Left-arm pacer Sheldon Cotrell and all-rounders Roston Chase and Kyle Mayers have been ruled out of the upcoming T20I series against Pakistan after testing positive for COVID-19 upon their arrival in Karachi on December 9.

Besides the trio, a non-coaching member of the touring team management also tested positive, Cricket West Indies said in a statement.

All the four positive persons, who were fully vaccinated and are asymptomatic, will now undergo a period of self isolation for 10 days after which again they will be tested.

"Our arrival testing protocols in Pakistan have confirmed four (4) COVID-19 positives.

"These were confirmed whilst the players and staff were still in room isolation, so despite this significant setback to our preparation plans, we are confident that the tour can continue as everyone else returned negative PCRs prior to their arrival into Pakistan and two negative PCRs since they have been in Karachi," Johnny Grave, CEO of CWI said.

"The risk of COVID-19 infection is impossible to remove completely from a cricket tour, in spite of the fact that many of our players have been living in bio-secure bubbles almost continuously since before the CPL.

"This unusual loss of three players from our squad will seriously impact our team preparations, but the rest of the squad are in good spirits."

All four individuals are now under the care and supervision of the team physician, Dr Akshai Mansingh.

The three-match T20I series between West Indies and Pakistan starts on Monday here at the National Stadium.