The California Department of Public Health has declared an epidemic of whooping cough in the Golden State. In the last two weeks alone, 800 new cases of whooping cough have been reported. As of June 10, there have been 3,458 reported cases in 2014 so far, which is more than were seen in the entirety of 2013. To combat the spread of this condition, health officials are encouraging vaccinations.

According to the U.S. Centers for Disease Control and Prevention (CDC), whooping cough or pertussis is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis. Pertussis is known for uncontrollable, violent coughing which often makes it hard to breathe. After fits of many coughs, someone with pertussis often needs to take deep breathes which result in a “whooping” sound, giving the condition the colloquial name “whooping cough.”

Though there are varying levels of severity, whooping cough can be fatal, especially in babies that are less than one year old. California public health officials suggest that the Tdap vaccination is the best method of prevention. It can be given to infants who are at least 6 weeks of age and to pregnant women to protect newborns and infants until that point. Older children and adults should also get vaccinated.

Pertussis has a cyclical presence, with a peak every three to five years. The last peak was in 2010. Unfortunately, the Orange County Register notes that a change in the vaccination to reduce side effects resulted in the vaccine offering less protection. This change has enhanced the spread of whooping cough this time around.