slightly old article but I didn’t see it posted.
This, from the article, indicates the danger of not being vaccinated.:
From 2000 through 2014, there were 277 deaths from whooping cough reported in the United States, according to the CDC. Almost all of the deaths (241 of the 277) were babies younger than 3 months of age, who are too young to be protected against whooping cough by getting the shots.
But, an updated vaccine is needed as some strains are pertactin-deficient. http://www.cdc.gov/pertussis/pertactin-neg-strain.html