The United States has done something amazing: developed and authorized three new vaccines and vaccinated half of its adult population, all within 17 months of learning of a new disease, Covid-19. Yet vaccine demand is falling—daily doses administered have been declining for the past seven weeks. There are now fewer doses administered each day than on the day Joe Biden took office. Almost one-fifth of unvaccinated people, in a recent poll by the Kaiser Family Foundation, say they definitely won’t get the shot or will only do so if required.
This is neither surprising nor concerning. People respond to risk. Year after year, less than half of the U.S. population chooses to be vaccinated for the seasonal flu. The primary reasons Americans give for skipping the shots are safety concerns and doubts about the effectiveness and need for vaccination. People cite the same concerns about the Covid-19 vaccines.
The demand for vaccines is determined by people weighing the benefits of vaccines (decreasing the probability of serious illness, hospitalization and death) against the risks (side effects, known and potentially unknown).
Demand for vaccination, reflected by daily doses administered, is waning as the risk of disease decreases. By early April, a study by the Competitive Enterprise Institute found the level of vaccine immunity in the population—19% fully immunized, 32% receiving at least one dose—plus a likely 200 million people with natural immunity from Covid-19 infection and recovery, was enough to decrease transmission of Covid-19 significantly and put herd immunity in sight. Covid-19 cases, hospitalizations and deaths declined, resulting in a decreased willingness of unvaccinated people to be inoculated.
Covid-19 disease severity is closely correlated with advancing age. People under 18 account for 0.1% of Covid-19 deaths. People under 50 comprise two-thirds of the U.S. population, but only 4.7% of Covid-19 deaths. Those 65 and older account for more than 80% of the deaths.