A likely explanation for this finding is that the prevention of RAL resistance may require a consistently high level of boosted PI adherence that is often not achieved outside of a clinical trial.
There were also substantial differences in levels of boosting between the three scenarios based on empirical data.
High levels of background titres and low levels of boosting affect estimates of cumulative incidence of influenza infection derived from seroepidemiological studies.
We also constructed four illustrative scenarios for baseline levels of antibodies prior and levels of boosting following infection in the simulated studies.
Assays capable of reliably detecting low levels of boosting after infection would greatly improve the performance of longitudinal studies when conditions are difficult.
These differences propagated through to different and substantial patterns of bias for all scenarios other than those with very low background titre and high levels of boosting.
There were substantial differences between the background antibody titres and levels of boosting within three of our illustrative scenarios which were based on empirical data.
The improvement of Scenario C compared with Scenario B was because of the more consistent levels of boosting in Scenario C. Both longitudinal and cross-sectional designs performed well under the assumptions of Scenario D in which there were very high levels of boosting and very low levels of background immunity.
We found that plausibly high levels of background immunity (perhaps due to cross-reactivity) and plausibly low levels of boosting following infection could introduce substantial biases to the estimates of cumulative incidence.
Scenario B performed the worst, with both longitudinal and cross-sectional designs substantially underestimating the cumulative incidences because of the high levels of detectable antibody and low levels of boosting.
Levels of boosting and background immunity significantly affect the accuracy of seroprevalence estimations, and depending on these levels of immunity responses, different survey designs should be used to estimate seroprevalences.
