Another volatile day of trading in health care stocks unfolded March 13, after a trebling of broader market carnage the day before and the declaration of a national emergency by U.S. President Donald Trump Friday afternoon. Substantial declines hit shares of Moderna Inc., Vaxart Inc. and Inovio Pharmaceuticals Inc., all of which had recently rallied on optimism over coronavirus-fighting efforts. Biopharma shares saw some recovery, with both the S&P 500 Health Care Sector and Nasdaq biotechnology indices each rising a bit more than 2% each before Friday's close.