Open AccessNasopharyngeal pneumococcal carriage in South Asian infants: Results of observational cohort studies in vaccinated and unvaccinated populations
Author(s) -
Aditi Apte,
Girish Dayma,
Hakka Naziat,
Linda Williams,
Sonali Sanghavi,
Jamal Uddin,
Anand Kawade,
Maksuda Islam,
Sanchita Kar,
You Li,
Moe H. Kyaw,
Sanjay Juvekar,
Harry Campbell,
Harish Nair,
Samir K. Saha,
Ashish Bavdekar
Publication year - 2021
Publication title -
journal of global health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.581
H-Index - 34
eISSN - 2047-2986
pISSN - 2047-2978
DOI - 10.7189/jogh.11.04054
Subject(s) - carriage , medicine , serotype , pneumococcal conjugate vaccine , cohort , streptococcus pneumoniae , cohort study , pneumococcal infections , pediatrics , virology , biology , antibiotics , microbiology and biotechnology , pathology
Background Nasopharyngeal pneumococcal carriage (NPC) is a prerequisite for invasive pneumococcal disease and reduced carriage of vaccine serotypes is a marker for the protection offered by the pneumococcal conjugate vaccine (PCV). The present study reports NPC during the first year of life in a vaccinated (with PCV10) cohort in Bangladesh and an unvaccinated cohort in India. Methods A total of 450 and 459 infants were recruited from India and Bangladesh respectively within 0-7 days after birth. Nasopharyngeal swabs were collected at baseline, 18 and 36 weeks after birth. The swabs were processed for pneumococcal culture and identification of serotypes by the Quellung test and polymerase chain reaction (PCR). An identical protocol was applied at both sites. Results Prevalence of NPC was 48% in the Indian and 54.8% in the Bangladeshi cohort at 18 weeks. It increased to 53% and 64.8% respectively at 36 weeks. The average prevalence of vaccine serotypes was higher in the Indian cohort (17.8% vs 9.8% for PCV-10 and 26.1% vs17.6% for PCV-13) with 6A, 6B, 19F, 23F, and 19A as the common serotypes. On the other hand, the prevalence of non-vaccine serotypes was higher (43.6% vs 27.1% for non-PCV13) in the Bangladeshi cohort with 34, 15B, 17F, and 35B as the common serotypes. Overcrowding was associated with increased risk of pneumococcal carriage. The present PCV-13 vaccine would cover 28%-30% and 47%-48% serotypes in the Bangladeshi and Indian cohorts respectively. Conclusions South Asian infants get colonised with pneumococci early in infancy; predominantly vaccine serotypes in PCV naïve population (India) and non-vaccine serotypes in the vaccinated population (Bangladesh). These local findings are important to inform the public health policy and the development of higher valent pneumococcal vaccines.