Prevnar

From Wikipedia, the free encyclopedia

Prevnar is a a seven-valent pneumococcal conjugate vaccine manufactured by Wyeth and used to protect infants and young children against pneumococcal disease. Prevnar contains the cell membrane sugars of seven serotypes of Streptococcus pneumonia, conjugated with Diphtheria proteins. Prevnar does not contain living ingredients.^[1]

Contents 1 Production technique 2 Centers for Disease Control recommendation 3 Efficacy 4 Evidence supporting addition to routine vaccination schedules 4.1 Key Supporters of Prevnar 5 Clinical study 6 Efficacy, neurotoxicity and allergic reactions 7 Sales 8 Controversy 9 References and notes 10 External links

[edit] Production technique

Prevnar is produced from seven genetically engineered strains of streptococcus pneumoniae bacteria. The charactersitic bacterial capsule sugars are linked to diphtheria toxin (Corynebacterium diphtheriae)

[edit] Centers for Disease Control recommendation

In 2001, the Centers for Disease Control (CDC), upon advice from its Advisory Committee on Immunization Practices, recommended the vaccine be administered to every infant and young child in the US. The resulting demand outstripped production, creating shortages not resolved until 2004. All children, according to current US vaccination schedules, should receive four doses, at two, four, six, and again between twelve and fifteen months of age. Adding the four injections, to an already crowded US vaccination schedule, brought the total number of routine vaccinations up to twenty in 2001.

[edit] Efficacy

Prevnar's efficacy has been demonstrated by research, funded by Wyeth, that found seven percent fewer new earaches and 0.1% fewer instances of invasive pneumococcal disease.^{[citation needed]} Studies suggest that Prevnar may interfere with the efficacy of two other vaccines (pertussis and IPV) and may interfere with the Varicella and MMR vaccine.^{[citation needed]}

Prevnar is directed for administration to immune-suppressed children.

[edit] Evidence supporting addition to routine vaccination schedules

According to one study, doctor visits by those who were diagnosed as having chronic ear infections and who took Prevnar dropped about 20 percent, and there was a similar 20 percent reduction in the number of children who needed tube implants to fight the infections, and overall ear infections were reduced by 9 percent.

For US children under the age of two, the chance of being diagnosed with an invasive pneumococcal disease was determined to be about 0.15%, or about one child in 666. Pneumococcal meningitis in childhood has been 'associated with' a mortality rate of approximately 1 in 178,571 children. According to data from the product insert, after one dose of the vaccine 0.016% of the recipients (3 out of 18,906) were diagnosed with invasive pneumococcal disease; 0.14% of controls (27 out of 18,910 injected with a different vaccine) got invasive pneumococcal disease. Thus, it was determined Prevnar decreases by 88% a child's chance of getting invasive pneumococcal disease (by approximately 0.124%, or 1 in 808).

According to a press release from Wyeth, "...a major clinical trial conducted by Kaiser Permanente.suggested that the vaccine is effective against invasive pneumococcal disease caused by seven serotypes (strains) of the bacteria most prevalent among children in the U.S." According to the Harvard Medical School, the Kaiser study was supported by a grant from Wyeth.

According to the Wyeth funded research, "The study showed that children in the vaccine group fared better than those in the comparison group in other ways. In the primary analysis of all acute otitis media episodes (i.e. earaches), children receiving the investigational 7-valent pnemococcal vaccine (i.e. Prevnar) had 7 percent fewer new episodes."

[edit] Key Supporters of Prevnar

Key supporters of adding Prevnar to universal vaccination schedules included:

• Dr. Steven Black, Kaiser Permanente
• Dr. Henry Shinefield, Kaiser Permanente
• Dr. Stephen I. Pelton, Boston Medical Center
• Dr. Jerome Klein, Boston Medical Center
• Dr. Margaret B. Rennels, University of Maryland Medical Center
• Dr. Kathryn M. Edwards, Vanderbilt University School of Medicine

Drs. Black and Shinefield undertook most of the studies on Prevnar which proved its efficacy and safety. In promoting the idea of adding four more injections to the universal US vaccination schedule, Dr. Black asserted, "This vaccine is urgently needed...It is great news for parents and physicians." Dr. Shinefield has said, "It's a remarkable vaccine that will have a dramatic effect." The two Kaiser doctors have spoken at medical conferences throughout the world promoting Prevnar to their medical colleagues.

[edit] Clinical study

Prevnar was administered to nearly 20,000 children prior to licensure, and the side effects were evaluated. The study did not show an increase the rate of diabetes, respiratory problems, or weight loss. However, rashes were found to occur in about one percent of children, and vomiting in almost ten percent, but such side effect rates are not unusual for vaccinations. According to the manufacturer's insert, croup, pneumonia, asthma, bronchiolitis, and wheezing were associated with the administration of Prevnar.

Of the 17,066 subjects who received at least one dose of Prevnar, there were 162 visits to the emergency room and eight reported seizures within three days of vaccination. Twelve deaths occurred among Prevnar recipients, compared to 21 deaths that occurred in the 'control group'; however, both groups received experimental vaccines. How these numbers compare to unvaccinated children was not disclosed.

[edit] Efficacy, neurotoxicity and allergic reactions

When compared to an experimental vaccine used as a control, evidence for Prevnar's efficacy has been demonstrated by research that found seven percent fewer new earaches and 0.1% fewer instances of invasive pneumococcal disease. Studies suggest that Prevnar may interfere with the efficacy of two other vaccines (pertussis and IPV) and may interfere with the Varicella and MMR vaccine.

According to the American Academy of Pediatrics, Prevnar may prove to be among the most reactogenic among currently marketed vaccines. Prevnar is directed for administration to immune-suppressed children

Pediatricians are warned to be ready for possible allergic or anaphylactic reactions from administration of the vaccine. Prevnar contains aluminium, a known neurotoxin. Each .5 milliliter dose of Prevnar includes .125 mg of aluminum. According to the American Academy of Pediatrics, "Aluminum is now being implicated as interfering with a variety of cellular and metabolic processes in the nervous system and in other tissues."

[edit] Sales

When introduced in 2000, at a price point pegged at $59 (double the cost of many other vaccines; excluding physician fees) per injection (four per child starting at two months old), Prevnar was expected to deliver sales of between $300-$500 million per year for Wyeth. In the United States alone, seven million children were initially targeted to receive Prevnar. Actual sales in that first year were reportedly $461 million for 2000. With revenues far outpacing early projections, Prevnar is among Wyeth's top revenue producers, with sales in 2005 of $1.5 billion, up 43 percent from 2004.

Market analysts see Prevnar as being among the vanguard of new vaccines expected to become huge profit generators. Successful application of new product design and production techniques in marketing of new vaccines like Prevnar, tethered to concerns that vaccines may be the only effective weapon against a raft of emerging antibiotic resistant pathogens, have induced major drug companies to accelerate the development of hundreds of new vaccines through the approval process. With a coveted slot on universal vaccine schedules at stake, the marketing campaign for Prevnar began a year before actual sales, to ensure that Prevnar sold well from the git go. The initial campaign was a resounding success, vaulting Prevnar to the very top of the sales charts among all vaccines by 2001.

Alongside Effexor XR, Enbrel, and Protonix, Prevnar ranks among Wyeth's big four established products at or above $1 billion or more in annual sales.

[edit] Controversy

Many of the medical professionals and scientists involved in the testing and approval process for Prevnar had or still have significant conflict of interest problems, according to critics, who also question the vaccine's efficacy and safety testing, Because Prevnar is genetically engineered, a combination of different types and components of bacteria, critics have insisted on reevaluation of Prevnar's inclusion in universal vaccination schedules conducted by researchers uncompromised by conflict of interest issues. Critics also question whether the vaccine has any efficacy whatsoever, while pointing to Wyeth's admission that Prevnar does interfere with the efficacy of other vaccines.

Critics also contend that the political lobbying of vaccine industry, in attempting to assure that every child must receive every vaccine they decide is necessary, is primarily driven by the higher priority placed upon protecting shareholder profits than upon than the health of citizens. Under these circumstances, critics contend, there must be a reevaluation, by independent doctors and scientists, of whether or not there is an actual need for yet another addition to vaccination schedules, particularly in light of the small number of children possibly at risk from serious pneumococcal disease complications.

Further questions have been raised about whether Prevnar should be included in universal vaccination schedules at all, given the relatively minimal risks involved for most children. According to a 1994 report published by the American Academy of Pediatrics, children who are most at risk of pneumococcal infections are generally limited to those with specific predisposing factors, "(Pneumococcal Infections) are more likely to occur when predisposing conditions exist, including immunoglobulin deficiency, Hodgkin's disease, congenital or acquired immunodeficiency (including HIV), nephrotic syndrome, some viral upper respiratory tract infections, splenic dysfunction, splenectomy and organ transplantation." However, most healthy children do not have these risk factors, and immunodeficient children may not be able to elicit an appropriate immune response to Prevnar.

[edit] References and notes

1. ^ Pneumococcal 7-valent Conjugate Vaccine (Diphtheria CRM₁₉₇ Protein). Wyeth (2006).

• Black S, Shinefield H, Fireman B, Lewis E, Ray P, Hansen J, Elvin L, Ensor K, Hackell J, Siber G, Malinoski F, Madore D, Chang I, Kohberger R, Watson W, Austrian R, Edwards K (Mar 2000). "Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Northern California Kaiser Permanente Vaccine Study Center Group.". Pediatr Infect Dis J 19 (3): 187-95. PMID 10749457.  with followup paper:
  Black S, Shinefield H (Dec 2002). "Safety and efficacy of the seven-valent pneumococcal conjugate vaccine: evidence from Northern California.". Eur J Pediatr 161 (Suppl 2): S127-31. PMID 12494258. 
• Lieu T, Ray G, Black S, Butler J, Klein J, Breiman R, Miller M, Shinefield H (Mar 15 2000). "Projected cost-effectiveness of pneumococcal conjugate vaccination of healthy infants and young children.". JAMA 283 (11): 1460-8. PMID 10732936. 
• Shinefield H, Black S, Ray P, Chang I, Lewis N, Fireman B, Hackell J, Paradiso P, Siber G, Kohberger R, Madore D, Malinowski F, Kimura A, Le C, Landaw I, Aguilar J, Hansen J (Sep 1999). "Safety and immunogenicity of heptavalent pneumococcal CRM197 conjugate vaccine in infants and toddlers.". Pediatr Infect Dis J 18 (9): 757-63. PMID 10493334. 
• Shinefield H, Black S (Apr 2000). "Efficacy of pneumococcal conjugate vaccines in large scale field trials.". Pediatr Infect Dis J 19 (4): 394-7. PMID 10783042. 

[edit] External links

• Wyeth.com - 'We bring to the world pharmaceutical and health care products that improve lives and deliver outstanding value to our customers and shareholders', Wyeth homepage
• 909Shot.com - 'Pneumococcal Disease and Vaccine', National Vaccine Information Center (NVIC)
• AHP.com - American Home Products Corporation's Pneumococcal Conjugate Vaccine for Children Receives Priority Review status from FDA' (July 21, 1999)
• Medscape.com - 'Prevnar alters middle ear pathogens'
• Mercola.com - 'Prevnar Vaccine: Nearly Half a Billion In Sales Last Year', Tim O'Reiley, Daily Record (March 5, 2001)
• NCCN.net - 'Critique of Prevnar Vaccine', Michael Horwin, MA (September 19, 2000)
• VaccineTruth.org - 'Prevnar: The replacement effect - Concern over a vaccine that causes unintended increase in related infections', John Dudley Miller (May 23, 2003)