Public Health

The Power of Herd Immunity

The state of California is currently debating legislation that will require all children to be vaccinated. Senate bill 277 will ensure that 10 childhood diseases will be prevented as the law will direct that vaccines for these diseases must be administered prior to admission to kindergarten or any daycare setting. Under this proposed law, only medical exemptions will be allowed to circumvent mandatory vaccination.

Vaccine exemptions exist in many forms and vary from state to state as to which are legal and how they are granted. One major type is that of a personal exemption. These exemptions are based on the belief that vaccines do more harm that good or that calling for mandatory vaccination is an infringement on personal liberty, that no government entity has the right to mandate vaccination. Personal exemptions however greatly undermine the power of medical exemptions which are important for those who cannot be vaccinated due to documented medical conditions. Religious exemptions are granted when vaccination policies are at odds with a person’s religious beliefs. Of the exemptions I have just briefly described, religious and medical exemptions appear to be the most reasonable to grant as the practice of one’s religion is a right granted by the constitution while medical as I mentioned is stating that the vaccine could be harmful to an individual’s health due to a preexisting medical condition.

No matter which of the three exemptions are granted, vaccination is still very important. Establishment of herd immunity and maintaining a high percentage of vaccinated individuals within a population reduces the incidence of disease within a population. How? I will use a very simplistic example with ten people (we know that this is an inappropriate sample size, but this is to illustrate the point).

Scenario 1: Of the ten people in this population, only 1 is vaccinated (10% vaccination rate), 1 person is infected (10% infection rate) and the remaining eight people are not vaccinated. Thus, we have 80% of this example population that is susceptible to disease and with a low vaccination rate, infection is rapid among the non-vaccinated.

Scenario 2: Vaccination rate increases to 50% (5 vaccinated individuals), only one infected individual and four non-vaccinated. Here, susceptibility has been halved from scenario 1 (40%) but it is still not enough to keep infection from passing readily through this population.

Maximum protection of the population (vaccinated as well as the non-vaccinated), we need the vaccination rate to be at 90% or higher and only 10% of the population is susceptible to infection. Looking at that, 10% may still be too high of a susceptibility rate but what this number really means is that the chances of infection are greatly lowered and can really be better defined as sporadic. This is due to the high percentage of the population that acts essentially to buffer the effects of the infection among the population.

In a perfect world, 100% of the population would be vaccinated, thus no one would suffer from disease. A rate of 90% is acceptable, although with the current state of vaccination in the U.S., this number has dwindled, placing us in a very dire state. If not for yourself. vaccinate for the good of all. Our fortunes against infectious disease rise and fall with every action we take or every opportunity we squander.

Rubella elimination in the Americas and the Vaccine effectiveness argument

Vaccines are arguably the most successful public health intervention of the 20th Century. The successes that have been noted in reducing disease and deaths are immeasurable and hopefully there are many more successes to come with the current work being done with Polio. Within the last 15-20 years, the anti-vaccine movement has become a major player not only in debating the effectiveness and safety of vaccines, they have become an entrenched force that has driven down the community (Herd) effectiveness of vaccine through their non-compliance with vaccination standards. Many of their main arguments are invalid (autism/vaccine link) and their stubbornness to comply claiming personal exemptions bring harm to children. Each position previously mentioned is one in the same since many anti-vaxers forgo vaccines because of a personal belief and/or their rights are being infringed upon by a paternalistic governmental force.

This week, it was reported that Rubella has been eliminated from the Americas. This is highly historic as the efforts and gains made in the Americas can begin the worldwide elimination of Rubella worldwide. To what can we thank for this development? It would have to be the MMR vaccine! Through the use of the MMR vaccine, we have the power to eliminate vaccine prevenatble disease worldwide to end major suffering. Vaccine preventable diseases can be eliminated from out world and bring about a higher standard of health, improving life expectancy, reducing infant and child mortality due to these diseases and have a major effect on health costs.

Preventative health from a vaccination standpoint makes sense as we look not only to reduce disease burden, but we also want to reduce health costs for treatments later in life. Vaccination is an investment, there are costs to vaccination but those paying the costs must see these costs as investments in individual and community health. These investments MUST be made at the beginning of life to control health costs at the end of life. More investment at the front end keeps health costs low, improves overall coverage for all and can allow for coverage more more acute and complex health issues later in life. There is no excuse for not wanting to vaccinate when we can see that their effects on disease burden are obvious!

The tug-of-war between pro-vaccine and anti-vaccine movements continue. With smallpox declared eradicated 35 years ago and two other diseases heading towards eradication, another check can be placed in the column for the pro-vaccine movement while the foundation of the anti-vaccine movement suffers another blow.

The Jenny McCarthy Mistake

ABC today announced that Jenny McCarthy will replace Elisabeth Hasselbeck as a co-host of the daily talker, “The View.” I normally don’t talk pop culture here but this is a significant hire for many of the wrong reasons. Many know Ms. McCarthy from her days on MTV and Playboy but I think her most infamous activities have been as an active anti-vaccine crusader due to the misinformed view that vaccine use caused autism.

Since the refutation of this link, there has been a gradual ramping down of the rhetoric linking the two but the damage has been done. It is amazing how in the age that we live in, we have gone from an era of little information, trusting our medical professionals almost blindly to information overload and the potential to spread total misinformation. The age of the internet provides all of us with powerful tools to question many things around us but it is the validity of the information that we acquire that makes the difference. Jenny McCarthy is now a figurehead in an already uphill battle in maintaining herd immunity or more simply a high, constant level of people within a population who are vaccinated against controllable diseases. Giving her this forum I think is highly irresponsible on ABC’s behalf and could act as a soapbox for more widely disseminated discussion and misinformation to a population that is overloaded with all types of information from many questionable sources.¬†