本文发表在 rolia.net 枫下论坛I find the following from US CDC website
Why do children need so many shots?
There are 12 potentially serious diseases that vaccines protect against: Measles, Mumps, Rubella (German Measles), Diphtheria, Tetanus (lockjaw), Pertussis (Whooping Cough), Polio, Haemophilus Influenzae type b (Hib Disease), Hepatitis B, Varicella(Chickenpox), Hepatitis A, and Pneumococcal disease. At least one shot is needed for each of these diseases, and for some of them several doses are required for the best
protection.
This adds up to a lot of shots, and several are usually given at the same time. Some parents worry that it is not safe to give several shots at once, or that they may not work as well, or that they will overload the child's immune system. But studies have shown these fears to be unfounded. Vaccinations are just as safe and just as effective when given together as they are when given separately. The immune system
is exposed to many foreign substances every day, and will not be overburdened by vaccines.
Several "combination vaccines" already exist (such as MMR and DTaP) in which multiple vaccines are given in a single shot, and this reduces the number of shots needed. More combinations are being developed, so in the future, even fewer shots will be needed for the same number of vaccines.更多精彩文章及讨论，请光临枫下论坛 rolia.net
Why do children need so many shots?
There are 12 potentially serious diseases that vaccines protect against: Measles, Mumps, Rubella (German Measles), Diphtheria, Tetanus (lockjaw), Pertussis (Whooping Cough), Polio, Haemophilus Influenzae type b (Hib Disease), Hepatitis B, Varicella(Chickenpox), Hepatitis A, and Pneumococcal disease. At least one shot is needed for each of these diseases, and for some of them several doses are required for the best
protection.
This adds up to a lot of shots, and several are usually given at the same time. Some parents worry that it is not safe to give several shots at once, or that they may not work as well, or that they will overload the child's immune system. But studies have shown these fears to be unfounded. Vaccinations are just as safe and just as effective when given together as they are when given separately. The immune system
is exposed to many foreign substances every day, and will not be overburdened by vaccines.
Several "combination vaccines" already exist (such as MMR and DTaP) in which multiple vaccines are given in a single shot, and this reduces the number of shots needed. More combinations are being developed, so in the future, even fewer shots will be needed for the same number of vaccines.更多精彩文章及讨论，请光临枫下论坛 rolia.net