Trying to reach “herd immunity” without a COVID-19 vaccine is a disastrous pandemic response strategy

Since the start of the coronavirus pandemic, use of the term “herd immunity” has spread almost as fast as the virus. But its use is fraught with misconceptions. In the U.K., officials briefly considered a herd immunity strategy to protect the most vulnerable members of its population by encouraging others to become exposed and develop immunity to the virus. Others reignited the discussion by focusing on how far we are from herd immunity. But trying to reach herd immunity without a vaccine would be a disastrous pandemic response strategy. As mathematics and computer science professors, we think it is important to understand what herd immunity actually is, when it’s a viable strategy and why, without a vaccine, it cannot reduce deaths and illnesses from the current pandemic. What is herd immunity? Epidemiologists define the herd immunity threshold for a given virus as the percentage of the population that must be immune to ensure that...