Interactions Between Caregiving and Sex and the Antibody Response to COVID-19 Vaccination

Objective: Antibody response to vaccination is a powerful paradigm for studying the effects of chronic stress on immune function. In the present study, we used this paradigm to examine the interaction between caregiving (as a type of chronic stress) and sex on the antibody response to a single dose of a COVID-19 vaccination; recent research has called for examination of sex differences on health outcomes among family caregivers. A three-way interaction between caregiving, sex, and psychological distress was also examined. Methods: COVID-19 antibody data were extracted from 165 caregivers (98 females) and 386 non-caregivers (244 females) from the UK’s Understanding Society COVID-19 study. Relevant sociodemographics, health and lifestyle, and distress variables were gathered as potential covariates. Results: In a 2 2 ANOVA, we found that the interaction between caregiving and sex was significant; male caregivers had a lower antibody response to the vaccine compared to female caregivers (F(1,547), =24.82, p < .001, η²_p = 0.043). Following adjustment, male caregivers had the lowest antibody response relative to all other groups. The three-way interaction model, controlling for covariates, was also significant (R^{2 =} 0.013, p = .049); the conditional effects for the three-way interaction revealed that male caregivers, compared to the other groups, had a lower antibody response at both low and medium levels of psychological distress. Conclusion: This study found evidence of a three-way interaction between caregiving, sex, and distress on antibody response. Male caregivers had poorer antibody response to a single shot of the COVID-19 vaccination than female caregivers and male and female non-caregivers, and this was evident at low and medium levels of distress. Our findings will be discussed in relation to the caregiver and sex interactions during the pandemic.