4. Ke Hong , Wei Cao , Zhengyin Liu , Ling Lin , Xing Zhou , Yan Zeng , Yuan Wei , Li Chen , Xiaosheng Liu , Yang Han , Lianguo Ruan & Taisheng Li (2020): Prolonged presence of viral nucleic acid in clinically recovered COVID-19 patients was not associated with effective infectiousness, Emerging Microbes & Infections, DOI: 10.1080/22221751.2020.1827983
5. Hu, F., Chen, F., Ou, Z. et al. A compromised specific humoral immune response against the SARS-CoV-2 receptor-binding domain is related to viral persistence and periodic shedding in the gastrointestinal tract. Cell Mol Immunol 17, 1119–1125 (2020). https://doi.org/10.1038/s41423-020-00550-2
7. To, K. K. W., Hung, I. F. N., Ip, J. D., Chu, A. W. H., Chan, W. M., Tam, A. R., ... & Yuen, K. Y. (2020). COVID-19 re-infection by a phylogenetically distinct SARS-coronavirus-2 strain confirmed by whole genome sequencing. Clinical infectious diseases.
11.Ward, H., Atchison, C. J., Whitaker, M., Ainslie, K. E., Elliot, J., Okell, L. C., ... & Elliot, P. (2020). Antibody prevalence for SARS-CoV-2 in England following first peak of the pandemic: REACT2 study in 100,000 adults. MedRxiv.