Fewer than 1 in 5 US parents say they'll get Covid-19 vaccines for kids under 5 as soon as they can, survey finds

Excerpt from the article: US children under 5 are getting closer to authorized Covid-19 vaccines, but most parents may be reluctant to actually get them when they become available, a new survey found. According to the Kaiser Family Foundation's Vaccine Monitor survey, published Wednesday, only 18% of parents of children under 5 said they would vaccinate their child against Covid-19 as soon as a vaccine was available.

What measure was used to summarize parents' willingness to have their children vaccinated? A. Cumulative incidence/ B. Incidence rate/ C. Prevalence