Social contact patterns with acquaintances and strangers related to influenza in the post-pandemic era

Aim To investigate the social contact patterns of Chinese residents in the post COVID-19 pandemic period, explore the associations between the different contact patterns and incidence of influenza. Subject and methods A cross-sectional social contact survey was conducted on Chinese residents from December 9, 2021, to January 20, 2022. The contact was divided into participant–acquaintance (P–A) and participant–stranger (P–S), and the generalized linear model (GLM) was used to explore their impact on the incidence of influenza. Results The contact frequency of P–S was higher than that of P–A (3.41 V.S. 1.94), but the average contact duration of P–S was much shorter than that of P–A (0.20 h V.S. 5.53 h). P–A contact mainly occurred among peers as well as family members. However, P–S contact was concentrated in the middle-aged population. In GLM, the influence of P–S on the incidence of influenza was higher (OR = 2.63, 95% CI 2.29–3.02) than that of P–A (OR = 1.82, 95% CI 1.56–2.13), especially on the weekend (P–S OR = 4.31, 95% CI 2.31–8.01) and in recreation places (P–S OR = 4.94, 95% CI 2.26–10.78). Conclusions Social contact will increase the incidence rate of influenza. Therefore, when contacting with strangers, especially in recreation places, personal protective behavior should be strengthened.