Streptococcus pneumoniae also referred to as pneumococcus, is part of the normal bacterial flora of the upper respiratory tract of humans. Carriage of the organism is affected by a wide range of factors such as age, acute respiratory tract infection and immunosuppression [
1,
2]. An important characteristic of the pneumococcus is the presence of a polysaccharide capsule, which defines over 90 capsular types and is the basis of current pneumococcal vaccines [
3,
4]. Clinically, the pneumococcus causes several invasive and non-invasive diseases including pneumonia, meningitis, septicaemia, sinusitis and acute otitis media. There are about one million new pneumococcal infections every year, majority of which occur in the developing world where children < 5 years are most affected, and the organism is responsible for 10–20% of all deaths in this age group [
5]. HIV infected children have about forty times greater risk of invasive pneumococcal disease compared to healthy children; these infections are more likely to be fatal and importantly the incidence does not decline with age as in healthy people [
6].
The vast burden of the pneumococcus underlies the importance of control through vaccination, and recently, pneumococcal conjugate vaccines are being introduced into the childhood vaccination programmes of many developing countries (
http://www.gavi.org/,
www.view-hub.org). Two types of pneumococcal conjugate vaccines (PCVs) are currently in use and they include the 10-valent vaccine which comprises pneumococcal serotypes 4, 6B, 9V, 14, 18C, 19 F, 23 F, 1, 5, 7F and the 13-valent vaccine which has three additional serotypes of 3, 6A, 19A [
4]. Pneumococcal conjugate vaccines have been shown to be superior to the previous pneumococcal polyvalent polysaccharide vaccine (PPV 23) [
7]. Though PPV23 contains 23 serotypes (1, 2, 3, 4, 5, 6B, 7F, 8, 9 N, 9V, 10, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F, 33F), it provides limited protection in immunocompromised individuals and infants [
7]. Despite current pneumococcal conjugate vaccines offering great hope in reducing pneumococcal disease burden, they are not a panacea for pneumococcal infections as the vaccines cover only a limited number of serotypes. It has been observed that non-vaccine serotypes of the pneumococcus have been increasing in prevalence since the introduction of the vaccines [
8,
9], and therefore highlight the need for post vaccination surveillance.
Pneumococcal carriage is the precursor for development of pneumococcal disease, and is also responsible for transmission of the organism from person-to-person [
10]. Recent pneumococcal vaccines are based on reducing pneumococcal carriage, hence incidence of pneumococcal disease [
7]. Thus, pneumococcal carriage studies represent a suitable model for understanding host-pathogen interaction of the pneumococcus as well as providing vaccine related epidemiological data of this important human pathogen. In Ghana, the few studies carried out on pneumococcal carriage focused on either healthy populations [
11] or the general population [
12]. Consequently, there is hardly any data on pneumococcal carriage with regard to risk populations such as HIV patients. With the recent availability of routine pneumococcal vaccination in the country, there is an urgent need for the relevant epidemiological data on risk populations of pneumococcal disease, in order to inform vaccination policies. In this study, we present pneumococcal carriage data for HIV infected children attending a referral hospital in Ghana, thereby providing information on carriage prevalence, risk factors of carriage and serotype distribution.