Seasonal Influenza Vaccine Effectiveness, 2015-2016

Table. Influenza virus type and subtype among influenza-positive patients
Virus Type Number % Total
Influenza A 856 65
H3N2 72 6
H1N1 (pdm09) 768 59
No subtype determined 16 1
Influenza B 456 35
B Yamagata 253 19
B Victoria 200 15
Lineage not determined 3 <1

Coinfections present include: 5 cases coinfected with Influenza A (H3N2) and Influenza B Yamagata; 1 case coinfected with Influenza A (H3N2) and Influenza B Yamagata (lineage not determined); 1 case coinfected with Influenza A (not subtyped) and Influenza B Yamagata; 3 cases coinfected with Influenza B Yamagata and Influenza B/Victoria

Table. Influenza vaccine effectiveness for all vaccine types, Against influenza A or B viruses
Age group (years) Influenza positive
Total
Influenza positive
(% Vaccinated)
Influenza negative
Total
Influenza negative
(% Vaccinated)
Adjusted VE % Adjusted 95% CI
All ages 1309 (38) 5570 (52) 48% (43 to 55)
6 mos–8 254 (34) 1272 (50) 51% (33 to 64)
9–17 164 (20) 694 (40) 59% (36 to 74)
18–49 499 (29) 1957 (43) 52% (39 to 61)
50–64 283 (53) 918 (61) 26% (2 to 44)
≥65 109 (72) 729 (81) 42% (6 to 64)
Table. Influenza vaccine effectiveness for all vaccine types, Influenza A (H1N1) viruses
Age group (years) Influenza positive Total Influenza positive (% Vaccinated) Influenza negative Total Influenza negative (% Vaccinated) Adjusted VE % Adjusted 95% CI
All ages 768 (40) 5,570 (52) 45% (34 to 53)
6 mos–8 160 (36) 1272 (50) 49% (26 to 65)
9–17 51 (22) 694 (40) 63% (22 to 82)
18–49 311 (32) 1,957 (43) 46% (29 to 59)
50–64 194 (57) 918 (61) 10% (-26 to 36)
≥65 52 (60) 729 (81) 66% (36 to 81)
Table. Influenza vaccine effectiveness for all vaccine types, Influenza B viruses
Age group (years) Influenza positive Total Influenza positive (% Vaccinated) Influenza negative Total Influenza negative (% Vaccinated) Adjusted VE % Adjusted 95% CI
All ages 456 (33) 5,570 (52) 55% (44 to 64)
6 mos–8 89 (33) 1,272 (50) 50% (17 to 70)
9–17 107 (21) 694 (40) 53% (19 to 72)
18–49 145 (21) 1,957 (43) 68% (51 to 79)
50–64 73 (44) 918 (61) 48% (14 to 69)
≥65 42 (86) 729 (81) -34% (-236 to 47)
Table. Influenza vaccine effectiveness for all vaccine types, Against Influenza B Virus lineage
Age group (years) Influenza positive Total Influenza positive (% Vaccinated) Influenza negative Total Influenza negative (% Vaccinated) Adjusted VE % Adjusted 95% CI
B Victoria

     All Ages200(30)5,570(52)49%(30 to 64)B Yamagata

     All Ages253(36)5,570(52)57%(42 to 67)

Table. Influenza vaccine effectiveness for Inactivated Influenza Vaccine in children, Against Influenza A or B Viruses
Age group (years) Influenza positive Total Influenza positive (% Vaccinated) Influenza negative Total Influenza negative (% Vaccinated) Adjusted VE % Adjusted 95% CI
2-17 357 (21) 1,551 (39) 60% (47 to 70)
2-8 203 (25) 895 (41) 56% (37 to 70)
9–17 154 (15) 656 (36) 66% (44 to 80)
Table. Influenza vaccine effectiveness for Live Attenuated Influenza Vaccines in Children, Against Influenza A or B Viruses
Age group (years) Influenza positive Total Influenza positive (% Vaccinated) Influenza negative Total Influenza negative (% Vaccinated) Adjusted VE % Adjusted 95% CI
2-17 319 (11) 1,043 (10) 5% (-47 to 39)
2-8 178 (14) 588 (11) 0% (-75 to 43)
9–17 141 (7) 455 (8) 17% (-84 to 63)