On August 30, 2021,?after a systematic review of the data,?the Advisory Committee on Immunization Practices revised its interim recommendation to a standard recommendation for use of the Pfizer-BioNTech?COVID-19 vaccine in persons aged =16 years for the prevention of COVID-19. Continued use of the Pfizer-BioNTech COVID-19 vaccine, now fully approved by the FDA in persons aged =16 years, is recommended based on increased certainty that its benefits (prevention of asymptomatic infection, COVID-19, and associated hospitalization and death) outweigh vaccine-associated risks.

During a COVID-19 outbreak involving the Delta variant in a highly vaccinated incarcerated population, transmission rates were high, even among vaccinated persons. Although attack rates, hospitalizations, and deaths were higher among unvaccinated than among vaccinated persons, duration of positive serial test results was similar for both groups. Infectious virus was cultured from vaccinated and unvaccinated infected persons.

The focus of COVID-19 response strategies has often been on behavior change as a primary means of decreasing contact networks and thus transmission chains. However, contact patterns are driven, in large part, by socioeconomic inequities and structural racism and are nonmodifiable at the individual level in the absence of specific support.

Since last March, research teams around the world have scoured the genomes of more than 100,000 people with COVID-19, hoping to find genetic clues to who will be hit hardest by an infection with the virus SARS-CoV-2. What?s emerged from this effort is a dozen or so genetic variants that have a strong statistical association with a person?s chances of developing COVID-19 and becoming gravely ill with the disease.

Viral variants of concern may emerge with dangerous resistance to the immunity generated by the current vaccines to prevent coronavirus disease 2019 (Covid-19). Moreover, if some variants of concern have increased transmissibility or virulence, the importance of efficient public health measures and vaccination programs will increase. The global response must be both timely and science based.

Our results show that the B.1.617.1 variant was 6.8 times less susceptible, and the B.1.617.2 variant was 2.9 times less susceptible, to neutralization by serum from persons who had recovered from Covid-19 and from vaccinated persons than was the WA1/2020 variant. Despite this finding, a majority of the convalescent serum samples (79% [19 of 24 samples] against B.1.617.1 and 96% [23 of 24 samples] against B.1.617.2) and all serum samples from vaccinated persons still had detectable neutralizing activity above the threshold of detection against both variants through 3 months after infection or after the second dose of vaccine.

The highly contagious delta variant now accounts for more than 51% of COVID-19 cases in the U.S., according to new estimates released by the Centers for Disease Control and Prevention. The variant, also known as B.1.617.2, was first detected in India and is spreading quickly across the globe.