INFORMED CHOICE
DPT and childhood immunizations
DPT and childhood immunizations
In a compulsory inoculation program, it is the responsibility of the developers, promoters and enforcers to prove safety and efficacy
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INFORMED CHOICE
DPT and childhood immunizations In a compulsory inoculation program, it is the responsibility of the developers, promoters and enforcers to prove safety and efficacy
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Two national parent organizations are calling on President Bush to issue an Executive Order to compel drug companies to remove mercury preservatives from vaccines in order to protect developing fetuses, infants and children from potential immune and brain system damage. Unlocking Autism (UA), a national, non-profit autism awareness organization, and the non-profit National Vaccine Information Center (NVIC), the largest and oldest vaccine safety organization in the U.S., are asking the President to enforce a 1999 directive to drug companies by the Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) to remove mercury from all vaccines.
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The benefits an adolescent booster program would provide are debatable.
There has been increased interest here in the United States in immunizing adolescents against pertussis. The impetus for this has been the rise in the number of cases of pertussis reported in the past decade in this age group. In addition to the morbidity pertussis produces in adolescents and is projected to cause even in older individuals (Clin Infect Dis. 2004;39:20), it also is a source of infection for younger children and infants (JAMA. 2003;290:2968). There also has been an increase in cases in the first year of life, when the risk of death or hospitalization is greatest (JAMA. 2003;290:2968). It is postulated that increasing immunity of potential mothers may confer protection on their newborns, which might prevent pertussis in those too young to be immunized.
During the 1990s, the rates of pertussis in those younger than 2 months of age increased from 72 to 107 per 100,000, and for those younger than 4 months, from 63 to 89 per 100,000 as compared with the rates in the ‘80s. The number of deaths during the two decades increased from 61 to 93 per 100,000 (JAMA. 2003;290:2968).
The Hawthorne effect However, there are some that question what would be gained by an adolescent immunization program (Clin Infect Dis. 2004;39:29). Even if it were found to have merit, there would be major hurdles to surmount in implementing it given the difficulty in accessing this group. Although the increase in pertussis in the newborn is credible, there is some concern about the reported rise in cases in the older groups.
Both figures may have increased by the ‘Hawthorne effect,’ ie, when you measure something you influence the results. As we are told the problem is getting worse, we start looking for cases. The number of cultures for pertussis obtained within 10 days of onset rose from 40% to 78% between 1994 and 1996 in the state of Massachusetts (J Infect Dis. 1999;28:1230).
To what extent of these increases represent a Hawthorne effect is difficult to discern. One might simply compare the rates of infection by testing sera collected from adults at the present time and a similar group collected 10 or 20 years ago. That is, if one knows what to measure. Many would choose antibody against pertussis toxin, which apparently is less likely to result from cross-reacting antibody from related bacteria and has a shorter half-life than some of the other pertussis antibodies (Vaccine. 2003,21:3442 ; J Infect Dis. 2004; 190:535).
Neither the CDC nor WHO accepts any serologic test as acceptable criterion for confirming the diagnosis of pertussis.
It is likely that some of the apparent increase in cases, particularly in older individuals, from whom isolation of the organism is more difficult, may be due to the increased popularity of serologic tests. These have become more popular coincident with the rise in incidence during the past decade. The increase in reported cases in older individuals has been weighted by the reporting from a few states, at least one of which has relied heavily on serologic diagnosis (J Infect Dis. 1999;28:1230).
Despite the caveat about relying on antibody measurements, some have used these to promote particular pertussis vaccines over others. The FDA, in a letter to all vaccine manufacturers in 1998, has warned that there are ‘no clinical data on file that would support any claim or suggestion of clinical superiority or benefit regarding the numbers of combinations of pertussis antigens contained in the DTaP vaccines.’ Serologic data have been used to support the use of booster doses in adolescents (J Infect Dis. 2004;190:535), although the licensure of the acellular pertussis vaccines had been based on clinical trials because of the lack of serologic correlates of protection. Several other countries have adolescent pertussis immunization programs, and perhaps, it would be prudent to just wait and see what is accomplished in these countries.
How much protection? It is unclear if protection would be conferred on adolescent vaccinees or the duration of such protection and how much would be conferred on their babies. Based on serologic studies, it is estimated that immunoglobulin G (IgG) antibody will remain ‘above threshold’ for four to 13 years. It appears, however, that this ‘threshold’ is defined as ‘the lower limit of the precision of the assay’ rather than the protective titer (J Infect Dis. 2004;190:535). IgG antibody is transmitted to infants, but how much protection this would confer in actual terms, given the uncertainty about the protective effects of various antibodies, the persistence of passively acquired antibody and the levels of maternal antibody at the time of gestation, are all unknown.
It is important that we address the problem of adolescent health care. There are vaccines that may be useful in this group, including those against meningococci, human papillomaviruses and pertussis. Immunization of babies has been credited by some as bringing them into the medical care system, and perhaps, this can be accomplished for adolescents. We certainly can do a better job of addressing the health problems of this group than we are doing at the present time. Finally, it may be a propitious time for vaccine producers to develop a better pertussis vaccine than we now have rather than trying to repackage the existing vaccine. Of the components of diphtheria-tetanus-pertussis vaccine, the latter has done the least to eliminate disease. Alternative approaches using existing vaccines, eg, immunization of adolescents, pregnant woman or newborns, have their proponents, but all have significant drawbacks.
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Editor’s Note: My colleague, Dr. Brunell, is a bit cautious about pertussis vaccine in adolescents. When it becomes available I will vigorously promote use of this vaccine in adolescents and young adults.
—Theodore C. Eickhoff, MD
So many parents are worried today about the side-effects of vaccinations, and many more are likely to be anxious soon. A book released at the start of this month, "Evidence of Harm" by David Kirby, raises questions about the controversial link between autism and mercury in childhood vaccines.
Besides the mercury-autism link, parents question the benefits of the hepatitis B vaccine, which is administered three times before the age of 18 months. The risk of an adverse reaction from the vaccine -- hospitalization or death -- is roughly the same as the lifetime risk of contracting the disease. Does it seem right, on balance, to put your child's life at risk when he or she could be hit by a car long before sharing an infected needle?
Some 26 vaccinations are recommended for children before age 2, and while doctors keep telling us they are safe, more parents (and doctors) are fighting for the right to decline vaccinations and still enter children in school, day care centers and summer camps.
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Illustration of diphtheritic throat, from French's Index of Differential Diagnosis |
The debate reflects our fears of polio and smallpox receding into history, even while our confidence in medical professionals and science plummets. What parent believes it's an acceptable risk that his or her 2-year-old could be brain damaged by a DPT (diphtheria, pertussis and tetanus) shot -- as was the son of the founder of the National Vaccine Information Center, Barbara Loe Fisher? Has anyone worried about their kid contracting diphtheria for a good three generations or more?
As our fear of these diseases recedes, as vaccines bring the illnesses under control, what we fear more are the pharmaceuticals themselves.
Alison Fujito of McCandless, a member of the parenthood panel, which contributes to this column, has a mild form of autism known as Asperger's syndrome. She lives with the torment that a vaccine could have contributed to his condition. The past 40 years have witnessed a rise in mass-vaccination policy in the United States, along with a skyrocketing of autism cases to where 1 in 500 children are afflicted.
Alison points out that mercury that was formerly present in nearly all childhood vaccines -- and can now still be found in flu and chicken pox shots -- has been proven to harm the nervous systems of young children, even babies in the womb.
"Look up acrodynia, a condition written about in the early 1900s that sounds exactly like autism and was shown to be caused by teething powder containing mercury," Alison writes. "The disease disappeared when the teething powder was taken off the market."
Medical authorities make mistakes. The rotavirus vaccine, to prevent severe diarrhea, was introduced in August 1998 and withdrawn less than a year later, when it appeared to cause bowel obstructions. Thimerosal, a preservative in many vaccines, has been removed because it is suspected of causing mercury poisoning in infants. Although a link between thimerosal and autism has been disproved in many studies, other studies say the link is real, and Congress has held hearings on the issue.
While medical researchers may find a risk of 1 in 100 acceptable -- or 1 in 1 million -- how can that 1 millionth parent rationalize the risk? Don't the elimination of the rotavirus vaccine and thimerosal demonstrate that immunization policy is imperfect?
In this environment, I think parents should have a right to refuse vaccines. Another parenthood panel member, Sue MacDonald of Cincinnati, a journalist who writes about health issues, says that some vaccines seem more worth having than others. For example, she says, chickenpox means a week of sickness without the vaccine. With it, a child can be sick for five to six days.
"Bottom line," Sue writes, "is it's more income for the drug company and not much health benefit for society."
Another panel member, Donna Wright of Gibsonia, says that alternative health professionals are willing to write letters exempting children from school requirements for vaccines. Presumably, this works for day care and summer camp as well.
It's a lot to ask of parents that we second-guess the medical community. But we have learned to be suspicious. Scientific assessments of acceptable risk don't play well when your child's life is in your hands. It's a lot easier to sign a waiver before surgery saying you know you might die, as an adult, than to sign over that same responsibility for your child.
A newswire story about the Kirby book recommended that anyone with questions visit the Web site www.immunizationinfo.org. So, I did. It is reassuring, but in such a naďve way that I just had to laugh. The site, sponsored by the National Network for Immunization Information, says it is backed by the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society and a host of other mainstream medical organizations. The naivete of the site is that many of us don't take mainstream medical advice at face value any more.
Too bad. The organization's Web site is quite comforting. All that's required is that we trust the authors.
WASHINGTON — Physicians are becoming increasingly aware that pertussis is not a bygone illness, but one that is periodically resurfacing, despite rising vaccination rates.
In the last 20 years or so, pertussis cases have spiked and plummeted, but the overall picture is that rates have risen, especially for very young infants and adolescents in the United States and abroad, according to presentations at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
At the meeting, sponsored by the American Society for Microbiology, epidemiologists and scientists debated the causes of the rise and potential strategies for heading off spread of the illness to the youngest infants, who aren't eligible for vaccination and are most likely to experience devastating illness or to die from infection.
Trudy V. Murphy, M.D., of the Centers for Disease Control and Prevention's National Immunization Program, presented data showing that reported pertussis cases dropped from a peak of more than 250,000 in the 1930s to 100,000 in the 1940s after introduction of the diphtheria-tetanus-pertussis vaccine, and then further declined through the 1950s, to an all-time low of 1,006 cases in 1976.
Rates stayed low into the 1980s but began to rise in the mid-1980s. There were a little more than 10,000 cases in 2003, Dr. Murphy said.
In the United States, the incidence is highest for children under 1 year and for adolescents aged 10-19 years, she said. Data from Massachusetts, which has a tight surveillance system, reflects that trend, showing the greatest number of cases in both those age groups.
Most of the outbreaks, defined as more than five cases, were in schools over the 1999-2003 period. There were peaks of 42 outbreaks in 2000 and 49 in 2003, although there were only 12 in 2001 and 17 in 2002.
Pertussis still affects adults, as well, which may explain why infants are being infected, Dr. Murphy said.
An analysis of pertussis in children under 4 months in four states found that of the known sources of the illness, 16% came from adults aged 20-39. Seven percent of the cases came from adolescents. Thus, it appears that adolescents and adults are infecting unvaccinated infants, she said.
And yet physicians often aren't on the lookout for pertussis in the older age groups. "It's hard to find an internist who will tell you pertussis exists in adults," she said.
Other nations also have registered a pertussis increase in very young infants, adolescents and adults. In British Columbia, for instance, rates among adolescents spiked in 2000, the most recent data available, Dr. Murphy noted.
Scott Halperin, M.D., a pediatrics professor at Dalhousie University in Halifax, N.S., confirmed that there has been an increase in cases in Canadian adults, adolescents, and very young infants.
Canada has begun a program to vaccinate adolescents. The first groups were vaccinated in Newfoundland 5 years ago; since then, there have been no cases in teens there. Immunizations, which are recommended but not mandatory, have continued across the provinces, he said.
Canada is using Aventis Pasteur's vaccine, Adacel, which is approved in that country and Germany. Adacel, a DTP formulation, is aimed at adolescents and adults aged 11-64 years. Aventis applied for Food and Drug Administration approval of Adacel in August 2004.
GlaxoSmithKline also submitted a DTP formulation, Boostrix, to the FDA this summer; it is aimed at adolescents aged 10-18 years. Boostrix is already approved in Australia, Asia, Europe, and South America, according to company press releases.
The United States and Canada aren't alone in terms of rising pertussis rates. In a poster at the ICAAC meeting, Alberto Tozzi, M.D., of Bambino Gesu Hospital in Rome reported data from the Surveillance Community Network for Vaccine Preventable Infectious Diseases (EUVAC-NET), a project funded by the European Parliament and Council. Sixteen western European countries participate, and from 1998 to 2002, they reported 80,000 pertussis cases. There were 32 deaths, primarily in children less than 6 months old. Infants under 1 year had the highest frequency of disease; rates were stable in 10- to 14-year-olds, but increased 115% in those over 14 years.
France, Malta, Germany, and Australia have begun vaccinating adolescents to protect them and to prevent spread to unvaccinated infants.
There's still no definitive explanation as to why adults and adolescents are getting pertussis. It could be due to greater recognition of the illness, waning immunity from vaccination, or changes in the circulating pathogen.
Carl-Heinz Wirsing von Koenig, M.D., director of the laboratory at Klinkum Krefeld (Germany) noted that reporting has increased and that diagnosis in children has improved thanks to polymerase chain reaction (PCR) testing, which is reliable in that group. Children are also easily diagnosed by the 'whoop' made when coughing.
But PCR and serology testing is less reliable in adults, and there is very little agreement on testing standards, which makes diagnosis more difficult, he said.
Nicole Guiso, Ph.D., chief of the National Center for Infectious Diseases at Institut Pasteur, Paris, presented data exploring whether 40 years of vaccination had changed the evolution and pathogenicity of Bordetella pertussis, the bacteria responsible for the illness. Her answer: So far, it seems like there has been little change that would suggest that current vaccines would be ineffective.
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July 13, 2004 -- GET ready for the next round of vaccine hysteria over the new pertussis (whooping cough) booster shot, a godsend designed to protect adolescents when their infant immunization wears off. Whooping cough is a dangerous disease. Adults can get a mild form that seems like the common cold (there may be a cough, but no "whoop") and then spread it unwittingly and the death rate for unvaccinated infants under age 2 is 10 percent.
Young children have trouble catching their breath when they whoop, often vomit afterward and may miss several days of school. Elderly folks can get pneumonia or break their ribs from all thecoughing.
Whooping cough is on the rise, because the immunizations of infancy have been found to wear off after five or 10 years. There were 10,000 cases in the U.S. in 2003, the highest number in 35 years, and a full one third of these were underprotected adolescents. But the true number is far greater, probably close to 100,000. A recent study discovered that 20 percent of people who have a persistent cough areactually suffering unknowingly from pertussis.
Since whooping cough can cause infants to stop breathing (30 percent), or get pneumonia (10 percent), why would anyone question the need for an effective vaccine?
| "Do you mean to tell me, since 1929, we've been using thimerosal and the only test that you know of is the one that was done in '29? And every one of those people had meningitis and they all died?" -Congressman Dan Burton (R-IN) questioning Dr. William Egan, FDA at the June 6, 2002 Congressional Hearing |
In recent years, a variety of conspiracy theorists, junkscientists and aggressive lawyers have fostered hysteria about childhood and even adult vaccinations. The unsubstantiated claim is that vaccines have a high risk of causing autism and/or mercurypoisoning.
The available data don't back up that theory but even if they did, it wouldn't apply to the new pertussis vaccine, which is very safe. Fears of autism and mercury shouldn't expand to a distrust of any product a drug company rushes to market.
The new acellular Boostrix (combining boosters to tetanus, diptheria and pertussis) is the least irritating or inflaming of vaccines. It has not been associated with mercury or autism or with any undue side effects, for that matter. Not that this will stop the refuseniks from protesting if the vaccine is made mandatory.
The nice thing for vaccine hysterics is a phenomenon known as herd immunity: If almost everybody gets the booster shot, the few who refuse will still be at much lower risk for getting the disease, because there will be less pertussis to catch, and it won't spread aseasily, since those of us who retain our immunity can't act as carriers.
On the other hand, if enough people refuse this booster because of unrealistic fears, the problem could get a lot worse and more infants could die unnecessarily. A temporary ban on the measles vaccine in England in the late '90s led to the deaths of several children from measles.
Pertussis also kills young children, though the early childhood vaccine program has saved many lives. But now we need a booster in place to prevent the unwitting passage of this bug to those we seek to protect. In the world of preventive medicine, nothing could be simpler or more important.
NEW YORK (Reuters Health) Feb 03 - Findings from a review and meta-analysis, reported in the February issue of The Lancet Infectious Diseases, suggest that the aluminum salts found in DTP vaccines cause no serious or lasting adverse effects.
Although such salts have been used for decades as vaccine adjuvants, there have been reports linking them to various problems, including macrophagic myofasciitis, a progressive disorder involving muscle wasting and fatigue. Determining the safety of aluminum is important because replacing the compound would be a huge undertaking requiring numerous safety trials before new vaccines become available, the researchers note.
To investigate the safety of aluminum-containing DTP vaccines, Dr. Tom Jefferson, from Cochrane Vaccines Field in Rome, and colleagues reviewed eight studies that recorded patient outcomes following vaccination and the amount of aluminum in the vaccine. In addition, a meta-analysis was performed on data from five studies.
Immunization with an aluminum-containing vaccine was tied to an increased risk of injection site erythema and induration in young children, and with prolonged local pain in older children. In contrast, there was no evidence in either age group linking such vaccines to serious or lasting adverse effects.
"Despite a lack of good-quality evidence we do not recommend that any further research on this topic is undertaken," the authors conclude.
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Pertussis Infection in Fully Vaccinated Children in Day-Care Centers, Israel
[Emerging Infectious Diseases 6(5),2000. Centers for Disease Control]
Abstract
We tested 46 fully vaccinated children in two day-care centers in Israel who
were exposed to a fatal case of pertussis infection. Only two of five
children who tested positive for Bordetella pertussis met the World Health
Organization's case definition for pertussis. Vaccinated children may be
asymptomatic reservoirs for infection. [Emerging Infectious Diseases 6(5),
2000. Centers for Disease Control]
Introduction
Pertussis, an acute disease of the upper respiratory tract caused by the
gram-negative bacillus Bordetella pertussis, lasts 6 to 8 weeks and has three
clinical stages. The initial (catarrhal) stage resembles a common cold with a
mild cough. The second (paroxysmal) stage is characterized by episodes of
repetitive coughing during a single expiration, followed by a sudden
inspiration that generates the typical "whoop." The final (convalescent)
stage, which lasts 1 to 2 weeks, marks a decrease in the severity and
frequency of the cough.
Since the introduction of routine childhood vaccine, pertussis has been considered preventable, and pertussis-associated illness and deaths are uncommon[2]. However, vaccine-induced immunity wanes after 5 to 10 years, making the vaccinated host vulnerable to infection[3]. This susceptibility has been described in outbreaks of pertussis infection in highly vaccinated populations[3-6].
A recent study by Yaari et al. showed that infection in a vaccinated person causes milder, nonspecific disease, without the three classical clinical stages[7]. Whooping cough is seen in only 6% of such cases; instead, the illness is characterized by a nonspecific, prolonged cough, lasting several weeks to months. Because of these atypical symptoms, pertussis infection is underdiagnosed in adults and adolescents, who may be reservoirs for infection of unvaccinated infants[8-10]. In a study in France, up to 80% of infections in unvaccinated children were acquired from siblings and parents, suggesting that adults and even young siblings play a fundamental role in the transmission of pertussis[11].
We demonstrated B. pertussis infection in fully vaccinated children ages 2-3 years and 5-6 years who had contact with an infected child. We investigated whether younger or recently vaccinated children may be protected from classical clinical illness but remain susceptible to infection and become asymptomatic carriers.
The Study
We examined the family of a 4-month-old infant who died of pertussis in
Israel, as well as children at two day-care centers that two siblings had
attended during the infant's illness. The two siblings, ages 2 and 5 years,
attended different day-care centers, for ages 2-3 years and 5-6 years,
respectively. Both siblings continued to attend the centers despite
paroxysmal cough for 4 to 5 weeks. Thirty other children attended the
day-care center for the 2- to 3-year-old group. Sixteen other children
attended the center for the 5- to 6-year-old group.
In the infant's family, a third sibling, age 11 years, also had a paroxysmal cough of 4 to 5 weeks duration. The 35-year-old mother had a 3-month history of persistent cough. An 18-year-old aunt, who took care of the infant and lived in the same house, reported a mild respiratory illness without paroxysmal cough. None of the family members had a whooping episode, cyanosis, or pneumonia (Figure).
All the children in the day-care centers had been immunized in infancy with all four doses of Pasteur diphtheria-tetanus toxoid pertussis (DTP) vaccine, which includes a booster dose at 12 months of age. The Pasteur vaccine contains 1 immunization dose (ID) of purified diphtheria toxoid, 1 ID of purified tetanus toxoid, and >4 IU of B. pertussis. All family members of the infant were also fully vaccinated with four doses of DTP. The infant had received only the first dose of vaccine at 2 months of age.
The five family members of the infant and the 46 children in the two day-care centers were tested for B. pertussis. Two nasopharyngeal specimens were taken with Dacron swabs (Medical Wire, MEDECO, Corsham, UK); one specimen was used for culture and the other for polymerase chain reaction (PCR) testing. The culture specimen was immediately spread on charcoal agar plates (Hy Labs, Rehovot, Israel), which were incubated at 37°C for 14 days. Serum samples were also taken from every study participant for specific testing for immunoglobulin (Ig) M, IgA, and IgG antibodies to B. pertussis by an enzyme immunoassay (EIA) with whole-cell antigens (Panbio, East Brisbane, Australia)[12]. Primers for the repeated insertion sequences were used in a semi-nested PCR assay[13-14]. The upstream primer sequence gATTCAATAggTTgTATgCATggTT and downstream primer AATTgCTggACCAT TCgAgTCgACG were used in the first PCR, which included 5 µL sample DNA, reaction buffer (10 mM Tris-HCl, 50 mM KCl, 1.5 mM MgCl2, 0.1% Triton X-100), 1 µM of each primer, 200 µM deoxynucleotide triphosphate, and 1 U Taq polymerase (Boehringer Mannheim, Germany) in a 25-µL volume[14]. Statistical analysis was performed by the two-tailed Fischer's exact test.
A person with positive PCR results was considered to have B. pertussis colonization of the nasopharynx. A person with positive IgM serum antibodies was considered to have had a recent infection. There were no culture-positive results, and nasopharyngeal aspirates were not available from the infant. Positivity by PCR or IgM did not indicate presence of symptoms.
Information on clinical symptoms was obtained from each person by a detailed questionnaire. The children in the day-care centers were followed clinically for 8 weeks after laboratory testing. All family members had been treated with erythromycin before testing, but no antibiotics were administered to the children in the day-care centers.
Eleven percent of the children in the two day-care centers were PCR positive, indicating nasopharyngeal colonization: 4 (25%) of the 16 5- to 6-year-old and 1 (3%) of the 30 2- to 3-year-old children (p <.05). Nine (55%) 5- to 6-year-old children were positive for serum IgM antibodies, and 4 (25%) were IgA positive. Three (10%) of the 2- to 3-year-old children were IgM positive, and 1 (3%) had IgA antibodies. Nasopharyngeal colonization was found more frequently in the 5- to 6-year-old than in the 2- to 3-year-old children (4/16 vs. 1/30, p <.05). This trend was also constant with IgM and IgA serum antibodies (9/16 vs. 3/30, p <.001 and 4/16 vs. 0/30, p <.01, respectively). In the index family, four of five members were positive by PCR, including all three siblings of the infant and the 18-year-old aunt. The 35-year-old mother, who was treated with erythromycin before testing, was negative by PCR. All five family members, including the mother, had high levels of IgM antibodies, indicating recent infection. The 4-month-old infant was seronegative for all subclasses of Ig antibodies to B. pertussis. No cultures were grown from the three groups.
According to a modified World Health Organization (WHO) case definition, two (11%) of the five children colonized with B. pertussis in the two day-care centers had the typical course of pertussis infection, with 3 weeks of paroxysmal cough (Table)[1]. The other three children who were positive by PCR had only a mild, nonspecific cough during follow-up.
Conclusions
The effects of whole-cell pertussis vaccine wane after 5 to 10 years, and
infection in a vaccinated person causes nonspecific symptoms[3-7]. Vaccinated
adolescents and adults may serve as reservoirs for silent infection and
become potential transmitters to unprotected infants[3-11]. The whole-cell
vaccine for pertussis is protective only against clinical disease, not
against infection[15-17]. Therefore, even young, recently vaccinated children
may serve as reservoirs and potential transmitters of infection.
We used PCR, EIA, and culture to confirm B. pertussis infection in two highly
vaccinated groups of children in two day-care centers. Three (10%) of 30 2-
to 3-year-old children were seropositive for recent infection; one had
nasopharyngeal colonization and a clinical illness that met the modified WHO
case definition. In the day-care center for the 5- to 6-year-old group, 9
(55%) of 16 children were IgM positive, 4 (25%) of whom had nasopharyngeal
colonization. Of these four children, three had nonspecific cough, and only
one met the modified WHO definition for pertussis. None of the children in
our study, including those who met the WHO definition, had been examined by a
physician before our investigation.
Children who were seropositive and remained both asymptomatic and PCR negative probably had sufficient immunity from vaccines or natural boosters to protect them against persistent colonization and clinical disease. Their seropositivity could not be due to vaccine because the children were tested more than a year after having been vaccinated. Yet not all the children were protected from infection and from colonization with the bacteria. Whether a child who is serologically or PCR positive for pertussis and is clinically asymptomatic is a potential transmitter of infection has not been established. What is certain, however, is that vaccine-induced immunity against infection does not persist throughout adulthood. In France, booster vaccinations have been recommended for adolescents and teenagers[18]. We found that immunity does not even persist into early childhood in some cases.. We also observed that DPT vaccine does not fully protect children against the level of clinical disease defined by WHO. Our results indicate that children ages 5-6 years and possibly younger, ages 2-3 years, play a role as silent reservoirs in the transmission of pertussis in the community. More studies are needed to find the immunologic basis of protection against infection and colonization and thus an effective way to eradicate pertussis.
..fully immunized children were likely the vector which exposed an immunized infant to pertussis which killed him
There were several things I wanted to be sure listmates noticed from your posting. The first is that the infant who died was vaccinated on schedule, but did not develop antibodies to the vaccine, and apparently, could not make antibodies to the real infection that he acquired at four months, either. Did his exposure come from a vaccinated "carrier", like one of his siblings who might have gotten it from someone vaccinated and asymptomatic who was at his sibling's daycare center? Was this infant really thought to be the original vector for this disease just because his fate was the worst of all the children tested?
I wish the study had been more explicit about whether or not this infant had experienced direct contact with the children at both day care centers, especially since the abstract said the day care children "were exposed to a fatal case of pertussis infection". It is clear that the child's siblings who were also PCR positive and carrying the infection could themselves have infected the day care community or their sibling without the necessity of the infant ever being at the daycare himself.
There is a point in very early infancy when the priority of the immune system is to develop TOLERANCE to antigens that it presumes OUGHT to be there. That is probably the reason why breastmilk contains living organisms that will be allowed to coexist with the child throughout the rest of life, because a particular set of living organisms with foreign DNA and foreign protein need to be considered "self". This would include organisms for which IgG antibodies from mother did not cross the placenta in utero. This "permissive" design is how we are able to tolerate commensal bacteria in the gut which provide important help to our chemistry: these organisms are in our systems so early that they do not get attacked by our immune system.
The shift that allows the immune system to be able to recognize germs as foreign is gradual. Some children will not develop a mature immune system until later than other children. In animal studies, this shift occurs at a different pace with different antigens (p 10.12)*, and not all strains of an animal will have equal "resistance" once their immune system can respond (Fig. 11.24)*. There are likely some genetics working to make different the time when one person vs. another will lose tolerance to a particular germ and be able to compose a successful defense.
Perhaps this child's immune system still interpreted the vaccine at 2 months as something that should be considered self, and that was the reason that he or she could not overcome the infection that occurred later. (Fig. 12.1)* The possibility exists that this child died because of being vaccinated out of sync with his individual development because he was vaccinated on a recommended schedule. Without exposure to the early vaccine, there is the chance he may have been able to develop antibodies after exposure to the infection at four months. He might have gotten sick, certainly, but he might have survived. This issue is not without precedent: similar problems occurred when the measles vaccine was introduced to children who were too young in the third world.
The study gives the impression that the unfortunate consequence of this child's vulnerability may have been that others in the community (who were vaccinated) also became infected and capable of spreading the germ without realizing it; but really, the child who died functioned as a red flag to identify a disease that was capable of spreading unnoticed and undiagnosed within a vaccinated community.
There is another possibility that this child was genetically incapable of making antibodies to that infection, but that seems unlikely since all of his family members were able to seroconvert, and had high levels of IgM.
If we think hard about this study, we will find that it really reinforces the logic behind the recent opinion given by the Members of the Association of American Physicians and Surgeons (AAPS) calling for an end to mandatory childhood vaccines. This group was not calling for a ban of vaccines, but were wanting vaccines to be used with more prudence, and with the specific and tailored guidance of each child's personal physician. Changing the focus of responsibility to someone who knows the child and his medical history might not only be far more successful at protecting the individual child, but may also be better at protecting the community at large. Of course, for this to work as a public policy, we need a much greater scientific effort to be made to understand the differences in individual responses to diseases that become a focus of public health policy and we also need to focus equal effort into understanding individual responses to vaccine.
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Graph from The Immune Trio, Quakertown, Pennsylvania |
The first trivalent vaccine for prevention of diphtheria, tetanus and pertussis was licensed for use in the United States in 1940. Early on there were studies linking the vaccine, in rare cases, to seizures, anaphylaxis, high-pitched screaming and brain damage. Typically a child receives 5 doses. In 1981 the Japanese began using a safer vaccine, substituting acellular pertussis for the whole-cell pertussis antigen. It wasn't until 1996 before the US government licensed this safer, less profitable version (DTaP); unfortunately old stores of the vaccine were never recalled.
"Delay of DPT immunization until 2 years of age in Japan has resulted in a dramatic decline in adverse side effects. In the period of 1970-1974, when DPT vaccination was begun at 3 to 5 months of age, the Japanese national compensation system paid out claims for 57 permanent severe damage vaccine cases, and 37 deaths.
"During the ensuing six year period 1975-1980, when DPT injections were delayed to 24 months of age, severe reactions from the vaccine were reduced to a total of eight with three deaths. This represents an 85 to 90 percent reduction in severe cases of damage and death." -Raymond Obomsawin, M.D.
"These data show that DPT vaccination may be a generally unrecognized major cause of sudden infant and early childhood death, and that the risks of immunization may outweigh its potential benefits. A need for re-evaluation and possible modification of current vaccination procedures is indicated by this study." -William C. Torch, M.D., Director of Child Neurology, Department of Pediatrics, University of Nevada School of Medicine
 | Disclaimer / Investigate: The intent of this website is to raise awareness about the controversial aspects of vaccination. Many vaccines still contain thimerosal (49.6% ethylmercury by weight.) While mercury is a highly toxic element second only to radioactive plutonium, when combined with other ingredients, specifically aluminum and formaldehyde, the synergistic effects increase 10,000-fold. Individuals who suffer from chronic mercury exposure will have a unique expression of symptoms. This presentation is not to be construed as medical or legal advice: locate and confer with a trusted physician and lawyer. |