Friday, April 5th, 2013
The varicella vaccine, which immunizes against the virus that causes chickenpox, has been found in a new study published online in the journal Pediatrics to be highly effective after one dose, and even moreso after two doses. More from The New York Times:
Before 1995, when the varicella vaccine came into widespread use, chickenpox affected about 90 percent of the population, leading to thousands of hospitalizations and about 100 deaths a year.
“Now a very safe vaccine will totally prevent it from happening,” said the lead author, Dr. Roger Baxter, co-director of the Kaiser Permanente Vaccine Study Center in Oakland, Calif.
Between June and November 1995, researchers began studying 7,585 children vaccinated between the ages of 1 and 2. They interviewed their parents every six months, asking about the occurrence of both chickenpox and shingles, the painful rash that can occur after recovery from chickenpox. In June 2006, a second vaccine dose was recommended, and the researchers followed those cases through the end of the study in 2009.
The analysis, published online in Pediatrics, found 1,505 cases of chickenpox, all except 30 of which were mild or moderate, involving less than 300 lesions. There were no cases among children who received a second dose.
Image: Infant getting vaccine, via Shutterstock
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Friday, March 29th, 2013
Another study, this one from the Centers for Disease Control and Prevention, has found no connection between vaccines and autism spectrum disorders (ASD). This is the latest in a series of research studies that followed a highly controversial 1998 report in the British journal The Lancet, which alleged a causal link between vaccines and ASD. That article was recanted in 2010. More on the new CDC study from NBC News:
In the first six months of life, children receive as many as 19 vaccine doses of six different vaccines, and by the time they are 6 years old, a total of 25 doses from 10 vaccines.
In a 2011 survey, about a third of parents expressed concerns that their child received too many vaccines before age 2, and too many vaccines on a single day.
Previous studies have found no link between the number of vaccines a child receives and their risk of several neurological conditions (though these studies did not specifically consider autism).
The new study went a step further by looking at the link between a child’s total exposure to antigens — the proteins in vaccines that stimulate the body’s immune system — and his or her risk of autism.
The researchers looked at total antigen exposure rather than the total number of vaccines kids received because, at the root of parents’ concerns is the idea that “somehow they provide too much immunological stimulation, more so than a young child’s immune system can handle,” said study researcher Dr. Frank DeStefano, of the Centers for Disease Control and Prevention. (The sheer number of vaccines would not be as good a measure of immunological response because vaccines contain different numbers of antigens, and some protect against more than one disease, DeStefano said.)
DeStefano and colleagues analyzed information from about 250 children with autism and 750 children without autism, born between 1994 and 1999.
Children with autism were exposed to about same total number of antigens as children without autism at ages 3 months, 7 months and 2 years. There was also no difference between the two groups in terms of the total number of antigens they were exposed to on a single day.
“Parental concerns that their children are receiving too many vaccines in the first two years of life, or too many vaccines at a single doctor visit are not supported in terms of an increased risk of autism,” the researchers write in the March 29 issue of the Journal of Pediatrics.
Previous CDC research has shown that most U.S. children–as high as 95 percent–still receive vaccines on the recommended schedule. In 2011, a study from the Institutes of Medicine also found no causal link between autism and vaccines.
Image: Baby receiving vaccine, via Shutterstock
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Thursday, March 28th, 2013
The vaccine against human papillomavirus (HPV), which can cause cervical cancer among other ailments, is in the news again after a survey published in the journal Pediatrics announced that the overwhelming majority of girls have not received the vaccine despite the urging of major medical groups. The New York Times has more:
Just 35 percent of girls 13 to 17 have received a full course of the vaccine, which inoculates against the strains of human papillomavirus that can cause cervical cancer, according to 2011 data from the Centers for Disease Control and Prevention. And a study in Pediatrics this month, also based on C.D.C. data, says the intent to vaccinate is declining: 44 percent of parents in 2010 said they did not intend to vaccinate, up from 40 percent in 2008.
Alarmed by the stubbornly low rates, doctors and federal health officials are brainstorming about how to get more children vaccinated.
“Behind these numbers are people who will develop cervical cancer that could have been prevented,” said Dr. Bruce Gellin, director of the National Vaccine Program Office at the Department of Health and Human Services. At a meeting in Washington last month, federal and local officials, doctors and other health workers explored ways to make the shots more accessible. Some suggested giving the first of the three doses required to complete the vaccine at a doctor’s office and the other two at schools or pharmacies.
Others argued for a greater emphasis on cancer prevention, playing down the fact that the vaccine prevents a sexually transmitted disease. The STD link has put off many parents who are loath to talk about sex with their children.
Image: Girl getting a shot, via Shutterstock
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Tuesday, March 19th, 2013
A survey of parents has found that many teenagers are not receiving vaccine boosters that are readily available, proven safe, and important protectors against serious but preventable diseases. CNN.com reports:
“These vaccines are safe and effective and people should really have their teens get them,” says Dr. Paul Darden, lead author of the study and professor of pediatrics at the University of Oklahoma College of Medicine. “Parents say pediatricians are telling them about the vaccines, yet they just don’t seem to understand why they are necessary or are skeptical about their safety.”
When parents of teens were asked why their children didn’t receive certain forms of the tetanus, diphtheria, pertussis (Tdap) and meningitis vaccine, some parents noted these shots were not recommended or not necessary, according to the study. Others did not have a reason.
Regarding the controversial and fairly new vaccine that protects against the sexually transmitted human papillomavirus – which has been linked to cancer – some parents also said it was not necessary. In other cases parents noted their children were not sexually active or were not the appropriate age to receive the vaccine.
Concerns of mothers and fathers about the safety of the HPV vaccine grew each year, from 4.5% in 2008 to 16.4% in 2010, according to the study. The number of parents who said they would not vaccinate their children for HPV increased from 39.8% in 2008 to 43.9% in 2010. The main concern was safety.
Investigators were surprised, because the vaccine has been found to be very effective in preventing the virus that causes cervical cancer in young women.
“We thought perhaps many parents would think the HPV vaccine would give kids permission to have sex, and therefore not allow their children to get it. But that wasn’t it,” explained Darden. “They seemed to be skeptical of its safety, which is odd, because it’s shown to be effective with few side effects. We have a vaccine that protects against cancer. Why not vaccinate your child? I don’t get it.”
Image: Teen girl getting a shot, via Shutterstock
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Friday, January 18th, 2013
During a dangerous flu season, health experts are emphasizing that the vaccine is safe–and important–for pregnant women. The Associated Press reports on a new Norwegian study that confirms the vaccine’s safety during pregnancy:
A large study offers reassuring news for pregnant women: It’s safe to get a flu shot.
The research found no evidence that the vaccine increases the risk of losing a fetus, and may prevent some deaths. Getting the flu while pregnant makes fetal death more likely, the Norwegian research showed.
The flu vaccine has long been considered safe for pregnant women and their fetuses. U.S. health officials began recommending flu shots for them more than five decades ago, following a higher death rate in pregnant women during a flu pandemic in the late 1950s.
But the study is perhaps the largest look at the safety and value of flu vaccination during pregnancy, experts say.
“This is the kind of information we need to provide our patients when discussing that flu vaccine is important for everyone, particularly for pregnant women,” said Dr. Geeta Swamy, a researcher who studies vaccines and pregnant women at Duke University Medical Center.
For more, read What Pregnant Women Need to Know About the Flu on Parents.com.
Image: Pregnant woman getting shot, via Shutterstock
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