Table 4 2018 yellow fever experiment results.

*P < 0.05, **P < .01, ***P < .005 (two-sided); OLS models with robust standard errors. Respondents are members of Survey Sampling International’s online panel in Brazil. For each outcome measure, higher values indicate greater belief in the claim or claims in question [measured on a Likert scale ranging from “not at all accurate” (1) to “very accurate” (4); see the Supplementary Materials for wording]. “Misperception belief” is a composite measure calculated as the mean of the three items listed. All misperception measures are false. “T” and “F” indicate true and false, respectively, for the other outcome measures.

(A) Correction effects on targeted yellow fever misperceptions
Misperception beliefs
(mean)
Yellow fever vaccine
ineffective
Life-threatening
side effects
Propolis protects from yellow fever
Myths correction−0.20***−0.03−0.20***−0.38***
(0.04)(0.06)(0.06)(0.06)
Constant (placebo)1.98***1.82***2.00***2.13***
(0.03)(0.04)(0.04)(0.04)
n1063107210721075
(B) Correction effects on other yellow fever beliefs
Spreads
via
mosquito
bite (T)
No
effective
vaccine (F)
Same
mosquito as
Zika (T)
Symptoms
include
fever,
vomiting (T)
Disease
can be
fatal (T)
Government
recommends
vaccine (T)
Yellow fever
in cities (T)
Vaccine
causes
immune
damage (F)
Hoax by
drug
companies (F)
Myths
correction
0.040.010.36***0.02−0.07*0.110.03−0.14*0.03
(0.04)(0.05)(0.06)(0.04)(0.04)(0.06)(0.04)(0.06)(0.05)
Constant
(placebo)
3.77***1.55***3.10***3.68***3.82***3.09***3.51***2.01***1.45***
(0.03)(0.03)(0.05)(0.02)(0.02)(0.04)(0.03)(0.04)(0.03)
n106810771070107510731073107310741068