Table 3.

Summary of evidence for potential hypotheses to explain vaccine resistance predictions in the reviewed studies

Does vaccine resistance vary by:
…pathogen?	There was considerable variation in findings within studies of the same pathogen, though only S. pneumoniae was examined in more than two studies.
…region?	Geographic location did not appear to influence whether studies predicted vaccine resistance; studies in the same region (e.g. European countries) had varied predictions.
…vaccine characteristics?	Studies of theoretical vaccines that do not yet exist predicted a wider range of vaccine resistance outcomes compared to studies of well-documented extant vaccines which more consistently predicted mild to moderate vaccine resistance (see results paragraph nine for further details).
…model type?	Agent-based or statistical models did not predict outcomes markedly different from the majority of studies, which used compartmental models.
…model parameters?	Within studies that conducted sensitivity analyses, model prediction proved to be influenced by parameter choice, though cross-immunity was the only factor that consistently influenced predictions of vaccine resistance in studies that included it (see results paragraph eleven for further details).