(CNN) More than 1,400 Seattle Public Schools students are still at risk of being excluded from school if they don't provide verified vaccination records by Wednesday, school system spokesman Tim Robinson said.

That's down from last month when 2,200 needed to update their records. Robinson said he expects the number will keep declining as the January 8 deadline approaches.

The district -- serving more than 50,000 students across 104 schools -- sponsored three free immunization clinics since last month, when staff sent out a letter warning parents students would not be able to return without complete vaccination records.

At least 135 students were immunized at those clinics, Robinson said.

This is all following a Washington state law that went into effect over the summer, which says families can't use personal and philosophical reasons to avoid having their children vaccinated with the MMR (measles, mumps and rubella) vaccine, the state's department of health said.

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