Many older Americans, including those in nursing homes, aren’t getting booster shots.The Food and Drug Administration on Thursday approved the latest slate of annual Covid vaccines, clearing the way for Americans 6 months and older to receive updated shots in the midst of a prolonged summer surge of the virus.Pfizer and Moderna, the vaccine makers, are expected to begin shipping vaccines to pharmacies and doctors’ offices within days. The shots are tailored to a version of the virus that took off this spring before giving way to closely related variants, all of which appear to spread faster.For the frailest Americans, who have been dying of Covid in growing numbers this summer, the shots could offer a reprieve from a virus that disproportionately endangers those whose vaccinations are out of date.But the approval is occurring months after wily new variants began driving up infections, a matter of consternation for some scientists who have urged faster turnarounds for updated shots.In recent weeks, people have been hospitalized with Covid at a rate nearly twice as high as during the same time last summer. By late July, Covid was killing roughly 600 Americans each week, a substantial drop from this winter but double the number from this spring.The availability of boosters has not translated into actual vaccinations. By spring, only one in five adults had received last year’s updated Covid vaccine. Even older Americans, who are at far greater risk of being severely sickened, largely spurned the shots, with only 40 percent of people 75 and older taking last year’s vaccine.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.