Multiple myeloma. Is a patient at high risk for pneumonias?

Increased risk. Patients with multiple myeloma have a suppressed immune system. This increases the risk for pneumonias and other infections.
Yes. One of the most common causes of death in myeloma is infection. Evidence on the effect of immunization in myeloma is relatively weak, but still suggested in guidelines. Ref for a 1980-2002 study -- http://jco.Ascopubs.Org/content/23/36/9219.Long -- conclusion a tenth of patients die within 60 days of diagnosis of mm. Infection and renal failure are the main direct causes of early mortality...