Sunday, April 5, 2015

CDC's too-early measles vaccination rule has left millions of vaccinated Americans without protection/ Pediatrics

Lots of babies get measles in Africa and India, and it is a significant cause of death there.  A great deal of work has gone into developing measles vaccines that can be given to children at younger and younger ages, especially in Africa, for this reason. 

But in the United States, endemic measles has been eliminated. It does not circulate here, except when a case arrives from overseas. Yet here too, the recommended age for a first measles vaccine has been changed over time. It used to be 15 months; now it is 12 months.

Actually, measles is not endemic anywhere in the Americas (yes, the entire Western Hemisphere) because public health agencies, especially the Pan American Health Organization, have vaccinated children in the farthest reaches of Latin America. The public health systems have done a great job of controlling the spread of measles cases, when they appear from overseas. Even in the poorest countries of our hemisphere, measles (as well as mumps and rubella) has not reestablished endemicity. [And, since Third World countries have handily controlled the spread of measles measles, one expects the CDC to have no difficulty doing the same here.]

The only way to absolutely prevent all measles cases is to close your borders, and no one suggests doing that. Fewer than one person per million in the Western Hemisphere gets measles each year. 

In Europe, Africa and Asia the measles situation is different. But we are here.

It has long been known that the younger you are when you receive a measles vaccine, the less likely you are to achieve immunity. For example, in a 1978 CDC article published in the journal Pediatrics, Walter Orenstein (later director of the US National Immunization Program) et al. wrote:

... we carried out a case control study of vaccine failure in a recent measles epidemic. Compared to children vaccinated at ages 15 months or older, we found an increased risk of vaccine failure among those vaccinated at 12 to 14 months (relative risk = 19.2, 95% confidence interval = 4.6 to 80.1). In order to sort out the influence of age at vaccination from elapsed time since vaccination, we subjected the data to discrminant analysis. Age at vaccination subsumed all of the effect of duration of time since vaccination. Thus, we find no evidence of waning immunity over time.
It's remarkable: children vaccinated at 12-14 months were at 19 times the risk of measles vaccine failure (i.e., catching measles) as those vaccinated at 15 months.
This lesson was not forgotten.  

Here is CDC 's 1989 acknowledgement that it increased the age for MMR to 15 months to improve effectiveness:
In 1963, the recommended age for vaccination was 9 months, but in 1965 it was changed to 12 months, and in 1976 it was changed to 15 months because of evidence demonstrating greater efficacy when children were vaccinated at these ages. Persons vaccinated before the first birthday needed to be revaccinated.
As recently as 2013 CDC noted:
This range of [measles vaccine] effectiveness also can be attributed to age at vaccination (i.e., the 85% vaccine effectiveness represented children vaccinated at age 12 months, whereas the ≥94% vaccine effectiveness represented children vaccinated at age ≥15 months.
What may be less well known is that if you receive your first measles vaccination at a young age, you are probably less likely to gain strong immunity from subsequent doses of measles vaccine, compared to those who received their initial measles vaccine at a later age.

Canada had a large measles outbreak in 2011.  There were over 750 cases in the province of Quebec alone, five times as many cases as the Disneyland epidemic.  

In a study of one school which had 110 measles cases, about half the children who developed measles had received two or more MMR doses, and about half were unvaccinated.

In efforts to understand the high rate of vaccine failure, it was found that children in the school who received their first MMR dose between 12-14 months had a vaccine failure rate of 7%, while children who received their first dose at 15 months or older had a vaccine failure rate of only 2.5%.

"An unexpected finding from this outbreak investigation was that in 2-dose recipients, VE [vaccine efficacy] was greater with older age at first dose, from 93% at 12 months to 97.5% at 15 months. The risk of measles was 2 to 4 times greater when children were first vaccinated between 12 and 14 months versus 15 months. Older age at the second dose or longer interval between doses did not influence this observation."
This Canadian government study concluded:
"Although unvaccinated people should remain the prime target for measles vaccination, the unexpected vulnerability we have identified in twice vaccinated people could ultimately lead to failed measles elimination efforts. If the effect of early vaccination permanently alters the ability to respond to subsequent doses, even adding a third or fourth dose may not provide long-lasting protection. Therefore, it is critical to understand the mechanisms of primary vaccine failure or loss of vaccine protection that our findings may signal."
The US is not like Africa when it comes to measles. No babies have died from measles in the US for more than 15 years. We can afford to wait a few months to give the first MMR dose, and optimize vaccine-induced protection for our children. If we are going to take the risks inherent in using any vaccine or drug, we owe it to ourselves to maximize the benefits we can gain from them.

Delaying the MMR for 3 months appears to be a much more effective way to optimize herd immunity than increasing the number of doses, or reducing exemptions. CDC surely knows its directive to give the MMR at 12 months has increased the number of vaccinated Americans susceptible to measles, probably several-fold. Why hasn't CDC acted on this knowledge, and revised the age for giving the first MMR?

In fact, were it to do so, there might not even be a need for the second MMR, according to Orenstein's 1978 article.

Instead of admitting this problem and moving forward,
"... here's what director of CDC's National Center for Immunization and Respiratory Diseases Anne Schuchat had to say last month: "This is not a problem of the measles vaccine not working. It's a problem of the measles vaccine not being used." She also said, "There's no harm in getting another MMR (measles, mumps and rubella) vaccine."'
Might Dr. Anne Schuchat not know what Dr. Walter Orenstein and others at CDC know about the best age to start MMR?  It's not likely, because they worked together at CDC for many years; because each has been the director of the National Immunization Program; and furthermore, because they have co-written several articles on vaccines.* 

But note the incestuous relationship between CDC and Merck:
CDC has ignored its own measles vaccine science, with increased vaccine sales but reduced population immunity the result.  Which begs the question: who do CDC and Dr. Schuchat really work for?  

After a number of separate lab mishaps at CDC that exposed scientists (with no knowledge or warning) to live bird flu, anthrax and Ebola, CDC's director had an advisory committee look into the matter.  In January, the committee concluded that CDC lacked a "culture of safety."  Given all the above, should we be blindly taking CDC's advice? **  

Instead, a CDC housecleaning is in order, with the goal of promoting the development of more effective and safer ways to vaccinate.

*  In addition to serving on the National Vaccine Advisory Committee together, Drs. Schuchat and Orenstein have co-authored the following papers:

  1. Vaccine-preventable diseases, immunizations, and the Epidemic Intelligence Service. Hinman AR, Orenstein WA, Schuchat A. Am J Epidemiol. 2011 Dec 1;174(11 Suppl):S16-22.
  2. Vaccine-preventable diseases, immunizations, and MMWR--1961-2011. Hinman AR, Orenstein WA, Schuchat A; Centers for Disease Control and Prevention (CDC). MMWR Surveill Summ. 2011 Oct 7;60 Suppl 4:49-57.
  3. Incidence of macrolide resistance in Streptococcus pneumoniae after introduction of the pneumococcal conjugate vaccine: population-based assessment. Stephens DS, Zughaier SM, Whitney CG, Baughman WS, Barker L, Gay K, Jackson D, Orenstein WA, Arnold K, Schuchat A, Farley MM; Georgia Emerging Infections Program. Lancet. 2005 Mar 5-11;365(9462):855-63.
**  CDC lacks a culture of safety.  Just 3 months ago, an advisory committee to the CDC Director issued its recommendations to improve safety at CDC.  The report began with the following words: "Observation: Leadership commitment toward safety has been inconsistent and insufficient at multiple levels. Safety, including lab safety, is viewed by many as something separate from and outside the primary missions of public health and research.

The committee's final observation began: "We are very concerned that the CDC is on the way to losing credibility. The CDC must not see itself as "special." The internal controls and rules that the rest of the world works under also apply to CDC."  

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