Commentary To reach herd immunity for COVID-19, according to the National Institutes for Health (NIH), the United States needs to reach an estimated 80 percent to 85 percent immunity level. As things stand, meeting that goal through vaccination will fail because, unlike Democrats who are being vaccinated in overwhelming numbers, almost half of Republicans–44 percent, according to Pew—are balking. As stressed last week to The Hill by a worried Francis Collins, the NIH’s director, “The hesitancy will begin to become the defining factor on whether we reach herd immunity or not.” Collins has a daunting challenge. Among the biggest factors driving skepticism, finds Pew, is lack of trust in the vaccine research and development process as well as tepid trust in scientists themselves. Among Republicans, only 26 percent have a great deal of confidence in medical scientists to act in the public’s best interest, a percentage that has fallen since …