An outbreak of chlamydia at a Texas school that teaches abstinence has reached “epidemic proportions” infecting 1-in-15.

The Crane Independent School recorded 20 cases of the sexually transmitted infection among its 300 students, US media reported.

The school is rethinking its approach to sex education, but one top official at the school backs the status quo, local TV news station K-FOR reported.

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“We do have an abstinence curriculum, and that’s (sic) evidently ain’t (sic) working,”Crane Independent School District superintendent Jim Rumage said in a letter to parents.

“We need to do all we can, although it’s the parents’ responsibility to educate their kids on sexual education,” Mr Rumage said.

The district oversees three schools at elementary, middle and high school level.

The US Centre for Disease Control classed the school outbreak as “epidemic proportions”, K-FOR reported.

But Mr Rumage said the abstinence program seemed to back the “worth the wait” sexual education program that teaches abstinence.

“If kids are not having any sexual activity, they can’t get this disease … that’s not a bad program,” Mr Rumage said.

The region around the school has a chlamydia rate of 535.8 per 100,000 people in 2013, which puts the infection rate at about 0.5 per cent, a tenth of the figure at the school, according to Texas health statistics.

The My San Antonio news website reported the school will hold a meeting with parents to look at any changes to the sex education program on May 19.