For attendance in Pennsylvania schools, the following immunizations are required:

4 doses of tetanus, diphtheria, and acellular pertussis (1 dose on or after the 4th birthday)

4 doses of Polio (4th dose on or after the 4th birthday)

2 doses of measles, mumps, rubella

3 doses of hepatitis B

2 doses of varicella or evidence of immunity

* On the first day of 7th grade, the following vaccines are required: 1 dose of tetanus, diphtheria, acellular pertussis (Tdap), and 1 dose of meningococcal conjugate vaccine (MCV) 

More information can be found here: Pennsylvania School Vaccination Requirements