Characteristics and serotype distribution of childhood cases of invasive pneumococcal disease following pneumococcal conjugate vaccination in England and Wales, 2006-14
Background The 7-valent (PCV7) and 13-valent (PCV13) pneumococcal conjugate vaccines are
highly effective in preventing invasive pneumococcal disease (IPD) caused by vaccine serotypes.
Vaccine failure (vaccine-type IPD after age-appropriate immunisation) is rare. Little is known about
the risk, clinical characteristics or outcomes of PCV13 compared to PCV7 vaccine failure.
Methods Public Health England conducts IPD surveillance and provides a national reference
service for serotyping pneumococcal isolates in England and Wales. We compared the
epidemiology, rates, risk factors, serotype distribution, clinical characteristics, and outcomes of IPD
in children with PCV13 and PCV7 vaccine failure.
Results A total of 163 episodes of PCV failure were confirmed in 161 children over eight years (04
September 2006 to 03 September 2014) in ten birth cohorts. After three vaccine doses, PCV7 and
PCV13 failure rates were 0.19/100,000 (95% CI, 0.10-0.33; 57 cases) and 0.66/100,000 (95% CI,
0.44-0.99; 104 cases) vaccinated person-years, respectively. Children with PCV13 failure were
more likely to be healthy (87/105 [82.9%] vs. 37/56 [66.1%]; P=0.02), present with bacteremic lower
respiratory tract infection (61/105 [58.1%] vs. 11/56 [19.6%]; P<0.001) and develop empyema
(41/61 [67.2%] vs. 1/11 [9.1%]; P<0.001) compared to PCV7 failures. Serotypes 3 (n=38, 36.2%)
and 19A (n=30, 28.6%) were responsible for most PCV13 failures. Five children died (3.1%; 95%
CI, 1.0-7.1%), including four with co-morbidities.
Conclusions PCV failure is rare and, compared to PCV7 serotypes, the additional PCV13
serotypes are more likely to cause bacteremic lower respiratory tract infection and empyema in
healthy vaccinated children
