The study, which included 2,246 participants at high risk of developing severe symptoms and who had not been fully vaccinated, reveals that the pill can reduce the risk of hospitalization and death from COVID by 89% if taken within three days of the onset of symptoms, the company said Tuesday. Waiting five days to take the pill only slightly reduces its effectiveness to 88%. Around 6.5% of patients in the study who took the placebo pill were hospitalized, compared to only .7% of the people who took the Paxlovid pill. None of the patients in the study who took Paxlovid during the onset of COVID died. 

Notably, the pill is also a “potent inhibitor” of an enzyme associated with Omicron, according to laboratory analyses done by the company. This suggests that the antiviral pill’s effectiveness against Omicron is “robust” and will be able to interrupt the variant’s ability to replicate within the body. Pfizer is currently conducting additional studies of antiviral effectiveness against the Omicron variant.

“Emerging variants of concern, like Omicron, have exacerbated the need for accessible treatment options for those who contract the virus, and we are confident that, if authorized or approved, this potential treatment could be a critical tool to help quell the pandemic,” said the 

CEO of Pfizer Albert Bourla in a statement.

The pill’s effectiveness at reducing severe COVID symptoms was even stronger in elderly people. For participants 65 years and older, the pill reduced the potential for severe illness by 94%.

The study’s results announced on Tuesday follows an earlier Pfizer’s study released in November, which reported very similar results, with a reduced risk of 89% for hospitalization and no deaths. Just after Pfizer’s initial study last month, Merck clarified that their own antiviral pill’s effectiveness against hospitalization and death had declined from 50% to 30%. 

Pfizer also released an analysis of an ongoing clinical trial of Paxlovid on Tuesday. The population included both unvaccinated and vaccinated adults with lower risk of severe illness than the previous trial. The population treated with the antiviral pill was 70% less likely to be hospitalized than the untreated group, and had no deaths. 

The Centers for Disease Control and Prevention list the U.S. at a high level of community transmission. There are currently about 66,547 patients hospitalized for COVID-19, according to The New York Times tracker.

Treatment with Paxlovid would mean taking three pills twice a day over the course of five days, according to an NBC report. The pill is designed to interrupt the virus’ ability to replicate inside the body.

Pfizer’s new data has already been sent to the Food and Drug Administration, where their request for an Emergency Use Authorization (EUA) is pending, the company said. With extra data to confirm the pill’s efficacy, the company plans to have 80 million of the Paxlovid treatment available globally in 2022.

“Vaccination remains the first line of defense and the best tool we have against COVID-19. We also believe it is important that we have treatment options available to support those who become ill from, or are exposed to, the virus,” a spokesperson for Pfizer told Fortune.