(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.) S. Jay Olshansky, University of Illinois at Chicago; Leonard Hayflick, University of California, San Francisco, and Ronald Hershow, University of Illinois at Chicago (THE CONVERSATION) A federal judge has dismissed a lawsuit filed by employees at a Houston hospital who did not want to be vaccinated for COVID-19, claiming that COVID-19 vaccines are unsafe.