The Effect of Vaccine Literacy on Parental Trust and Intention to Vaccinate after a Major Vaccine Scandal

"[S]hortly after a major vaccine scandal, higher literacy might help balance out some of the potentially negative consequences of exposure to contradictory information, which otherwise might lead to vaccine hesitancy or refusal."

There are a number of examples illustrating how misleading media reports may threaten trust and vaccination uptake across the globe. For instance, in 2003 in Nigeria, rumours were spread that the distribution of oral polio vaccines was an American conspiracy to spread HIV and cause infertility, which hampered previously successful efforts to reduce polio in the area. Health literacy, and more specifically vaccine literacy, might be a factor in reducing the negative effects of exposure to misleading reports on vaccination. This study explores the association between vaccine literacy and vaccination-related outcomes after misleading reports on a scandal concerning locally produced childhood vaccines emerged in 2016 in China.

The article begins by reviewing the literature on health literacy and vaccine hesitancy, defining the terms "functional health literacy" (reading and writing skills in a medical environment) and "critical health literacy" (being able to critically assess different sources and information and to systematically compare different outlets). Health literacy in the context of vaccination has proven to be a complex issue. Overall, research in the field is scarce, and further investigation is needed to draw systematic conclusions about the relationship between health literacy and vaccination-related outcomes (including compliance, intention, or trust).

To make headway in this quest, the researchers look at one vaccination controversy in China. In 2016, a former pharmacist, along with 202 contacts in 18 provinces, was caught by the police delivering vaccines to medical facilities that had not been stored in approved storage conditions. Parents, especially those whose children had been potentially exposed to the compromised vaccines, turned to social media outlets to discuss the issue and look for additional information. Reportedly, while the China Food and Drug Administration (CFDA) held a press conference to clarify the low risk of the compromised vaccines and, supported by the World Health Organization (WHO) China, provided further information on their website, "they failed to convincingly provide information on the issue".

Data for this study came from a cross-sectional survey that was conducted in Hangzhou, in the province of Zhejiang, China, in April 2016. Two kindergartens and one community health centre (CHC) were randomly selected in each of two districts. The total sample consisted of 520 men and 1,344 women overall. The main outcome variables are captured by these questions: "Do you trust domestically produced vaccines after this scandal?" and "After this scandal, would you choose domestically produced vaccines for your children?" Trust in domestically produced vaccines was measured using a 5-point Likert scale.

With regard to health literacy, the majority (71.7%) of respondents reported having difficulties finding comprehensive and correct information about the vaccine scandal, and 50.9% of the respondents indicated that it was difficult for them to understand the information they received about the scandal. On the other hand, only 29% of the respondents were able to correctly identify that the compromised vaccines were not effective but harmless. Female respondents had fewer difficulties in finding and understanding information on the vaccine scandal (p< 0.05). Parents with higher education had fewer difficulties understanding information about the vaccine scandal (p< 0.001) and were more likely to identify the correct answer with regard to the potential consequences of the compromised vaccines (p< 0.001).

After adjusting for social demographic characteristics, parents who had better functional vaccine literacy in understanding information concerning the vaccine scandal (odds ratio (OR) = 1.81, 95% confidence interval (CI) [1.15-2.86]; OR = 1.42, 95% CI [1.02-2.00]) and better critical health literacy (OR = 3.49 95% [2.53-4.83]; OR = 2.03, 95% CI [1.61-2.57]) were more likely to trust and choose domestically produced vaccines. Parents with undergraduate (OR = 0.59, 95% CI [0.39-0.90]) and graduate (OR = 0.44, 95% CI [0.24-0.82]) education were less likely to trust domestically produced vaccines than parents with lower education.

The study investigated trust and intention to vaccinate directly after the occurrence of a major vaccine scandal. Thus, it demonstrated the effects of health literacy on rather short-term outcomes, supporting the assumption of health literacy being an important factor in reducing the negative consequences of exposure to misleading information. This study also found that even though higher educational levels were associated with higher vaccine literacy, individuals with higher education were less likely to trust domestically produced vaccines. One possible explanation for this finding could be that parents with higher educational levels set a higher standard for vaccine safety.

"As China is launching the Healthy China 2030 and aiming to improve health literacy of the general population, efforts should be made to eradicate the difficulty for people to access and understand accurate information (functional health literacy) and to accurately interpret them (critical health literacy). Focusing on both functional and critical health literacy and tailoring toward different population groups could help to narrow the gap."