Impact of the 13-Valent Pneumococcal Conjugate Vaccine (PCV13) on Invasive Pneumococcal Disease in Alaska

Wednesday, June 22, 2016: 2:07 PM
Tikahtnu A, Dena'ina Convention Center
Michael G. Bruce , Centers for Disease Control and Prevention, Anchorage, AK
Rosalyn Singleton , Centers for Disease Control and Prevention, Anchorage, AK
Lisa Bulkow , Centers for Disease Control and Prevention, Anchorage, AK
Karen M. Rudolph , Centers for Disease Control and Prevention, Anchorage, AK
Tammy Zulz , Centers for Disease Control and Prevention, Anchorage, AK
Debby Hurlburt , Centers for Disease Control and Prevention, Anchorage, AK
Tom Hennessy , Centers for Disease Control and Prevention, Anchorage, AK
BACKGROUND: Alaska Native (AN) children have experienced high rates of invasive pneumococcal disease (IPD). In March 2010, PCV13 was introduced statewide in Alaska.  We evaluated the impact of PCV13 on IPD in children and adults, 5.75 years after introduction.

METHODS: Pneumococcal sterile site isolates, reported through state-wide surveillance, were serotyped using standard methods.  We defined a pre-PCV13 time period 2005-2008 and post-PCV13 time period 2011-2015; excluding 2009–2010 because PCV13 was introduced pre-licensure in one high-risk region in 2009.

RESULTS: Among Alaska children <5 years, PCV13 serotypes comprised 62% of IPD in the pre-PCV13 period and 22% in the PCV13 period.  Among all Alaska children <5 years, IPD rates decreased from 60.9 (pre) to 21.8 (post) per 100,000/yr (P<.001); PCV13 serotype IPD decreased from 37.7 to 4.8 (P<.001).  Among AN children <5 years, IPD rates decreased from 149.2 to 49.8 (P<.001); PCV13 serotype IPD decreased from 87.0 to 11.8 (P<.001); non-PCV13 serotype IPD did not change significantly. Among persons > 50 years, the post-vaccine IPD rate was not significantly different from the baseline period, but declined in persons 18-49 years (45%, P<0.001); this decline was similar in AN and non-AN persons (46%, P<0.001, 46%, P<0.001, respectively).

CONCLUSIONS:  Almost 6 years after PCV13 introduction, overall IPD and PCV13-serotype IPD rates have decreased substantially in Alaska children <5 years of age when compared with 2005-2008. We observed evidence of indirect effect among adults with a 45% reduction in IPD among persons 18-49 years.