**Background:** The COVID-19 pandemic has caused over 1 million deaths in the U.S. While 79.1% of the U.S. population has received at least 1 dose of COVID-19 vaccines, disparities in vaccine uptake persist across racial, ethnic, and socioeconomic lines. Although vaccine hesitancy has been studied extensively, psychosocial factors such as social support remain underexplored. Prior studies on social support and vaccine uptake were limited to specific populations (e.g., German employees, Greek nurses, older adults in Hong Kong) and lacked generalizability. This study aimed to assess the association between perceived social support and COVID-19 vaccination in a nationally representative U.S. sample.
**Methods:** This cross-sectional study analyzed secondary data from the 2021 wave of the National Health Interview Survey (NHIS), a nationally representative household survey of the U.S. civilian non-institutionalized population. The Sample Adult response rate was 50.9%. Data on 21,107 adults with available COVID-19 vaccination and social support information were analyzed. Perceived social support was measured by the question: "How often do you get the social and emotional support you need?" Responses of "always" or "usually" were classified as strong support, "sometimes" as some support, and "rarely" or "never" as weak support. COVID-19 vaccination was defined as receiving at least 1 dose. Binomial logistic regressions were estimated, adjusting for demographic characteristics (age, sex, race/ethnicity) and socioeconomic characteristics (marital status, education, household income, insurance coverage, employment status), plus urban/rural residence, U.S. region, and interview month fixed effects. Analyses used complex survey weights and were conducted in Stata 17.0.
**Key Results:** Over 80% of respondents reported strong social support, 11% reported some support, and 7% reported weak support. Overall, 71.7% of respondents were vaccinated against COVID-19. Vaccination rates were 72.5% among those with strong social support, 69.7% among those with some support, and 65.4% among those with weak support—a difference of 7.1 percentage points (95% CI=3.9, 10.2) between strong and weak support groups. In unadjusted analysis, respondents with weak social support were 28.2% less likely to be vaccinated (OR=0.718, 95% CI=0.623, 0.827). After full adjustment for sociodemographic and socioeconomic covariates, those with weak social support remained 21.1% less likely to be vaccinated (OR=0.789, 95% CI=0.678, 0.918). The association was stronger among older adults: respondents aged ≥65 years with weak social support were 29.9% less likely to be vaccinated after full adjustment (OR=0.701, 95% CI=0.517, 0.952), while among those aged <65 years the association was attenuated (OR=0.819, 95% CI=0.689, 0.974). Among specific age subgroups (18–24, 25–49, 50–64 years), the lower odds associated with weak social support were not statistically significant after full adjustment.
**Clinical Implications:** This study provides evidence that perceived social support is an independent psychosocial factor associated with COVID-19 vaccine uptake in the U.S. population, even after controlling for demographic and socioeconomic confounders. The effect was most pronounced among older adults (≥65 years), who otherwise had the highest vaccination rates (87.5%). Potential mechanisms include social influence, social control, belonging, and trust. Public health interventions aimed at improving vaccine uptake may benefit from strategies that strengthen social support networks, particularly among socially isolated individuals. However, the cross-sectional design precludes causal inference, and the study lacked state-level identifiers and a time reference for the social support question. Future research should explore causal pathways and the role of social support in younger adult populations.