League One Accrington Stanley have recorded 19 positive Covid-19 tests among their players and staff, with the club now entering an isolation period.
Stanley have had four League One games called off and will not play before 7 November's FA Cup tie against Tranmere.
Meanwhile, eight positive Covid-19 cases have seen League Two Scunthorpe United's next three matches postponed.
The Iron had been set to play Salford City on Tuesday, Colchester United on Friday and Port Vale on 3 November.
A Scunthorpe statement said a further 10 players are self-isolating after being in close contact with the positive cases.
"The club [Scunthorpe] has advised the EFL it is unable to safely fulfil the fixtures," a club statement added.
"The club is following all of Public Heath England and the EFL's Covid-19 protocols and will not name the players in question."
Scunthorpe's remaining 10 players and staff will stop training for seven days as a precaution.
Tuesday's announcement came around seven hours before the club's scheduled kick-off against Salford City, who sent their "best wishes for a speedy recovery" to those affected.
Scunthorpe are 23rd in the fourth tier, having won one, drawn one and lost six of their opening eight League Two games this term.
Additionally, BBC Wiltshire reports that Swindon Town have confirmed another positive Covid-19 case at the Robins, taking their total number of cases to five.
Stanley 'understandably disappointed'
Swindon had - like Accrington - seen both seen their past two matches called off because of positive tests, before Tuesday saw confirmation that Stanley's next two games against Plymouth (31 October) and Hull (3 November) will also not go ahead.
Accrington are 10th in the third tier, while newly-promoted Swindon sit 21st - the pair had originally been set to go head-to-head on Tuesday.
"We are understandably disappointed to be missing these games in what is an already unusual season without fans in the stadium," Stanley owner Andy Holt told the club website.
"The club is following Public Health England and the EFL's Covid-19 protocols and all the first team players and management will isolate for the required period.
"Thankfully all those affected appear to be showing minor symptoms and we wish them all a speedy recovery."