A total of 1,008 individuals were tested on Monday and Tuesday, with the four positive cases emanating from a total of three clubs.
The affected persons will have to self-isolate for seven days, as per protocol.
Six players and staff from three Premier League clubs tested positive for the virus when the first tests were done on May 19 including Watford’s Adrian Mariappa and Burnley assistant manager Ian Woan.
Two more positive cases were detected in the second round of testing last week, with one of those being Bournemouth goalkeeper Aaron Ramsdale.
"The Premier League can today confirm that on Monday 25 May and Tuesday 26 May, 1008 players and club staff were tested for Covid-19. Of these, four have tested positive from three clubs," a league statement said.
"Players or club staff who have tested positive will now self-isolate for a period of seven days.
"Previously, between 19-22 May, 996 players and club staff were tested for Covid-19, of which two tested positive from two clubs. Some 748 players and club staff were tested for Covid-19 on 17-18 May, with six testing positive from three clubs.
"For the fourth round of testing, the number of tests available to each club will be increased from 50 to 60.
"The Premier League is providing this aggregated information for the purposes of competition integrity and transparency. No specific details as to clubs or individuals will be provided by the League and results will be made public after each round of testing."
Premier League clubs have been cleared to resume group training towards the top flight’s resumption next month.
