COVID-19 strategies built around 'herd immunity' are problematic
The idea of building herd immunity—increasing the number of infected to such a degree that naturally occurring immunity would outstrip the coronavirus, while isolating the elderly and others at greatest risk of the disease—has been tossed around in the United States, the United Kingdom and elsewhere. This week, however, U.K. officials appear to be backing away from that approach.
But the kind of "herd immunity" strategy being discussed in the U.K. does not acknowledge a critical gap in our understanding of COVID-19, said Dr. Judith Wasserheit, chair of the University of Washington Department of Global Health and co-director of the MetaCenter for Pandemic Preparedness and Global Health Security to provide some perspective on the tactic.
The extensive interaction across age groups in most communities makes separation a challenge, she said.
"Grandparents are often the primary people taking care of children and adolescents while parents work (including working remotely), especially in lower-income families; and young adults are often the people who care for parents and other older adults who can no longer function completely independently," Dr. Wasserheit said.
"Infection with this virus seems to be more likely to be mild, minimally symptomatic or asymptomatic in children, adolescents and young adults, and we know that transmission can occur in these settings. So it would be quite challenging to separate older adults from potentially infectious younger members of the population.
"In addition, we do not know how frequently immunity occurs after infection with this virus, and if it occurs, how strong that immunity is and how long it lasts."