Effectiveness of a 2+1 dose schedule pneumococcal conjugate vaccination programme on invasive pneumococcal disease among children in Norway

Abstract

The 7-valent pneumococcal conjugate vaccine (PCV-7) was licensed in Norway in 2001. In July 2006, PCV-7 was introduced in the Norwegian Childhood Vaccination Programme in a 2+1 dose schedule, with immunizations administered at 3, 5 and 12 months of age. PCV-7 was offered through the vaccination programme to all children born from January 2006, i.e. a catch-up for children aged 3-6 months. Prior to 2006 the use of PCV-7 was negligible. The effectiveness of the PCV-7 vaccination programme was assessed using data on invasive pneumococcal disease (IPD) incidence obtained from the Norwegian Surveillance System for Communicable Diseases, serotype distribution from the National Reference Laboratory for Pneumococci, and vaccine coverage and vaccination status from the Norwegian National Vaccination Register. Vaccine coverage quickly reached high levels; 95% of children >3 months born from January 2006 had received at least one immunization with PCV-7. The incidence rate of IPD among children <2 years rapidly declined; the rate of vaccine serotype IPD in this age group fell from an average of 47.1 cases/100,000 population in the 2 years prior to PCV-7 introduction to 13.7 cases/100,000 population in 2007. The incidence rate of nonvaccine serotype IPD remained stable. The vaccine programme effectiveness was estimated to be 74% (95% CI 57-85%). No vaccine failure was seen after complete primary immunization with two vaccine doses. Our findings indicate that PCV-7 provides highly effective protection against vaccine serotype IPD when administered in a 2+1 dose schedule.

Effectiveness of the ten-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) against invasive pneumococcal disease: a cluster randomised trial

“…The incidence is lower compared to US data before PCV7 but comparable to European incidence figures ranging from 54·2 to 67·7 per 100 000 person-years in the corresponding age group. 3,4,25 We failed to enrol high proportions of age-eligible children in all the clusters. The main reason was refusal to participate as the trial exclusion criteria mainly followed the contraindications of the NVP, coverage of which is extremely high (>95%).…”

“…[1][2][3][4][5][6] IPD has also decreased among unvaccinated populations (herd protection). However, an increase in IPD caused by pneumococcal serotypes other than those contained in the vaccine (replacement) has been detected both in vaccinated and unvaccinated populations.…”

Sentinel versus population-based surveillance of pneumococcal conjugate vaccine effectiveness

“…Although serotyping pneumococcal isolates is difficult in many settings with limited laboratory facilities, the use of techniques based on the polymerase chain reaction may provide a practical solution. [26][27][28] Population-based surveillance systems have shown a decline in IPD within 1 to 2 years of vaccine introduction 2,29 and sentinel systems may do the same. However, in our study, a sentinel system's reliability in measuring the vaccine's effect on IPD, whether or not caused by serotypes included in PCV7, increased with the passage of time.…”

Update on the Use of Conjugate Pneumococcal Vaccines in Childhood

“…From this data, two doses given prior to 7 months of age with an additional booster at 12 to 16 months provided 96% (95% CI 75-100%) vaccine effectiveness against IPD. Vestrheim et al (20) described the effectiveness of a three-dose schedule using PNEU-C-7 in Norwegian children. The program was introduced into the routine infant schedule in July 2006 with doses at 3, 5 and 12 months of age.…”