The Czech Surveillance System for Invasive Pneumococcal Disease, 2008-2013: A Follow-Up Assessment and Sensitivity Estimation

Abstract

BackgroundInvasive pneumococcal disease (IPD) is caused by Streptococcus pneumoniae and mostly presents as pneumonia, sepsis or meningitis. A notable portion of IPD cases is vaccine preventable and the pneumococcal conjugate vaccine (PCV) was introduced into the routine childhood immunization programs in many countries during the last decades.ObjectivesBefore PCV introduction in the Czech Republic in 2010, a national surveillance system for IPD was implemented in 2008 and further improved in 2011. In this study, we describe the new surveillance system for the first time and measure its sensitivity between 2010 and 2013 using the capture-recapture method. Furthermore, we describe the recent epidemiological trend of IPD, taking sensitivity estimates into account.Results and ConclusionsBetween 2010 and 2013 the estimated sensitivity of the overall IPD surveillance increased from 81% to 99%. The sensitivity of individual reporting sources increased from 72% to 87% for the laboratory system and from 31% to 89% for the epidemiological notification system. Crucial for this improvement was the introduction of quarterly report reminders in 2011. Due to positive source dependency, the presented sensitivity estimates are most probably overestimated and reflect the upper limit of reporting completeness. Stratification showed variation in sensitivity of reporting particularly according to region.An effect of the PVC vaccination in the Czech Republic is visible in the incidence of IPD in target age groups (<5y). This influence was not evident in the total IPD incidence and may interfere with increasing sensitivity of reporting. In 2013, an increase in the IPD incidence was observed. This finding requires further observation and a detailed vaccine impact analysis is needed to assess the current immunization strategy.

Effect of childhood pneumococcal conjugate vaccination on invasive disease in older adults of 10 European countries: implications for adult vaccination

“…For each site we accounted for missing serotype data by assuming the same serotype distribution in cases with and without serotype information, by calendar year. For three sites that reported a change in surveillance sensitivity over the surveillance period, we adjusted the number of reported cases to the sensitivity for each period, as described elsewhere 18–20. We computed annual incidence rates per site and serotype by dividing the numbers of cases adjusted for missing serotyping data and under-reporting by the respective source population.…”

Surveillance of pneumococcal diseases in Central and Eastern Europe

“…In Slovakia, for example, the IPD incidence is highest in children < 1 year and increased between 1997 and 2013 59 . In Czech Republic, following the introduction of PCV in 2010, both the total incidence and the incidence in the 0–4-year age group decreased from 2011 to 2012 and increased again in 2013 60 . Between 2012 and 2013, the incidence of IPD in Czech Republic increased from 1.8 to 9.2/100,000 in infants < year of age, and from 2.7 to 3.8/100,000 in those aged 1–4 years.…”

“…59 In Czech Republic, following the introduction of PCV in 2010, both the total incidence and the incidence in the 0–4-year age group decreased from 2011 to 2012 and increased again in 2013. 60 Between 2012 and 2013, the incidence of IPD in Czech Republic increased from 1.8 to 9.2/100,000 in infants < year of age, and from 2.7 to 3.8/100,000 in those aged 1–4 years. In the same period, the IPD incidence in older adults also increased from 3.3 to 4.3/100,000 in those aged 40–64 years and 8.1 to 10.2/100,000 in those aged ≥65 years; the CFR in over-65s was 22.2%.…”

Invasive Pneumococcal Disease in Tuscany Region, Italy, 2016–2017: Integrating Multiple Data Sources to Investigate Underreporting

“…The observed higher level of underreporting among older subjects has already been described for IPD [ 20 , 21 ] and may be linked to a lower level of hospitalization in this population group or, in the case of severe illness in the elderly, to the tendency not to give a specific diagnosis. Furthermore, a geographical variability in IPD underreporting has been described in the literature [ 20 , 22 ], correlated to the distance between laboratories and hospitals [ 20 ]. This observation is compatible with the findings from this study, as a higher level of underreporting was described in the Southeast LHA, characterized by a larger area and lower population density as compared to other regional LHAs.…”

“…Capture–recapture analysis is a well-established method to estimate the quality of reporting systems, and it was previously applied to IPD and other invasive bacterial diseases [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ].…”