CCR5 and influenza: In humans, functional CCR5 deficiency does not cause strong immune suppression, but ccr5Δ32 homozygosity was associated with four times more fatal infections than average during the 2009–2011 influenza season in Spain (Falcon et al, 2015) and fatal infections by the West Nile Virus in the United States (Lim & Murphy, 2011).