Merck's oral antiviral is less effective than previously thought
The S&P 500 is trading near session lows with a 1.9% decline in a risk-off trade. Merck (MRK 78.68, -3.66, -4.5%) is a notable laggard with a 4.5% decline after a study showed its COVID-19 oral antiviral was less effective than previously thought. The late-stage study indicated a 30% efficacy rate of reducing death or hospitalization, versus 48% from early results.  Moderna (MRNA 332.68, +59.27, +21.6%) and Pfizer (PFE 54.51, +3.61, +7.1%), meanwhile, are up big on the prospect for increased vaccine demand. MRNA is up 22%, and PFE is up 7%.