Press release
Pneumococcal conjugate vaccines (PCVs) protect children from the dangerous Streptococcus pneumoniae bacterium, the most common cause of severe pneumonia, septicaemia, and meningitis.
PCVs have saved more than 1.6 million lives since they were introduced in 2000. However, the relatively high cost of PCVs pose a barrier for sustainable access in many countries.
Measures to increase access to the vaccine have recently been recommended by World Health Organisation (WHO), following extensive research, including landmark studies at the MRC Unit The Gambia at LSHTM and trials in countries such as Vietnam, South Africa, India, the UK, Kenya, and Niger. This research has focused on strategies to increase PCV coverage, reduce costs, and save more lives, especially among vulnerable communities, by evaluating reduced-dose schedules and fractional dosing approaches.
ThePneumococcal Vaccine Schedules (PVS) study at the MRC Unit the Gambia was conducted in close collaboration with the Gambian Ministry of Health (MoH). It evaluated whether a two-dose (1p+1) schedule of PCV was safe and as effective as the standard three-dose (3p+0) schedule. The reduction from three to two doses would lower national and global costs of PCV, simplify vaccination schedules, free up resources for other immunisation efforts, and mean fewer injections for infants.
Initiated in 2019, the study enrolled 33,001 infants in rural Gambia over 4 years, providing the alternative 1p+1 schedule or the standard 3p+0 schedule to all infants resident in the study area. The findings of PVS show that the 1p+1 schedule is safe and just as effective as the 3p+0 schedule at preventing pneumococcal diseases and controlling the transmission of pneumococcal bacteria in the community.
The WHO has now expanded their recommendations on PCV use, to allow countries with high vaccine coverage, strong existing community immunity and sufficient surveillance capacity to give two instead of the usual three doses or administer fractional doses.WHO published the new policy in its Weekly Epidemiological Record (WER) based on recommendations from its Strategic Advisory Group of Experts on Immunisation (SAGE), following a thorough review of global evidence.
Commenting on the new policy, Professor Umberto D’Alessandro, Unit Director at MRCG at LSHTM, emphasised, “the new policy marks a critical step forward inglobal immunisation efforts. The PVS study is an example of how local partnerships in research can shape impactful global health policy. The introduction of a simplified vaccine schedule could significantly increase access to life-saving vaccines, particularly in resource-limited settings, thus reducing childhood mortality from pneumococcal disease.”
Dr Grant Mackenzie, Principal Investigator for the PVS study, commented on the study’s potential to transform vaccine access, “The PVS study, a 4-year collaborative effort between the MRCG and the MoH, aimed at evaluating the effectiveness of a two-dose compared to three-dose PCV schedule. PVS indicated that the two-dose schedule can be considered for adoption in many settings, widening the reach to more children, with greater sustainability at the country level and for international partners.”
The findings of PVS will continue to play a crucial role in shaping global immunisation policy, enhancing the reach and impact of PCV programmes worldwide. The study was funded through the UKRI’s Joint Global Health Trials scheme, UK MRC, Wellcome Trust, UKAid Direct, UK NIHR, UK NIHR Mucosal Pathogens Research Unit, and the Gates Foundation.
