Four months after their two dose regiments are administered, Moderna’s COVID-19 vaccine is more effective at preventing hospitalization than the Pfizer jab, according to data from 18 states released Friday by the Centers for Disease Control and Prevention.

Moderna’s efficacy against hospitalization at the 120-day mark is 92%. Pfizer’s is 77% and Johnson & Johnson is 68%.

“Although these real-world data suggest some variation in levels of protection by vaccine, all FDA-approved or authorized COVID-19 vaccines provide substantial protection against COVID-19 hospitalization,” the CDC notes.

The data was collected from 21 hospitals from March to August.

Over that entire period – not just at the four month mark – Moderna was the most effective at preventing hospitalizations, providing 93% protection. Pfizer provided 88% protection and Johnson & Johnson 71%. In other words, Moderna’s protection degraded just 1 percentage point after 120 days, while Pfizer and Johnson & Johnson saw bigger slips.

But the number at the four month mark is important because it offers public health officials a snap shot on how quickly the vaccines’ virus-fighting powers wane.

On Friday, an independent advisory panel to the Food and Drug Administration met to consider if they should recommend Pfizer booster shots. Their decision is not binding, but The New York Times reports, “The panel’s earlier meetings to consider coronavirus vaccine authorizations were mostly agreeable, ending in decisive votes in favor of the F.D.A.’s presumed position.”

President Joe Biden announced in August that he wanted to offer boosters by the end of September but he was waiting for approval from regulators.