The phrase "herd immunity" is tossed a lot these days. I've often seen it used as ammunition against parents who choose not to vaccinate, with something along the lines of, "the only reason your unvaccinated child is so healthy is because those of us who vaccinate are keeping disease rates down". Is this really true? I decided to dig deeper to find out.

Natural Herd Immunity vs Vaccine Herd Immunity

Herd immunity requires the assurance that a large percentage of the ‘herd’ (population) is immune and therefore unable to pass on disease. The theory is based on natural immunity, which provides lifelong or long term immunity. [1] Whether vaccination can be substituted for natural immunity when considering herd immunity, is an entirely different question.

Just how effective a vaccine is at providing immunity isn't easy to gauge. Vaccination provides essentially a half-hearted immune response to infection. It may often provide a strong antibody reaction, but unfortunately provides a very poor innate immune response. [2] Despite this, traditionally vaccine effectiveness has been based on measuring antibody levels produced by the body in response to the vaccine, and the fact that vaccines illicit a poor innate immune response has largely been ignored.

However, recent research has put the traditional theory that antibodies are required for immunity into question. It is now known that antibody levels cannot accurately predict immunity. A person can have high levels of antibodies but still become infected, and conversely a person can have low levels of antibodies but not become infected. In fact, in 2012 Moseman et al revealed that antibodies were not even required to gain immunity and that antibodies elicited by vaccines could not by themselves provide adequate immunity. [3]

Pollard et al (2009) noted that children vaccinated with the Hib conjugate vaccine still suffered from Hib disease despite the presence of B-cell immunological memory:

"These children mount a memory immune response to infection but still suffer from Hib disease, which supports our view that the presence of immunological memory does not guarantee protection. These observations strongly suggest that B-cell memory (the kind of immune memory induced via vaccination) might not be as important as longlasting antibodies (T-cell memory cells induced via natural infection) for long-term protection against a rapidly invasive pathogen." [3a]

Despite this, vaccine manufacturers continue to use antibody testing to rate their products effectiveness. As inadequate as antibody-based immunity conferred by vaccines is, it is further subject to rapid decline soon after vaccine administration, in some cases even after numerous boosters.

In 2012 Klein et al studied the waning effect of the whooping cough (pertussis) vaccine and discovered:

 “The risk of pertussis increased by 42% each year after the fifth DTaP dose.” [4] 

In stark contrast, in 2009 Wearing et al determined that , on average, whooping cough immunity lasts at least 30 years and perhaps as long as 70 years after natural infection. [5]

It's no surprise then that vaccines are often demonstrated to be ineffective in real world situations. For example numerous outbreaks of measles, mumps, whooping cough, chicken pox, influenza, and polio have been documented in highly vaccination populations. [6-23, 24-27, 28-35, 36-40, 41-62, 63-64]

Asymptomatic infection after vaccination

"Our data suggests that the current schedule of acellular pertussis vaccine doses is insufficient to prevent outbreaks of pertussis." [65a]

Likewise, in 2013 researchers Sala-Farré et al. studied whooping cough incidence in Vallès with similar conclusions:

"Despite high levels of vaccination coverage, pertussis circulation cannot be controlled at all. The results question the efficacy of the present immunization programmes." [65b]

In addition, the Centers for Disease Control has admitted that unvaccinated people are not the cause of recent whooping cough incidence:

"Even though children who haven't received DTaP vaccines are at least 8 times more likely to get pertussis than children who received all 5 recommended doses of DTaP, they are not the driving force behind the large scale outbreaks or epidemics...We often see people blaming pertussis outbreaks on people coming to the US from other counties. This is not the case. Pertussis was never eliminated from the US like measles or polio, so there's always the chance for it to get into a community. Plus, every country vaccinates against pertussis." [65c]

"The observation that acellular pertussis, which induces an immune response mismatched to that induced by natural infection, fails to prevent colonization or transmission provides a plausible explanation for the resurgence of pertussis and suggests that optimal control of pertussis will require the development of improved vaccines." [65]

The risks associated with the acellular whooping cough vaccine, which has been in use since 1991 [68], have been known as early as 2000, yet no recall of the vaccine was made. [69] This is a major problem that should have been caught in preliminary trials, before the vaccine was licensed to begin with.

But wait, there's more

The whooping cough vaccine isn't alone. The measles vaccine shares similar problems.

Vaccine-Induced Infection

Other vaccines have also proven to be problematic. The chicken pox (varicella) and rotavirus vaccines have been documented numerous times causing infection in vaccine recipients and spreading the infection to others. The chicken pox vaccine has also been documented multiple times causing herpes zoster, a related virus with 3 times the morbidity and 5 times the mortality of varicella, in vaccine recipients. [69-93, 94-100]

The measles vaccine may also suffer from a similar problem to the chicken pox and rotavirus vaccines. Researchers Valsamakis et al (1999) studied how the vaccine-based measles virus changed over time when allowed to replicate for an extended period of time in human tissue. They discovered that it grew in strength, evolving back to a strength similar to that of the wild-type measles virus from which it was derived. The researchers warned that individuals with immune deficiency may suffer adverse outcomes if vaccinated, as they may be unable to clear the original, weakened, vaccine-based measles virus, allowing the virus to replicate for an extended period of time and grow to full strength. [101]