I read in the news the dtap vaccine is less effective than once thought?

True: It appears that the length of protection from the current ap part of the vaccine is shorter than that of the older, less well tolerated p vaccine. Boosters in adults are now recommended even in 2nd or 3rd semester of pregnancy are advised all to "cocoon' the new born, not yet immunized baby who is most at risk for complications.

Yes: The formulation of the vaccine changed in 1997 and it is believed that the immunity does not last as long as previous vaccine.

Trade off: The whole cell pertussis vaccine we used up to the 90's was, more or less, ground up dead pertussis germs.It produced longer immunity than the current synthetic vaccine, but it was a mess. Infants often had fever> 102 starting with the second dose,occasional seizures, and we couldn't give it to anyone over six due to the side effects.I doubt that we would ever go back to that old technology.