however, our study reveals contrasting results, indicating that children vaccinated against covid-19 who contracted the virus had an increased risk of developing new-onset asthma (hr=2.745, 95% ci=2.521, 2.99). this could be attributed to various factors, including immune response to the vaccine, the interaction between the vaccine and the virus, or other unrelated environmental or genetic factors. our subgroup analysis identified higher risks among younger age groups and black or african american individuals. following covid-19 infection, infants developed a strong mucosal immune response marked by inflammatory cytokines, ifn-, and th-17 and neutrophil markers like il-17, il-8, and cxcl1 [40]. this response led to further respiratory inflammation and associated symptoms, which may explain why younger age groups have a higher risk of developing asthma. regarding ethnicity, a large database analysis of adults across three national cohorts (uk, south korea, japan) found consistent results, indicating that post-covid-19 effects on allergic diseases are not influenced by race [7]. however, the above study focused on adults and mainly included data from asian countries. for children, we speculate that the immune response of black individuals after covid-19 infection may be influenced by genetics, socioeconomic status, and health disparities, but more research is needed to confirm this.
United States