Herd Immunity

Vaccination against human papilloma virus was recommended for U.S. girls almost five years ago. In October, a government advisory committee also recommended routine vaccination for boys ages 11 and 12.   But vaccinating girls only makes the most sense, researchers said Tuesday. Using mathematical models, researchers in the Netherlands found vaccinating girls is the best way to reduce heterosexual transmission because girls have the highest prevalence of the virus. Immunizing the group with the highest prevalence achieves the largest population-wide reduction of the virus.

California is among the 18 states that make it easy for parents to refuse to vaccinate their children who attend public schools. All they have to do is sign a form saying that inoculations run counter to their personal beliefs. Most states require a religious-belief exemption, which results in dramatically higher vaccination rates. A bill by Assemblyman Richard Pan (D-Sacramento), a pediatrician, would tighten the state's rules. To claim the personal-belief exemption, parents would be required under AB 2109 to discuss the risks and benefits of vaccination with a health professional; then they would be free to make up their own minds.

Vaccinating children who are more than a year old against varicella, or chicken pox, also provides "tremendous indirect benefits" to young babies, researchers reported Monday in the journal Pediatrics. The U.S. implemented a variella vaccine program in 1995, offering the vaccine to children 12 months and older.  But younger babies who aren't old enough to get the vaccine are protected through so-called "herd immunity" -- because fewer older kids develop chicken pox, the younger children are less likely to be exposed to the virus.

Declining rates of childhood vaccination have been worrying public health officials for the past several years--although this year's figures show an uptick. The health of children -- and society at large--depends on herd immunity, meaning that enough people are immune to an illness to keep even the unvaccinated safe. There just isn't enough of the illness around to make it a problem. That's why parents who don't vaccinate their children can boast that there have been no potentially deadly illnesses in their houses.

Dear Parents, I'm afraid we have some work to do. The Centers for Disease Control and Prevention recently published a report on childhood immunizations and our own state of Washington had the highest proportion of kindergartners who hadn't been vaccinated, at 6.2%. At the other end of the spectrum, Mississippi had the best performance with fewer than 1% of kids unvaccinated. That's right, Mississippi. Maybe we could learn a thing or two from the parents down there. I know we've discussed this before, but please indulge me because it's really important.

Score one for the anti-vaccine parents: The federal government recently concluded, in response to a claim, that vaccines may have triggered one young girl's autism. Score many more for the doctors: Study after study has shown inoculation to be an infinitesimal part of a vast and complex syndrome. Yet the number of California parents seeking exemptions from vaccination, based on their personal beliefs, is rising and in various counties ranges from 5% to 15% -- high enough to endanger vaccinated children as well.

Declining rates of childhood vaccination have been worrying public health officials for the past several years--although this year's figures show an uptick. The health of children -- and society at large--depends on herd immunity, meaning that enough people are immune to an illness to keep even the unvaccinated safe. There just isn't enough of the illness around to make it a problem. That's why parents who don't vaccinate their children can boast that there have been no potentially deadly illnesses in their houses.

California is among the 18 states that make it easy for parents to refuse to vaccinate their children who attend public schools. All they have to do is sign a form saying that inoculations run counter to their personal beliefs. Most states require a religious-belief exemption, which results in dramatically higher vaccination rates. A bill by Assemblyman Richard Pan (D-Sacramento), a pediatrician, would tighten the state's rules. To claim the personal-belief exemption, parents would be required under AB 2109 to discuss the risks and benefits of vaccination with a health professional; then they would be free to make up their own minds.

To no one's surprise, a new clinical trial demonstrates that the human papilloma virus vaccine Gardasil is as good at protecting men as it is in protecting women, researchers reported Wednesday. A clinical trial in more than 4,000 boys and men demonstrated that the vaccine was more than 90% successful in preventing genital lesions caused by the four strains of HPV that the vaccine is active against, about the same level of protection demonstrated for women. The vaccine is currently approved in the United States for both males and females over the age of 9, but current recommendations call for administration only to females.

Contrary to what baby boomers might assume, the term "conscientious objector" didn't originate with the Vietnam War. It was first used in the late 19th century to describe opponents of England's mandatory smallpox vaccinations, who received special exemption from the inoculations. Their opposition to the vaccine was as shortsighted, and as unfounded in science, as the objections of parents today who refuse to recognize the importance of inoculation not just to their children but to public health.

Vaccination against human papilloma virus was recommended for U.S. girls almost five years ago. In October, a government advisory committee also recommended routine vaccination for boys ages 11 and 12.   But vaccinating girls only makes the most sense, researchers said Tuesday. Using mathematical models, researchers in the Netherlands found vaccinating girls is the best way to reduce heterosexual transmission because girls have the highest prevalence of the virus. Immunizing the group with the highest prevalence achieves the largest population-wide reduction of the virus.

Vaccinating children who are more than a year old against varicella, or chicken pox, also provides "tremendous indirect benefits" to young babies, researchers reported Monday in the journal Pediatrics. The U.S. implemented a variella vaccine program in 1995, offering the vaccine to children 12 months and older.  But younger babies who aren't old enough to get the vaccine are protected through so-called "herd immunity" -- because fewer older kids develop chicken pox, the younger children are less likely to be exposed to the virus.

Contrary to what baby boomers might assume, the term "conscientious objector" didn't originate with the Vietnam War. It was first used in the late 19th century to describe opponents of England's mandatory smallpox vaccinations, who received special exemption from the inoculations. Their opposition to the vaccine was as shortsighted, and as unfounded in science, as the objections of parents today who refuse to recognize the importance of inoculation not just to their children but to public health.

Dear Parents, I'm afraid we have some work to do. The Centers for Disease Control and Prevention recently published a report on childhood immunizations and our own state of Washington had the highest proportion of kindergartners who hadn't been vaccinated, at 6.2%. At the other end of the spectrum, Mississippi had the best performance with fewer than 1% of kids unvaccinated. That's right, Mississippi. Maybe we could learn a thing or two from the parents down there. I know we've discussed this before, but please indulge me because it's really important.

No matter how many times the medical community reassures parents that vaccines are safe and necessary to prevent life-threatening diseases, some people remain unconvinced. "I believe that herd immunity is a complete myth," says J.B. Handley, co-founder of an autism advocacy organization called Generation Rescue that is critical of the way vaccinations are carried out in the U.S. "It's a tactic used to scare the public. " Handley, a father of three in Portland, Ore., has an 8-year-old son with autism.

As students return to middle schools and high schools in California this fall, they will need more than fresh notebooks and apples for their teachers. Thanks to a state law that took effect last month, students entering grades 7 through 12 will need proof that they received a vaccine for whooping cough. The law was prompted by last year's outbreak of the highly contagious respiratory infection, which is also known as pertussis. Nearly 9,500 cases were reported in California, the most in 65 years, according to the Centers for Disease Control and Prevention.

Giving flu vaccines to as many school-age children as possible, by delivering it at school, for example, can help protect an entire community from flu, according to a new study. Researchers led by Dr. W. Paul Glezen at Baylor College of Medicine created a study in which live attenuated influenza vaccine, which is a nasal spray, was offered to children at elementary schools in eastern Bell County, Texas, in the fall and early winter of 2007. Almost 48% of the elementary-school children were vaccinated.

No matter how many times the medical community reassures parents that vaccines are safe and necessary to prevent life-threatening diseases, some people remain unconvinced. "I believe that herd immunity is a complete myth," says J.B. Handley, co-founder of an autism advocacy organization called Generation Rescue that is critical of the way vaccinations are carried out in the U.S. "It's a tactic used to scare the public. " Handley, a father of three in Portland, Ore., has an 8-year-old son with autism.

To no one's surprise, a new clinical trial demonstrates that the human papilloma virus vaccine Gardasil is as good at protecting men as it is in protecting women, researchers reported Wednesday. A clinical trial in more than 4,000 boys and men demonstrated that the vaccine was more than 90% successful in preventing genital lesions caused by the four strains of HPV that the vaccine is active against, about the same level of protection demonstrated for women. The vaccine is currently approved in the United States for both males and females over the age of 9, but current recommendations call for administration only to females.

Giving flu vaccines to as many school-age children as possible, by delivering it at school, for example, can help protect an entire community from flu, according to a new study. Researchers led by Dr. W. Paul Glezen at Baylor College of Medicine created a study in which live attenuated influenza vaccine, which is a nasal spray, was offered to children at elementary schools in eastern Bell County, Texas, in the fall and early winter of 2007. Almost 48% of the elementary-school children were vaccinated.