Messy Mix? Combined vaccine yields fewer antibodies
Nathan Seppa
Thanks to modern medicine, children in the United States can look forward to receiving up to 20 vaccinations during early childhood. It's all for a good cause, but try telling that to a baby.
Scientists attempting to minimize the number of injections by bunching together vaccines now report the curious finding that one of the component vaccines doesn't seem to work as well in combination as it does when administered by itself. Moreover, two other vaccines administered with the combination vaccine also lost some of their protective potency.
Researchers in England randomly chose 119 infants to vaccinate against group C meningitis in a series of shots. Another 115 infants got a combination vaccine called 9-valent, which includes the group C meningitis vaccine and eight others for various types of meningitis and pneumonia.
At each of three monthly visits, both groups of infants also received a shot containing vaccines against diphtheria, whooping cough, tetanus, and the type of meningitis caused by Hemophilus influenzae bacteria (Hib). They received oral polio vaccine, too. Thus, each child got two shots and an oral polio dose at 2, 3, and 4 months of age.
Blood drawn from the infants at age 5 months showed that the children who had received the 9-valent vaccine had made only one-fourth as much antibody against group C meningitis as had the infants getting the meningitis-only vaccine, the researchers report in the April 13 Journal of the American Medical Association.
Also, infants getting the 9-valent shot made significantly less antibody for fighting diphtheria and Hib meningitis than did those getting the simple group C meningitis shots, says study coauthor Jim P. Buttery of the Murdoch Children's Research Institute in Melbourne, Australia. Buttery worked on the study while at the University of Oxford in England.
"This study doesn't rule out that [polyvalent] formulations might work well," says Sally A. Quataert of the University of Rochester in New York. Rather, it shows that polyvalent-vaccine studies need to be rigidly controlled, she says. For example, the group C meningitis vaccine given to children as part of the 9-valent shot came from a different batch of vaccine than did that given on its own, leaving room for differences, she says.
Buttery suspects that the volume of certain ingredients in a 9-valent vaccine might be at fault for the multivaccine's poor performance when given in combination with other vaccines. He points specifically to the large amounts of carrier proteins—molecules added to vaccines to boost immunity—in the formulation of the 9-valent vaccine. Researchers now need to ascertain whether these proteins might actually be interfering with the immune response, says Buttery.
Wyeth, the Madison, N.J.–based company that developed the 9-valent vaccine, funded the study. Last year, the company dropped efforts to market the 9-valent vaccine in the United States so that it could concentrate on Prevnar, a 7-valent vaccine that is widely used for prevention of meningitis and pneumonia. Meanwhile, Wyeth is developing a 13-valent vaccine that would protect children against group C meningitis and 12 other strains of bacteria that cause meningitis, pneumonia, or the blood infection septicemia.
********
References:
Buttery, J.P., et al. 2005. Immunogenicity and safety of a combination pneumococcal-meningococcal vaccine in infants. Journal of the American Medical Association 293(April 13):1751–1758. Abstract available at http://dx.doi.org/10.1001/jama.293.14.1751.
Further Readings:
Harder, B. 2003. Africa faces new meningitis threat. Science News 163(April 19):253. Available to subscribers at http://www.sciencenews.org/articles/20030419/note16.asp.
Levine, M.M., and M.B. Sztein. 2004. Vaccine development strategies for improving immunization: The role of modern immunology. Nature Immunology 5(May):460–464. Available at http://dx.doi.org/10.1038/ni0504-460.
Snape, M.D., et al. 2005. Lack of serum bactericidal activity in preschool children two years after a single dose of serogroup C meningococcal polysaccharide-protein conjugate vaccine. Pediatric Infectious Disease Journal 24(February):128–131. Abstract available at http://www.pidj.com/pt/re/pidj/abstract.00006454-200502000-00008.htm.
Trotter, C.L., et al. 2004. Effectiveness of meningococcal serogroup C conjugate vaccine 4 years after introduction. Lancet 364(July 24):365–367. Abstract available at http://dx.doi.org/10.1016/S0140-6736(04)16725-1.
Whitney, C.G., et al. 2003. Decline in invasive pneumococcal disease after the introduction of protein-polysaccharide conjugate vaccine. New England Journal of Medicine 348(May 1):1737–1746. Available at http://content.nejm.org/cgi/content/full/348/18/1737.
Additional information about meningitis vaccines can be found at http://www.wyeth.co.uk/about/innovations_sub_vaccine.htm.
Additional information about meningitis can be found at http://www.meningitis.org/ and http://www.meningitis-trust.org/.
Sources:
Jim P. Buttery
Paediatric Infectious Diseases Unit
Department of General Medicine
Murdoch Childrens Research Institute
University of Melbourne
Department of Pediatrics
Royal Children's Hospital
Flemington Road
Parkville, Victoria 3052
Australia
Sally A. Quataert
University of Rochester
Human Immunology Center Core Laboratory
Center for Vaccine Biology and Immunology
601 Elmwood Avenue
Box 609
Rochester, NY 14642-8609
From Science News, Volume 167, No. 16, April 16, 2005, p. 243.
