COVID-19 vaccine acceptance among Chinese and American middle-aged and elderly adults：A discrete choice experiment and propensity score matching study (Preprint)
Authors: Li Xialei , Feng Bojunhao , Jia Xiaocen , Guo Xiayi , He Zonglin , Liu Taoran , Yu Wenli , Ming Wai-Kit , Wu Yibo 
Published: June 2021

BACKGROUND

The COVID-19 epidemic is still far from over, and vaccination is considered an effective tool to curb its spread. Middle-aged and elderly people are more likely to be infected with the virus because of their frality and weaker immune systems. Therefore, it worth exploring their acceptance and preference of COVID-19 vaccines. Such data will help to develop and promote the COVID-19 vaccines.

OBJECTIVE

To qualify the acceptance and attribute preference of COVID-19 vaccines among middle-aged and elderly people in China and the United States.

METHODS

Quota sampling was used to investigate the demographic information and vaccine acceptance of middle-aged and elderly populations in China and the US. Through a discrete selection experiment, various attributes were set to quantify respondents’ preference in a vaccine trade-off. Propensity score matching methods were used to eliminate demographic difference between the two countries.

RESULTS

After propensity score matching, a total of 1604 respondents (802 from China and 802 from the US) were included. 71.7% and 74.7% of respondents in China and the US were willing to be vaccinated, and the social environment in China hinders vaccination, while the United States does the opposite. The CLOGIT showed that efficacy and the cost of vaccination are the two most important attributes for the public in China and the US (“efficacy” for the US, “cost” for China). Respondents preferred vaccines with 95% efficacy (China: odds ratio[OR] 1.82, 95%CI 1.71–1.94, P < .001; the US: odds ratio[OR] 6.40, 95% CI 5.97–6.85, P < .001; reference: 55% efficacy) and free (China: odds ratio[OR] 2.02, 95% CI 1.89–2.16, P < .001; the US: odds ratio[OR] 2.85, 95%CI 2.65-3.06, P < .001; reference: $200). Also, milder adverse effects and longer duration of the vaccine working were positively correlated with the public acceptance and willingness to receive the COVID-19 vaccine. Through the analysis of willingness to pay, the public was most willing to pay for reducing the vaccine’s adverse effects (37.476USD for the US, 140.503USD for China). However, the American public was willing to pay for a prolonged time of the vaccine working(1.375 USD per day increase).

CONCLUSIONS

Efforts should be made to increase vaccine acceptance among the middle-aged and elderly in China and the US. We propose that the two countries’ governments should strengthen the popularization of scientific and promote reasonable vaccine-related information to reduce the hindrance of the social environment to the public boycott of the vaccine. To make the public more willing to be vaccinated and achieve herd immunity, the two countries should reasonably regulate vaccine pricing, and scientists and pharmaceutical companies should remain committed to improving the efficacy of the vaccine, reducing adverse effects, prolonging the duration of vaccine works, and shortening the time for the vaccine to start working.