New England Journal of Medicine publishes a 4,931-person case control study assessing the effectiveness of mRNA vaccines among US healthcare workers, three-quarters of whom had at least one pre-existing condition associated with severe COVID-19. The study was conducted from 28 December 2020 through 29 May 2021, and estimated the effectiveness of partial vaccination (from 14 days after the first dose through six days after the second dose) and full vaccination (seven or more days after the second dose). Overall, 45 percent of case participants –who tested positive for COVID-19 – were vaccinated (78 percent with Pfizer/BioNTech; 21 percent with Moderna) and 79 percent of control participants – who tested negative – were vaccinated (79 percent with Pfizer/BioNTech and 20 percent with Moderna). The study found that partial vaccination with any vaccine was 79.7 percent effective against symptomatic COVID-19, and full vaccination was 90.9 percent effective ( 88.8 percent for the Pfizer/BioNTech vaccine, versus 96.3 percent for the Moderna vaccine). Vaccine efficacy among a group of partially and fully vaccinated participants with immunocompromising conditions was 39.1 percent. Source

• Pfizer/BioNTech announces that it has made a deal with the Biden administration for 500 million doses of coronavirus vaccine which will be donated overseas. Source

• Globally, over six billion doses of coronavirus vaccines have been administered, although unequally: high income countries are vaccinated people over 20 times faster than low-income countries. Source

• Clover Biopharmaceuticals issues a press release to announce results from its over 30,000-person phase II/III trial of SCB-2019, its adjuvanted, protein-based coronavirus vaccine candidate. The company reported that SCB-2019 was 100 percent effective against severe COVID-19 and hospitalization, 83.7 percent effective against moderate-to-severe COVID-19, and 78.7 percent effective against COVID-19 of any severity caused by the Delta variant. Clover plans to submit applications for conditional approval by the end of 2021. Source

• SAB Biotherapeutics issues a press release to announce a $60.5 million award from BARDA and the US Department of Defence (adding to the over $200 million it has received from the US government), for advanced clinical development of SAB-185, a polyclonal antibody. SAB-185 is currently under in a phase II/III trial in non-hospitalized patients with mild to moderate COVID-19 who are at risk for disease progression. Source

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