US coronavirus: Just over 50% of eligible Americans are fully vaccinated against Covid-19. But pace needs to pick up before a dangerous variant can take hold, Fauci says

But experts have warned that a Covid-19 variant first identified in India and now rising to prominence in the United Kingdom — the Delta variant, or B.1.617.2 — could pose considerable danger to those who are unvaccinated, including those who were previously infected by older strains.

Fauci, the National Institute of Allergy and Infectious Diseases director, warned that the Delta variant “may be associated…