Table 1 Characteristics of excluded studies

Amin [4]

This was a review [4]

Zulkifli et al. [17]

Study was a systematic review [17]

Butov et al. [18]

Study used V-5 Immunitor, an intervention not under this review [18]

Nikolaeva et al. [19]

The study did not report of the outcomes of interest [19]

Nikolaeva et al. [19]

This study [20] was duplicate of study [19]

Nikolaeva et al. [19]

The study did not report any of the outcomes of interest, the study looked particularly at the effect of Dzherelo on immunological and virological responses (T-lymphocyte and viral load among TB/HIV patients) [20].

Prihoda et al. [21]

Not a comparative study, in addition, all the participants received the intervention in combination with some other immunomodulators [21].

Prihoda et al. [22]

The study compared Dzherelo (Immunoxel) with other forms of immunotherapies (Svitanok and Lizorm) [22].

Prihoda et al. [23]

This study [23] was a duplicate of study [21].