Following are excerpts from a Pfizer-BioNTech document titled REG 174 INFORMATION FOR UK HEALTHCARE PROFESSIONALS ...
4.5 Interaction with other medicinal products and other forms of interaction
No interaction studies have been performed.
Concomitant administration of COVID-19 mRNA Vaccine BNT162b2 with other vaccines has not been studied (see section 5.1).
Do not mix COVID-19 mRNA Vaccine BNT162b2 with other vaccines/products in the same syringe.
4.6 Fertility, pregnancy and lactation
Pregnancy
There are no or limited amount of data from the use of COVID-19 mRNA Vaccine BNT162b2.
Animal reproductive toxicity studies have not been completed. COVID-19 mRNA Vaccine
BNT162b2 is not recommended during pregnancy.
For women of childbearing age, pregnancy should be excluded before vaccination. In addition, women of childbearing age should be advised to avoid pregnancy for at least 2 months after their second dose.
Breast-feeding
It is unknown whether COVID-19 mRNA Vaccine BNT162b2 is excreted in human milk. A risk to the newborns/infants cannot be excluded. COVID-19 mRNA Vaccine BNT162b2 should not be used during breast-feeding.
Fertility
It is unknown whether COVID-19 mRNA Vaccine BNT162b2 has an impact on fertility.