[13] The 182 patients enrolled into the study showed symptoms of acute vaginitis, and most of them had been treated for months with topical or oral antibiotics or antimycotics without success.

[13] Further studies on the therapeutic and preventive efficacy of lactobacillus vaccines alone or in combination to antimicrobial treatment in bacterial vaginitis have produced similar results.

Verling reported vaccinating 42 patients with candida-induced chronic colpo-vaginitis with SolcoTrichovac, who had shown resistance to usual fungicidal treatment such as topical amphotericin B, nystatin and povidone-iodine.

[18] In many women prone to recurrent urinary tract infections, the mucosal surfaces of the vaginal introitus are colonized by Escherichia coli and Enterococci, rather than Lactobacilli.

[32] In the proposed scenario, the dysbiotic vaginal environment is continually seeding the bladder with infectious microbes leading to a persistent or recurrent urinary tract infection.

[38] The booster injection raises the serum antibody titres in most cases back to similar levels to those found shortly after primary vaccination and ensures renewed immune protection for about 2 further years.

Systemic vaccination reactions commonly include fatigue, flu-like symptoms, a raised temperature between 37 and 38 °C (98.6 and 100.4 °F), shivering, headache, dizziness, nausea and a swelling of the inguinal lymph nodes.

Further contraindications are acute fever, active tuberculosis, severe hematopoietic disorders, decompensated cardiac or renal insufficiency, autoimmune and immunoproliferative diseases.

[43] Rüttgers on the other hand described SolcoTrichovac as an anti-adhesive vaccine, suggesting that the induced antibodies and perhaps other mechanisms inhibit the adhesion of microbes to epithelial cells in a largely nonspecific manner.

[2][44][45] Studies into cellular immunity are technically challenging in humans owing to the difficulty of sampling lymphoid tissues as opposed to secretions, and none has been performed so far on lactobacillus vaccines.

The geometric mean of the agglutination titres increased from the basal level of 1:56 before vaccination to 1:320 after finishing the primary immunization program, and it was still 1:140 one year later.

Rüttgers observed that this group of patients by large overlapped with those, that had had reinfections during the follow-up period of 12 months, and concluded that vaginal sIgA concentration is a better correlate to immune protection than serum antibody titres.

[55] Aberrant strains of Lactobacilli are incapable to effectively control the vaginal microbiota, leading to an overgrowth of a mixed flora of aerobic, anaerobic and microaerophilic bacterial species.

[56] Karkut observed a significant reduction in the incidence of Escherichia coli (55% to 23%), Group B Streptococci (37% to 10%), Enterococci (36% to 12%), Bacteroides (25% to 3%) and Gardnerella vaginalis (37% to 9%) in 94 patients treated for recurrent bacterial vaginitis eight weeks after initial injection.

Treatment with the experimental bacterial vaccines was capable to eliminate trichomoniasis in 28% of infected patients and resolved or alleviated many of the examined urogenital conditions.

[33] After this initial breakthrough, Újhelyi and his coworkers directed their efforts into the development and optimization of Gynevac, a composite bacterial vaccine, containing five aberrant, polymorphic Lactobacillus strains.

[11] In two prospective studies performed between 1976 and 1982 in rural, socioeconomically disadvantaged Kazincbarcika with the enrollment of nearly 3500 pregnant women, lactobacillus vaccination appeared to reduce the incidence of preterm birth by about 40%.

[42] Today Gynatren is the only lactobacillus vaccine marketed for the treatment of non-specific bacterial vaginitis and trichomoniasis, and it is mostly only prescribed by a select few gynaecologists in the DACH countries and Hungary.

The technical and theoretical advances in the fields of microbiology, immunology and vaccinology of the past few decades could help shed new light on the still not fully clarified mode of action of these clinically promising vaccines.

More research is warranted to elucidate the distinct properties of "aberrant" strains of Lactobacilli, the exact mechanism by which they contribute to or accompany pathologies, the determinants of colonization in different groups of individuals.

[33] He considered colonization with "aberrant", unprotective strains of lactobacilli, and their persistence even after protozoan infection has been cleared, a chronic post-infectious complication, and introduced the term "lactobacillus syndrome" for the condition[33] (not to be confused with the distinct pathologies of cytolytic vaginosis[77] and vaginal lactobacillosis[85][86][87]).

[88] McGrory and Garber reported a significant prolongation of T. vaginalis infection in estrogenized BALB/c mice intravaginally preinoculated with 1×109 cells of L. acidophilus ATCC 4356 (originating from the human pharynx) in comparison to animals that had not been pretreated.

[95] The anti-trichomonal effect of SolcoTrichovac has led multiple researchers to investigate the possibility of shared surface antigens between the specific strains used in the vaccine and T. vaginalis.

An intriguing hypothesis was advanced by Alain de Weck that suggests horizontal gene transfer between specific aberrant strains of Lactobacilli used in SolcoTrichovac and T. vaginalis, which leads to their (possible) cross-immunogenicity.

[99][100] Audrey de Koning argues that lateral transfer of the N-acetylneuraminate lyase gene from Pasteurellaceae to T. vaginalis may have been a key factor in the adaptation of Trichomonas to parasitism.

[101] In an analogous manner, Buret et al. suggest gene exchanges between enteropathogens and normal microbiota during acute enteric infection as one of the possible causative factors behind post-infectious intestinal inflammatory disorders.

[102] Goisis and his colleagues proposed an alternative hypothesis on the mechanism of action of SolcoTrichovac, suggesting that anti-lactobacillus antibodies may stimulate proliferation of lactobacilli rather than their (strain-specific) damage or inhibition.

[110] In contrast, direct translocation of non-sIgA-coated microbes or microbial products across the epithelium preferentially results in proinflammatory signalling and a systemic response against the invading agent, involving affinity-matured serum antibodies of the classes IgA, IgE and IgG.

[114][104] Goisis et al. described lactobacillus vaccination as a means to systemically boost a diminished pool of lactobacillus-specific vaginal antibodies, likely increasing the potential for immune exclusion and tolerogenic responses to the microorganisms.

[4] Although Goisis et al. announced ongoing experiments and preliminary results to prove this theory, as well as the possible cross-reactivity of "normal", ecologically beneficial lactobacilli with antibodies directed against the strains used in SolcoTrichovac,[28] a conclusive report has not been publicized to date.