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How Well Does COVID-19 Vaccination Protect Against the Delta Variant?

In a U.K. observational study, two doses of the Pfizer-BioNTech and Oxford/AstraZeneca vaccines had 88% and 67% effectiveness, respectively, against the Delta variant. As the Delta (B.1.617.2) SARS-CoV-2 variant fuels a global surge in COVID-19, an urgent clinical question concerns how effective the available vaccines are against this variant. Using […]

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Variant Proportions

Monitoring Variant Proportions Variants of SARS-CoV-2, the virus that causes COVID-19, are expected to continue to emerge. Some will emerge and disappear, and others will emerge and continue to spread and may replace previous variants. For example, the variant of the virus that caused the first U.S. COVID-19 cases in […]

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EU-Approved COVID-19 Vaccines Protect Against Delta Variant, Says Official

(Reuters) – Europe’s drug regulator said on Thursday the COVID-19 vaccines approved in the European Union offered protection against all coronavirus variants, including Delta, but called for active monitoring by vaccine manufacturers to stay alert. “There have been a number of variants over the last months and we expect more,” […]

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Pinpointing the Infectiousness of SARS-CoV-2 and Its Alpha (B.1.1.7) Variant

Asymptomatic infected individuals (and those infected with Alpha) had relatively high viral loads; samples from Alpha cases also had higher probability of viral culture positivity. Determining the infectiousness of individuals with COVID-19 requires considering degree of symptoms, time point within disease course, and whether the infection involves wild-type SARS-CoV-2 or […]

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SARS-CoV-2 Variant Classifications and Definitions

Key Points Genetic variants of SARS-CoV-2 have been emerging and circulating around the world throughout the COVID-19 pandemic. Viral mutations and variants in the United States are routinely monitored through sequence-based surveillance, laboratory studies, and epidemiological investigations. A US government interagency group developed a Variant Classification scheme that defines three […]

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