Oral drug to prevent COVID-19 after exposure reaches US market

Overview

Updated Jul 29

For years, the only move after a close COVID-19 exposure was to wait and watch for symptoms. Now there is a pill for that.

Shionogi's ensitrelvir, sold as XOCOVA, is the first oral drug cleared in the US to prevent COVID-19 after contact with an infected person. In its main trial, a five-day course cut the chance of symptomatic illness by 67 percent. The list price is about $1,400, so insurance coverage may decide who actually gets it.

Why it matters

Anyone exposed to COVID-19 now has a pill that can lower the odds of getting sick, if they start it within three days.

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Key Indicators

67%

Drop in symptomatic COVID-19

Relative risk reduction versus placebo through day 10 in the SCORPIO-PEP trial.

76%

Reduction in high-risk group

Effect was larger in a prespecified subgroup of high-risk participants.

$1,400

List price per course

Price before insurance for the five-day, once-daily regimen.

2,387

Trial participants

Household contacts aged 12 and up enrolled in the global Phase 3 study.

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Isao Teshirogi

President and Chief Executive Officer, Shionogi & Co.

Leading Shionogi's push to sell ensitrelvir beyond Japan

Organizations Involved

Shionogi & Co.

Pharmaceutical company

Maker and marketer of ensitrelvir (XOCOVA)

Osaka-based drugmaker that developed the oral antiviral ensitrelvir with Hokkaido University.

U.S. Food and Drug Administration

Federal regulatory agency

Approved XOCOVA for post-exposure prevention

The US regulator that decides which drugs can be sold and for what use.

Pfizer Inc.

Pharmaceutical company

Competitor whose Paxlovid failed as a prevention drug

Maker of Paxlovid, the leading oral COVID-19 treatment, which fell short as a prevention drug.

Timeline

April 2022 July 2026

10 events Latest: July 28th, 2026 · 2 months ago

Tap a bar to jump to that date

July 2026
XOCOVA goes on sale in the US
Latest Launch

Shionogi announced US availability of the five-day pill regimen, priced at about $1,400 before insurance.
July 28th, 2026
June 2026
Japan approves XOCOVA for children aged 6 to 11
Regulatory

Japan cleared a pediatric dosage of ensitrelvir for children aged 6 to under 12 years weighing at least 20 kg, along with new 25 mg tablets sized for smaller patients. The label covers treatment of COVID-19, not prevention.
June 19th, 2026
May 2026
FDA approves ensitrelvir for prevention
Regulatory

The FDA cleared XOCOVA to prevent COVID-19 in people 12 and older after exposure. It is the first oral drug with that use.
May 31st, 2026
New England Journal of Medicine publishes the data
Publication

The journal published SCORPIO-PEP results: symptomatic COVID-19 hit 2.9 percent on ensitrelvir versus 9.0 percent on placebo, a 67 percent reduction.
May 13th, 2026
March 2026
Japan approves the prevention use
Regulatory

Japan added post-exposure prevention as an approved use for ensitrelvir, ahead of the US decision.
March 23rd, 2026
March 2025
Prevention results shown at CROI
Trial Result

Shionogi presented SCORPIO-PEP data at a scientific conference, the first oral antiviral to prevent COVID-19 after exposure in a Phase 3 study.
March 10th, 2025
March 2024
Japan upgrades to standard approval
Regulatory

Japan converted the emergency clearance into full standard approval for treating SARS-CoV-2 infection.
March 5th, 2024
June 2023
SCORPIO-PEP prevention trial begins
Trial

Shionogi launched a global Phase 3 study testing ensitrelvir in household contacts of infected people. Enrollment ran through September 2024.
June 1st, 2023
November 2022
Japan grants emergency approval for treatment
Regulatory

Japan's health ministry cleared ensitrelvir (Xocova) to treat SARS-CoV-2 infection under its emergency approval system.
November 22nd, 2022
April 2022
Paxlovid falls short as a prevention drug
Trial Result

Pfizer's EPIC-PEP trial failed to show a statistically significant benefit for Paxlovid as post-exposure prevention. The result left a gap in the market.
April 29th, 2022

Scenarios

Shionogi reports US XOCOVA sales in its financial results

Likely Resolves by Aug 31, 2027

Discussed by: Shionogi investor filings; pharmaceutical trade press

The launch gives Shionogi a US revenue line for the first time. If uptake is real, the company will name a US or Americas figure for XOCOVA in a quarterly or annual report. Weak demand, driven by the $1,400 price and a tight 72-hour window, could leave the number too small to break out.

FDA extends ensitrelvir to children under 12

Possible Resolves by Jul 28, 2028

Discussed by: Shionogi pipeline disclosures; Contemporary Pediatrics

Shionogi has pursued pediatric use elsewhere, including a Japanese filing for children as young as six. A US pediatric approval would widen the drug's reach to households with young kids, the setting where the trial was run. It depends on new data and an FDA review.

Ensitrelvir wins a US treatment indication

Uncertain Resolves by Jul 28, 2028

Discussed by: AJMC; infectious-disease clinicians

In the US, ensitrelvir is approved only for prevention, not for treating people already sick, after its treatment trial fell short of the US bar. A new or reanalyzed study could change that and put the pill in direct competition with Paxlovid. Approval would require fresh FDA action.

A second oral drug reaches the US market for prevention

Unlikely Resolves by Jul 28, 2028

Discussed by: Pharmaceutical trade press; industry analysts

Ensitrelvir is the only oral post-exposure option after Paxlovid failed at that job. A rival could revive a prevention program and file for approval, ending the monopoly. Most large makers have stepped back from COVID-19 antivirals, making near-term competition a long shot.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

November 2000

Tamiflu approved for flu prevention (2000)

The FDA cleared oseltamivir (Tamiflu) to prevent influenza in people exposed to a sick household member, not just to treat those already ill. A short course taken after contact lowered the chance of coming down with flu.

Then

Doctors began prescribing Tamiflu to families and nursing homes during outbreaks.

Now

Post-exposure antiviral use became a standard tool in managing seasonal flu clusters.

Why this matters now

It shows the same treat-and-prevent playbook that ensitrelvir now brings to COVID-19.

April 2022

Paxlovid EPIC-PEP trial (2022)

Pfizer tested its oral antiviral Paxlovid as a way to prevent COVID-19 in people exposed by a household member. The pill cut symptomatic infection by 32 to 37 percent, but the results were not statistically significant.

Then

Pfizer dropped the prevention use and kept Paxlovid as a treatment.

Now

The failure left no oral option for people who wanted protection right after an exposure.

Why this matters now

Ensitrelvir succeeded where Paxlovid did not, which is why it can claim a first.

January 2023

Evusheld loses its authorization (2023)

Evusheld, an antibody shot from AstraZeneca, was authorized to prevent COVID-19 in people with weak immune systems. New Omicron subvariants slipped past the antibodies, and the FDA pulled its authorization.

Then

Immunocompromised patients lost their main preventive option overnight.

Now

It exposed how fast the evolving virus can defeat prevention tools tied to specific variants.

Why this matters now

Ensitrelvir targets a viral protein that mutates less than the spike antibodies aim at, a point Shionogi stresses for durability.