WASHINGTON (CBS News) — Federal health officials said Wednesday that vaccinated Americans will need to get booster shots eight months after receiving their second dose of a COVID-19 vaccine to maximize its protection against the virus and extend its durability.

The nation’s leading public health and medical experts from the Department of Health and Human Services announced in a joint statement that the Biden administration is prepared to begin offering the boosters the week of September 20 and starting eight months after Americans received their second doses of Pfizer and Moderna’s two-shot vaccines.

Americans who were first to get vaccinated against COVID-19 — health care providers, nursing home residents and the elderly — will likely be eligible for a booster late next month, the public health officials said. The Biden administration will also launch efforts to deliver boosters directly to residents of long-term care facilities.