Es against 10-, or 13- of the more than 90 pneumococcal serotypes are now used in many countries, resulting in a substantial decline in invasive disease and carriage of vaccine serotypes [5, 6]. Despite this Oxaliplatin web success, serotypes not targeted by the vaccine have increased among healthy carriers and could potentially become important causes of invasive diseases. As Brazil started nationwide vaccination with 10-valent pneumococcal conjugate vaccine (PCV10) in 2010, it is essential to have information on pneumococcal carriage in the pre-vaccine era to assess potential vaccine impact. Many studies have been conducted in Brazil to investigate the distribution of pneumococcal serotypes from invasive disease and nasopharyngeal colonization. However, there are no reports of prospective studies conducted in communities. The previous studies were undertaken in schools and daycare settings, which represent important risk factors for the SC144 custom synthesis transmission and circulation of pneumococcus [7, 8]. In addition, a previous cross-sectional study that we conducted in a slum community in Salvador did not observe an association between prevalence of carriage with the size of the household or numbers of household contacts. It was hypothesized that study design and sample size could have affected the ability to adequately evaluate the effect of risk factors related to population or household density [9]. Thus, we carried out a cohort study of pneumococcal carriage in a slum community in Salvador to describe the risk factors for carrier status of S. pneumoniae in children under five years old. We also determined the distribution of serotypes, characterized antimicrobial susceptibility, and defined the possible coverage provided by the 10 or 13 valent pneumococcal conjugate vaccine (PCV10 or PCV13).Vaccine. Author manuscript; available in PMC 2017 February 03.Menezes et al.PageMethodsStudy site and population The study was conducted in the Pau da Lima community, which is situated in the periphery of Salvador, a city of 2.7 million inhabitants [10] in Northeast Brazil. We selected an area of 0.46 km2 where a cohort study for leptospirosis was conducted in 2003. As a part of this study, a census was completed during visits to 3,689 households; this identified 14,122 inhabitants, of which 8 (n=1, 131) were aged < 5 years [11]. A total of 130 households were randomly selected within the census tract in order to have 203 children < 5 years old enrolled in the study. This sample size was based on a previous study conducted in Salvador, where 65 of Children < 5 years were colonized at a single time-point [9]. Eligible subjects, defined as children 1 to 59 months of age who lived continuously in one of the selected households during the month prior to recruitment, were enrolled into the study according to informed consent procedures approved by the Oswaldo Cruz Foundation, Brazilian Ministry of Health. Data collection During house visits, a standardized questionnaire was used to document information on demographics, underlying medical conditions, hospitalizations, occurrence of an upper respiratory tract infection (URTI) in the previous month, antibiotic therapy in the last four weeks before the visit, childcare arrangements, school attendance and household inhabitants' habits such as smoking. Information for children was obtained by interviewing the parent or legal guardian. Household crowding was defined as the number of people divided by the number of rooms in the house,.Es against 10-, or 13- of the more than 90 pneumococcal serotypes are now used in many countries, resulting in a substantial decline in invasive disease and carriage of vaccine serotypes [5, 6]. Despite this success, serotypes not targeted by the vaccine have increased among healthy carriers and could potentially become important causes of invasive diseases. As Brazil started nationwide vaccination with 10-valent pneumococcal conjugate vaccine (PCV10) in 2010, it is essential to have information on pneumococcal carriage in the pre-vaccine era to assess potential vaccine impact. Many studies have been conducted in Brazil to investigate the distribution of pneumococcal serotypes from invasive disease and nasopharyngeal colonization. However, there are no reports of prospective studies conducted in communities. The previous studies were undertaken in schools and daycare settings, which represent important risk factors for the transmission and circulation of pneumococcus [7, 8]. In addition, a previous cross-sectional study that we conducted in a slum community in Salvador did not observe an association between prevalence of carriage with the size of the household or numbers of household contacts. It was hypothesized that study design and sample size could have affected the ability to adequately evaluate the effect of risk factors related to population or household density [9]. Thus, we carried out a cohort study of pneumococcal carriage in a slum community in Salvador to describe the risk factors for carrier status of S. pneumoniae in children under five years old. We also determined the distribution of serotypes, characterized antimicrobial susceptibility, and defined the possible coverage provided by the 10 or 13 valent pneumococcal conjugate vaccine (PCV10 or PCV13).Vaccine. Author manuscript; available in PMC 2017 February 03.Menezes et al.PageMethodsStudy site and population The study was conducted in the Pau da Lima community, which is situated in the periphery of Salvador, a city of 2.7 million inhabitants [10] in Northeast Brazil. We selected an area of 0.46 km2 where a cohort study for leptospirosis was conducted in 2003. As a part of this study, a census was completed during visits to 3,689 households; this identified 14,122 inhabitants, of which 8 (n=1, 131) were aged < 5 years [11]. A total of 130 households were randomly selected within the census tract in order to have 203 children < 5 years old enrolled in the study. This sample size was based on a previous study conducted in Salvador, where 65 of Children < 5 years were colonized at a single time-point [9]. Eligible subjects, defined as children 1 to 59 months of age who lived continuously in one of the selected households during the month prior to recruitment, were enrolled into the study according to informed consent procedures approved by the Oswaldo Cruz Foundation, Brazilian Ministry of Health. Data collection During house visits, a standardized questionnaire was used to document information on demographics, underlying medical conditions, hospitalizations, occurrence of an upper respiratory tract infection (URTI) in the previous month, antibiotic therapy in the last four weeks before the visit, childcare arrangements, school attendance and household inhabitants' habits such as smoking. Information for children was obtained by interviewing the parent or legal guardian. Household crowding was defined as the number of people divided by the number of rooms in the house,.