Table 3. SCIT versus SLIT: the available evidence.
| Studies on: | SCIT | SLIT |
| Dose-effect relationship | studied for various allergens (14) | studied for various allergens (14) |
| Definition of the optimal dose | documented in one DBPC trial of a mite allergen (23) | documented in one DBPC trial of a grass-pollen tablet (24) |
| Efficacy after 1 year of treatment | determined for multiple allergens in DBPC trials, some of which were on a large scale (10, 37, 39, 40, e1, e2) | determined in large-scale DBPC trials for grass-pollen extracts (11, 26, 30, e13– e19) |
| Efficacy after 2 and 3 years of treatment | shown in trials of various allergens (e3) | shown in large-scale DBPC trials of grass-pollen extracts (29, 30, e13) |
| Sustained therapeutic benefit | shown in multiple trials, most of which were controlled (6, 24, 36, e20) | shown in trials of adequate size for grass-pollen extracts for adults (27, 28) |
| Efficacy for allergic asthma | shown for various allergens (39) | small effect in meta-analysis (e21) |
| Asthma prevention | no DBPC trials; positive findings in controlled trials (e22) | no DBPC trials; positive findings (e23) |
| Prevention of new sensitization | shown in controlled trials of individual allergens (e22) | no DBPC trials; positive findings (e24) |
SCIT, subcutaneous immunotherapy; SLIT, sublingual immunotherapy; DBPC, double-blind, placebo-controlled