The school's headmaster told Action News late Monday that 60 people in the school community - students, faculty, and staff - are showing signs of the respiratory infection.
There have been at least 16 cases confirmed among students in the elementary grades at Bryn Athyn.
The first case was reported to the county health department on October 14th.
Antibiotics were provided to anyone with symptoms.
And the pertussis vaccine was offered to all students and faculty in the Bryn Athyn complex, which includes the church school, as well as the Academy of the New Church, which is a high school.
Whooping cough is a contagious bacterial infection.
Vaccination in childhood is standard.
It's also recommended that teenagers and adults get a booster shot of that vaccine. And recently, the Centers for Disease Control and Prevention recommended that those 60 and over who are around small children also get boosters. In adults, whooping cough may be mild, just a "nagging cough that doesn't want to do away."
However, parents can get a waiver for that on religious, medical, or philosophical grounds.
Bryn Athyn is a faith-based school.
Last year in Montgomery County, there were 99 confirmed cases of whooping cough.
This year, to date there have been 74 cases, including a two-month old baby who died from complications of the infection.