Merck & Co Inc said on Tuesday its COVID-19 pill was ineffective in reducing the risk of infection in people exposed to an infected individual in the same household.

The pill, Lagevrio, also known as molnupiravir, is already approved in markets, including the United States and Europe, to treat high-risk COVID-19 patients.

The late-stage trial showed that participants treated with the pill were 23.6% less likely to develop COVID than those given a placebo, failing to meet the main goal of the trial, Merck said.

Last June, Pfizer Inc halted enrollments in a trial for its COVID-19 antiviral drug, Paxlovid, to treat standard-risk patients after a study showed the treatment was not effective in reducing symptoms in that group.

(Reporting by Manas Mishra and Sriparna Roy in Bengaluru; Editing by Savio D'Souza)