DOCTORS are hoping health education and peer pressure in drug addict circles will help combat the outbreak of tetanus which has claimed 13 lives. Three more addicts have been admitted to hospital since Friday suffering from the disease, bringing the total known cases since the beginning of November to 33. Only two addicts who contracted the disease have been released from hospital after treatment. While the source of the outbreak is officially unknown, the Health Department believes contaminated heroin is responsible. So far, 1,453 addicts - out of a possible population of 20,000 - have been vaccinated against the disease at one of the territory's 23 methadone clinics. Senior medical and health officer Dr Mak Ying-wai, in charge of the Violet Peel Methadone Clinic in Wan Chai, said addicts were being given health education when they attended the clinics. ''We are offering the vaccination in 23 clinics. Some are accepting it and some aren't,'' he said. ''But more people are accepting it after we give them health education - what the effects are and the importance of the vaccination.'' Dr Mak said the vaccinations were being given to existing patients but clinics would welcome more street addicts coming forward. ''There's a certain amount of peer pressure in drug addicts' circles. We believe people will go back to the street and tell their friends.'' Dr Mak said he believed addicts would complete the course of vaccination which requires three injections in six months for 10 years' protection.