GNU R seroincidence calculator tool
Antibody levels measured in a cross-sectional population samples can be
translated into an estimate of the frequency with which seroconversions
(new infections) occur. In order to interpret the measured
cross-sectional antibody levels, parameters which predict the decay of
antibodies must be known. In previously published reports (Simonsen et
al. 2009 and Versteegh et al. 2005), this information has been obtained
from longitudinal studies on subjects who had culture-confirmed
Salmonella and Campylobacter infections. A Bayesian back-calculation
model was used to convert antibody measurements into an estimation of
time since infection. This can be used to estimate the seroincidence in
the cross-sectional sample of population. For both the longitudinal and
cross-sectional measurements of antibody concentrations, the indirect
ELISA was used. The models are only valid for persons over 18 years. The
seroincidence estimates are suitable for monitoring the effect of
control programmes when representative cross-sectional serum samples are
available for analyses. These provide more accurate information on the
infection pressure in humans across countries.
