"So while they have now had two negative tests, they will have to get tested again to get two negative tests in a row that are in accordance with PCB's testing process and the protocols we have set up", PCB CEO Wasim Khan said in a statement.
All members of Pakistan's touring party will have been tested prior to travel, the European Central Bank said, with those testing positive for Covid-19 not permitted to travel with the advance group on Sunday.
The team's masseur Malang Ali tested positive twice. Former captain Mohammed Hafeez claimed he has tested negative, followed by another positive.
Pakistani squad will be without some key players during England series after they were dropped from the squad for being tested positive for cornavirus, the Pakistan Cricket Board has said.
'With the Test series being played first in August, [head coach] Misbah [ul-Haq] is satisfied with the group of players that are travelling on Sunday as the focus will be on red-ball preparation. "They will undergo third round of testing at some stage next week and if their tests remain negative, then the PCB will make arrangements to send them to England".
On Saturday, Mohammad Hafeez, Wahab Riaz, Mohammad Hasnain, Shadab Khan, Fakhar Zaman and Mohammad Rizwan were tested negative for COVID-19.
Meanwhile, bowling coach Waqar Younis is heading from Australia to England via Dubai on Saturday to join the Pakistan squad there, and will be appearing for Covid-19 test after arriving there.
Of the five reserve players, he said four - Moosa Khan, Rohail Nazir, Bilal Asif and Mohammad Nawaz - had tested negative and one - Imran Butt - had tested positive. During the isolation period, the team will be allowed to train and practice. "The side will move to Derbyshire on July 13".
Squad flying off on Sunday includes Azhar Ali (Test captain), Babar Azam (T20 captain), Abid Ali, Imam-ul-Haq, Shan Masood, Asad Shafiq, Fawad Alam, Iftikhar Ahmad, Khushdil Shah, Sarfaraz Ahmed, Faheem Ashraf, Mohammad Abbas, Naseem Shah, Shaheen Afridi, Sohail Khan, Usman Shinwari, Imad Wasim, and Yasir Shah.