Pneumococcal Serotype Evolution and Burden in European Adults in the Last Decade: A Systematic Review

Abstract

Pneumococcal disease is a major cause of morbidity/mortality worldwide, and vaccination is an important measure in its prevention. Despite European children being vaccinated with pneumococcal conjugate vaccines (PCVs), pneumococcal infections are still a major cause of morbidity/mortality in adults with risk conditions and their vaccination might be an important prevention strategy. New PCVs have been approved, but information is lacking on their potential impact in European adults. In our review, we searched PubMed, MEDLINE, and Embase for studies on the additional PCV20 serotypes (concerning incidence, prevalence, disease severity, lethality, and antimicrobial resistance) in European adults, between January 2010 and April 2022, having included 118 articles and data from 33 countries. We found that these serotypes have become more prevalent in both invasive and non-invasive pneumococcal disease (IPD and NIPD), representing a significant proportion of cases (serotypes 8, 12F, 22F) and more serious disease and/or lethality (10A, 11A, 15B, 22F), showing antimicrobial resistance (11A, 15B, 33F), and/or affecting more vulnerable individuals such as the elderly, immunocompromised patients, and those with comorbidities (8, 10A, 11A, 15B, 22F). The relevance of pneumococcal adult carriers (11A, 15B, 22F, and 8) was also identified. Altogether, our data showed an increase in the additional PCV20 serotypes’ prevalence, accounting for a proportion of approximately 60% of all pneumococcal isolates in IPD in European adults since 2018/2019. Data suggest that adults, as older and/or more vulnerable patients, would benefit from vaccination with higher-coverage PCVs, and that PCV20 may address an unmet medical need.

Antimicrobial Resistance of Streptococcus pneumoniae Clinical Serotypes between 2017 and 2022 in Crete, Greece

“…Serotype 11A was the most prevalent serotype during the study period, more commonly associated with non-IPD cases in the elderly. In recent years, serotype 11A is a prevalent serotype in Europe, accounting for 2 - 7% IPD and 9 - 10% non-IPD [ 20 ]. Several studies have shown that 11A has low invasive potential, and is associated with antibiotic non-susceptibility and increased risk of death [ 21 22 23 24 ].…”

“…Similarly, a significant increase in penicillin resistance was also observed from 1.9% over the period 2017 - 2019 to 20.3% over the years 2020 - 2022. The increasing rates in PNSP was in part due to increases in pneumococcal diseases caused by serotypes not included in PCV13, and the persistence of serotype 19A [ 20 ].…”

A narrative review of genomic characteristics, serotype, immunogenicity, and vaccine development of Streptococcus pneumoniae capsular polysaccharide

“…In high-income countries, some of these serotypes have been shown to cause more severe clinical manifestations such as meningitis [ 64 ]. In Europe, a systematic review found that these seven serotypes have an increasing trend in IPD incidence prevalence in adults [ 65 ]. PCV20 covers serotype 8, 10A, 11A, 12F, 15B, 22F, and 33F was licensed for adults >18 years in 2021 ( Fig.…”

Impact of Demographic Developments and PCV13 Vaccination on the Future Burden of Pneumococcal Diseases in Germany—An Integrated Probabilistic Differential Equation Approach

“…According to the Global Burden of Disease Study, pneumococcal pneumonia was responsible for 1.5 million deaths in 2015, where 55.4% of all deaths were caused by lower respiratory tract infections [2]. Pneumococcal diseases are classified into two main categories: invasive pneumococcal disease (IPD) and noninvasive pneumococcal disease (NIPD) [3,4]. IPD is diagnosed when the bacterium is typically identified in sterile bodily fluids, leading to severe infections such as meningitis, sepsis, or bacteremic pneumonia [3,5].…”

“…IPD incidence is impacted by various factors, including vaccination coverage, geographical location, underlying health conditions, smoking, and age [7]. Young children, infants, immunocompromised individuals, and the elderly bear the highest disease burden, both in developed and less developed countries [4,[7][8][9]. Specifically, children under 5 years old and elderly individuals aged 65 and above are particularly susceptible to developing pneumococcal disease [10].…”