Immunocompromised children: what are their infectious risks from the unvaccinated?

In the last few days there have been multiple news articles and testimonies in the Maine and Vermont legislatures about the need to impose vaccine mandates to protect immunocompromised children.[1] [2]  I attended the vaccine bills' hearing in Augusta, Maine on May 11, which lasted into the night. I also attended the Vermont Senate hearing 3 weeks earlier.  The Vermont Senate committee said it would only hear testimony from physicians, which is why I was invited. Not very many doctors are familiar with the vaccine literature. Vaccines are, surprisingly, an arcane area of medicine. 

Unfortunately, I heard not a single expert (at either hearing) provide any data about the magnitude of the problem that vaccine mandates are supposed to fix.  In fact, I was quite surprised to learn that helping the immunocompromised seemed to be the major justification to remove vaccine exemptions.

I heard no one mention the fact that vaccine efficacies of 40%, 60%, 80% (approximately correct for influenza, diphtheria, mumps vaccines) might also pose some risk to the immunodeficient.  (These are just examples; most other vaccines have efficacy in the 60-90% range.) Actually, any statistician could tell you that low efficacy poses considerably more risk than exemption rates of 1-5% in Maine (depending on which required vaccine we are discussing). Vaccines with low efficacy make the claim of herd immunity a joke--but did even one "expert" at the hearings know or care?

How much risk is actually posed by “vaccine-preventable” diseases to the immunocompromised? I reviewed the most common infections seen in those at highest risk: stem cell transplant recipients[3] and leukemia patients.[4]

Here is what I found.

"The limited data show that community acquired respiratory viruses (CARVs) and herpesviruses are the most common pathogens. Among the causes of CARV respiratory tract infections, a preponderance of respiratory syncytial virus (RSV) and parainfluenza virus (PIV) are reported, followed by influenza virus and human metapneumovirus (HMPV).  In the herpesvirus family, the incidence of herpes simplex virus (HSV) and varicella zoster virus (VZV) infections as well as cytomegalovirus (CMV) diseases have significantly decreased because of effective prophylaxis. The reports on human herpes virus (HHV)-6 diseases are increasing...

Other viruses, such as herpesviruses and adenovirus, may also result in respiratory infections... Herpesvirus pneumonia is usually caused by reactivation of latent viruses which occurs in severe immunosuppression.

... viral encephalitis was mainly caused by human herpes virus (HHV)-6, followed by EBV, HSV, JC virus, CMV, VZV in the recipients of allo-HSCT. Our data showed that herpesvirus-associated encephalitis was mainly caused by EBV followed by HSV, CMV and VZV...

The most frequent pathogens of viral hepatitis are hepatitis B virus (HBV) and hepatitis C virus (HCV). Besides these, other viruses such as CMV and HSV may also result in hepatitis. Hepatitis B and C can be caused by either virus reactivation or blood transmission..." 

There are also many bacterial and fungal infections they may develop: too many to list.  Of the many infections these patients tend to develop, the only 3 infections commonly seen, for which there exists a vaccine and which spread between children, are chickenpox (varicella zoster virus or VZV), influenza, and rotavirus.

Rotavirus is a relatively mild gastrointestinal virus and mortality, even in those with impaired immunity, is rare.[5] 

Influenza is a real concern, but influenza vaccines are notoriously ineffective.  This year, CDC said the vaccine had 19% efficacy.[6]  (A Canadian study found no efficacy for this year's flu vaccine.) Over the past ten years, CDC’s efficacy estimates for influenza vaccines averaged 40%.[7]  So even if everyone in America was vaccinated, you could not generate herd immunity for influenza.  You could not achieve the desired "cocoon" for those most vulnerable.

Chickenpox is caused by a virus that, once you have been infected, will live forever in your nerve cells. The vaccine virus also does this.  Immunocompromised patients developing chickenpox/VZV infections are usually reactivating latent virus long present in their own bodies.  Only very rarely are they “catching” chickenpox virus from someone else. Fortunately, we have antiviral drugs and immune globulin to prevent and treat these common reactivations.

Let me repeat:  vulnerable, immunodeficient children are susceptible to many viral, bacterial and fungal infections, but these are very rarely caused by child to child spread of microorganisms for which we have vaccines. They are listed in footnotes 3 and 4.  

It is troubling that vulnerable families have been encouraged to fear and stigmatize unvaccinated children, when the rates of primary and secondary vaccine failures (i.e., number of vaccinated kids who lack immunity despite their vaccinations) are far greater than the rates of children lacking vaccinations.  [CDC's 2012-13 kindergarten vaccine exemption rates by state ranged from a low of 0.1% to a high of 6.5%.]  In fact, the vaccine failures pose a much larger risk. But are the immunocompromised suffering and dying due to other childrens' vaccine failures? We are not hearing about it. If the vulnerable are not being harmed by vaccinated children who lack immunity, then it follows they are not suffering from exposure to the unvaccinated, either.

Don’t vulnerable families have enough real problems, without adding unfounded and unjustified fears? Isn't it time to drop this canard?

As I said in an earlier post, the last measles deaths in the United States (there were 2) occurred in 2003.  One was elderly; the other was aged 13 and had had a bone marrow transplant. I was unable to learn if his infection was from a vaccine strain or wild-type measles virus.  Not a single American has died from measles since.

We need to know if vulnerable, immunocompromised children are catching and dying from vaccine-preventable diseases, and from whom they are catching these diseases:  from the vaccinated, from the unvaccinated, or from their own latent viruses?  From vaccine strains or wild-type infections?

How many children are affected?  Where are they?  Which diseases are killing them? I am not finding evidence of a problem in the medical literature.

Before we "fix" it, can someone describe the dimensions of this problem? Does this problem even exist?  

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[1] Portland Press Herald http://www.pressherald.com/2015/05/10/a-maine-teen-has-to-ask-is-everyone-in-this-room-vaccinated/

[2] Vermont Public Radio http://digital.vpr.net/post/passions-flare-hearing-proposal-eliminate-philosophical-exemption

[3] http://www.jhoonline.org/content/pdf/1756-8722-6-94.pdf

[4] http://cdn.intechopen.com/pdfs-wm/39664.pdf

[5] http://www.jhoonline.org/content/pdf/1756-8722-6-94.pdf

[6] http://www.cdc.gov/flu/professionals/vaccination/effectiveness-studies.htm

[7] http://www.cdc.gov/flu/professionals/vaccination/effectiveness-studies.htm