Second boosters for under-50s on hold amid drive to speed up new vaccine

Officials are hoping vaccine makers — Moderna and Pfizer and its German partner, BioNTech — are able to make the updated shots available as soon as early to mid-September instead of later in the fall, said three officials who spoke on the condition of anonymity because they were not authorized to talk about the issue.

The retooled boosters will contain components from the omicron subvariants BA.4 and BA.5 as well as the original formula, which was based on the version of the virus that spread globally in early 2020. The hope is that the redesigned boosters will be more effective in dealing with an evolving virus.

In late June, FDA advisers recommended including an omicron component in retooled boosters, and the agency directed the manufacturers to do so. The companies indicated they would probably deliver the new shots in October. But since then, officials have urged the firms to move faster in producing the shots. If the new boosters are available by early to mid-September, the officials said, it is unlikely the administration would authorize a second dose of the current boosters for people younger than 50.