Dominance of vaccine serotypes in pediatric invasive pneumococcal infections in Portugal (2012–2015)
Authors: Silva-Costa Catarina , Brito Maria J. , Aguiar Sandra I. , Lopes Joana P. , Ramirez Mário , Melo-Cristino José ,   Portuguese Group for the Study of Streptococcal Infections, Vaz Teresa , Gião Marília , Ferreira Rui , Bruschy Fonseca Ana , Oliveira Henrique , Silva Ana Cristina , Costa Hermínia , Silva Maria Fátima , Afonso Maria Amélia , Pinto Margarida , Chantre Odete , Marques João , Peres Isabel , Daniel Isabel , Canas Ema , Ferreira Teresa , Marcelo Cristina , Monteiro Lurdes , Marques Lito Luís , Martins Filomena , Pessanha Maria Ana , Gonçalves Elsa , Morais Teresa , Marques Teresa , Toscano Cristina , Lopes Paulo , Felício Luísa , Lameirão Angelina , Mota Vieira Ana Paula , Tomaz Margarida , Bento Rosa , Ramos Maria Helena , Castro Ana Paula , Fonseca Fernando , Castro Ana Paula , Ribeiro Graça , Ribeiro Rui Tomé , Pontes Celeste , Boaventura Luísa , Chaves Catarina , Reis Teresa , Canhoto Nuno , Afonso Teresa , Pina Teresa , Peres Helena , Fontes Ilse , Martinho Paulo , Domingos Ana , Marrão Gina , Grossinho José , Ribeiro Manuela , Gonçalves Helena , Faustino Alberta , Alves Adelaide , Iglesias Maria Cármen , Pinheiro Maria Paula , Semedo R. , Coutinho Adriana , Cabral Luísa , Neto Olga , Sancho Luísa , Diogo José , Rodrigues Ana , Nascimento Isabel , Ramalheira Elmano , Bessa Fernanda , Diaz Raquel , Vale Isabel , Carvalho Ana , Ribeiro José Miguel , Read Maria Antónia , Alves Valquíria , Monteiro Margarida , Raposo Engrácia , Magalhães Maria Lurdes , Rochas Helena , Silva Anabela , Rodrigues Margarida , Freitas José Mota , Vieira Sandra , Meneses Maria Favila , Germano de Sousa José , Bettencourt Viana Mariana , Terra Isaura , Rodrigues Vitória , Pereira Patrícia , Duarte Jesuína , Pinto Paula , Moreira Ezequiel , Ataíde Ferreira João , Vicente Adília , Paixão Paulo , Novais Natália ,   Portuguese Study Group of Invasive Pneumococcal Disease of the Pediatric Infectious Disease Society, Aires Sónia , Ferreira Cristina , Gaspar Eurico , Ferreira Manuela , Pereira Fernanda , Dinis Maria José , Sousa Álvaro , Teixeira Paulo , Amorim José , Monteiro Cláudia , Carvalho Isabel , Arosa Sofia , Guedes Margarida , Marques Laura , Braga Ana , Tavares Margarida , Cunha Isabel , Vicente Lurdes , Zarcos Maria Manuel , Almeida Helena , Almeida Silvia , Rodrigues Fernanda , Resende Cristina , Afonso Eulália , Mendes Luísa , Faria Cristina , Teixeira Ana Luísa , Mendes António , Tomé Teresa , Rebelo Mónica , Pereira Filomena , Rodrigues Gustavo , Costa Alexandra , Teixeira Ana , Lima Sofia , Laima Érica , Nunes Maria Ana S. , Prata Filipa , Flores Pedro , Brandão Manuela , Calado Nunes João , Massa Rosário , Cunha Florbela , Correia Paula , Brito Anabela , Franco João , Didelet Cristina , Veiga Estela , Cruz Carla , Seves Graça , Novais Céu , Virtuoso Maria João , Guerreiro Nancy , Cavaco Amélia , Gomes Francisco , Gomes Dora , Monteiro Isabel 
Published: January 2019

We evaluated the impact of continued 13-valent pneumococcal conjugate vaccine (PCV13) use in the private market (uptake of 61%) in pediatric invasive pneumococcal disease (pIPD) in Portugal (2012–2015). The most frequently detected serotypes were: 3 (n = 32, 13.8%), 14 (n = 23, 9.9%), 1 (n = 23, 9.9%), 7F (n = 15, 6.4%), 19A (n = 13, 5.6%), 6B and 15B/C (both n = 12, 5.2%), and 24F, 10A and 12B (all with n = 10, 4.3%). Taken together, non-PCV13 serotypes were responsible for 42.2% of pIPD with a known serotype. The use of PCR to detect and serotype pneumococci in both pleural and cerebrospinal fluid samples contributed to 18.1% (n = 47) of all pIPD. Serotype 3 was mostly detected by PCR (n = 21/32, 65.6%) and resulted from a relevant number of vaccine failures. The incidence of pIPD varied in the different age groups but without a clear trend. There were no obvious declines of the incidence of pIPD due to serotypes included in any of the PCVs, and PCV13 serotypes still accounted for the majority of pIPD (57.8%). Our study indicates that a higher vaccination uptake may be necessary to realize the full benefits of PCVs, even after 15 years of moderate use, and highlights the importance of using molecular methods in pIPD surveillance, since these can lead to substantially increased case ascertainment and identification of particular serotypes as causes of pIPD.