The Biden administration announced Wednesday it was recommending people who have been fully inoculated against Covid-19 receive a booster shot of vaccine to better protect the public as the delta variant surges across the country.

“Based on our latest assessment, the current protection against severe disease, hospitalization and death could diminish in the months ahead, especially among people who are at higher risk or were vaccinated during the earlier phases of the vaccination rollout,” according to a statement issued by Biden administration health officials. “For that reason, we conclude that a booster shot will be needed to maximize vaccine-induced protection and prolong its durability.”

The statement said health officials recommended people receive a booster shot eight months after their second dose of vaccine.

The Biden administration has developed plans to offer the boosters starting the week of September 20, pending an Food and Drug Administration evaluation into the effectiveness and safety of receiving a third dose of vaccines produced by Pfizer and Moderna, the statement said.

The first to receive boosters will be those who got the earliest doses of vaccine, a group that largely consists of health care workers and nursing home residents.

The statement added that health officials expect booster shots will also be needed for those who received the one-shot Johnson & Johnson vaccine. That vaccine did not roll out until March, and the statement said more data was needed to assess when those shots might be necessary.

“Our top priority remains staying ahead of the virus and protecting the American people from Covid-19 with safe, effective and long-lasting vaccines especially in the context of a constantly changing virus,” the health officials said.