There is so much debate on vaccine safety, etc I think it is interesting to look at the other unintended consequences of vaccination. This is from an old post: http://messageboards.ivillage.com/iv-ppvaccinedb/?msg=4211.24  and talks about the shifting of the age in which people are susceptible to getting disease.
"Instead vaccination programs are shifting the demographic in which people get some of these diseases to ages where the complications are greater."
Responding in advance to myself because I know I will be asked to defend the above statement... so here is my defense for my belief based on a post I made on an another board:
You can also argue with some of the VPDs that more vaccination leads to a more vulnerable newborn population (measles) or adult population (chicken pox). By this I mean the age at which people might get the disease shifts (too younger or older or both), making the disease potentially more harmful.
Using measles as an example, maternal antibodies cross the placenta and offer protection to a newborn (who can not be vaccinated for measles at birth). The effects of maternal antibody transfer are much higher for mothers who have had wild measles.
It strikes me that mother nature intended protection to be conferred via maternal antibodies and breastfeeding.
Why muck with intentions of mother nature? Which is what the vaccine program has done: mothers no longer get measles and no longer pass those antibodies to the newborns leaving them extremely vulnerable because most Doctors give the first dose of MMR vaccine between 12-15 months.
"In addition, measles susceptibility of infants younger than 1 year of age may have increased. During the 1989–1991 measles resurgence, incidence rates for infants were more than twice as high as those in any other age group. The mothers of many infants who developed measles were young, and their measles immunity was most often due to vaccination rather than infection with wild virus. As a result, a smaller amount of antibody was transferred across the placenta to the fetus, compared with antibody transfer from mothers who had higher antibody titers resulting from wild-virus infection. The lower quantity of antibody resulted in immunity that waned more rapidly, making infants susceptible at a younger age than in the past." Soure: CDC Pink Book: http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/meas.pdf 
Chicken pox vaccine, only now are we seeing when secondary vaccine failure might occur and when boosters may be added to the schedule. Chicken pox contracted as a child rarely has serious consequences. Those consequences however become more serious with age. Which the reason a lot of people who selectively vaccinate omit this vaccine.
"In the New England Journal of Medicine, the researchers confirm what doctors have already known — that the vaccine has sharply reduced the number of cases in children but that its protection does not last long. With fewer natural cases of the disease, the study says, unvaccinated children or those whose first dose of the vaccine fails to work are getting chickenpox later in life, when the risk of complications is higher. “If you’re unvaccinated and you get it later in life, there’s a 20-times greater risk of dying compared to a child, and a 10- to 15-times greater chance of getting hospitalized,” said Dr. Jane Seward of the Centers for Disease Control and Prevention in Atlanta, who worked on the study....The United States has been vaccinating against chickenpox since 1995. But tests have shown that the vaccine is not very effective in 15 percent to 20 percent of children who receive only one dose. A second dose would provide extra protection, but it is not clear how much..." - Reuters, New York Times , March 15, 2007, Chickenpox Vaccine Loses Effectiveness in Study http://www.nytimes.com/2007/03/15/health/15pox.html?ex=1331611200&en=8439a613bed73800&ei=5088&partner=rssnyt&emc=rss 
"Children between the ages of 8 and 12 years who had been vaccinated at least 5 years previously were significantly more likely to have moderate or severe disease than were those who had been vaccinated less than 5 years previously. The annual rate of breakthrough varicella significantly increased with the time since vaccination, from 1.6 cases per 1000 person-years within 1 year after vaccination to 9.0 per 1000 person-years at 5 years and 58.2 per 1000 person-years at 9 years." - Sandra Chavez, M.D. et al., New England Journal of Medicine Loss of Vaccine-Induced Immunity to Varicella over Time, March 15, 2007 http://content.nejm.org/cgi/content/abstract/356/11/1121 
Recently in the Canadian media there was an interesting discussion on immunological memory which also leads to "less community". For those unfamiliar with the term see:
Before vaccination became commonplace, adults often came in contact with youngsters suffering from mumps, measles and the other childhood diseases. That remained the case in the early days of vaccine administration when these diseases still commonly circulated.
If people had protection - natural or vaccine-acquired - those exposures were actually helpful. They acted as a sort of natural booster shot, reminding the immune system to be on guard for this threat.
Some experts now wonder whether these unrecorded natural boosts may have led the medical community to overestimate the durability of immunity generated by childhood vaccinations. These days, few people are getting natural boosting to these diseases.
Questions about the durability of immunity are on the minds of public health authorities in countries where childhood vaccines have been in use the longest, says Jane Seward, an expert in vaccine-preventable diseases with the U.S. Centers for Disease Control in Atlanta.
"It's certainly a reasonable hypothesis that immunity might wane more quickly in the absence of external boosting. Whether that's the case or not, we don't know. But it's a reasonable thing to postulate," she says.
I am going to use myself has an example because I have had measles, rubella, mumps and chicken pox. So after the MMR was introduced initially the wild virus still circulated boosted my immunological memory. As a result, it also artificially inflated the estimated vaccine efficacy, because people who got the vaccine, still encountered the viruses occasionally.
As vaccine uptake increased, the ability for immunity to be "boosted" by natural exposure disappeared. Such logic is being admitted to now as in the above article and is leading to research on "adult booster" schedules.
The above to me, illustrates that when vaccine programs are introduced the "long-term" consequences to the community or herd are not known and still not known as this has been area identified for further research. So we still won't know for decades.
This leads me to conclude:
1) Without the wild version of diseases circulating around - vaccines lose their efficacy (secondary vaccine failure) and someone like me who had natural immunity is not getting my immunological memory triggered.
2) Conclusion 1 results in adults being more vulnerable to childhood illnesses (Mumps in Iowa: http://content.nejm.org/cgi/content/abstract/358/15/1580 ), which generally have more serious or dangerous consequences for grown-ups than for children.
3) Conclusion 1 also leads to infants being born with significantly less passive immunity (measles was my example) from their mothers, putting them at risk of serious complications (possibly even death).
Isn't it possible that Mother Nature knows more about protecting people from disease than the vaccine manufacturers?