That paragraph is taken out of context. Here's the entire study. The research was specifically regarding protocols as directed by manufacturer's....not veterinarians.
haywardstudyonvaccines
Taken directly from the above.
One control group was not vaccinated and the other group was vaccinated with a commercial multivalent vaccine at 8, 10, 12, 16, and 20 weeks of age and with a rabies vaccine at 16 weeks of age.
I know of no vet who would vaccinate any puppy this many times.