Th1 cells (IMAGE) University of Gothenburg Caption Th1 cells remain active against SARS-CoV-2 for at least 20 months after infection. Image: Portrait photo of Anna Martner (photo: Elin Lindström) Credit Martner et al/PNAS Usage Restrictions For editorial use when publishing news linked to the University of Gothenburg. Not for commercial use. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.