Leaked CDC document: vaccinated people spreading Delta variant

Vaccinated people spreading Delta variant just as quickly as the unvaccinated: Leaked CDC document
[Media report.] The delta variant of the coronavirus appears to cause more severe illness than earlier variants and spreads as easily as chickenpox. It cites a combination of recently obtained, still-unpublished data from outbreak investigations and outside studies showing that vaccinated individuals infected with delta may be able to transmit the virus as easily as those who are unvaccinated. Vaccinated people infected with delta have measurable viral loads similar to those who are unvaccinated and infected with the variant. The document is an internal Centers for Disease Control and Prevention slide presentation, shared within the CDC and obtained by The Washington Post.

Read: Internal CDC document on breakthrough infections
[CDC Powerpoint.] An internal CDC document urges officials to “acknowledge the war has changed” and improve the public’s understanding of breakthrough infections.

Neutralizing Activity of Sera from Sputnik V-Vaccinated People against Variants of Concern (VOC: B.1.1.7, B.1.351, P.1, B.1.617.2, B.1.617.3) and Moscow Endemic SARS-CoV-2 Variants
Virus-neutralizing activity (VNA) of sera obtained from people vaccinated with Sputnik V in relation to internationally relevant genetic lineages B.1.1.7, B.1.351, P.1, B.1.617.2, B.1.617.3 and Moscow endemic variants B.1.1.141 (T385I) and B.1.1.317 (S477N, A522S) with mutations in the RBD domain has been assessed. The data obtained indicate no significant differences in VNA against B.1.1.7, B.1.617.3 and local genetic lineages B.1.1.141 (T385I), B.1.1.317 (S477N, A522S) with RBD mutations. For the B.1.351, P.1, and B.1.617.2 statistically significant 3.1-, 2.8-, and 2.5-fold, respectively, VNA reduction was observed. Notably, this decrease is lower than that reported in publications for other vaccines.

Delta variants of SARS-CoV-2 cause significantly increased vaccine breakthrough COVID-19 cases in Houston, Texas
[Preprint.] We sequenced the genomes of 4,920 SARS-CoV-2 from patient samples acquired March 15, 2021 through July 24, 2021 in the Houston Methodist hospital system and studied vaccine breakthrough cases. During the study period Delta variants increased to cause 94% of all COVID-19 cases and spread throughout the metropolitan Houston area. In addition, Delta variants caused a significantly higher rate of vaccine breakthrough cases (17.4% compared to 5.8% for all other variants). Importantly, only 8.4% of all COVID-19 cases occurred in fully vaccinated individuals, and relatively few of these patients required hospitalization. Individuals with vaccine breakthrough cases caused by Delta variants (n = 194) had a low median PCR cycle threshold (Ct) value (a proxy for high virus load), and this value was not significantly different than the median Ct value observed in unvaccinated patients with COVID-19 caused by Delta variants. These data are consistent with the potential ability of fully vaccinated individuals to transmit SARS-CoV-2 to others. Our genomic and epidemiologic data emphasize that vaccines used in the United States are highly effective in decreasing severe COVID-19 disease, hospitalizations, and deaths.

A Possible Role of Remdesivir and Plasma Therapy in the Selective Sweep and Emergence of New SARS-CoV-2 Variants
Since summer 2020, SARS-CoV-2 strains at the origin of the COVID-19 pandemic have suddenly been replaced by new SARS-CoV-2 variants, some of which are highly transmissible and spread at a high rate. The usual coronavirus mutation rate through genetic drift alone cannot account for such rapid changes. Recent reports of the occurrence of such mutations in immunocompromised patients who received remdesivir and/or convalescent plasma or monoclonal antibodies to treat prolonged SARS-CoV-2 infections led us to hypothesize that experimental therapies that fail to cure the patients from COVID-19 could favor the emergence of immune escape SARS-CoV-2 variants. We review here the data that support this hypothesis and urge physicians and clinical trial promoters to systematically monitor viral mutations.