The revelation that in the absence of circulating chickenpox virus, adults who had experienced chickenpox as children are at an increased risk of shingles, was reported in a recent Scandals. Clearly, the prospect for an increased risk of adult shingles as a result of vaccination is worrisome, as is using vaccination to solve a problem vaccination itself has caused.
As disturbing as this particular result is, however, is it legitimate to assume that this result, while unfortunate, is just an isolated outcome and of no relevance to other vaccines and the diseases they are designed to prevent? Or are there implications for vaccination policy beyond the specific relationship between chickenpox vaccine and the potential for shingles in adults?
Unfortunately, this does not appear to be an isolated outcome. In a 1999 study entitled "Reduced passive measles immunity in infants of mothers who have not been exposed to measles outbreaks" and published in the Scandinavian Journal of Infectious Diseases, it was reported that "Geometric mean titres (GMTs) of cord blood NT (measles) antibodies gradually decreased after 1989 and the GMTs of the most recently born infants were significantly lower than those of infants born in the first few years of the study. These observations suggest that even in mothers who experienced natural measles in childhood, recurrent exposure to natural measles is necessary in order to maintain adequate antibody levels for effective passive immunity of their infants".
While the conclusion drawn by the authors of this study was that naturally measles-immune mothers, in the absence of periodic exposure to measles, do not appear to pass on immunity to their infants, the implication of this study is that measles vaccination, to whatever extent it prevents circulation of measles virus, may prevent those who are naturally immune to measles from maintaining their immunity.
It has long been assumed that measles immunity is lifelong. According to Krugman et al, in his citation of the Panum report of a 1846 epidemic of measles in the Faroe Islands, it was allegedly demonstrated "that repeated exposure to the disease was not a necessary prerequisite for permanent immunity to measles". The 1999 study cited above, however, would seem to refute this widely accepted conclusion.
Thus it would appear that those who have naturally experienced two diseases at least, i.e., chickenpox and measles, require repeated exposure in order to avoid immunity loss.
Do these unexpected results, in fact, indicate that natural immunity is not automatically lifelong? Can natural immunity actually wane under certain circumstances?
If so, what are those circumstances?
Does vaccination interfere with lifelong immunity? If so, is the loss of this very important and effective aspect of immunity an acceptable risk of vaccination?
Where is the follow-up of this important study?
Are once naturally immune children, because of vaccination, now going to be at risk for so-called "vaccine preventable" diseases as adults?
If so, what does this say about "expert" understanding of the immune system?
And what does this study, and its implications, say about the wisdom of vaccination in general? Is it really prudent to tinker with such a complex and critical biological process, particularly in the absence of disease (as is the case with vaccines given to healthy infants, children and adults)?
Look for the next Scandals on Friday, June 7, 2002.