Association between meteorological variations and the superspreading potential of SARS-CoV-2 infections

• Published in: Environment international 2024-06, Vol.188, p.108762-108762, Article 108762
• Main Authors: Chong, Ka Chun, Zhao, Shi, Hung, Chi Tim, Jia, Katherine Min, Ho, Janice Ying-en, Lam, Holly Ching Yu, Jiang, Xiaoting, Li, Conglu, Lin, Guozhang, Yam, Carrie Ho Kwan, Chow, Tsz Yu, Wang, Yawen, Li, Kehang, Wang, Huwen, Wei, Yuchen, Guo, Zihao, Yeoh, Eng Kiong
• Format: Article
• Language: English
• Subjects: Contact tracing; COVID-19 weather; GAM; Super-spreading
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2024.108762

•Meteorological impact on COVID-19 superspreading was rarely studied.•We used comprehensive contact tracing data to estimate superspreading potential.•Cold condition and higher rainfall were related to a lower superspreading potential.•U-shaped relationship between relative humidity and superspreading was observed. While many investigations examined the association between environmental covariates and COVID-19 incidence, none have examined their relationship with superspreading, a characteristic describing very few individuals disproportionally infecting a large number of people. Contact tracing data of all the laboratory-confirmed COVID-19 cases in Hong Kong from February 16, 2020 to April 30, 2021 were used to form the infection clusters for estimating the time-varying dispersion parameter (kt), a measure of superspreading potential. Generalized additive models with identity link function were used to examine the association between negative-log kt (larger means higher superspreading potential) and the environmental covariates, adjusted with mobility metrics that account for the effect of social distancing measures. A total of 6,645 clusters covering 11,717 cases were reported over the study period. After centering at the median temperature, a lower ambient temperature at 10th percentile (18.2 °C) was significantly associated with a lower estimate of negative-log kt (adjusted expected change: −0.239 [95 % CI: −0.431 to −0.048]). While a U-shaped relationship between relative humidity and negative-log kt was observed, an inverted U-shaped relationship with actual vapour pressure was found. A higher total rainfall was significantly associated with lower estimates of negative-log kt. This study demonstrated a link between meteorological factors and the superspreading potential of COVID-19. We speculated that cold weather and rainy days reduced the social activities of individuals minimizing the interaction with others and the risk of spreading the diseases in high-risk facilities or large clusters, while the extremities of relative humidity may favor the stability and survival of the SARS-CoV-2 virus.