WASHINGTON — The Biden administration published revised guidelines Wednesday for nursing home visits during the coronavirus pandemic, allowing guests to go inside to see residents regardless of whether they or the residents have been vaccinated.

The recommendations, released by the Centers for Medicare and Medicaid Services with comment from the Centers for Disease Control and Prevention, are the first revision to the federal government’s nursing home guidance since September.

Federal officials said in the new guidance that outdoor visits were still preferable because of a lower risk of transmission, even when residents and guests have been fully vaccinated.

In a statement laying out the reasons for updating the recommendations, Dr. Lee A. Fleisher, the chief medical officer at the Centers for Medicare and Medicaid Services, cited the millions of vaccines administered to nursing home residents and staff and a decline in coronavirus cases in nursing homes.

“CMS recognizes the psychological, emotional and physical toll that prolonged isolation and separation from family have taken on nursing home residents and their families,” he said.

Earlier in the pandemic, the coronavirus raced through long-term care facilities in the United States, accounting for more than a third of all virus deaths since late spring. But since the arrival of vaccines, new cases in nursing homes have fallen steeply, outpacing national declines.

The recommendations, which are not legally binding, did come with suggested limits, saying that “responsible indoor visitation” should be allowed at all times unless a guest is visiting an unvaccinated resident in a county where the COVID-19 positivity rate is higher than 10% and less than 70% of residents in the nursing home have been fully vaccinated. The guidance also says to limit visits if residents have COVID-19 or are in quarantine.

So-called compassionate care visits — when a resident’s health has severely deteriorated — should be allowed regardless of vaccination status or the county’s positivity rate, the guidance said.