COVID-19 may have more than one variant of the virus attacking them, according to a pair of new studies published earlier this year.Researchers for the two studies — one published in January, the other in February — say their evidence suggests less dominant variants may be simultaneously present in the same infected individual, with some cloaking themselves from the immune system.That could make it difficult for infected patients to get rid of COVID-19 from their systems entirely, said Kapil Gupta, lead author of the January study, in a statement Tuesday.“Some of these variants may use kidney or spleen cells as their niche to hide, while the body is busy defending against the dominant virus type,” Gupta said.