TABLE 6.

Most common inaccurate ideas found in explanations of how vaccines work, in order of prevalence, and their raw agreement levels, Cohen’s kappa, and prevalence in all student responses

Misconceptiona	Raw agreement	Cohen’s kappab	% All student responses (n = 635)
A vaccine contains the pathogen in an unmodified form. “It’s a cocktail of different things, including whatever virus its meant to protect you from, gets injected into bloodstream so your immune system can begin to build antibodies against it.”—EBM student	88%	0.75	28% (n = 180)
Vaccines are primarily a treatment or a cure. “It even helps to clean out an infection you might already have.”—EBM student	92%	0.67	11% (n = 67)
A vaccine directly harms or fights the pathogen, not through the immune system. “A vaccine works by a doctor/nurse injecting fluid into your body. The fluid is the actual injection that fights off diseases.”—PH student	95%	0.70	6.9% (n = 44)
Vaccines are mainly injected directly into the bloodstream. “A vaccine is injected through a vein which would mean that it goes through the inferior vena cava of the heart and eventually distributes from the aorta to the systemic circulation.”—ABM student	92%	0.58	6.9% (n = 44)
A single vaccine provides immunity to all pathogens or diseases “Through there the body will take in the vaccine and is used to help take over the body so no other known disease can take over the body.”—EBM student	92%	0.25	6.8% (n = 43)

^aExamples are given of each idea, and the words that most directly correspond to the idea are bolded.

^bCohen’s kappas of 0.20–0.40 are considered to indicate “fair” agreements, 0.40–0.60 to be “moderate” agreement, 0.60–0.80 to be “substantial” agreement,” and 0.80–1 to be “excellent” agreement (Landis and Koch, 1977).