Study on Antibody Persistence Following Meningitis Vaccination in Burkina Faso
Background of the Meningitis Problem in Africa
A recent study conducted by Yaro and colleagues examined the durability of antibody levels after a meningitis vaccination campaign in Burkina Faso. The aim was to determine the necessity and timing of potential booster vaccinations. The African meningitis belt, which extends across sub-Saharan Africa, experiences recurrent outbreaks of meningococcal meningitis, a serious bacterial infection affecting the brain and spinal cord.
In 2010, the Meningitis Vaccine Project developed a vaccine, PsA-TT, targeting Neisseria meningitidis (NmA), the primary bacterial strain behind these epidemics. Following its introduction through a mass vaccination initiative, there has been a notable decrease in NmA-related meningitis cases. However, uncertainty remains regarding the duration of the vaccine’s protective effects and the timing for a booster dose.
Duration of Vaccine Protection
Current clinical studies suggest that the vaccine may offer protection for a minimum of 10 years. Nonetheless, these projections may not accurately reflect the broader population due to factors such as the lack of natural immune boosters and immigration from regions with unvaccinated individuals. Additionally, methodological limitations in existing clinical studies hinder precise predictions about the vaccine’s protective duration against NmA.
Research Methodology
To explore the persistence of antibodies against NmA, Yaro and colleagues conducted a study in Bobo-Dioulasso, nearly five years post-vaccination campaign. They enrolled 599 participants for their 2013 survey and 647 for the 2016 survey. The findings were published in Clinical Infectious Diseases.
Blood samples were collected from participants to measure antibody levels against the NmA reference strain F8236 (SBA-ref), NmA strain 3125 (SBA-3125), and NmA-specific immunoglobulin G (IgG). The analysis involved comparing antibody levels across five years among different age groups.
Key Findings
The study revealed a significant reduction in antibody levels at the population level five years after the vaccination. Younger participants exhibited a more pronounced decline in antibodies compared to older individuals. Specifically, the analysis indicated a -87% and -43% decline in SBA-ref, -99% and -78% decline in SBA-3125, and -89% and -63% decline in NmA-specific IgG for younger and older participants, respectively.
Based on these observations, the authors predict that older individuals’ antibody levels may revert to pre-vaccination levels after 11 years for SBA-ref and SBA-3125, and after 9 years for NmA-specific IgG. Conversely, younger individuals are expected to return to pre-vaccination levels after 12, 8, and 6 years, based on SBA-ref, SBA-3125, and IgG, respectively.
Conclusion and Future Directions
The study highlights a steady decline in antibody levels following a single dose of the meningitis vaccine, indicating a future need for booster vaccinations. However, determining the optimal timing for these boosters requires further investigation into which antibody indicators most accurately predict protection against meningitis. Recent studies suggest that antibodies against the NmA strain 3125 may serve as the best predictor, although additional validation is necessary.
In conclusion, this research represents significant progress towards understanding when an additional meningitis vaccine booster may be needed, contributing to global efforts in controlling meningitis outbreaks.
Written by Haisam Shah, BSc
Reference: Yaro, S., Njanpop-Lafourcade, B. M., Ouangraoua, S., Ouoba, A., Kpoda, H., Findlow, H., … & Gessner, B. (2018). Antibody Persistence at the Population Level 5 Years After Mass Vaccination With Meningococcal Serogroup A Conjugate Vaccine (PsA-TT) in Burkina Faso: Need for a Booster Campaign?. Clinical Infectious Diseases.