Verona and Udinese said on Tuesday that they had 19 new Covid-19 cases between their playing squads and coaching staff, two days before the Serie A season restarts.
In a statement, Verona said eight players had caught the virus ahead of their trip to Spezia on Thursday, all of whom have been vaccinated.
Udinese, who travel to Fiorentina on the same day, then announced that they had recorded nine positive tests, with seven of those among the first-team squad.
Neither club revealed which players had tested positive nor what condition they were in.
As yet no decision has been made on whether either club will be able to fulfil their first fixtures of 2022, as local health authorities can bar teams from travelling.
That has already happened this season to Salernitana, whose match at Udinese late last month was abandoned after they were blocked from making the trip north.
Salernitana have been hit by a swathe of cases with nine players positive for the virus ahead of their home match with Venezia, also on Thursday.