The nurse, Shyamala B, was roughed up and her arm was twisted by the accused during a vaccination drive at the GLP school in Edavoor.
The police said the attackers were local residents of rural Malappuram.
The vaccination drive is being held across Kerala to vaccinate children upto the age of 15 years against Measles and Rubella.
Some groups in Malappuram, traditionally, have been resistant to vaccinations. (ANI)