California coronavirus strain may be more infectious—and lethal

California coronavirus strain may be more infectious—and lethal: Other data suggest the variant is more contagious. The scientists found that people infected with the variant harbored about twice as much virus in their noses, an index of viral shedding, which may make them more infectious to others. In the lab, viruses engineered to carry a key mutation found in the variant were better than control viruses at infecting human cells and lunglike structures called organoids. And in one nursing home where the variant took hold, it spread severalfold faster than in four other nursing home outbreaks caused by other viral variants. “The evidence is growing that this [variant] is more transmissible than [its] immediate competitors,” although not as transmissible as some other variants of concern, says William Hanage, an expert on viral evolution at the Harvard T.H. Chan School of Public Health. (Variants of concern are coronaviruses with mutations that make them more likely to spread, evade vaccines, or make people sicker.)