The Changing Epidemiology of Childhood Pneumococcal Disease in Korea

Abstract

The wide use of antimicrobial agents and 7-valent pneumococcal conjugate vaccine (PCV7) has led to major changes in the epidemiology of childhood pneumococcal diseases. In Korea, data on the population-based incidence of childhood invasive pneumococcal diseases (IPD) are not available; however, institution-based surveillance data suggest a substantial burden of childhood IPD. Following the introduction of the PCV7 in Korea in 2003, the proportion of IPD caused by vaccine-type pneumococci has decreased, while non-PCV7 serotypes, especially serotypes 19A and 6A, whose proportions had been increasing before the introduction of the vaccine, became predominant among childhood IPD isolates. This article reviews the overall impact of PCV7 utilization and summarizes the results obtained so far. Continuous monitoring and gathering of scientific evidence for the epidemiological transition of pneumococcal carriage and IPD will be important for the management of pneumococcal infections in Korea.

The changes of prevalence and etiology of pediatric pneumonia from National Emergency Department Information System in Korea, between 2007 and 2014

“…Currently, we only identified a lowering in the prevalence of pneumonia types caused by serotypes included in the PCV7, with S. pneumoniae strains that cause invasive infection becoming less frequent, as well as being less frequently identified in oropharyngeal swabs obtained from healthy children [ 15 , 19 ]. Overall, however, there is a paucity of data regarding changes in the incidence of pneumococcal infections in children in Korea after the introduction of the PCV10 and the PCV13, as well on the overall effects of these vaccines [ 26 ]. A detailed evaluation of the effects of pneumonia vaccines in Korea is challenging as it requires accurate specimen collection and identification of bacteria, as well as laboratories and researchers to support the entire research process.…”

Health and economic burden associated with 15-valent pneumococcal conjugate vaccine serotypes in Korea and Hong Kong

“…Regarding serotype 3, a survey of incidence rates in Hong Kong from 1995 to 2017 found that IPD cases due to serotype 3 were steadily increasing across all vaccine eras. 17 Consistent with this, several studies have demonstrated a lack of PCV13 effectiveness against IPD caused by serotype 3, 18 , 40 and studies from the United States and the United Kingdom have highlighted the persistence of serotype 3 after PCV13 introduction. 40 , 44 , 45 , 46 Together, these findings highlight the importance of retaining the protection against the vaccine-type serotypes as new PCVs are developed.…”

“… 17 Consistent with this, several studies have demonstrated a lack of PCV13 effectiveness against IPD caused by serotype 3, 18 , 40 and studies from the United States and the United Kingdom have highlighted the persistence of serotype 3 after PCV13 introduction. 40 , 44 , 45 , 46 Together, these findings highlight the importance of retaining the protection against the vaccine-type serotypes as new PCVs are developed. Moreover, higher-valency PCVs have been found to elicit lower immune responses relative to first-generation PCVs for the shared serotypes, 47 and this phenomenon, known as ‘geometric mean concentration creep’, becomes more pronounced as more serotypes are added.…”

Determining the frequency of Streptococcus pneumoniae carriers and its microbial resistance in children

“…No charges were imposed on individuals for carrying out this plan, and the provisions of the Helsinki Declaration were made. Samples were taken with the parents' written permission by an experienced laboratory technician and with the help of sterile swabs orally and from the back of the throat (in the area of the palatine tonsils) (15,16). The limitation of this study was to obtain the medical history and records of the subjects to confirm the accuracy of information obtained from the patient's parents about the underlying disease or history of antibiotic use.…”