BackgroundUnderstanding how perceptions around immunity certificates are influenced by individual characteristics is important to inform evidence-based policy making and implementation strategies for services around immunity and vaccine certification.ObjectiveThis study aimed to assess what were the main individual factors influencing people’s perception of the importance of using COVID-19 immunity certificates, including health beliefs about COVID-19, vaccination views, sociodemographics, and lifestyle factors.MethodsA cross-sectional web-based survey with a nationally representative sample in the United Kingdom was conducted on August 3, 2021. Responses were collected and analyzed from 534 participants, aged 18 years and older, who were residents of the United Kingdom. The primary outcome measure (dependent variable) was the participants’ perceived importance of using immunity certificates, computed as an index of 6 items. The following individual drivers were used as the independent variables: (1) personal beliefs about COVID-19 (using constructs adapted from the Health Belief Model), (2) personal views on vaccination, (3) willingness to share immunity status with service providers, and (4) variables related to respondents’ lifestyle and sociodemographic characteristics.ResultsThe perceived importance of immunity certificates was higher among respondents who felt that contracting COVID-19 would have a severe negative impact on their health (β=0.2564;P<.001) and felt safer if vaccinated (β=0.1552;P<.001). The prospect of future economic recovery positively influenced the perceived importance of immunity certificates. Respondents who were employed or self-employed (β=–0.2412;P=.001) or experienced an increase in income after the COVID-19 pandemic (β=–0.1287;P=.002) perceived the use of immunity certificates as less important compared to those who were unemployed or had retired or those who had experienced a reduction in their income during the pandemic.ConclusionsThe findings of our survey suggest that more vulnerable members in our society (those unemployed or retired and those who believe that COVID-19 would have a severe impact on their health) and people who experienced a reduction in income during the pandemic perceived the severity of not using immunity certificates in their daily life as higher.