WASHINGTON (NewsNation Now) — The Centers for Disease Control and Prevention announced new insight Tuesday about how long the COVID-19 vaccine protects people from the coronavirus. These new details come as hospitalizations across the country are trending slightly downward — although they’re still at the highest level since winter.

Dr. Rochelle Walensky, the CDC’s top official, warned that the vaccine’s effectiveness might weaken over time and appears to decline in its ability to keep seniors out of the hospital.

Walensky says for people over 75, the protection from hospitalization drops to just above 80%.

According to data recently reviewed by a panel of vaccine experts advising the CDC, the vaccine still offers great protection against hospitalization for adults under 75, even during the surge of the delta variant at 94% effective.

The new analysis includes data from when the delta variant has become dominant.

“It is our own data, as well as international data, that has led us to be concerned that the waning we’re seeing for infection will soon lead to waning that we would see for hospitalizations, severe disease and death. Which is why it’s so critical now to plan ahead to remain ahead of the virus,” Walensky said.

It’s why the Biden administration is preparing to roll out booster shots. Previously, the administration said those should be available at the end of September.

Asked whether it’s safe for Americans to travel over Labor Day, Walensky said it would be safe for vaccinated people wearing masks, but people should use their own risk assessment.