By Rachael Rettner
MyHealthNewsDaily

The number of measles cases and outbreaks spiked last year, with unvaccinated people making up the majority of those affected, according to a new report from the Centers for Disease Control and Prevention.

In 2011, there were 222 cases of measles in the United States. That's the highest number reported measles cases in the united states in 15 years, said Dr. Anne Schuchat, director of CDC's Office of Infectious Diseases, speaking to reporters today.

The number is also more than triple the number of cases in 2009 and 2010, according to the report.

About half of the 2011 cases occurred during outbreaks, which are defined as at least three cases that are linked to each other. Last year, there were 17 measles outbreaks, well above the average of four for the previous decade.

Among patients who were U.S. residents, 72 percent of cases developed in people who had not received the measles vaccination, or had unknown vaccination history, despite being eligible for the vaccine. (Twenty-six cases occurred in people living outside the U.S.)

Fifty patients were children between 16 months and 19 years old who had not been vaccinated for philosophic or religious reasons or personal objections, the report says.

Since 2000, measles has been considered eliminated in the United States. The disease occurs here mostly when people become infected after traveling to other countries and transmit the disease to others upon their return. Indeed, 90 percent of the cases in 2011 had their origins in other countries, including 52 U.S. citizens who became ill after traveling abroad.

"The increase in measles importations and outbreaks during 2011 serves as a reminder that measles remains endemic in many parts of the world and unvaccinated U.S. residents continue to place themselves and others in their communities at risk for measles and its complications," the report says.

In 2011, more than 30,000 cases of measles were reported in European countries, with France, Italy, Romania, Spain and Germany having the majority of cases.

The measles, mumps and rubella vaccine is recommended for all children ages 12 to 15 months, with a booster shot at age 4 to 6 years. Children as young as 6 months can recieve the vaccine if there are plans for the family to travel abraod. Adults should be vaccinated if they did not recieve the vaccine when they were younger.

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By Rachael Rettner
MyHealthNewsDaily

Tim Boyle / Getty Images file

As cases of a disease decrease, people can start believing the risk from the vaccine is more than the threat of disease.

Vaccine scares, which lead portions of the population to forgo vaccination, could become more common as more diseases are eradicated, researchers say.

That's because, as cases of a disease decrease, people become complacent about their risk, and the threat of vaccines — whether imagined or real — seems greater than the threat of disease, said Chris Bauch, a professor in the department of mathematics and statistics at the University of Guelph in Ontario.

"High vaccine coverage is inherently unstable," Bauch said. Unless vaccination is mandatory, "I think we'll see more of this problem in the future," he said, referring to vaccine scares.

Vaccine scares are a problem because, when vaccination rates drop, preventable diseases such as measles and whooping cough can make a comeback. However, there may be ways to soften the blow of these scares.

Bauch and colleagues have constructed a mathematical model to predict the course of vaccine scares, including when they will peak and how long they will last.

Such models could one day be used to test the effectiveness of public health campaigns that aim to increase vaccination rates, Bauch said. For instance, the model could determine what type of campaign will work best: one that emphasizes the safety of the vaccine, or the danger of the disease, Bauch said.

To test their model, Bauch and colleagues used real data from two vaccine scares in the United Kingdom — the whooping cough vaccine scare in the 1970s and the measles-mumps-rubella (MMR) vaccine scare in the 1990s.

The researchers found their model could explain the rise and fall of vaccine coverage, and could also predict the vaccine scare outcomes.

One factor crucial to the success of the model was the inclusion of social learning, meaning the way in which people learn vaccinating behaviors from one another, Bauch said.

The model explained why it took four to five years after the start of the vaccine scares for vaccine coverage to reach its minimum. If threat of disease and the perceived threat of vaccines were the only factors that played into vaccination rates, one would expect vaccine coverage to dip significantly after people heard news reports questioning the safety of the vaccines.

However, because social learning plays a role, this was not the case. Declines in vaccine coverage take time because non-vaccinating behaviors have to "spread" from parent to parent, Bauch said.

The study will be published in the April issue of the journal PLoS Computational Biology.

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The nation's largest pediatrician group today released its new schedule of recommended childhood vaccinations. It made three major changes to its previous recommendations, after a federal advisory panel of experts reviewed recent evidence from vaccine studies.

The biggest change is the new recommendation that boys should be vaccinated against human papillomavirus (HPV). Since 2006, the HPV vaccine has been recommended for girls, primarily to help prevent cervical cancer, and in 2009, the experts advised that boys "could" be given the shots, too.

The stronger wording in the new recommendations, that boys "should" be given the shots, came about because new data showed giving boys the vaccine can help lessen the odds of HPV-associated cancers in men and in women, said Dr. H. Cody Meissner, chief of pediatric infectious disease at the Floating Hospital for Children at Tufts Medical Center in Boston.

Meissner was part of the group of experts updating this year's recommendations from the American Academy of Pediatrics; the panel also included experts from the Centers for Disease and Prevention, which had previously recommended the HPV vaccine for boys.

The new vaccination schedules are published today (Feb. 1) in the journal Pediatrics.

Routine HPV vaccinations for boys

The new guidelines call for boys to get the first of the three doses of HPV vaccine at age 11 or 12, the same age the shot is recommended for girls.

HPV vaccinations are also advised for young men ages 13 to 21 if they've not yet had all three shots. It may be given to boys as young as 9 and to men between 22 and 26. 

Young people are encouraged to get all three shots, given over a 6-month period, before they become sexually active.

"Every parent likes to think their child is not sexually active in their early teen years," Meissner said. "But if you wait until they're sexually active, you miss the benefit of the vaccine."

The vaccine has been known to protect against genital warts in males and females, and recent evidence has shown it can prevent anal cancer in men and women. The HPV vaccine has also been shown to be protective against penile cancers, as well as head and neck cancers.

Updates to meningococcal and flu vaccines

The meningococcal and flu vaccines are the focus of the other two changes to the guidelines.

A booster dose of the meningococcal vaccine is now recommended for children at age 16. The previous schedule recommended children be routinely immunized against meningococcal disease, which prevents most types of meningitis, when they are 11 or 12.

Infectious disease experts had thought that one dose of meningococcal vaccine would protect a young person through the college years, Meissner said. "But data became available that the vaccine doesn't last that long, and the risk goes up late in the teen years," he said.

Teens are now advised to get a booster dose to make sure that protection is maintained through the high-risk window, which occurs between 16 and 21 years, when many are living in close quarters, such as in college dormitories.

Some slight tweaks were also made to flu shot recommendations. This was the second year the AAP is recommending that children 6 months and older need to get the annual flu shot, Meissner said.

The new schedule clarifies the guidance for giving the flu shot to kids with egg allergies. Studies have shown the amount of egg protein in the flu vaccine is not enough to produce an allergic reaction in those with mild allergies, who can eat cooked eggs, Meissner said. Still, the flu shot may not be appropriate for people with a severe egg allergy, he said.

Advice for parents

A lot of parents are nervous about the number of shots recommended for children and teenagers these days, and they want to know how long each vaccine has been around, and how serious the risk is if their child does not get it, said Dr. Peter Greenspan, medical director of MassGeneral Hospital for Children in Boston.

He said he has noticed that parents are getting increasingly discerning about immunizations. "I find that parents really want to know the whys about the vaccines, which is entirely appropriate and important information for doctors to share," Greenspan said.

When new changes are made to the vaccination schedule, he said, "it's just a matter of explanation and discussion with your pediatrician."

Pass it on: Experts now recommend that pre-teen boys get vaccinated against HPV, that 16-year-olds be vaccinated against meningitis and that almost all children receive a flu shot annually.

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A group of compounds used in a variety of products, including water-resistant clothing and microwave popcorn, may prevent childhood vaccinations from working properly, a new study says.

In the study, children who had higher concentrations of these compounds, called perfluorinated compounds (PFCs), in their blood had lower immune responses to diphtheria and tetanus vaccinations. An insufficient immune response to a vaccination can mean a child is actually vulnerable to catching a disease even though they've been vaccinated against it.

Indeed, the levels of antibodies in the blood of some children exposed to PFCs indicated they were not protected against these diseases by age 7.

"When we take our kids to the doctor's office to get their shots, we expect that the vaccines are going to work," said study researcher Dr. Philippe Grandjean, of the Harvard School of Public Health in Boston. "What we found was that there was an increasing risk that they didn’t work if the kids had been exposed to the PFCs," Grandjean said.

The study is provocative, but the findings are not of immediate public health concern, said Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt University in Nashville. Despite the link found in this study, vaccines have largely protected the public against diphtheria and tetanus over the same period of time that PFCs have accumulated in the environment, Schaffner said.

"These are illnesses that have been virtually eliminated from children," in the United States, Schaffner said.

However, Schaffner said investigations into the link between vaccines' effectiveness and PFCs, along with other potential environmental hazards, should continue.

The study will be published tomorrow (Jan. 25) in the Journal of the American Medical Association.

PFCs have thousands of uses in manufacturing, and most people have the compounds in their bodies, Grandjean said. They are slow to break down and persist for many years in the environment.

Studies in animals have suggested PFCs may lower the body's immune response, but their impact on people's health is unclear.

Grandjean and colleagues analyzed data from 587 children living in the Faroe Islands, in the northern Atlantic Ocean between Scotland and Iceland. These islands were chosen because their inhabitants frequently consume seafood, which is associated with increased exposure to PFCs. Still, overall,levels of PFCs in this area are similar to those found in other countries, including the United States, Grandjean said.

The researchers measured levels of PFCs in the blood of 5-year-old children, and tested the children's  immune response to tetanus and diphtheria vaccinations at ages 5 and 7. The kids received complete vaccinations against these diseases, including a booster shot at age 5.

The higher the levels of PFCs were in the blood, the lower the children's response was to the vaccines.

A doubling of the exposure to PFCs was associated with a 49 percent lower level of blood antibodies in children at age 7, Grandjean said.

Children with some of the highest levels of PFCs were two to four times more likely to have antibodies in their blood at a level below what is thought to protect against these diseases.

The study "emphasizes the importance of making sure that the world does not pollute the natural environment," Schaffner said. "Clearly, greater efforts must be made to keep these perfluorinated compounds out of the environment," hesaid.

It's not clear exactly how people come to accumulate levels of PFCs in their body, so advice on how to avoid them may not necessarily work. But Grandjean said, "It would be prudent to avoid microwave popcorn [and] treatment of furniture, carpets, shoes and clothing with stain repellants," unless they are known not to contain PFCs.

Future studies into the health impact of PFCs should examine their effect on the immune system, Grandjean said. The researchers would also like to know if exposure to PFCs is associated with a reduced immune response to other vaccinations.

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Flu vaccines don’t work as well as previously thought, although they’re still the best protection available against seasonal influenza, researchers report Tuesday.

Overall, flu shots in adults 18 to 65 are 59 percent effective, the scientists estimate. Evidence for protection in people 65 and older was lacking, they write in a paper published online by The Lancet.

They reached their conclusions by pooling the results—an approach called a meta-analysis--of 31 studies of flu vaccine. The effectiveness varied from year to year in the studies analyzed. In several flu seasons, there was no evidence of effectiveness.

The new finding contrasts with the conclusion of meta-analyses by the respected Cochrane Collaboration, which last year found that flu shots were 73 percent effective in adults.

“The studies we present are the very best studies that we have for the last 70 years,” says Michael Osterholm, lead author of the new report and director of the Center for Infectious Disease Research & Policy at the University of Minnesota.

A major difference between Osterholm’s meta-analysis and the Cochrane reviews is the type of studies they included. Osterholm’s used only studies that confirmed the presence of influenza virus in sick people with either sophisticated polymerase chain reaction technology, or PCR, or laboratory cultures. PCR can take a single piece of DNA and generate thousands to millions of copies.

The Cochrane reviews, on the other hand, included studies that determined whether sick people had the flu by checking to see whether they had elevated levels of flu antibodies in their blood, not whether influenza virus was present.

The problem, Osterholm says, is that the antibodies don't become noticeably elevated in three out of four people who contract influenza after getting a  flu shot.  So, he says, the studies in the Cochrane review probably missed diagnosing influenza in many people who became sick after getting flu shots.

While flu shots contain inactivated, or killed, influenza virus, the nasal-spray flu vaccine, sold as FluMist, contains live, albeit weakened, virus. Osterholm’s meta-analysis found that FluMist consistently was most effective in children 6 months to 7 years old. One study suggested it was also effective in people over 65, but FluMist is approved in the United States only for those age 2 through 49.

In related news, the Food and Drug Administration is cautioning against using jet injectors, such as PharmaJet, with flu vaccine. The only vaccine currently approved for use with a jet injector is the measles, mumps and rubella, or MMR, vaccine.

 “Jet injectors represent a different method of delivery that has the potential to change the characteristics of an approved vaccine,” according to the FDA.

Kroger, Publix and Walgreens have administered flu vaccine with jet injectors, agency spokeswoman Shelly Burgess says. But, says Centers for Disease Control and Prevention spokesman Tom Skinner, neither the CDC nor the FDA think it’s necessary for people immunized with a jet injector to be re-vaccinated.

Earlier this week, news about a malaria vaccine that is 50 percent effective “drew cheers from the biomedical and policy communities,” notes Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania. It would be ironic if people decided not to get a flu shot because, though 59 percent effective, it’s not as effective as previously thought, Caplan says.

“We certainly need more effective vaccines, and governments should start putting serious resources into developing them,” Caplan says.

Osterholm agrees. He says vaccine manufacturers have told him they’re reluctant to invest in a new-and-improved flu vaccine because the one on the market now is cheap, safe and recommended for people of all ages. “We shouldn’t get rid of it,” Osterholm says, “but it’s not nearly the vaccine that we need for the future.”

Despite the lack of studies that included people over 65 in Osterholm’s meta-analysis, “the vaccine works reasonably well” in that age group, says Andrew Pavia, chair of the Infectious Disease Society of America Pandemic Influenza Task Force.

“The good news about this paper,” says Pavia, chief of the division of pediatric infectious diseases at the University of Utah, “is it hopefully will stimulate interest in new vaccines.”

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Young children who receive vaccinations against whooping cough are not fully protected against the disease three to six years after their shots, a new study suggests.

Currently, kids receive five doses of the pertussis vaccine, with the final injection given between ages four and six. A pertussis booster shot is recommended for adolescents.

In the new study, vaccinated kids developed pertussis anyway — and the number of pertussis cases progressively increased each year following the kids' final vaccination. Children were seven times more likely to develop pertussis six years after vaccination than one year after vaccination.

Researchers knew that pertussis vaccine protection waned with time. But studies had not looked cases of pertussis in vaccinated children this young before, said study researcher Sara Tartof, a medical epidemiologist at the Centers of Disease Control and Prevention.

The new findings underscore the importance of the booster shot for adolescents.

"It's really important for kids to get that booster at 11 or 12 years of age," Tartof said.

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The new findings are not enough to warrant a change in children's vaccination schedules, Tartof said. However, future studies should examine factors that may affect how much protection the vaccine gives, including the age at which it is given, Tartof said.

The first version of the whooping cough vaccine, known as the whole cell pertussis vaccine, had long lasting immunity. Its protection was thought to last much of life, said Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt University. However, this vaccination often caused reactions at the injection site, such as redness and swelling.

Because of concerns about safety, a new, more purified version of the vaccine was created. Childhood vaccination with the acellular pertussis vaccines began in 1997, Schaffner said. Researchers are still studying how long immunity lasts with this vaccine.

The vaccines for diphtheria, tetanus and pertussis are given to children together in a single injection, nicknamed DTaP. Tartof and colleagues examined the immunization records of more than 220,000 children born in Minnesota between 1998 and 2003.

Information from the state's pertussis surveillance system was used to determine which kids came down with pertussis. Children were included in the study only if they received all five doses of the pertussis vaccine. They were followed for up to six years after their final shot.

Between 2004 and 2010, 358 cases of pertussis were identified in these kids.

A child's risk of pertussis increased each year after their final shot.

Children were 1.6 times more likely to develop pertussis two years after vaccination than in the first year after vaccination. That risk increased to 2 times more likely during year three, and 2.6 times more likely over year four, compared with the risk at year 1.

By six years after vaccination, the risk had increased to 7 times what it was in the first year.

Tartof noted that if vaccinated children develop pertussis, their condition is less severe if they have received all five shots.

The finding "highlights the fact that pertussis immunity can be short lived," said Dr. Paul Offit, chief of the director of the Vaccine Education Center at the Children's Hospital of Philadelphia, who was not involved in the study.

And the results suggest that it is not unreasonable to consider more frequent booster vaccinations among teens and adults, Offit said.

Technically a person's last pertussis vaccination may be when they receive their booster at age 11 or 12 years old, Offit said. However, it's important that people in older age groups have immunity against pertussis because of the risk they may transmit the disease to infants.

Babies less than 6 months old are at greater risk of dying from pertussis, and they cannot begin to be vaccinated until they are two months old. Doctors want to "cocoon" infants by vaccinating all the adults and teens around them, Offit said.

The outbreaks of pertussis that have occurred in recent years are likely due to people deciding to forego vaccination, Offit said.

"When you make a choice not to vaccinate, then you are in trouble," Offit said. "Because the disease is always going to be around."

The study results argue for the enforcement of pertussis boosters in middle school childnren, Schaffner said. Without booster shots, there may be outbreaks of pertussis among this young population, he said.