Effectiveness over time of varicella vaccine.Vázquez M, LaRussa PS, Gershon AA, Muehlenbein CE, Steinberg SP, Niccolai LM, Shapiro ED. Effectiveness over time of varicella vaccine. JAMA 2004, 291: 851-5. PMID: 14970064, DOI: 10.1001/jama.291.7.851.Effectiveness over time of varicella vaccine.Vázquez M, LaRussa PS, Gershon AA, Muehlenbein CE, Steinberg SP, Niccolai LM, Shapiro ED. Effectiveness over time of varicella vaccine. JAMA 2004, 291: 851-5. PMID: 14970064, DOI: 10.1001/jama.291.7.851.