Pneumococcal serotypes in adults hospitalized with community-acquired pneumonia in Greece using urinary antigen detection tests: the EGNATIA study, November 2017 – April 2019

Abstract

Greece introduced a 13-valent pneumococcal conjugate vaccine (PCV13) into the infant national immunization program in 2010 (3 + 1 schedule until June 2019). Since 2015, PCV13 has been recommended for adults aged 19–64 years with comorbidities and adults ≥65 years sequentially with 23-valent pneumococcal polysaccharide vaccine (PPSV23). We examined pneumococcal serotype distribution among Greek adults aged ≥19 years hospitalized with community-acquired pneumonia (CAP) during November 2017-April 2019. This was an interim analysis of EGNATIA, a prospective study of adult hospitalized CAP in the cities of Ioannina and Kavala. Pneumococcus was identified using cultures, BinaxNow®, serotype-specific urinary antigen detection assays (UAD-1/2). Our analysis included overall 482 hospitalized CAP patients (mean age: 70.5 years; 56.4% male). 53.53% of patients belonged to the highest pneumonia severity index (PSI) classes (IV-V). Pneumococcus was detected in 65 (13.5%) patients, with more than half (57%) of cases detected only by UAD. Approximately two-thirds of pneumococcal CAP occurred in those aged ≥65 years (n = 40, 8.3% of CAP). More than half of pneumococcal CAP (n = 35, 53.8%) was caused by PCV13 serotypes. Most frequently detected PCV13 serotypes were 3, 19A, 23F, collectively accounting for 83% of PCV13 vaccine-type (VT) CAP and 6% of all-cause CAP. Overall, 82.9% of PCV13 VT CAP occurred among persons with an indication (age/risk-based) for PCV13 vaccination. Even with a mature PCV13 childhood immunization program, a persistent burden of PCV13 VT CAP exists in Greek adults. Strategies to increase PCV13 (and higher-valency PCVs, when licensed) coverage in adults should be implemented to reduce the disease burden.

Prevalence of Pneumococcal Serotypes in Community-Acquired Pneumonia among Older Adults in Italy: A Multicenter Cohort Study

“…In line with previous reports [ 23 , 24 , 25 , 26 ], PCV13 serotype 3 was the most frequent serotype detected in CAP in our study. The disease caused by serotype 3 is often more severe and may evade antibody-mediated clearance.…”

“…In adults, the proportion of CAP due to S. pneumoniae in high-income countries varies, with higher values reported in Spain [ 23 ] and the United Kingdom (UK) [ 24 ] and lower values in the US [ 25 ] and Greece [ 26 ]. A prospective cohort study on the etiology of CAP in older adults in four Spanish regions reported that 35.0% of CAP cases were due to S. pneumoniae and serotypes 3 and 8 were the most commonly detected [ 23 ].…”

“…In the UK study, no serotype could be determined in a large proportion of pCAP cases [ 24 ]. In the US, pneumococcus was identified in 8.8% of adults ≥ 65 years hospitalized for CAP [ 25 ] and a Greek study identified pneumococcus in 12.2% of CAP patients [ 26 ]. The results of these two studies [ 25 , 26 ] were more similar to our findings.…”

“…In the US, pneumococcus was identified in 8.8% of adults ≥ 65 years hospitalized for CAP [ 25 ] and a Greek study identified pneumococcus in 12.2% of CAP patients [ 26 ]. The results of these two studies [ 25 , 26 ] were more similar to our findings. The reasons for the differences between the studies may reflect the true epidemiologic differences in the countries (e.g., based on PCV coverage in children and adults, the use of the influenza vaccine, differences in the waves of co-infecting viral illnesses, the prevalence of underlying diseases or other factors) or methodologic differences such as the patient enrollment criteria, different criteria for defining CAP or differences in the criteria for hospitalizing patients with CAP.…”

Estimating the Clinical and Economic Impact of Switching from the 13-Valent Pneumococcal Conjugate Vaccine (PCV13) to Higher-Valent Options in Greek Infants

“…Historical trends from the US were used because of similarities in dosing schedules in Greece as of 2019 (3 + 1), uptake, program implementation, and catch-up programs for those aged less than 60 months both for PCV7 and for PCV13. Additionally, in a Greek study on adult hospitalized community-acquired pneumonia (CAP), the proportions of pneumococcus and PCV13 serotypes were comparable to those reported in a US CAP study but substantially lower than those reported in a Spanish study and a UK study, indicating similarities in pneumococcal epidemiology between Greece and the US [ 22 ]. Moreover, previous infant PCV modeling studies in Greece have used US epidemiological data for estimating future higher-valent vaccine effects [ 17 ].…”