Table 1.
Data summary by cohort and country.
Table 2.
Follow-up participation proportion, unadjusted odds ratios and odds ratios adjusted for the variables detailed in the Methods section and confidence intervals are shown for different recruitment methods of individuals enrolled in the Influenzanet study (stratified by country), Ninfea and ELF.
Figure 1.
Summary of the results reported in Table 2.
The effect of face-to-face recruitment on follow-up participation compared to offline recruitment is shown. Given that the studies are highly heterogeneous by design and target different populations, the pooled estimate should be considered as an average of the study-specific effects rather than as a causal estimate.
Figure 2.
Summary of the results reported in Table 2.
The effect of online recruitment on follow-up participation compared to offline recruitment is shown. Given that the studies are highly heterogeneous by design and target different populations, the pooled estimate should be considered as an average of the study-specific effects rather than as a causal estimate.