Infection with some types of norovirus appear to be rarer in people with some blood types than in others, see Norwalk Virus Infection and Disease Is Associated with ABO Histo-Blood Group Type, from the Journal of Infectious Diseases.
Results reported here suggest that individuals with an O phenotype have an increased susceptibility to NV infection and that those expressing the type B antigen are more resistant to NV infection and symptomatic disease
That study is from 2002 and has a few possible mechanisms for it in the Discussion section - however, there is a lot of "may" and "we suspect" and basically, that further research is needed.
Has there been any further research on this? Is there any lead as to what the mechanism behind this susceptibility of type O / immunity of blood type B is?