There are fewer students in class on Monday across Sarnia-Lambton.
Lambton Public Health Supervisor Erin Courtney said the health unit has not yet received updated immunization records or proof of exemption for 325 elementary and secondary students.
Courtney said students will be suspended from school until the necessary records are provided.
In December, about 2,600 letters were mailed out to parents of area students whose immunization records were not up to date and a final notice went out last month.
Parents can update records online at www.lambtonhealth.on.ca, by phone, or in person at the Exmouth Street health unit.
The records include immunizations for diphtheria, tetanus, polio, mumps, rubella, measles, meningitis, whooping cough and chicken pox.
