Pneumococcal disease and use of pneumococcal vaccines in Taiwan

Burden of Pneumococcal Disease in Young Children Due to Serotypes Contained in Different Pneumococcal Conjugate Vaccines in Eight Asian Countries and Territories

BACKGROUND

Pneumococcal disease (PD) is a major cause of morbidity and mortality in young children in Asia and globally. Pneumococcal conjugate vaccines (PCVs) have significantly reduced the burden of PD when included in pediatric national immunization programs (NIPs). This study estimates the clinical and economic burden of PD due to serotypes contained in different PCVs in children aged < 5 years in eight Asian countries/territories.

METHODS

Based on published data, a cohort-based decision analytic model was used to estimate annual PD cases, deaths, and direct medical costs associated with serotypes contained in PCV10, PCV13, PCV15, and PCV20.

RESULTS

PD incidence rates were lower in regions with PCV13 in their NIP than those without. Serotypes contained in higher but not lower valency PCVs resulted in a significant incremental clinical and economic burden, although the difference between PCV13 and PCV15 serotypes was generally small. Moving from PCV13 to PCV20 was estimated to result in greater clinical and economic burden reductions.

CONCLUSIONS

This study demonstrates the remaining and incremental burden of PD from PCV10 to PCV20 serotypes in young children in selected Asian regions. Extending NIP access to higher-valency PCVs with broader serotype coverage and improving vaccine uptake will help prevent morbidity and deaths and save healthcare costs.

Antimicrobial susceptibility and serotype replacement of Streptococcus pneumoniae in children before and after PCV13 introduction in Taiwan

BACKGROUND

Since 2015, 13-valent pneumococcal conjugate vaccine (PCV13) was included in the national immunization program in Taiwan. Subsequently, the serotypes of the main circulating Streptococcus pneumoniae strains have changed. PCV administration is also associated with changes in the antimicrobial susceptibility of S. pneumoniae strains. Therefore, in this study, we analyzed the serotype distribution and antimicrobial susceptibility of S. pneumoniae in pediatric infections.

METHODS

Children with S. pneumoniae infections, including invasive pneumococcal disease (IPD) and non-IPD, were enrolled from January 2010 to December 2020. The samples were collected from Mackay Memorial Hospital, MacKay Children's Hospital, and Hsinchu Mackay Hospital in Taiwan. We analyzed the epidemiology of sample collection site, infection diagnosis, and the serotype and antimicrobial susceptibility of S. pneumoniae strains. The study period was divided into time points before and after PCV13 administration.

RESULTS

In total, 322 isolates were collected during the study period. The incidence of IPD declined annually, from 29.7% before 2015 to 7.3% after 2015 (p < 0.001). The prevalence of serotype 19 A had increased gradually since 2010 but declined rapidly after 2013. Serotypes 15 A and 23 A were the most common serotypes after 2015. The non-susceptibility of the S. pneumoniae isolates to penicillin, cefotaxime, and ceftriaxone decreased. Based on meningitis breakpoints, the non-susceptibility to cefotaxime and ceftriaxone gradually decreased, but increased in 2020.

CONCLUSION

PCV13 was considerably effective in reducing the incidence of IPD in children; however, the prevalence of serotypes 15 A and 23 A increased. The increase in antimicrobial non-susceptibility caused by non-vaccine serotypes must be continuously monitored.

The pathological spectrum of pediatric kidney disease: 18-Year experience from a single tertiary care center in northern Taiwan

BACKGROUND

Glomerular disease is one of the leading causes of chronic kidney disease in children worldwide. Recent studies outlined the changing spectrum of glomerular disease in certain countries. Therefore, our study aimed to evaluate the histopathological patterns and changes in pediatric kidney disease over the past 18 years in northern Taiwan.

METHODS

This was a retrospective chart review study of pediatric patients (≤18 years of age) undergoing percutaneous renal biopsies (PRBs) of native kidneys between January 2002 and July 2020 from a Pediatric Care Center at Chang Gung Memorial Hospital, Taoyuan, Taiwan.

RESULTS

This study analyzed a total of 339 pediatric native PRBs. The mean age of the subjects was 13.7 ± 7.0 years (184 girls and 155 boys). The most common indications of PRBs included acute nephritic syndrome (55.7%), idiopathic nephrotic syndrome (22.7%), persistent asymptomatic hematuria (13.9%), and unexplained renal failure (7.7%). Our study revealed that proliferative lupus nephritis (LN), minimal change disease (MCD)-related nephrotic syndrome, and IgA nephropathy (IgAN) were the most frequent biopsy-proven pediatric glomerular diseases. In addition, we showed that severe acute post-streptococcal glomerulonephritis (APSGN) was infrequent and has not even been diagnosed since 2010.

CONCLUSION

Our result revealed that the spectrum of biopsy-proven pediatric kidney disease has not changed significantly over the past two decades. Furthermore, proliferative LN, MCD, and primary IgAN continue to be the most common histopathological diagnoses among Taiwanese children.

Impacts of Catch-Up Immunization program with the 13-Valent pneumococcal Conjugate vaccine in Taiwan: Focus on age-stratified differences and high-risk population (2001-2015)

BACKGROUND

Taiwan commenced a national catch-up immunization program with a 13-valent pneumococcal conjugate vaccine (PCV13) in 2013 for children aged 2-5 years old and in 2014 for children aged 1-5 years old. However, real-world nationwide evidence of both the direct protection and indirect protection of all-cause pneumonia and pneumococcal pneumonia has been scarce, especially among high-risk populations, defined as patients with chronic diseases or immunosuppression. The aim of this study was to examine the impact of the national PCV13 catch-up program on all-cause pneumonia and pneumococcal pneumonia among overall and high-risk populations using interrupted time series analysis.

METHODS

Using the National Health Insurance Research Database (NHIRD) from January 2001 to December 2015, we assessed the impact of this catch-up program by interrupted time-series analyses age-stratified (0-1, 2-4, 5-9, 10-17, 18-34, 35-49, 50-64, 65 + years old) incidence of pneumococcal pneumonia and all-cause pneumonia (100,000 person-quarter) among the overall and high-risk populations.

RESULTS

The impact of this program was most profound on the incidence of pneumococcal pneumonia in children aged 2-4 years old (level change -10.56 per 100,000 person-quarters, p = 0.04; trend change -2.93, p less than 0.01). Indirect protection among unvaccinated children (0-1 years old: trend change -1.19, p = 0.01; 5-9 years old: trend change -1.04, p = 0.03; 10-17 years old: level change -1.42 per 100,000 person-quarters, p = 0.03) was also found. The incidence of all-cause pneumonia also decreased in children aged 2-4 (level change -234.91 per 100,000 person-quarter, p = 0.058) and 5-9 years old (level change -173.96 per 100,000 person-quarter, p = 0.0424). However, we did not find a significant impact among most high-risk populations.

CONCLUSIONS

Our study suggests that the introduction of this catch-up program with PCV13 was associated with significant declines in the incidence of pneumococcal pneumonia and all-cause pneumonia in vaccinated children, and indirect protection from the program was also found in unvaccinated children.

Serious bacterial infections in young children with fever without source after discharge from emergency department: A National Health Insurance database cohort study

BACKGROUND

Well-appearing febrile young children discharged from the emergency department (ED) after medical assessment are still at risk for serious bacterial infections (SBI). The incidence of SBI and the effectiveness of laboratory tests in the pneumococcal conjugate vaccine era remain unknown.

METHODS

We conducted a study using Taiwan's National Health Insurance claims data from 2004 to 2014. Children aged 2-24 months discharged from the ED with a diagnosis compatible with fever without source (FWS) were enrolled.

RESULTS

The study identified 431,884 children from the ED with FWS. 13.53% of the children had revisits, 8.62% needed hospitalization and 1.57% developed SBI. Younger children had a higher SBI rate, but a lower revisit rate. The revisit rate was 12.22% for children aged 2-6 months, 13.61% for children aged 7-12 months and 13.77% for children aged 13-24 months (p < 0.0001). The SBI rate was 4.44% for children aged 2-6 months, 1.85% for children aged 2-6 months and 0.96% for children aged 13-24 months (p < 0.0001). Children with hemogram tests, compared to those without, had a higher revisit rate (16.30% vs. 13.15%, p < 0.0001), and a higher SBI rate in the children aged 13-24 months (1.30% vs. 0.92%, p < 0.0001); furthermore, children with urinalysis had a significantly higher revisit rate (14.42% vs. 13.24%, p < 0.0001) and higher SBI rate (2.10% vs. 1.40%, p < 0.0001).

CONCLUSION

Children with FWS aged 2-24 months who were discharged from ED after blood test and urinalysis were still at risk for SBI, especially those aged 2-6 months.

Predictors of Surgical Intervention for Pediatric Acute Rhinosinusitis with Periorbital Infection

Background: Medical versus surgical management of pediatric periorbital infection secondary to acute bacterial rhinosinusitis (ABRS) can be a dilemma for clinicians. This study aimed to evaluate the prognostic factors related to the need for surgical drainage and to help direct management decisions. Methods: Children admitted for periorbital infection secondary to ABRS between 2001 and 2019 were retrospectively reviewed. Demographics, clinical presentations, laboratory data, comorbidities, and computed tomography results were collected from medical records. Results: A total of 141 pediatric patients were enrolled. Forty-two patients (29.8%) required surgical intervention. Multivariate logistic regression analysis identified that delayed initiation of intravenous antibiotics from the onset of periorbital swelling (odds ratio [OR] = 1.94; p < 0.001) and proptosis at initial presentation (OR = 6.63; p = 0.008) were significantly associated with the need for surgical intervention. A C-reactive protein value of > 55.73 mg/L and initiation of intravenous antibiotic treatment > 2 days from the onset of periorbital swelling showed the best predictive power for surgery. Conclusions: Pediatric patients with delayed initiation of intravenous antibiotic treatment and initial presentation of proptosis had worse outcomes and required surgical intervention.

Substantial decline in invasive pneumococcal disease (IPD) during COVID-19 pandemic in Hong Kong

Compared with other countries, a more substantial decrease in the incidence of invasive pneumococcal disease was observed in Hong Kong, which is most likely attributable to the proactive mass adoption of face masks by the public. Human behavioral changes, particularly mask wearing, should be considered as an additional preventive strategy against invasive pneumococcal disease.

Longitudinal investigation of nasopharyngeal pneumococcal carriage in early childhood: The PATCH birth cohort study

Streptococcus pneumoniae is a common cause of infectious diseases such as pneumonia and sepsis. Its colonization is thought to be the first step in the development of invasive pneumococcal diseases. This study aimed to investigate pneumococcal colonization patterns in early childhood. A longitudinal birth cohort study was conducted for investigating nasopharyngeal colonized pneumococci at 1, 6, 12, 18, 24, and 36 months of age, particularly focusing on the serotype distribution and antimicrobial susceptibilities. Pneumococcal conjugate vaccine (PCV) effect on nasopharyngeal colonization was also assessed. During 2013-2017, 855 infants were enrolled and a total of 107 isolates were recovered from 95 infants during the first three years of life. In this period, the prevalence of pneumococcal colonization increased, with values ranging from 0.2% (2/834) at 1 month of age to 5.9% (19/323) at 36 months of age. The investigation of serotype revealed that 81.1% (73/90) belonged to the non-PCV13 serotypes-23A, 15A, 15C, and 15B. Moreover, PCV13 serotypes significantly decreased during 2014-2015, when routine PCV13 vaccination was initiated in Taiwan. PCV13 introduction may lead to the reduction in the rates of pneumococcal isolates resistant (R) to penicillin. Under conditional PCV13 vaccination, pneumococcal isolates primarily belonged to non-PCV13 serotypes. This non-PCV13 serotype replacement exhibited lower rates of penicillin R isolates, suggesting that PCV13 administration may reduce the antibiotic-nonsusceptible pneumococcal disease burden and antibiotic use.

The potential role of pneumococcal conjugate vaccine in reducing acute respiratory inflammation in community-acquired pneumococcal pneumonia

Background

Pneumococcal conjugate vaccine (PCV) reduces both invasive pneumococcal disease (IPD) and other pneumococcal infections worldwide. We investigated the impact of stepwise implementation of childhood PCV programs on the prevalence of pneumococcal pneumonia, severity of acute inflammation, and associations between breakthrough pneumonia and pneumococcal serotypes in Taiwan.

Methods

In total, 983 children diagnosed with community-acquired pneumococcal pneumonia were enrolled between January 2010 and December 2015.

Results

Proportions of pneumococcal vaccinations increased each year in age-stratified groups with PCV7 (32.2%) as the majority, followed by PCV13 (12.2%). The proportion of pneumococcal pneumonia decreased each year in age-stratified groups, especially in 2–5 year group. Serotype 19A is the leading serotype either in vaccinated (6.4%) or unvaccinated patients (5.2%). In particular, vaccinated patients had significantly higher lowest WBC, lower neutrophils, lower lymphocytes and lower CRP values than non-vaccinated patients (p < 0.05). After stratifying patients by breakthrough infection, those with breakthrough pneumococcal infection with vaccine coverage serotypes had more severe pneumonia disease (p < 0.05).

Conclusion

Systematic childhood pneumococcal vaccination reduced the prevalence of community-acquired pneumococcal pneumonia, especially in 2–5 year group. Serotype 19A was the major serotype for all vaccine types in patients with pneumococcal pneumonia and severity of acute inflammatory response was reduced in vaccinated patients.

Pediatric parapneumonic effusion before and after national pneumococcal vaccination programs in Taiwan

BACKGROUND

Reports on the effectiveness of pneumococcal conjugate vaccines (PCVs) on pediatric parapneumonic effusion are limited. We report the changes in cases and etiologies of pediatric parapneumonic effusion in a children's hospital before and after national PCV13 vaccination programs.

METHODS

We screened medical records of children 0-18 years admitted to the National Taiwan University Hospital with diagnoses of lobar pneumonia and parapneumonic effusion between 2008 and 2017. Patients with effusion analyses were included. Results of blood, pleural fluid, and respiratory specimens surveyed as standard care were analyzed.

RESULTS

Diagnostic testing revealed at least a pathogen in 85% of 202 children with lobar pneumonia and parapneumonic effusion. After national PCV13 immunization, pneumococcal empyema decreased by 72% among 2- to 5-year olds. Mycoplasma pneumoniae was the second most common etiology. There were marked differences in effusion characteristics, metabolic, and respiratory parameters between children infected with pneumococcus and M. pneumoniae.

CONCLUSION

The effectiveness of the national PCV13 immunization programs on pneumococcal empyema was evident and remained substantial after 4 years in Taiwan. Continuous surveillance is important to monitor the emergence of other pathogens including non-PCV serotypes and M. pneumoniae.

Thomsen-Friedenreich antigen activation as a predictor for clinical outcome of pediatric patients with invasive pneumococcal disease

BACKGROUND

The most severe form of pneumococcal disease is invasive pneumococcal disease (IPD), including empyema, sepsis and meningitis. Thomsen-Friedenreich antigen (TA; Galβ1-3GalNAc) activation is known to be a predictor of Streptococcus pneumoniae-associated hemolytic uremic syndrome (Sp-HUS). There have been limited data to correlate TA activation and overall disease severity of IPD in children. The study aimed to prove the positive correlation between TA activation and disease severity and to demonstrate the trend of TA level during the disease course.

METHODS

We retrospectively reviewed the medical records from 38 pediatric patients aged from 0 to 18 years with microbiologically-confirmed IPD between 2010 and 2015 at a medical center in Taiwan. All cases underwent TA activation testing by the fluorescence-labeled peanut lectin agglutination method. Medical information including demographic data, laboratory findings, co-morbidities, and outcome was collected and reviewed. We compared the clinical manifestations and associated co-morbidities between TA-positive and TA-negative patients.

RESULTS

Among the 38 patients, 25 (66%) showed TA activation. Compared to TA-negative patients, patients with TA activation had a statistically higher rate of prolonged anemia, thrombocytopenia, and acute kidney injury. TA-positive patients also had a longer intensive care unit stay and overall hospitalization days. The TA levels usually peaked 5-10 days after disease onset. Twenty-one pneumococcal isolates were recovered from the patients and serotyping was determined in 11 isolates: 10 serotype 19A and 1 serotype 3.

CONCLUSIONS

TA determination not only helps to diagnose Sp-HUS but also is a predictor for IPD severity. Among hospitalized patients with severe pneumococcal disease, the peak of TA level usually appeared 5-10 days after disease onset.

Higher Hospitalization Rate for Lower Airway Infection in Transfusion-Naïve Thalassemia Children

Few studies have addressed the risk of infection in transfusion-naïve thalassemia patients. We aimed to investigate whether transfusion-naïve thalassemia population has higher hospitalization rates for lower airway infection-related diseases than non-thalassemia population in children. A nationwide population-based retrospective cohort study was conducted using detailed medical records of the Taiwan National Health Insurance Research Database. Transfusion-naïve thalassemia patients were compared with a matched cohort at a ratio of 1:4. Data of the selected patients were adjusted for age, sex, and related comorbidities. We recorded the frequency of admissions or outpatient clinic visits for patients with a diagnosis of pneumonia or acute bronchitis/bronchiolitis. Based on our results, the hospitalization rates and incidence rate ratios of bronchitis/bronchiolitis and pneumonia for transfusion-naïve thalassemia children were all higher than those for non-thalassemia controls. Therefore, we conclude that transfusion-naïve thalassemia children are more likely to experience lower airway infections and have a higher probability of hospitalization for these conditions.

Evaluation of the impact of 13-valent pneumococcal conjugate vaccine immunization in children by surveillance of culture-confirmed pneumococcal disease: A prospective clinical microbiological study

The study aimed to investigate the impact of 13-valent pneumococcal conjugate vaccine (PCV13) immunization on the overall pneumococcal disease in children in Taiwan by surveillance of culture-confirmed pneumococcal disease (CCPD). This study was conducted in a medical center from 2012 to 2016. Clinical isolates of Streptococcus pneumoniae were prospectively collected from pediatric patients. Serotyping, multi-locus sequence typing, and antimicrobial susceptibility testing were performed. A total of 473 patients with CCPD, including 58 with invasive pneumococcal disease (IPD), were identified. The incidence of CCPD per 10,000 admissions decreased from 71.7 in 2012 to 27.0 in 2016. The proportion of additional PCV13 serotypes significantly decreased from 52.0% in 2012 to 21.7% in 2015 but increased slightly to 26.7% because of serotype 19A in 2016 (P < 0.0001). The proportion of non-vaccine serotypes (NVTs) increased significantly from 18.4% in 2012 to 66.7% in 2016, but the increase of the incidence of CCPD caused by NVTs was not considered significant (P = 0.0885). Genotyping identified predominant clones, ST63^15A, ST83^15B, and ST166/338^23A, for major NVTs. The penicillin non-susceptibility of PCV13 serotypes was significantly higher than that of NVTs (P < 0.0001). Surveillance of CCPD appears superior to IPD alone for evaluation of the overall impact of pneumococcal immunization. Serotype replacement occurred quickly after the use of PCV13, while the incidence of NVT infection did not show a significant increase in children over the years. The gradual introduction of PCV13 into national immunization program is effective in reducing overall pneumococcal disease in children.

Recommendations and guidelines for the treatment of pneumonia in Taiwan

Pneumonia is a leading cause of death worldwide, ranking third both globally and in Taiwan. This guideline was prepared by the 2017 Guidelines Recommendations for Evidence-based Antimicrobial agents use in Taiwan (GREAT) working group, formed under the auspices of the Infectious Diseases Society of Taiwan (IDST). A consensus meeting was held jointly by the IDST, Taiwan Society of Pulmonary and Critical Care Medicine (TSPCCM), the Medical Foundation in Memory of Dr. Deh-Lin Cheng, the Foundation of Professor Wei-Chuan Hsieh for Infectious Diseases Research and Education and CY Lee's Research Foundation for Pediatric Infectious Diseases and Vaccines. The final guideline was endorsed by the IDST and TSPCCM. The major differences between this guideline and the 2007 version include the following: the use of GRADE methodology for the evaluation of available evidence whenever applicable, the specific inclusion of healthcare-associated pneumonia as a category due to the unique medical system in Taiwan and inclusion of recommendations for treatment of pediatric pneumonia. This guideline includes the epidemiology and recommendations of antimicrobial treatment of community-acquired pneumonia, hospital-acquired pneumonia, ventilator-associated pneumonia, healthcare-associated pneumonia in adults and pediatric pneumonia.

Safety and Efficacy of Pneumococcal Vaccination in Pediatric Nephrotic Syndrome

Nephrotic syndrome affects both children and adults. Idiopathic nephrotic syndrome is reported to be one of the most frequent renal pathologies in childhood. Nephrotic children are at high risk for severe pneumococcal infections as one of the life-threatening complications of nephrotic syndrome due to involvement of the immunosuppressive regimen and the acquired immune deficiency induced by nephrotic syndrome including decreased plasma IgG and low complement system components. Aiming to prevent pneumococcal infection is of paramount importance especially in this era of ever-increasing pneumococcal resistance to penicillins and cephalosporins. The pneumococcal vaccines currently available are inactivated vaccines-the two main forms in use are polysaccharide vaccines and conjugated vaccines. However, the data supporting the use of these vaccines and to guide the timing and dosage recommendations is still limited for nephrotic children. Thus, this review discusses the evidences of immunogenicity and safety profile of both vaccinations on nephrotic patients as well as the effect of nephrotic syndrome treatment on vaccine seroresponses.

Outcomes of adjunctive steroid therapy in adult patients with bacterial meningitis in Taiwan: A nationwide population-based epidemiologic study

BACKGROUND

Although corticosteroids are an effective anti-inflammatory adjuvant therapy, the role of adjunctive steroid therapy in treating adult bacterial meningitis in Taiwan remains controversial.

METHODS

Cases of acute bacterial meningitis were identified from the annual hospitalization discharge claims of the National Health Insurance Research Database using International Classification of Diseases, Ninth Revision codes from January 2000 to December 2013. Patients were classified into two groups: (1) steroid group (adjunctive steroids and empirical antibiotics) and (2) placebo group (empirical antibiotics only).

RESULTS

There were 15,037 patients enrolled in this study; of these, 57% (7175/15,037) and 52% (7862/15,037) were placed in the placebo and steroid groups, respectively. The case-fatality rates were 11.5% (826/7175) in the placebo group and 19.9% (1562/7862) in the steroid groups during hospitalization (P = 0.77). Further, the hazard ratio (relative to placebo group) of in-hospital and one-year case fatality rate were 0.923 (95% confidence interval [CI]: 0.846-1.007, P = 0.073) and 1.514 (95% CI: 1.425-1.608, P < 0.0001) according to the multivariate Cox model after adjustment for age and sex.

CONCLUSION

On the basis of these results, steroid group had a more fulminant clinical course (e.g., acute respiratory failure and pneumonia, etc.), and unfavorable outcomes than placebo group. Therefore, more prospective, randomized, double-blind trials are warranted to evaluate the efficacy of adjunctive steroid therapy in treating adult bacterial meningitis in Taiwan.

Trend and outcome of sepsis in children: A nationwide cohort study

AIM

The aim of this study was to investigate the trend of incidence and outcome of paediatric sepsis in a population-based database.

METHODS

Children with sepsis were identified from the 23 million nationwide health insurance claims database of Taiwan. Sepsis was defined by the presence of single ICD-9 code for severe sepsis or septic shock or a combination of ICD-9 codes for infection and organ dysfunction. We analysed the trend of incidence, mortality and source of infection in three age groups: infant (28 days to 1 year), child (1-9 years) and adolescent (10-18 years).

RESULTS

From 2002 to 2012, we identified 38 582 paediatric patients with sepsis, of which 21.3% were infants, 52.8% were children and 25.8% were adolescents. The incidence of sepsis was 336.4 cases per 100 000 population in infants, 3.3 times higher than in children (101.5/100 000 cases) and 7.3 times higher than in adolescents (46.2/100 000 cases). While sepsis incidence decreased from 598.0 to 336.4 cases per 100 000 people in the infant population, it remained relatively unchanged in children and adolescents. For 90-day mortality, there were significant decreases in all three age groups (absolute decrease of 5.0% for infants, 3.7% for children and 14.4% for the adolescents). In the infant population, we observed a decrease in the incidence of lower respiratory tract infections, while the incidence of urinary tract infections remained unchanged.

CONCLUSIONS

The incidence and mortality of sepsis among paediatric patients have decreased substantially between 2002 and 2012, especially among infants. The widespread use of Haemophilus influenzae and pneumococcal vaccines in infants could be a possible explanation.

Non-typeable Streptococcus pneumoniae infection in a medical center in Taiwan after wide use of pneumococcal conjugate vaccine

BACKGROUND

Streptococcus pneumoniae is one of the most common pathogens to cause mucosal and invasive infection in humans. Most of the infection could be prevented through immunization by vaccines containing capsular polysaccharides but some infection may be caused by unencapsulated strains.

METHODS

Clinical isolates of S.pneumoniae from January 2012 to December 2015 at Chang Gung Memorial Hospital, Taiwan. Serotyping by PCR method was performed. Clinical and laboratory information of patients infected by non-typeable pneumococci (NTP) were collected and analyzed.

RESULTS

During the study period, 39 NTP isolates were identified. Most (21 of 39, 53.9%) were collected from purulent upper respiratory tract secretion. Others were from corneal abscess, sputum, and one from blood of a newborn. We recorded a 3.6-fold increase in the rate of isolation from 1.4% in 2012 to 5.0% in 2015 (p = 0.063). Co-infection was found in 24 cases; the major co-infecting pathogens included non-typeable Hemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus. Most (39 of 40, 97.5%) of the isolates were susceptible to both penicillin and ceftriaxone. The dominant sequence type ST1106 and an emerging sequence type ST7502 were recognized.

CONCLUSIONS

A gradual increase of NTP infection was found in northern Taiwan in the pneumococcal conjugate vaccine era. Non-typeable pneumococci can cause respiratory and ophthalmological mucosal infection. Invasive infection can occur in newborns or young infants. Most of the isolates remained susceptible to penicillin and ceftriaxone.

Redistribution of Streptococcus pneumoniae Serotypes After Nationwide 13-valent Pneumococcal Conjugate Vaccine Program in Children in Northern Taiwan

BACKGROUND

After the introduction of 13-valent pneumococcal conjugate vaccine (PCV13) against Streptococcus pneumoniae, public health officials in Taiwan monitored a decline in circulating vaccine serotypes and the emergence of nonvaccine serotypes in children with invasive pneumococcal disease. A gradually expanded PCV13 national immunization program was launched in 2013 in Taiwan. Here, we evaluate the changes in the distribution of pneumococcal serotypes and antimicrobial nonsusceptibility in children during the evolution of vaccination policy.

METHODS

S. pneumoniae isolates from children with pneumococcal disease were collected and serotyped from 2010 to 2015 in northern Taiwan. PCVs were administered at the recipients' expense between 2010 and 2012, and then PCV13 was partially reimbursed by the government beginning in 2013. The distribution and diversity of serotypes were analyzed along with their antimicrobial susceptibilities.

RESULTS

Among a total of 498 isolates, the proportion of invasive pneumococcal disease isolates declined (47.1%-10.6%) during the study period, and serotype diversity increased after 2011. Between 2010 and 2012, the dominant serotypes were 19A, 19F, 3, 6B and 14, and serotype 19A rose from 44.1% to 57.5%. Serotypes 19A, 15A, 19F and 15B were more prevalent from 2013 to 2015, and serotype 19A decreased from 42.1% to 4.5%. Serotypes 19F and 15A became the most commonly detected serotypes in 2015. Overall, PCV13 additional serotypes were reduced by 80% (P < 0.0001) but nonvaccine serotypes increased from 8.8% to 51.5% (P < 0.0001).

CONCLUSIONS

The step-by-step PCV13 national immunization program is effective against pneumococcal disease in Taiwanese children, mainly by reducing PCV13 additional serotypes.

Influenza vaccination might reduce the risk of ischemic stroke in patients with atrial fibrillation: A population-based cohort study

Purpose

Atrial fibrillation (AF) is associated with the risk of ischemic stroke, regardless of the administration of appropriate antithrombotic prophylaxis. This study investigated whether influenza vaccination is associated with the risk of ischemic stroke, to determine a solution to reduce this risk in patients with AF.

Methods

We used data from the Taiwan National Health Insurance Research Database. The study cohort comprised all patients diagnosed as having AF (n = 14 454) before January 1, 2005; these patients were followed until December 31, 2012. The index date was January 1, 2005. A propensity score was derived using a logistic regression model to estimate the effect of vaccination by accounting for covariates that predict receiving the intervention (vaccine). A Cox proportional hazard model was used to calculate the hazard ratios (HRs) of ischemic stroke in vaccinated and unvaccinated patients with AF.

Results

We included 6570 patients (2547 [38.77%] with and 4023 [61.23%] without influenza vaccination). The adjusted HRs (aHRs) of ischemic stroke were lower in the vaccinated patients than in the unvaccinated patients (influenza season, noninfluenza season, and all seasons: aHRs = 0.59, 0.50, and 0.55; P < 0.001, P < 0.001, and P < 0.001, respectively).

Conclusions

Influenza vaccination might exert a dose-response effect against ischemic stroke in patients with AF who have risk factors for ischemic stroke by reducing the incidence of ischemic stroke, particularly in those aged 65–74 and ≥75 y.

Pneumococcal vaccination and efficacy in patients with heterotaxy syndrome

BackgroundPneumococcal vaccines, including pneumococcal polysaccharide vaccine (PPV) and pneumococcal conjugated vaccine (PCV), are crucial in preventing invasive pneumococcal diseases. We analyzed the pneumococcal vaccination rate, efficacy, and durability in patients with heterotaxy.MethodsAll patients with heterotaxy and CCHD who were followed up at our institution between 2010 and 2015 were included. Pneumococcal vaccine status and geometric mean concentration (GMC) of serotypes 6B, 14, 19F, and 23F were analyzed. Splenic function was considered abnormal when the percentage of IgM memory B cell was less than 1%.ResultsThe GMCs of the four serotypes did not differ significantly between patients with heterotaxy and those with CCHD; the GMCs were also not affected by abnormal splenic function. Most patients had GMCs >0.35 μg/ml (protection level) 4-5 years after either PPV or PCV injection; however, it may decay gradually in some serotypes. In addition, 21.4% of 42 patients with heterotaxy did not receive pneumococcal vaccine, and none completely adhered to the vaccine guidelines.ConclusionsVaccine efficacy was acceptable, even in patients with abnormal splenic function. In some patients, the durability of PPV and PCV decreased with time, highlighting the importance of booster doses. Vaccination rate in patients with heterotaxy is unsatisfactory.

Invasive pneumococcal disease caused by ceftriaxone-resistant Streptococcus pneumoniae in Taiwan

BACKGROUND

Invasive pneumococcal disease (IPD) was associated with mortality, but the risk factors associated with mortality remains controversial.

METHODS

A retrospective cohort study was designed. All patients with IPD from 2011 to 2013 admitted in a medical center were screened and collected for their clinical presentations and laboratory characteristics.

RESULTS

Approximately half of the 134 IPD isolates derived from these patients belonged to three major serotypes (19A, 6A and 3), which are included in 13-valent pneumococcal conjugate vaccine (PCV13), but not in 7-valent pneumococcal conjugate vaccine (PCV7). Ceftriaxone resistance according to non-meningitis criteria was identified in 38% of the IPD isolates, and was the major independent risk factor associated with inappropriate initial therapy that subsequently contributed to mortality of the patients. Infection by serotype 6A, 15B, 19A, 19F, or 23F was the major independent risk factor associated with ceftriaxone resistance (non-meningitis criteria). 77.6% of these isolates belonged to additional PCV13 serotypes, with more than 40% expressing resistance to ceftriaxone. In terms of serotype coverage, PCV13 covered 94.1% of the IPD isolates with ceftriaxone resistance, in comparison to 21.6% only by PCV7.

CONCLUSIONS

The increase of ceftriaxone resistance in pneumococci in part driven by PCV7 vaccination in Taiwan is worrisome. The use of PCV13 in children as well as in the elderly population is likely to offer protection from the infection caused by ceftriaxone-resistant pneumococci. It is important to give an effective drug such as penicillin, fluoroquinolones or vancomycin in 2 days for improving outcome of IPD patients.

Impact of pneumococcal conjugate vaccine in children on the serotypic epidemiology of adult invasive pneumococcal diseases in Taiwan

BACKGROUND

Invasive pneumococcal disease (IPD) causes significant morbidity and mortality, especially in children and older adults. Pneumococcal 7-valent and 13-valent conjugate vaccines (PCV7 and PCV13) were introduced in Taiwan in 2005 and 2011, respectively, for children. This study was conducted to evaluate the impact of PCV administered in children on adult IPD.

METHODS

From the logbooks of microbiology laboratories, we retrospectively retrieved Streptococcus pneumoniae isolates, collected from normally sterile sites in adult patients. One hundred and fifty-seven consecutive, nonduplicated isolates were collected from one hospital during 2001 and 2003 (pre-PCV period) and 150 isolates from three hospitals from July 2011 to June 2015 (post-PCV period). Serotypes were determined by Quellung test.

RESULTS

Among the 307 isolates, 31 serotypes/serogroups were identified. PCV7 serotypes, particularly types 14 (31.2%), 23F (19.7%) and 6B (12.7%) dominated in the pre-PCV period (78.3%) but significantly decreased in the post-PCV period (36%) (p < 0.01). PCV13 specific serotypes (PCV13-PCV7) significantly increased from 7% of the isolates in the pre-PCV period to 28.7% of the isolates in the post-PCV period (p < 0.001), particularly type 19A (from 0.6% to 10%) and 6A (from 0 to 6.7%). Serotype 15B also increased significantly from 0.6% to 6.7% (p < 0.01). Nonvaccine serotypes increased significantly in the post-PCV period (11.5% to 22.0%, p < 0.05), particularly type 15A (from 0 to 4.4%, p < 0.01).

CONCLUSION

Serotype distribution of adult IPD in Taiwan has evolved after the introduction of PCV in children, indicating an indirect impact in adults. Continuous surveillance after the PCV13 vaccination program in children is needed.

Fluoroquinolone-nonsusceptible Streptococcus pneumoniae isolates from a medical center in the pneumococcal conjugate vaccine era

BACKGROUND/PURPOSE

Streptococcus pneumoniae is one of the most common pathogens to cause mucosal and invasive infection in humans. Resistance to fluoroquinolones (FQ) is associated with clinical failure when treating pneumococcal diseases and increase of mortality.

METHODS

We collected clinical isolates of S. pneumoniae from January 2011 to July 2015 at Chang Gung Memorial Hospital, Taoyuan, Taiwan. Susceptibility to FQ was examined by disk diffusion method. Levofloxacin or moxifloxacin-nonsusceptible S. pneumoniae isolates were analyzed by serotyping, multilocus sequence typing, and sequencing of the quinolone resistance-determining regions (QRDRs) of gyrA, gyrB, parC, and parE.

RESULTS

During the study period, 42 FQ-nonsusceptible pneumococcal isolates were identified. The rate increased from 1.6% of total pneumococcal isolates (2 of 127) in 2011 to 4.6% (13 of 283) in 2014, then decreased to 1.5% (3 of 202) in the first half of 2015. These isolates belonged to 13 serotypes, and serotype 14 (12 of 42, 33.3%) was the most prevalent. Most of the isolates belonged to international clones or their variants. After QRDR analysis, there were 19 isolates in five clusters that shared both the same sequence type and QRDR mutation.

CONCLUSIONS

FQ resistance initially emerged in either vaccine or nonvaccine serotypes. The majority of isolates were international clones or related variants, suggesting that resistance was disseminated through clonal spread. The wide use of pneumococcal conjugate vaccine since 2013 appears to have reduced the spread of FQ-nonsusceptible pneumococci.