Katayi Mwila-Kazimbaya, Miguel Pugliese Garcia, Samuel Bosomprah, Natasha Makabilo Laban, Caroline Cleopatra Chisenga, Sallie Robey Permar, Michelo Simuyandi, Sody Munsaka, Roma Chilengi
Rotavirus vaccines have been introduced into national immunization programmes to mitigate
morbidity and mortality associated rotavirus diarrhoea. Lower vaccine effectiveness
has however been noted in low-middle income countries, but little is known about the role of
maternal components found in breast milk. This study assessed the effect of lactoferrin, lactadherin,
and tenascin-c on rotavirus vaccine seroconversion.
This was a retrospective cohort study of 128 infants who had been fully immunized with
Rotarix™. Serum samples were collected from the infant at baseline and one month after
second rotavirus vaccine dose. Breast milk samples were collected from mothers at baseline.
Standard ELISA was used to determine titres of rotavirus-specific immunologlobulin G
and A in breast milk and serum as well as concentrations of lactoferrin, lactadherin, and
tenascin-c. Poisson regression model with robust standard error was used to estimate the
effect of breast milk components on seroconversion. The components were modelled on log
base 2 so that the effect would be interpreted as a doubling of the concentration.
In a multivariable analysis adjusting for maternal age, maternal HIV status, seropositivity at
baseline, sex, age of child at vaccination as well as breast milk IgA and IgG, we found evidence
of independent effect of LA (Adjusted IRR = 0.95; 95% CI = 0.91–0.99; P = 0.019) on
seroconversion while there was no evidence for TNC (Adjusted IRR = 1.00; 95% CI = 0.85–
1.17; P = 0.967) and LF (Adjusted RR = 1.01; 95% CI = 0.96–1.05); P = 0.802). We explored the joint effects of the three components but we found no evidence (Adjusted RR = 0.95;
95% CI = 0.81; P = 0.535).
High breast milk concentrations of lactadherin might play a role in infant’s failure to seroconvert
to rotavirus vaccines. Further research to understand this observed association is an