Elsevier

Vaccine

Volume 33, Issue 9, 25 February 2015, Pages 1135-1142
Vaccine

Early impact of PCV7/PCV13 sequential introduction to the national pediatric immunization plan, on adult invasive pneumococcal disease: A nationwide surveillance study

https://doi.org/10.1016/j.vaccine.2015.01.030Get rights and content

Abstract

Background

PCV7 was introduced as a universal childhood vaccination in Israel on July 2009 and was gradually replaced by PCV13 from November 2010. We report data on adult invasive pneumococcal disease (IPD), two years post PCV13 implementation.

Methods

An ongoing nationwide active surveillance (all 27 laboratories performing blood/CSF cultures nationwide), initiated in 2009, providing all blood/CSF Streptococcus pneumoniae isolated from persons ≥18 years. Capture-recapture method assured reporting of >95% cases. All isolates were serotyped in one central laboratory. Medical history and outcomes were recorded in ∼90%.

Results

Of 1809 IPD episodes, S. pneumoniae was isolated from the blood in 95% and most cases had pneumonia. Predisposing comorbidities were present in >70%. During the four study years, overall IPD incidence decreased from 9.2 to 7.2/100,000, incidence of pneumonia and particularly severe pneumonia cases decreased significantly from 6.6 to 4.7/100,000, (p = 0.029). Vaccine type (VT7/VT13) serotypes decreased by 70%/57% within 4 years. This was accompanied by a 52% increase in non-VT13 strains. These changes were most apparent in winter. PCV impact was most pronounced in younger adults (39% decrease in overall IPD with only a non-significant increase in non-VT13 cases) while in those >65 years a non-significant decrease in overall IPD was observed with a 64% increase in non-VT13 cases. Non-VT13 serotypes that increased significantly were 12F, 15A 10A and 6 C. A continuous reduction in isolates with penicillin MIC > 0.06 μg/ml was observed (26% to 11%, p < 0.001).

Conclusions

Four years after PCV7 and 2.5 years after PCV13 universal implementation in children, incidence of adult IPD caused by VT7 and VT13 decreased in all ages, mainly in younger adults. Despite increase in non-VT13 IPD, overall IPD decreased. Additional follow-up is needed to determine the long-term impact of PCV13.

Section snippets

Background

Streptococcus pneumoniae is the most common bacterial cause of pneumonia, meningitis and sinusitis in adults. Invasive pneumococcal disease (IPD) is a cause of high morbidity and mortality in the elderly as well as in younger adults with particular high-risk comorbidities [1]. Following 7-valent pneumococcal conjugate vaccine (PCV7) introduction in the USA in 2000, a dramatic decrease in IPD incidence was observed. This decrease in IPD in non-vaccinated adult population was attributed to the

Ethics statement

The study was conducted following protocols approved by the Sheba Medical Center Institutional Review Board (IRB) and the Soroka University Medical Center IRB. Since this was a retrospective observational study, the institutional review board waived the need for written informed consent from the participants and informed consent was not obtained. Therefore, all patient records/information were de-identified prior to analysis.

Study period

From July 1, 2009, when PCV7 was introduced to the pediatric NIP for

Vaccine uptake

In 2007–2008, when PCV7 was approved in Israel, but not yet included in the NIP, the proportion of 12–23 month old Jewish children with ≥2 PCV doses was estimated at ∼25%. Bedouin children only rarely received PCVs obtained in any non-NIP frame. In June 2009, 2010, 2011, 2012 and 2013, the proportion of 7–11 month old children who had received ≥2 doses of any PCV was 18%, 81%, 90%, 89% and 89%, respectively. The respective figures for PCV13 were 1%, 3%, 30%, 86% and 89%.

Overall and age-specific IPD incidence

The overall IPD

Discussion

This study reports a full nationwide data, with probably only minimal under-reporting, due to the capture-recapture study design. Only a few other countries have similar good population-based surveillance systems [12], [13], [14]. While IPD notification is mandatory in many European countries, they have reported a wide variation in notification, partly due to different surveillance methods which probably lead to significant under-diagnoses and under-reporting [15]. Moreover, most studies on IPD

Acknowledgments

We greatly acknowledge Ronit Trefler for serotyping, Etti Kreiff and Efrat Steinberger for their assistance in data management. We thank Aviva Goral for assistance in statistical analysis and data management.

The IAIPD is part of the IsraNIP project.

The study was supported in part by Wyeth (Pfizer), manufacturer of Prevnar7 and Prevnar13, grant no. 0887X1-4603. The commercial company had no role in designing the study, collecting the data, data analyses, interpretation of the data, writing the

References (23)

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    For example, in Israel, no data from adults were collected prior to PCV7 introduction. Therefore, studies that assess PCV herd effects in adults in Israel use IRs in the single year of PCV7 introduction as a proxy for baseline incidence [18,41]. Baseline data may also be difficult to obtain for many low-to-middle income countries with weak IPD surveillance systems.

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Results of this study have been partially presented at the 9th International Symposium on Pneumococci and Pneumococcal Diseases (ISPPD), at Hyderabad, India, March 2014.

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