Pertussis Outbreak at School in Contra Costa County

In mid-April, an outbreak of pertussis was reported at a private school in Contra Costa County. The school had a very high rate of personal belief exemptions for vaccines (up to 64% in one class).  Cases associated with this outbreak reside in Contra Costa and Alameda Counties. To date, there have been 20 cases among students and their family members.  The outbreak investigation uncovered additional students who had prolonged cough illness in the months prior to the reporting of the index case. At least three children with laboratory-confirmed pertussis did not receive antibiotics due to parental beliefs about medical treatment.  These children were excluded from school until they tested negative by PCR for B. pertussis.   

On May 9, the school closed for one day to implement an antibiotic policy and halt ongoing disease transmission. All pupils and staff who were uninfected and had not yet received antibiotic prophylaxis were given the option of receiving prophylaxis or exclusion from school for 21 days.  About 7% of the students did not receive antibiotics due to parental beliefs and were excluded.  There have been no new cases at that school since it instituted the antibiotic policy. The Contra Costa County health department will continue surveillance through the end of the school year.