Invasive Pneumococcal Disease in the Adult Population in Portugal (2019-2022)

12/05/2024

Despite the success of pneumococcal vaccination, Streptococcus pneumoniae remains an important cause of morbidity and mortality worldwide. In Portugal, 1303 adult invasive pneumococcal disease (IPD) isolates collected from 2019 to 2022 were phenotypically characterized. The number of IPD cases abruptly declined in 2020 due to the COVID-19 pandemic, but appears to be gradually returning to pre-pandemic levels. Among the 47 serotypes detected, the most frequent were serotypes 8 (21.8%), 3 (17.1%), 22F (5.5%), 11A (5.2%), 9N (4.9%) and 19A (3.9%), together accounting for 58.5% of adult IPD. Besides the prevalence of serotype 8, a significant rise in serotype 3 was noted in this four-year study. Additionally, a resurgence of serotype 4 was reported. Serotypes 11A and 22F increased in importance among the elderly, while serotypes 4, 8 and 12F decreased. Overall, the proportion of isolates expressing serotypes included in the available pneumococcal conjugate vaccines PCV7, PCV13, PCV15, PCV20 and 23-valent pneumococcal polysaccharide vaccine (PPV23) was 12.2%, 34.3%, 40.8%, 74.3% and 81.7%, respectively. Compared with previous studies, a higher rate of penicillin non-susceptibility was obtained (19.3%), while erythromycin resistance seems to be continuously decreasing over time, reaching 13.5% in 2019-2022. Serotypes 14 and 19A, both included inPCV13, were the major contributors to antimicrobial resistance, although IPD associated with these serotypes decreased. Since the overwhelming majority of pneumococcal invasive infections remained potentially vaccine-preventable, direct vaccination of the adult population, especially with the recently available PCV20, could be important in preventing IPD.

Authors in the community:

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  A

  Andreia Filipa Guerreiro Nunes

  ist1105328

Supervisors of this institution:

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  L

  Leonilde de Fátima Morais Moreira

  ist14082

industrial-biotechnology - Industrial Biotechnology

eng - English

Instituto Superior Técnico