WHO pressures China on pandemic origin
With call for ‘raw data’ and lab audits, WHO chief pressures China on pandemic origin probe
[Science news report.] Tedros Adhanom Ghebreyesus is urging China to increase its transparency about the early days of the COVID-19 pandemic and allow greater access to its labs to help resolve the origin of SARS-CoV-2. Tedros also says WHO will create a new body to conduct the next phase of studies into the emergence of the virus.
China rebuffs WHO claims that it obstructed COVID-19 investigation
[Media report.] China's foreign ministry spokesman Zhao Lijian insisted the country had allowed experts "to see the original data that needed special attention", although "some information involves personal privacy and cannot be copied and taken out of the country". Zhao also dismissed Tedros' claims that "there was a premature push" to rule out the theory that the virus could have leaked from a virology lab in the central Chinese city.
Relative Ratios of Human Seasonal Coronavirus Antibodies Predict the Efficiency of Cross-Neutralization of SARS-CoV-2 Spike Binding to ACE2
[Preprint.] Here we performed a cross-sectional analysis of cross-reactivity and cross-neutralization to three SARS-CoV-2 antigens using pre-pandemic serum from four different groups: pediatrics and adolescents (<21 yrs of age), persons 21 to 70 yrs of age, persons older than 70 yrs of age, and persons living with HCV or HIV. We find that antibody cross-reactivity to SARS-CoV-2 antigens varied between 1.6% and 15.3% depending on the cohort and the isotype-antigen pair analyzed. We also demonstrate a broad range of neutralizing activity (0-45%) in pre-pandemic serum that interferes with SARS-CoV-2 spike attachment to ACE2. We identified antibodies to NL63 and OC43 as being the two most important predictors of latent variables responsible for protection, and 229E as being the least weighted. Our data support that exposure to sCoVs triggers various cellular and immune responses that influence the efficiency of SARS-CoV-2 spike binding to ACE2, and may impact COVID-19 disease severity through various other latent variables.
Viral infection and transmission in a large well-traced outbreak caused by the Delta SARS-CoV-2 variant
[Preprint.] We report the first local transmission of the Delta SARS-CoV-2 variant in mainland China. All 167 infections could be traced back to the first index case. The investigation on daily sequential PCR testing of the quarantined subjects indicated the viral load of the first positive test of Delta infections was ∼1000 times higher than that of the 19A/19B strains infections back in the initial epidemic wave of 2020, suggesting the potential faster viral replication rate and more infectiousness of the Delta variant at the early stage of the infection.
Rapid spread of the SARS-CoV-2 Delta variant in some French regions, June 2021
We analysed 9,030 RT-PCR variant-specific screening tests performed on samples collected in France in patients from 5 to 80 years old between 31 May and 21 June 2021. We found that samples bearing the L452R mutation but not the E484K or the E484Q mutation (consistent with the Delta variant), tended to increase in the Hauts-de-France, Île-de-France, Normandie, and Provence-Alpes-Côte d'Azur regions. The estimated transmission advantages of 79% (95% CI: 52–110%) the Delta variant over the Alpha variant are in line with that estimated in the UK.