Pneumococcal carriage and serotype distribution among children with and without pneumonia in Mozambique, 2014-2016

Abstract

BackgroundPneumococcal colonization is a precursor to pneumonia, and pneumococcal conjugate vaccines (PCV) can decrease vaccine-type (VT) colonization. Pneumococcal colonization studies are traditionally done among healthy children in the community; however, VT colonization prevalence may differ between these children and those with pneumonia. We assessed overall and VT pneumococcal colonization and factors associated with colonization among children with and without pneumonia after Mozambique introduced 10-valent PCV (PCV10) in 2013.MethodsWe used data from ongoing pneumonia surveillance in children aged <5 years and from cross-sectional nasopharyngeal colonization surveys conducted in October 2014 –April 2015 and October 2015 –May 2016. Pneumonia was defined using WHO standard criteria for radiologically confirmed pneumonia. Children with pneumonia enrolled from January 2014 –April 2016 were compared to children without pneumonia enrolled from the cross-sectional surveys. Clinical data and nasopharyngeal (NP) swabs were collected from each child. NP specimens were cultured for pneumococci, and culture-negative specimens from children with pneumonia underwent polymerase chain reaction (PCR).ResultsOf 778 and 927 children with and without pneumonia, 97.4% and 27.0% were exposed to antibiotics before swab collection, respectively. Based on culture, pneumococcal colonization was 45.1% for children with and 84.5% for children without pneumonia (P<0.001); VT pneumococcal colonization was 18.6% for children with and 23.4% for children without pneumonia (P = 0.02). The addition of PCR in children with pneumonia increased overall and VT-pneumococcal colonization to 79.2% and 31.1%, respectively. In multivariable analysis including PCR results, pneumonia was associated with VT pneumococcal colonization (adjusted OR: 1.4, 95%CI: 1.10–1.78).ConclusionVaccine-type pneumococcal colonization remains common among children with and without pneumonia post-PCV10 introduction in Mozambique. In a population of children with high antibiotic exposure, the use of PCR for culture-negative NP swabs can improve assessment of pneumococcal colonization and circulating serotypes.

Pathogens in the upper respiratory tract of Congolese children with radiologically confirmed pneumonia

“…PCV13 serotypes/serogroups were more commonly identified than non-PCV13 serotypes/groups (63% versus 37%). This was in contrast to a study performed in Mozambique, in which half of the identified serotypes were included in the vaccine [46]. However, we may have under-estimated the frequency of non-PCV13 serotypes.…”

Dried blood spots for Streptococcus pneumoniae and Haemophilus influenzae detection and serotyping among children < 5 years old in rural Mozambique

“…Pneumococcal nasopharyngeal carriage prevalence, considering the detection by culture and qPCR, was high for children with pneumonia (80%) and for those who were healthy (80.8%), like what has been previously reported in cross-sectional pneumococcal carriage surveys conducted in the same rural area in Mozambique [27,28].…”

“…Collection of specimens from pneumonia children after they received antibiotics, including any antibiotics received before admission as well, may have reduced detection of pneumococcal DNA from their specimens. A crosssectional survey conducted in the same period and area of Mozambique found 97.4% of children with pneumonia had antibiotics recently compared to 27% among children without pneumonia [27]. The vaccination status of the children was obtained, and Mozambique has high vaccine coverage [28].…”

High residual carriage of vaccine-serotype Streptococcus pneumoniae after introduction of pneumococcal conjugate vaccine in Malawi

“…Vaccine trials and post-routine-introduction studies in sSA have demonstrated substantial direct effects of PCV against IPD, pneumonia, and all-cause mortality among young children [20][21][22][23] . Though PCV impact is not directly comparable between countries, and regions given differences in PCV implementation strategies (formulations and schedules), these countries (e.g., Malawi [PCV13; 3 + 0] 13 , The Gambia [PCV7 and PCV13; 2 + 1] 20,21 , Kenya [PCV10; 3 + 0] 22 , South Africa [PCV7 and PCV13; 2 + 1] 23,24 , and Mozambique [PCV13; 3 + 0] 25 ,) have consistently reported higher residual VT carriage than HICs (United Kingdom [PCV7 and PCV13; 2 + 1] 17 , Netherlands [PCV7 and PCV10; 3 + 1 and 2 + 1] 26 , USA [PCV7 and PCV13; 3 + 1] 27 ). See Supplementary Table 2 for an overview of regional differences in residual VT carriage prevalence after the introduction of PCV into routine Extended Programmes on Immunisation [EPIs]).…”