Ask Dr. Paul Offit

Probably the best example is the influenza vaccine, which for decades was made in hen's eggs. Now we have a mammalian-cell-based vaccine, which in many ways is an easier and more reliable way to make the vaccine. The challenge, however, was that this is an entirely new product. Therefore, both the product, the manufacturing protocol, and the building in which the product is made have to be licensed as a new product, which is an enormously expensive thing to do for what is not a big ticket item. Vaccine profits will always pale in comparison to drugs as vaccines are given just once or at most a few times during one's lifetime, whereas some drugs are given every day.

Regarding the first part of your question, I think that the single greatest factor that led to an anti-vaccine backlash (which began in the early 1800s in response to the smallpox vaccine) was vaccine mandates. I think if you ask the professional anti-vaccine groups what would cause them to stop their activities they would say to make vaccines optional. This, of course, would be a disaster for society as it would no doubt lead to an erosion of vaccine rates and an increase in vaccine-preventable diseases.

Regarding the second part of your question, I would argue that vaccines are the safest, best tested medical products that we put into our bodies. So the issue isn't one of data (plenty of data are available to address these concerns). The issue is one of making those data compelling. And that is where I think we have fallen short. We have to be able to grab the attention of the media and the public with the data that can exonerate vaccine fears.

The intradermal site is rich in dendritic cells and, consequently, an excellent site for inducing immune responses. The best current example being the intradermal influenza vaccine.

So one could reasonably argue that the site would be excellent with the exception of oral vaccines (like rotavirus or oral polio) or live attenuated viral vaccines (like measles, mumps, rubella, or varicella). Indeed, the site could be of great value for diphtheria, pertussis, tetanus, Hib, pneumococcus, hepatitis B, HPV, or inactivated polio vaccines. The difficulty of course is that the path to licensure of a new product going up against existing vaccines is steep.

Smallpox was a disease that has probably killed more than 500 million people. In many ways, the disease changed the course of history for nations that were overwhelmed by the infection or monarchs who were killed by it. The vaccine, which was invented in the late 1700s by Edward Jenner, has eliminated the disease from the face of the earth. This disease, which killed about 1 of every 3 people infected, and often left survivors blind, is now an historical footnote because of the vaccine. No story shows the power of vaccines more than this one.

I think the next big breakthrough will be a meningococcal vaccine that contains cross-reactive proteins that protect against all 5 prevalent serogroups; specifically, serogroups , A, C, Y, W, and B. Although the incidence of meningococcal disease in infants and adolescents has declined in the last 10 years, this is still and important disease to prevent. The current meningococcal vaccine doesn't contain a polysaccharide that protects against serogroup B, the most important cause of disease in infants and young children and an important cause of disease in adolescents.

My fantasy vaccine technology would be microencapsulation. There is no reason why all vaccines couldn't be given by mouth. This would address the most common concern parents have: painful injections. Microcapsules could be constructed to survive the acid-protease environment of the mouth and stomach and be made in such a way that antigen release could occur in the small intestine, which is a rich source of B cells, T cells, and antigen presenting cells. Also, microcapsules could be targeted to specific antigen-presenting cells depending on the type of immune response desired.

The problem is that this would be a lot of work and there is very little financial incentive to do it. But as long as we're dreaming, this is mine

Yes. Although it is apparently going to take much longer than originally hoped.

The reasons for optimism are that it has been eradicated from developing nations and that there are now only three countries (Pakistan, Afghanistan, and Nigeria) that have continued to suffer endemic disease. But the disease has now been eradicated from India, a hopeful sign.

The problem at this point isn't money or availability of vaccines; it's political will in the countries that continue to have a problem. The other problem is that the oral polio vaccine viruses can rarely revert to neurovirulent type and can survive in sewage.

I think the biggest obstacle is an increasingly greater burden of regulatory issues by the Food and Drug Administration. It's much more difficult to make vaccines today than 15 years ago. Today, companies are asked to rule out relatively rare adverse events pre-licensure.

The best answer to that question is to eat lots of fruits and vegetables and make sure you go out into the sun about 15 minutes per day at least twice per week. Then you'll get everything you need. This notion we have that all will be well if we take supplemental vitamins in pill form is just incorrect. There are several websites (Harvard's being one) that explain how you can get all the vitamins you need based on how many calories you are consuming during the day.

Unfortunately, you fears are well-founded. That's because no vaccine is 100 percent effective.

To support this statement, there was a study reported in the Journal of Infectious Diseases about a measles outbreak in the Netherlands that involved several thousand people. Surprisingly, you were more like to catch measles if you were vaccinated and living in a highly unvaccinated community than if you were unvaccinated living in a highly vaccinated community. In other words, you were better off living in a situation where you were unlikely to catch measles (i.e., a highly vaccinated community) than if you were in a situation where your risk of exposure was great.