Five different SARS-CoV-2 variants were chosen and scientists studied how the human immune system responded to them. The variants included Alpha, Delta, and three others that emerged before Alpha. In the study published in Microbiology Spectrum journal, the researchers found that the immune system could not produce the defence molecules against the Delta variant as effectively as the other variants. While infection due to the other four variants alerted the immune system quickly, the Delta variant could silently replicate in the host cells.
