Pfizer testing pill aimed at preventing COVID-19 infection

Pfizer has started testing its potential COVID-19 treatment as a preventive medicine aimed at warding off the virus if a close contact gets it.

The drugmaker says it will study the pill it is developing in combination with a low dose of the HIV drug ritonavir in people who are at least 18 years old and live in the same household with someone who is infected. The pill aims to block a key enzyme that the virus needs to replicate. Pfizer plans to enroll 2,660 people in the late-stage study.

Researchers expect that the use of ritonavir will help slow the breakdown of the potential treatment so it remains active longer to help fight the virus.

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