County of Marin Health and Human Services

Pertussis (Whooping Cough)

Marin County Public Health is actively monitoring pertussis, also called whooping cough. Pertussis incidence typically spikes every 3-4 years. The last major pertussis outbreak in Marin occurred during the 2018-19 winter season, when we saw nearly 300 cases.

As of March 27, 2024, 113 pertussis cases have been reported to Marin County Public Health. Some of these cases have been related to school-based transmission. Children and adolescents with persistent cough should be evaluated for pertussis by their healthcare provider. Marin Medical Reserve Corps is supporting Public Health with contact investigation, which focuses on pertussis vaccinations during pregnancy, cocooning, and timely infant vaccinations.

Updated:  April 6, 2024

Pertussis, also known as whooping cough, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis

Pertussis spreads easily from person to person mainly through droplets produced by coughing or sneezing. The disease is most dangerous in infants, and is a significant cause of disease and death in this age group.

The first symptoms generally appear 7 to 10 days after infection. They include a mild fever, runny nose and cough, which in typical cases gradually develops into a hacking cough followed by whooping (hence the common name of whooping cough). 

Pertussis Vaccine

Pertussis vaccines are effective, but not perfect. They offer good levels of protection during the first two years after getting the vaccine, but the protection decreases over time (“waning immunity”).  For this reason, we tend to see pertussis more in middle and high school age populations. Those who are vaccinated tend to have less severe disease.

Vaccination remains the best defense against pertussis, along with appropriate screening, treatment, and prophylaxis for high risk contacts.  Anyone who is around an infant less than one year of age should have current pertussis vaccination.

Marin County Public Health Recommends: 

  1. Vaccinate infants, children, adolescents, and adults according to the ACIP schedule. Most importantly, pregnant women should receive the Tdap vaccine between 27-36 weeks of pregnancy to protect infants.
  2. Cocoon newborns.  Cocooning is vaccinating everyone in close contact to the newborn so that there is a cocoon of safety from pertussis, influenza, and vaccine-preventable diseases around the newborn until they can develop immunity at around one year of life from their own vaccines.
  3. Think pertussis. If other household members are or have been recently sick with a respiratory illness, particularly if with violent coughing fits and vomiting after coughing, discuss with your health care provider. People who have been vaccinated for pertussis often present with mild symptoms.    
  4. Test for pertussis. Testing is most critical for symptomatic persons who are either high risk or may expose someone who is high risk. Persons considered at “high risk” of pertussis include infants (< 1 year old), pregnant women (especially in the third trimester), and anyone who may expose infants or pregnant women.
  5. Treat pertussis cases with a course of appropriate antimicrobial therapy. The recommended antimicrobial agents for treatment or chemoprophylaxis of pertussis are azithromycin, clarithromycin, and erythromycin.
  6. Stop the spread.  If you or your child is sick with pertussis, prevent spreading the illness to others by staying at home until at least 5 days of antibiotics are completed, or if the sick person did not receive antibiotics, stay at home until 21 days since the cough started.