It's understandable for parents to worry about "too many, too soon", but there's a common misunderstanding behind it.
Babies can handle it
From the moment of birth, a baby's immune system meets large numbers of microbes constantly. The antigens in vaccines are tiny by comparison. Studies show that following the schedule with several vaccines doesn't overload or weaken a baby's immune system.
The schedule is built around risk
Vaccines are timed around the age at which a baby is most likely to catch a given disease and most likely to suffer serious complications. The hepatitis B vaccine is given at birth, for example, because infection at birth carries the highest risk of developing chronic liver disease. Other vaccines are timed for when the antibodies a baby received from its mother start to fade and the baby needs its own protection.
Delaying has a cost
Postponing vaccines or stretching out the intervals leaves a baby unprotected while still vulnerable, widening the window for catching a preventable disease.
The Hong Kong programme
The Hong Kong Childhood Immunisation Programme provides a series of vaccines from birth through secondary school, with children aged 0 to 5 vaccinated at Maternal and Child Health Centres. The safety and effectiveness of the programme's vaccines are supported by long-term evidence.