Abstract
Longitudinal evidence of differential pertussis antibody durability following natural infection among vaccinated children living in contrasting malaria transmission settings in coastal Kenya
Safari, M. S.
Gicheru, E. T.
Mburu, M. W.
Makori, T. O.
Nyawa, O.
Odoyo, S. O.
Shee, F.
Ndungu, F.
Foley, D. J.
Nyagwange, J.
Chege, T.
Sande, C. J.
Vaccine. 2026; 88128837
Permanent descriptor
https://doi.org/10.1016/j.vaccine.2026.128837BACKGROUND: Despite widespread pertussis vaccination, re-surgent infections have been reported globally, driven partly by waning immunity after primary vaccination. While antibody decay patterns following vaccination are well described, little is known about the influence of malaria endemicity on the maintenance of pertussis-specific antibodies. METHODS: We analysed longitudinal serum samples from 92 children from two neighbouring communities on the Kenyan Coast with contrasting malaria transmission intensities: Junju (high transmission, n = 44) and Ngerenya (low transmission, n = 48). Participants were followed from childhood for up to 14 years, with annual serum sampling and continuous active malaria surveillance. Vaccination histories were verified through immunisation records. Pertussis toxin (PT) -specific IgG was quantified using an in-house protein microarray platform, and antibody dynamics were compared by vaccination status and background malaria exposure. RESULTS: Vaccinated children exhibited patterns of gradual post-vaccination antibody decay, with titres stabilising at low levels by approximately 10 years of age. Among vaccinated children who later experienced natural infection, anti-PT titres rose sharply before diverging by malaria transmission setting. In Ngerenya, antibody levels remained stably elevated for several years post-infection, whereas in Junju, antibodies decayed rapidly, returning to pre-boost levels within a few years. CONCLUSION: Chronic malaria exposure in early life, may be associated with accelerated waning of infection-induced pertussis antibodies. These findings may suggest that persistent malaria transmission may erode long-term humoral immunity, with implications for pertussis control and booster scheduling in endemic regions.