This study will evaluate the immunogenicity of a reduced dosing schedule of Pneumococcal Conjugate vaccine (PCV) PCV10 and PCV13, in which children will receive a primary dose at either 6 or 14 weeks of age, followed by a booster dose at 9 months of age (1+1 schedule), and compare this immune response to those who receive a two dose primary series (at 6 and 14 weeks of age) and booster dose at 9-months (2+1 schedule).

Pneumonia is the leading global cause of childhood death outside of the neonatal period, and contributes to 19% of the 10 million childhood deaths occurring annually, the majority of which occurs in industrialising countries. Despite the successes in improving primary healthcare in South Africa since 1994, pneumonia nevertheless remains a leading cause of childhood death in South Africa, aggravated by the HIV/AIDS epidemic. Streptococcus pneumoniae is recognised as the leading bacterial cause of pneumonia in children as well as having been identified as a common cause of super-imposed bacterial infection in individuals with respiratory virus-associated pneumonia.

In South Africa, the cost of procurement of PCV ($20 per dose) totals almost 50% of the total cost of all vaccines purchased for the national immunisation program. Similarly, PCV is the most expensive vaccine purchased by the Global Alliance for Vaccines and Immunisation (GAVI), which heavily funds vaccine procurement for low income countries. The sustainability of continued procurement of this vaccine at the current pricing in low-middle income countries remains uncertain.

This will be a randomized, open-label study (laboratory personnel will however be blinded) in which subjects are randomized to one of two (primary dose at either 6 or 14 weeks of age) 1+1 dosing schedules of PCV10 or PCV13, or to a 2+1 schedule of these vaccines. A total of 600 subjects will be randomized in a 1:1:1:1:1:1 ratio to one of the six groups. The study will be undertaken at an experienced research site in Johannesburg, South Africa, where the 600 children born to HIV-uninfected women are expected to be enrolled over a 12- month period.

Inclusion Criteria:

1. Signed informed consent by the parent/guardian of the child;
2. Born to an HIV-uninfected women, based on testing undertaken as part of standard of care during the last trimester of pregnancy;
3. Had not received any vaccine other than BCG and OPV (routinely given at birth) prior to enrolment;
4. Birth weight >2499g AND weight of child >3.5 kg at time of proposed randomization;
5. Aged 42-56 days of age at time of enrolment;
6. Available for the duration of the study;
7. Child is healthy based on medical history and physical examination of the study-staff.

Exclusion Criteria:

1. Any clinically significant major congenital abnormalities;
2. Previous hospitalization for a respiratory illness following discharge from hospital after birth;
3. Receipt of any other investigational drug/vaccine. Co-enrollment into non-investigational studies, including epidemiology studies, is allowed;
4. Any previous PCV vaccination;
5. Known allergy to any of the vaccine components;
6. Febrile illness (axillary temperature ≥37.8°C) at time of enrolment. These participants are eligible if the temperature resolves for at least 48 hours and they remain within the study defined window periods;
7. Planned relocation to outside of the study area during up until age of 2 years;
8. Receipt of blood transfusion or any other blood products (including immunoglobulins) since birth. Receipt of such products during the course of the study, will require withdrawal of the child from the study;
9. History of confirmed pneumococcal disease since birth;
10. Any known or suspected immunodeficiency condition which could affect immune response to vaccination.

The data will be made publically available, within one year of completion of the study to any investigators or BMGF nominated partners, who wish to use the data to address any specific questions not directly addressed under the study objectives and which the data would lend itself to