Depends on age
Infants have immune factors from mom from pregnancy
but it begins to wain after birth.
The infant immune system must be pushed so pertussis vaccine (&others) are usually given @2/4/6mo but can be given as early as 6wks if the disease is in the area.Boosters are given at 12-15m, 4-6yr & again @11-18yr. Pertussis vaccine provides a good but time limited protection.Discuss specific needs with your dr.