Comparing the Effectiveness of Reduced-Dose Pneumococcal Vaccination Schedules in Vietnam
|
Reviewed by Dat Tien Nguyen, B.A, ScM.
Translated by Nhi Phuong Quynh Le, B.A |
Posted on January 10th, 2025
|
Streptococcus pneumoniae is a common pathogen responsible for upper respiratory tract infections in young children. The infection can be prevented through vaccination, with the standard regimen consisting of 3 primary doses during early infancy or 2 primary doses within the first 6 months, followed by a booster after 9 months of age. While both vaccination schedules have proven effective, they can be costly, making it difficult for resource-limited countries to implement nationwide vaccination programs. To address this, a study funded by the Bill and Melinda Gates Foundation was conducted to compare the effectiveness of a reduced-dose vaccination program with the standard 3-dose schedule.
The cluster study was conducted in 24 out of the 27 communes in Nha Trang. At the time of the study's initiation, the national vaccination guidelines in the region did not recommend the use of pneumococcal vaccination. These 24 communes were randomly selected to implement one of four different vaccination schedules. In the 3p group, children in the communes received 3 primary doses at the second, third, and fourth months; the 2p+1 group received 2 primary doses at the second and fourth months, followed by 1 booster dose at 1 year old. Communes in the reduced-dose groups received either 1 primary dose at 2 months with a booster at 1 year old (1p+1) or just 1 booster at 1 year old (0p+1). Each intervention group consisted of approximately 700 children, and randomization was done to ensure balanced representation of rural and urban communities. The PCV10 formulation, supplied by GlaxoSmithKline, was used for the vaccinations. The PCV10 vaccine covers the 10 most common serotypes of Streptococcus pneumoniae and was selected because it was the only formulation approved by the Ministry of Health. The study continued until 2020, with analyses of pathogen carriage in the upper respiratory tract used to compare the efficacy of the different vaccination schedules. The researchers found that the reduced-dose schedules (1 primary + 1 booster and 1 booster alone) were equally effective as the standard 3-dose schedule in preventing pathogen carriage in infants and toddlers. This result aligns with previous studies conducted in India, South Africa, and the United Kingdom, where the 1 primary + 1 booster schedule was used. The author noted that due to the COVID-19 pandemic, data collected at the end of the study in 2020 might be biased because of social distancing measures.
The cluster study was conducted in 24 out of the 27 communes in Nha Trang. At the time of the study's initiation, the national vaccination guidelines in the region did not recommend the use of pneumococcal vaccination. These 24 communes were randomly selected to implement one of four different vaccination schedules. In the 3p group, children in the communes received 3 primary doses at the second, third, and fourth months; the 2p+1 group received 2 primary doses at the second and fourth months, followed by 1 booster dose at 1 year old. Communes in the reduced-dose groups received either 1 primary dose at 2 months with a booster at 1 year old (1p+1) or just 1 booster at 1 year old (0p+1). Each intervention group consisted of approximately 700 children, and randomization was done to ensure balanced representation of rural and urban communities. The PCV10 formulation, supplied by GlaxoSmithKline, was used for the vaccinations. The PCV10 vaccine covers the 10 most common serotypes of Streptococcus pneumoniae and was selected because it was the only formulation approved by the Ministry of Health. The study continued until 2020, with analyses of pathogen carriage in the upper respiratory tract used to compare the efficacy of the different vaccination schedules. The researchers found that the reduced-dose schedules (1 primary + 1 booster and 1 booster alone) were equally effective as the standard 3-dose schedule in preventing pathogen carriage in infants and toddlers. This result aligns with previous studies conducted in India, South Africa, and the United Kingdom, where the 1 primary + 1 booster schedule was used. The author noted that due to the COVID-19 pandemic, data collected at the end of the study in 2020 might be biased because of social distancing measures.