African swine fever virus Georgia isolate harboring deletions of 9GL and MGF360/505 genes is highly attenuated in swine but does not confer protection against parental virus challenge.

•Multiple deletions cause an increase the degree of attenuation ASFV in swine.•ASFV with 9GL and MGF505/360 does not induce protection against virulent ASFV.•Multiple deletions in ASFV require thorough experimental corroboration.