WHO participation concludes that global covid-19 infection rates may be higher than reported. The research, published in the journal PLOS Medicine, is based on a systematic review and meta-analysis of seroprevalence studies published between 1 January 2020 and 20 May 2022.

Regulatory agencies in the US and Europe - the FDA and the EMA - have licensed vaccination against Omicron focusing on different variants and sub-variants. Different procedures and studies in humans and animals have informed the agencies' decisions. Experts hope that these new doses will provide sufficient protection this autumn and winter to mitigate the impact of the next wave.

US researchers have designed an intranasal vaccination device that is capable of delivering immunising proteins through the mucosal surface. The research, published in Science Translational Medicine, shows that strong antibody responses against viruses such as HIV and SARS-CoV-2 have been achieved in mice and non-human primates.

After the acute phase of SARS-CoV-2 infection, children may develop long covid-19 symptoms. Research published in The Lancet Child and Adolescent Health examines the prevalence of these symptoms, quality of life, number of sick days, absences from school, and psychological and social outcomes in children aged 0-14 years who had been infected with SARS-CoV-2.