Ziv Yaffe has tested positive for COVID-19 twice, after originally testing positive for the virus last August. However, with this new South African strain, Yaffe said that he does not experience any symptoms, stating that he "feels great and did not infect anyone else," according to a report by Ynet. Yaffe, 57, tested positive for the new strain after returning to Israel from Turkey. He said that it was more difficult for him to deal with the virus when he had it last August. "I am neither a doctor nor a researcher, but I can say that personally, the first time I was indeed very ill," he said in the report. A possible explanation for not having any symptoms this time may be due to "antibodies from the original virus that protected against the disease when infected with the strain," according to Prof. Shai Efrati. Yaffe is currently participating in a study conducted by Efrati where he evaluates people's immune system after recovering from coronavirus. "Since then we have been following him, and over time we have seen that with everyone, the antibodies go down - but we do not know if this is enough to prevent another disease. It should be emphasized that antibodies do not necessarily prevent infection," Efrati added in the report.In his re-examination upon his return from Turkey, Yaffe was confirmed to have the South African strain. "He had the virus, but he wasn't sick," Efrati said. "His wife, daughters and grandchildren also lived with him - but none of them were infected." According to Efrati: "This is a case from which a lot can be learned. The antibodies he developed in August protected him from developing a disease," he told Ynet. "This means that the antibodies that developed from the original virus he had provided protection against disease even when infected with the South African mutation."As a result of increasing coronavirus cases, the Israeli government agreed to extend the current lockdown until Friday morning and the Knesset passed a bill which doubles the fine for violations of coronavirus regulations.