Impact of Vaccine Delay

Offit says he understands why parents are concerned about the number of vaccines their children receive.

"Most recently, with the addition of several new vaccines to the infant schedule, some parents have become concerned that children receive too many vaccines too early," Offit says in the article. "Given that young infants currently receive 14 different vaccines, requiring as many as five shots at a single visit and 26 inoculations by 2 years of age, the concern that children might be overwhelmed by too many vaccines is understandable."

But there is no scientific validation to justify their fears, Offit tells WebMD.

Any delay of vaccines increases the likelihood that children will develop controllable diseases such as pneumococcus, pertussis, and chickenpox, Offit says, and the evidence that vaccines work is overwhelming. "If you withhold or separate or delay vaccines, those children suffer the consequences, and children suffer."

He says that that enforcement of vaccine mandates, which were initiated because of measles outbreaks that swept across the U.S. in the mid-1970s, has dramatically reduced hospitalizations and deaths resulting from vaccine-preventable diseases. He also says that states with philosophical exemptions to vaccines have higher rates of vaccine-preventable diseases (such as pertussis) compared with states without such exemptions.

He writes that "recent outbreaks of measles in 15 states" were caused by groups of concerned parents who fell prey to unjustified fears.

Offit writes that many parents are wary of accepted recommendations in part because they harbor "a suspicion of profit motive driven by pharmaceutical companies" as well as "misinformation on the Internet."

"It's very easy to scare people," Offit says. "It's very hard to unscare them."