It is very true that you can have vagina infection without having any form of sexual intercourse! The vagina has a normal population of microorganisms called 'normal flora', which maintains its normal functioning and health.

Any interference with this system would result in an imbalance between the population of the protective and harmful bacteria. The main beneficial microorganisms are the lactobacilli which produce hydrogen peroxide, and any reduction in the level of this substance would result in infection by opportunistic organisms.

Three common conditions or ways you can have vaginal infection without sex include:

1. of Antibiotics

The use of antibiotics, especially on a long term produces vaginal infection. The reason for this is obvious. The high antibiotics concentration reduces the population of the protective vaginal flora, especially the lactobacilli. This would invariably promote the growth and proliferation of vagina yeast, especially Candida albicans.

2. Use of contraceptives

Oral contraceptive pills do not change the numbers of beneficial lactobacilli. They keep vagina pH at about 4.4, and do not change the thickness of protective vaginal skin cells. The use of oral contraceptive pill may reduce the risk of Bacteria Vaginosis with about 50%. However, the risk for yeast infections is increased when birth control pills are used.

DepoProvera is an injectable contraceptive which can decrease hydrogen peroxide producing bacteria within few months of use. The consequence of these is the presence of opportunistic infections like candidiasis. 

The use of spermicides with diaphragm or cervical cap can cause transient decrease in lactobacilli, and increase the proportion of E. Coli, enteroccoccus, and anaerobic gram negative bacteria.

3. Douching and use of antiseptic soaps

These products remove the good bacteria and impact on vagina health causing candida super-infection