3/31—14 countries and WHO accuse China of withholding data
14 countries and WHO chief accuse China of withholding data from pandemic origins investigation
[Media report.] In a joint statement, the United States and 13 other governments, including the United Kingdom, Australia and South Korea, expressed concerns over the study's limited access to "complete, original data and samples." The European Union issued its own statement, expressing the same concerns in softer language. On Tuesday, WHO head Tedros said the report's assessment on the lab leak theory was not "extensive enough," and further data and studies would be needed to reach more robust conclusions. "Although the team has concluded that a laboratory leak is the least likely hypothesis, this requires further investigation, potentially with additional missions involving specialist experts, which I am ready to deploy," Tedros said.
New SARS-CoV-2 Variants — Clinical, Public Health, and Vaccine Implications
With regard to escape from natural immunity, the B.1.1.7 variant showed a modest decrease in neutralization activity, by a factor of 1.5, whereas the 501Y.V2 (B.1.351) variant showed complete escape from neutralizing antibodies in 48% of convalescent serum samples (21 of 44) obtained from patients who had previously had Covid-19. The potential of variants to escape naturally induced and vaccine-induced immunity makes the development of next-generation vaccines that elicit broadly neutralizing activity against current and potential future variants a priority.
Assessing transmissibility of SARS-CoV-2 lineage B.1.1.7 in England
The S-gene target failures (SGTF) data indicate a transient shift in the age composition of reported cases, with a larger share of under 20 year olds among reported Variant of Concern (VOC) than non-VOC cases. There is a consensus among all analyses that the VOC has a substantial transmission advantage with a 50% to 100% higher reproduction number.
Risk of SARS-CoV-2 reinfection after natural infection
The quality, quantity, and durability of protective immunity elicited by natural infection with SARS-CoV-2 are poor relative to the much higher levels of virus-neutralising antibodies and T cells induced by the vaccines currently being administered globally. Emergence of variants of SARS-CoV-2 with variable escape from natural and vaccine-induced immunity complicates matters further. Precise correlates of protection against SARS-CoV-2 are not known, but emerging variants of concern might shift immunity below a protective margin, prompting the need for updated vaccines. Interestingly, vaccine responses even after single dose are substantially enhanced in individuals with a history of infection with SARS-CoV-2. These data are all confirmation, if it were needed, that for SARS-CoV-2 the hope of protective immunity through natural infections might not be within our reach, and a global vaccination programme with high efficacy vaccines is the enduring solution.
Immunity to SARS-CoV-2 variants of concern
Concern about the B.1.351 variant derives from analyses of its effects on neutralization activity. The variant shows substantial ablation of any virus-neutralizing activity of therapeutic monoclonal antibodies (mAbs). Preliminary data suggest a reduced neutralizing response in sera from ChAdOx1 nCoV-19 vaccinees and reduced efficacy in preventing mild to moderate COVID-19.