US Researchers See No Benefit To Delaying Children's Vaccines
- By Jennifer Corbett Dooren Of DOW JONES NEWSWIRES WASHINGTON -(Dow Jones)- Researchers in the U.S. have found no benefit to delaying childhood vaccines when looking at a group of children who received their vaccinations on time during the first year of life compared to children who weren't vaccinated according to schedule. One of the researchers, Michael J. Smith, a pediatric infectious-disease specialist at the University of Louisville School of Medicine in Kentucky, explained that some parents have been requesting alternative immunization schedules due to concerns that their children receive too many vaccines too soon. Smith and a colleague, Charles R. Woods--also a pediatric infectious-disease specialist--looked at a range of intelligence, speech and behavior tests conducted on children several years after receiving their infant vaccines and found few differences among children who received their vaccines on time compared to those who didn't. "This study suggests that delaying vaccines does not give infants any advantage in terms of brain development," Smith said. The study was published online Monday in the medical journal Pediatrics and is believed to be the first study addressing the issue of delayed vaccination. Smith's research took data collected for the U.S. Vaccine Safety Datalink project that was designed to look at the impact of the ingredient thimerosal and whether it had any impact on 42 neuropsychological tests that measured speech, language, intelligence, memory, fine motor coordination and behavior regulation in children ages 7 to 10 years old. Thimerosal, a mercury-containing preservative, was removed from children's vaccines a decade ago due to concerns that it might be linked to the onset of autism. (Thimerosal is still used in certain influenza vaccines that are made in bulk.) Smith's study looked at 1,047 children who were vaccinated between 1993 and 1997 and compared the outcomes on the 42 neuropsychological tests among a group of children who were vaccinated on time to those who weren't. To be considered vaccinated on time, children needed to receive 10 shots by the time they were seven months old. One analysis compared children who received all 10 shots on time to those who didn't, while another analysis compared children who received more vaccines compared to those who received fewer vaccines. Overall, both analyses found children in both groups did equally well, although children in the on-time vaccinated group did slightly better on an intelligence test and a little faster on a test that asked children to name things. "There's not a single variable where the delayed kids did better," Smith said, explaining that parents put their children at risk for developing some of the diseases against which the vaccines are designed to protect. "When you watch your kids get five shots, it's perfectly reasonable to ask if it's too much," said Dr. Paul Offit, chief of the division of infectious diseases at the Children's Hospital of Philadelphia, who wasn't involved in Smith's research. Offit is also a vaccine expert who helped to develop Merck & Co.'s (MRK) Rotateq rotavirus vaccine and who has served on the U.S. panel that oversees children and adult vaccination schedules. Recommended vaccines are designed to immunize children against 14 diseases and babies can receive up to 26 vaccines in their first year of life, Offit said, an amount that has doubled since the mid-1980s. Infants typically receive a Hepatitis B vaccine at birth and then receive about five vaccinations at two-, four- and six-months old. The vaccines protect against a range of illness such as polio, rotavirus, diphtheria, tetanus, pertussis and pneumococcal disease, which can cause meningitis and pneumonia. (At about 12-to-15 months, it is also recommended that children be vaccinated against measles, mumps and rubella, Hepatitis A and varicella, the virus that causes chicken pox.) All of the vaccines are administered in a two-to-four dose series and are given as injections, with the exception of the oral rotavirus vaccine. Offit said the amount of viral material in vaccines given to babies is "literally a drop in the ocean" compared to the amount of bacteria with which babies' immune systems cope each day. He said the amount of protein in one bacterium ranges from 2,000 to 6,000 while the total "antigenic" content of vaccines given to babies at one office visit is about 150. Despite lingering concerns about vaccine safety prompted in part by a now-withdrawn study that linked the measles, mumps and rubella vaccine to autism, government data show that more than 90% of babies are vaccinated while 76% of children ages 19 to 35 months received all of the recommended doses of key vaccines. Fewer than 1% of children receive no vaccines, according to data released last year by the Centers for Disease Control and Prevention. -By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com Click here to go to Dow Jones NewsPlus, a web front page of today's most important business and market news, analysis and commentary: http://www.djnewsplus.com/access/al?rnd=sYJWzrXfH0HeUErnhhDDPQ%3D%3D. You can use this link on the day this article is published and the following day.
