Tag Archives: vaccine

Shots urged as flu cases rise in Wisconsin

Wisconsin health officials say flu cases are on the rise and they are urging people to take precautions like getting a flu shot.

The Wisconsin Department of Health Services said on Dec. 28 there had been 161 influenza cases so far this season, and 95 hospitalizations, including eight children and 78 adults age 50 and older. Of those hospitalized with influenza, 63 percent were 65 or older.

State Health officer Karen McKeown says getting a flu shot is still one of the best ways to protect yourself and your family and friends from complications of the flu.

McKeown says other steps include practicing good hand-washing hygiene, covering your cough and not sharing drinking cups and straws.

 

Meningitis outbreak in Chicago’s gay community

Health officials in Chicago say last summer’s deadly outbreak of meningitis in gay and bisexual men is continuing with two new confirmed cases.

The Chicago Department of Public Health says this brings the total to nine cases linked to the outbreak, all in men who have sex with men. One man died last June.

The department says the outbreak is disproportionately affecting men with HIV and black men.

The department recommends vaccinations to all men who have sex with men, and is making affordable vaccines available around the city. A list of clinics and pharmacies can be found on the department’s website.

It can take up to two weeks for the vaccine to kick in. Health officials are urging men to get vaccinated as quickly as possible.

People who have had vaccines in the past might need booster shots.

Meningitis is transmitted through saliva, often by sharing drinks or cigarettes, and kissing. Symptoms including fever, headache, and stiff neck can show up 2–10 days after exposure.

Meningitis outbreaks have occurred in other gay communities over the past decade, including significant outbreaks in New York and Toronto. Outbreaks also occur in college dormitories on a fairly regular basis.

Scientists invent canine ‘contraceptive vaccine’

Veterinary scientists in Chile have invented a contraceptive vaccine for dogs, which can be used in both males and females, and may provide an inexpensive option to help control the country’s growing canine population.

Scientists from the University of Chile Veterinary and Livestock Faculty developed the vaccine from an existing formula used to sterilize pigs, as professor Leonardo Saenz explains.

“It began in Australia more or less in 1989. What we did was to take the concept of immuno-castration which already existed and we developed and improved for use in domestic animals, mainly in dogs, and to create an alternative for pigs, better than what already exists. The previous one was a vaccine by a pharmaceutical laboratory which needs two doses to take effect. In our case, only one dose is needed for the vaccine to take effect,” said Saenz.

According to Saenz, the effect of the vaccine is similar to that of a surgical castration without needing the resources and subsequent care such an operation requires.

It is also a reversible measure based on hormonal alterations.

“The vaccine is a recombinant protein generated in Escherichia coli. The protein is carried by inclusive bodies which are purified previously in Escherichia coli, and we create the vaccine using a polymer. Chitosan is used for pigs and this formula permits, or induces the formation of anti-bodies which neutralize the hormone Betatrophin, and these neutralizing anti-bodies prevent reproductive activity. There is no Progesterone or Estrogen in the females and no Testosterone in the males, which blocks reproductive activity and is a form of immunological castration,” said Saenz.

Veterinary scientists hope the vaccine will help to control the growing canine population in Chile, where surgical castration is only applied in small numbers. They expect the vaccine could be administered to a group three or four times greater than those that undergo surgery.

A further benefit of the vaccine, according to scientists, is that it has no side effects, unlike other forms of contraception.

“Since it is a vaccine which blocks the production of hormones, it does not function as a contraceptive but rather an immuno-castrator. The difference is that contraceptives prevent animals from going on heat. It will still engage in reproductive activity but it will not be able to fertilize. In this case, there are no hormones so there is no activity, there are no gametes so the animal is sterilized as a result of suppressed hormones. As there is a reduction in the hormonal activity, there are no side effects as is the case with hormonal contraceptives on which they put high quantities of contraceptive or hormones which induce alterations in the uterus and can be related to the appearance of some cancers. In this case that does not happen, we block that activity,” said Saenz.

The vaccine has been patented in Chile, Europe and the United States and is undergoing further tests in controlled conditions. In Chile, the final formula will have to be authorized by the Agricultural and Livestock Service, before it is commercialized. 

A number of other dog vaccines are currently under development globally, including one at the California Institute of Technology and another being tested by Oklahoma-based Spay First and the U.S. Department of Agriculture’s National Wildlife Research Center.

Want to avoid HIV? Take a pill

When Milwaukeean Josh Beck, 34, posts a profile on gay dating sites, he gets a lot of questions about his HIV status: “negative plus PrEP.”

PrEP is an acronym for “pre-exposure prophylaxis,” which means taking anti-retroviral medication to protect against acquiring HIV infection. PrEP is a growing strategy in combating HIV. It puts protection in place when at-risk people don’t use condoms or don’t know the true HIV status of their partners.

A number of online meeting sites for gay and bisexual men have begun adding the “negative plus PrEP” option to their apps, but the vast majority of primary care physicians in Wisconsin seem to know nothing about it.

Although most HIV-positive people are honest about their status, a large number of them don’t know theirs. As many as 60 percent of infected young gay and bisexual men are unaware of their status, according to a 2012 study.

Gay men cruising online and elsewhere might believe they’re negative based on their latest HIV test results. But they could have become infected since their last test without knowing it. Or they might have contracted the virus so soon before their last test that their bodies didn’t have enough time to develop the HIV antibodies that produce a positive test result.

Given these unknowns, a “negative plus PrEP” status is reassuring to prospective sex partners. “People seem much more comfortable because I’m on it,” Beck says. 

Beck learned about PrEP from an ad he saw in The Advocate and asked his doctor about it. Although his doctor had never heard of it, he looked into the treatment on Beck’s behalf and provided a referral.

Now Beck takes one Truvada pill per day, which research shows can provide him up to 97 percent protection from contracting HIV — if he takes the pill with food at the same time every day without fail. Failure to comply with the dosing guidelines lowers PrEP’s effectiveness significantly.

Truvada is a combination of two anti-retroviral drugs that are also used together to treat active HIV infections. Beck’s insurance covers the cost, which is much less than treating an HIV infection.

PrEP has been around for many years, and the U.S. Centers for Disease Control and Infection recommends it for some sexually active gay and bisexual men who are negative, as well as for some negative men whose partners are sexually active. But very few of the people who need it are aware of PrEP, according to a September 2104 survey by The Kaiser Family Foundation. The survey found that only 26 percent of gay and bisexual men knew there’s a treatment that can prevent HIV infection.

Dr. Andrew Petroll is trying to build awareness of PrEP among his peers in Wisconsin. Petroll is an infectious disease specialist with the Froedtert and Medical College of Wisconsin health network and an associate professor of psychiatry/behavioral medicine at the college’s Center for AIDS Intervention Research.

Even as he’s working to increase awareness of PrEP in Wisconsin, Petroll is conducting a survey to determine the level of PrEP awareness among physicians in the cities with the 10 highest populations of people living with HIV.

The lack of awareness concerning PrEP in Wisconsin is troublesome, because the strategy has had great impact elsewhere. In San Francisco, where both HIV-testing and PrEP are promoted aggressively, the HIV-infection rate has been coming down for the past three years, Petroll says.

He currently has about 40 Wisconsin patients on PrEP, including Beck.

“We’re seeing signs of an increase in demand for this (in Wisconsin),” Petroll says. “But people who are really interested in finding it are having a hard time getting it.”

Lack of awareness among physicians isn’t the only barrier to receiving PrEP. Some patients face discrimination from doctors when they ask about it, Petroll says. And doctors who are unfamiliar with PrEP are inclined to dismiss it due to dubious concerns.

Beck has heard many of those concerns, both from his primary care physician and from people online. “My doctor was concerned that, like with a lot of antibiotics, my system could build up a resistance to it,” Beck said.

That fear isn’t real, and it’s probably based on the way that HIV mutates into drug resistant strains, forcing infected patients to switch medications from time to time. But without HIV present in the body to mutate, the development of resistance is not a concern for HIV-negative people taking PrEP.

The major concern is side effects. The awful side effects associated with highly active anti-retroviral therapy are legendary. Truvada, however, was chosen for prevention not only because it works and is simple to take, but also because it has the fewest side effects in the anti-HIV drug arsenal, Petroll says.

There’s a 1-2 percent chance of kidney dysfunction for which Petroll monitors patients on a regular basis.

Beck says that he’s experienced virtually no side effects and there have been no indications of side effects in his routine blood work. He said people are more surprised by that than any other aspect of the treatment.

Like nearly everything else to do with HIV/AIDS, there’s also a political dimension to PrEP. Some activists believe it’s a cop-out, a shirking of personal responsibility.

Gay actor Zachary Quinto set off a firestorm on the subject when he criticized PrEP during an interview with Out magazine.

“We need to be really vigilant and open about the fact that these drugs are not to be taken to increase our ability to have recreational sex,” he said. “There’s an incredible underlying irresponsibility to that way of thinking … and we don’t yet know enough about this vein of medication to see where it’ll take us down the line.”

Petroll and Beck say the benefits far outweigh such concerns.

“It puts you in control if you’re not sure that your partner is always taking his meds or telling the truth about his status,” Petroll says.

When people are looking to have uncommitted relationships or one-night stands, it offers peace of mind if their condom slips or they’re too inebriated to use a condom, he adds.

Beck says he plans to remain on PrEP until he enters a committed relationship, and he’ll continue to educate people about it when he has the chance.

“I’m glad people ask me about it,” he says. “Every doctor I’ve talked to sees my medication list and whenever they’ve asked about (Truvada), they’ve thought it’s really cool that I’m being proactive. I’ve gotten nothing but support from people. I think the message is really starting to get out there.”

For more

To contact Dr. Andrew Petroll, visit froedtert.com and search the website’s “Find A Doctor” database.

Vaccine opposition ebbs and flows over centuries

They’re considered one of mankind’s greatest medical achievements, yet people have balked at vaccines almost since the time of the first vaccination — in 1796, when an English country doctor named Edward Jenner inoculated an 8-year-old boy against smallpox.

In the mid-1800s, people protested in the streets of Victorian England after the British government began requiring citizens to get the vaccination. Many opponents mistrusted doctors and were wary of a medical treatment they didn’t understand. In the early days, the closely related cowpox virus was used to immunize people against smallpox.

“People were afraid that if you got the cowpox vaccine you would turn into a cow,” said Dr. Paul Offit, a vaccine researcher at Children’s Hospital of Philadelphia who is an outspoken critic of anti-vaccination groups.

More than a century and a half later, there’s still an undercurrent of vaccine dislike and distrust in the United States as illustrated by the measles outbreak that started in December at Disneyland – likely brought in from overseas as has been the case in recent years. Many of those who got and spread the highly contagious illness hadn’t gotten the childhood shots.

All this despite medical science’s proven successes in wiping out not only the much-feared smallpox and polio, but nearly eliminating other serious illnesses like diphtheria, German measles, lockjaw and mumps in the United States. Through it all, anti-vaccine sentiments have ebbed and flowed.

“It is fair to say that for as long as we’ve had vaccines, governments have worked to promote those vaccines – and segments of the population have resisted,” said Jason Schwartz, a medical historian who studies vaccine policy at Princeton University.

In the U.S., opposition to vaccines was most intense in the late 1800s and early 1900s, said Susan Lederer, chair of medical history and bioethics at the University of Wisconsin.

That’s when organizations like the Anti-Vaccination League of America and the American Medical Liberty League led the charge. Some used photos depicting vaccinated children with scars and missing limbs and eyes, claiming immunizations were to blame.

“For a long time in history, people treated anti-vaxers as irrational and anti-progress – kind of a lunatic fringe. But there were good reasons to be leery of vaccines” back then, she said.

Vaccines sold at the time were unregulated, and many were not only ineffective but also risky because of how they were made or given. Some were not sterile and infected children with other germs, like tetanus.

But opposition faded. Legal challenges to school-attendance vaccination laws were shot down by the U.S. Supreme Court. Vaccine makers came under more federal regulation, and the shots were better and safer. And some of the richest and most influential opponents died off.

By the end of the 1930s, resistance had declined dramatically. And by the 1950s, the pendulum had swung. Medical science was widely respected, doctors were considered sages, and one of the nation’s greatest heroes was Dr. Jonas Salk – inventor of the polio vaccine.

Polio – a crippling and potentially fatal infectious disease – terrified the nation. In the early 1950s, outbreaks caused more than 15,000 cases of paralysis each year.

When researchers in 1955 showed Salk’s vaccine worked, the news spurred jubilation. One medical leader pleaded with adults not to grab the limited doses of the vaccine.

“Give the children priority,” begged Dr. Dwight Murray, chairman of the American Medical Association’s board of trustees.

Enthusiasm for the polio vaccine persisted even after news surfaced – only weeks later – that some early batches had caused polio in children.

“If something similar happened today, it’s hard to imagine a vaccination program going forward,” Princeton’s Schwartz said.

The anti-vaccine movement overall kept a fairly low profile until 1998, when a British medical journal published a now discredited study in which researcher Andrew Wakefield and his colleagues suggested a link between the combination measles-mumps-rubella vaccine and autism.

It was a small series of observations in just a dozen children, not a full medical study. But it exploded in the media, and resulted in a big drop in immunization rates in Britain. The effect was not nearly as dramatic in the U.S., but researchers estimate that as many as 125,000 children born in the late 1990s did not get the shots because of the report.

The United States then was on the verge of seeing the end of “homegrown” measles – health officials declared that goal accomplished in 2000. Still, the Wakefield study knocked even prominent U.S. vaccine experts off balance and emboldened vaccine skeptics and some legislators to raise alarms about vaccines. The years 1998 and 1999 marked a low point for those who championed vaccines, Schwartz said.

But the situation soon changed. When other researchers did larger and well-designed studies, they found no link to autism. Wakefield’s work was discredited and his paper retracted. But all this happened during an era of growing rates of autism diagnoses, and an array of parents groups and some celebrities continued to believe vaccines were the cause.

Overall, vaccination rates for kindergarten pupils have held steady across the country, although health officials have noted certain communities have seen increasing numbers of families who have refused to vaccinate their children.

The situation sat at a low boil until the Disneyland outbreak. It struck a nerve with public health advocates, parents who support vaccination and even comedians.

“I’ve never seen this level of anger at parents who’ve chosen not to vaccinate their children,” Offit said.

He thinks a large reason is that the outbreak was launched at Disneyland

“It’s the Garden of Eden. And what have we done? Brought this virus into the Garden of Eden,” he said.

Study: Potent new drug candidate blocks HIV strains

U.S. scientists say they have created a novel drug candidate that is so potent and universally effective, it might work as part of an unconventional vaccine and could be used in the fight against HIV/AIDS.

The research, which involved scientists from more than a dozen research institutions, was published February 18 online ahead of print by the prestigious journal Nature.

The study shows that the new drug candidate blocks every strain of HIV-1, HIV-2 and SIV (simian immunodeficiency virus) that has been isolated from humans or rhesus macaques, including the hardest-to-stop variants. It also protects against much-higher doses of virus than occur in most human transmission and does so for at least eight months after injection.

“Our compound is the broadest and most potent entry inhibitor described so far,” said Michael Farzan, a TSRI professor who led the effort announced on Feb. 18 by The Scripps Research Institute in Jupiter, Florida. “Unlike antibodies, which fail to neutralize a large fraction of HIV-1 strains, our protein has been effective against all strains tested, raising the possibility it could offer an effective HIV vaccine alternative.”

Blocking a Second Site

When HIV infects a cell, it targets the CD4 lymphocyte, an integral part of the body’s immune system. HIV fuses with the cell and inserts its own genetic material — in this case, single-stranded RNA — and transforms the host cell into an HIV manufacturing site.

The new study builds on previous discoveries by the Farzan laboratory, which show that a co-receptor called CCR5 contains unusual modifications in its critical HIV-binding region and that proteins based on this region can be used to prevent infection.

With this knowledge, Farzan and his team developed the new drug candidate so that it binds to two sites on the surface of the virus simultaneously, preventing entry of HIV into the host cell.

“When antibodies try to mimic the receptor, they touch a lot of other parts of the viral envelope that HIV can change with ease,” said TSRI research associate Matthew Gardner, the first author of the study with Lisa M. Kattenhorn of Harvard Medical School. “We’ve developed a direct mimic of the receptors without providing many avenues that the virus can use to escape, so we catch every virus thus far.”

The team also leveraged preexisting technology in designing a delivery vehicle — an engineered adeno-associated virus, a small, relatively innocuous virus that causes no disease. Once injected into muscle tissue, like HIV itself, the vehicle turns those cells into “factories” that could produce enough of the new protective protein to last for years, perhaps decades, Farzan said.

Data from the new study showed the drug candidate binds to the envelope of HIV-1 more potently than the best broadly neutralizing antibodies against the virus. Also, when macaque models were inoculated with the drug candidate, they were protected from multiple challenges by SIV.

“This is the culmination of more than a decade’s worth of work on the biochemistry of how HIV enters cells,” Farzan said. “When we did our original work on CCR5, people thought it was interesting, but no one saw the therapeutic potential. That potential is starting to be realized.”

In addition to Farzan, Gardner and Kattenhorn, authors of the study, “AAV-expressed eCD4-Ig provides durable protection from multiple SHIV challenges,” include Hema R. Kondur, Tatyana Dorfman, Charles C. Bailey, Christoph H. Fellinger, Vinita R. Josh, Brian D. Quinlan, Pascal Poignard and Dennis R. Burton of TSRI; Jessica J. Chiang, Michael D. Alpert, Annie Y. Yao and Ronald C. Desrosiers of Harvard Medical School; Kevin G. Haworth and Paula M. Cannon of the University of Southern California; Julie M. Decker and Beatrice H. Hahn of the University of Pennsylvania; Sebastian P. Fuchs and Jose M. Martinez-Navio of the University of Miami Miller School of Medicine; Hugo Mouquet and Michel C. Nussenzweig of The Rockefeller University; Jason Gorman, Baoshan Zhang and Peter D. Kwong of the National Institutes of Health; Michael Piatak Jr. and Jeffrey D. Lifson of the Frederick National Laboratory for Cancer Research; Guangping Gao of the University of Massachusetts Medical School; David T. Evans of the University of Wisconsin; and Michael S. Seaman of Beth Israel Deaconess Medical Center.

The work was supported by the National Institutes of Health through multiple grants.

UF researchers report cats may provide key to human HIV vaccine

Blood from HIV-infected humans shows an immune response against a cat AIDS virus protein, a surprise finding that could help scientists find a way to develop a human AIDS vaccine, according to researchers at the University of Florida and University of California, San Francisco.

Their findings appear in the October issue of the Journal of Virology. The discovery supports further exploration of a human AIDS vaccine derived from regions of the feline AIDS virus, according to a news release from UF.

“One major reason why there has been no successful HIV vaccine to date is that we do not know which parts of HIV to combine to produce the most effective vaccine,” stated Janet Yamamoto, a professor of retroviral immunology at the UF College of Veterinary Medicine and the study’s corresponding author.

The researchers are working on a T-cell-based HIV vaccine that activates an immune response in T cells from HIV-positive individuals against the feline AIDS virus. T-cell peptides are small pieces of protein that can prompt the body’s T cells to recognize viral peptides on infected cells and attack them. However, not all HIV peptides can work as vaccine components, Yamamoto said.

“In humans, some peptides stimulate immune responses, which either enhance HIV infection or have no effect at all, while others may have anti-HIV activities that are lost when the virus changes or mutates to avoid such immunity,” Yamamoto said. “So, we are looking for those viral peptides in the cat AIDS virus that can induce anti-HIV T-cell activities and do not mutate.”

In previous studies, scientists have combined various whole HIV proteins as vaccine components, but none have worked well enough to be used as a commercial vaccine.

“Surprisingly, we have found that certain peptides of the feline AIDS virus can work exceptionally well at producing human T cells that fight against HIV,” Yamamoto said.

The researchers isolated T cells from HIV-positive individuals and incubated these cells with different peptides that are crucial for survival of both human and feline AIDS viruses. They then compared the reactions they got with feline immunodeficiency virus (FIV) peptides to what they found using HIV-1 peptides.

“We found that one particular peptide region on FIV activated the patients’ T cells to kill the HIV,” Yamamoto said.

This feline viral region identified by human cells appears to be evolutionarily conserved — it is present in multiple AIDS-like viruses across animal species. “That means it must be a region so essential that it cannot mutate for the survival of the virus,” she said.

Yamamoto and her team believe that the feline AIDS virus can be used to identify regions of the human AIDS virus that might be more effectively used in a vaccine-development strategy for HIV.

“We want to stress that our findings do not mean that the feline AIDS virus infects humans, but rather that the cat virus resembles the human virus sufficiently so that this cross-reaction can be observed,” said study collaborator Dr. Jay A. Levy, a professor of medicine at UCSF.

To date, a T-cell-based vaccine has not been used to prevent any viral diseases, Yamamoto said.

“So we are now employing an immune system approach that has not been typically utilized to make a vaccine,” she said. “The possible use of the cat virus for this vaccine is unique.”

Michael Murphey-Corb, a professor in the department of microbiology and molecular genetics at the University of Pittsburgh, said, “Dr. Yamamoto has identified the immunological Achilles’ heel of HIV.”

Levy, along with Dr. Mobeen Rathore, director of the UF Center for HIV/AIDS Research, Education and Service in Jacksonville, and the University of South Florida in Tampa provided the blood from people living with HIV. Other collaborators include the UF College of Medicine, the Clinical and Translational Science Institute at UF, and LifeSouth Community Blood Centers of Gainesville.

New York City recommends meningitis vaccines for HIV-positive gay, bi men

The New York City Health Department has issued a local advisory recommending that any man who is HIV positive and has had intimate contact with another man met through a website, digital phone app, at a bar or party since Sept. 1 should be vaccinated against invasive meningococcal disease.

The recommendation follows reports of a spike in meningitis cases in the past five weeks.

The city health department began making the vaccine available on Oct. 5 at medical facilities throughout the area for men who meet the criteria but who cannot obtain the vaccine from their care providers.

The outbreak of invasive meningococcal disease among HIV-positive men in New York City is not related to the outbreak of meningitis in several states that is caused by a contaminated medication.



Also, vaccination prevents but does not treat current infection.

Common symptoms of meningitis are high fever, headache, stiff neck and rash that develop rapidly upon onset.

Symptoms may occur two-10 days after exposure, but usually within five days, according to a news release.

People who are HIV-positive and who experience these symptoms should seek medical care immediately, the NYCHD said.

The New York sites for the vaccine include:

Bronx

  • Jacobi Medical Center
  • Lincoln Medical and Mental Health Center

Brooklyn

  • Coney Island Hospital
  • Kings County Hospital Center
  • Woodhull Medical and Mental Health Center

Manhattan

  • Bellevue Hospital Center
  • Harlem Hospital Center

Queens

  • Elmhurst Hospital Center
  • Queens Hospital Center

Panel: Boys should get HPV vaccine given to girls

A vaccine against cervical cancer hasn’t been all that popular for girls. And now that it’s been recommended for boys, too, it might be even a harder sell for them.

A government advisory panel decided the vaccine should also be given to boys, in part to help prevent the cancer-causing virus through sex.

Public health officials have tried since 2006 to get parents to have their daughters vaccinated against the human papillomavirus, or HPV, which causes most of the cervical cancer in women.

They have had limited success, hitting a number of hurdles. Some parents distrust the safety of vaccines, especially newer products. Others don’t want to think about their daughters having sex one day, or worry that the vaccine essentially promotes promiscuous behavior.

The Oct. 25 vote by the Advisory Committee on Immunization Practices’ was the first to strongly recommend routine vaccination for boys, since the vaccine was first approved for them two years ago. Officials acknowledged the low rate in girls encouraged them to take a new, hard look.

Experts say a key benefit of routinely vaccinating boys could be preventing the spread of the virus to others through sex – making up somewhat for the disappointing vaccination rate in girls. But the recommendation is being framed as an important new measure against cancer in males.

“Today is another milestone in the nation’s battle against cancer,” said Dr. Anne Schuchat, a U.S. Centers for Disease Control and Prevention administrator who oversees the agency’s immunization programs.

Federal health officials usually adopt the panel’s recommendations and ask doctors and patients to follow them.

The vaccine has been advised for girls since 2006. Just 49 percent of adolescent girls have gotten at least the first of the three HPV shots. Only a third had gotten all three doses by last year.

“Pretty terrible,” Schuchat said.

Schuchat attributed the low rates for girls to confusion or misunderstanding by parents that they can wait until their daughter becomes sexually active. It works best if the shots are given before a girl or boy begins having sex.

Right-wing Christians argue the vaccine could promote promiscuous behavior. It has come up in the Republican presidential campaign. Texas Gov. Rick Perry came under attack for a 2007 executive order requiring adolescent girls to get the vaccine (with an opt-out clause). When far-right lawmakers rebelled, he backed down.

An estimated 75 to 80 percent of men and women are infected with HPV during their life, but most don’t develop symptoms or get sick, according to the CDC. Some infections lead to genital warts, cervical cancer and other cancers, including of the head and neck.

The HPV vaccine is approved for use in males and females ages 9 to 26; it is usually given to 11- and 12-year olds when they get other vaccines. The committee also recommended that males 13 to 21 years get vaccinated.

The Oct. 25 vote follows recent studies that show the vaccine prevents anal cancer in males, and may work against a type of throat cancer. A study that focused on gay men found it to be 75 percent effective against anal cancer.

While anal cancer has been increasing, it’s still fairly rare. Only about 7,000 U.S. cases in men each year are tied to the strains targeted in the HPV vaccine. In contrast, about 15,000 vaccine-preventable cervical cancers in women occur annually.

Preventing a cancer that’s primarily associated with gay men may not be much of a selling point, said Dr. Ranit Mishori, a family practice doctor in Washington, D.C. and an assistant professor at the Georgetown University School of Medicine.

“Some parents may say ‘Why are you vaccinating my son against anal cancer? He’s not gay! He’s not ever going to be gay!’I can see that will come up,” said Mishori, who supports the panel’s recommendation.

Schuchat indicated the CDC is ready for that kind of argument: “There’s no data suggesting that offering a vaccine against HPV will change people’s subsequent sexual behavior,” she said.

So far, the threat of genital warts hasn’t been persuasive: Some data suggest that less than 1.5 percent of adolescent males have gotten the vaccine over the past two years.

Meanwhile, some feel it’s unlikely that most parents will agree to get their sons vaccinated primarily to protect girls. A survey of 600 pediatricians last year found that nearly 70 percent of doctors thought families would deem vaccination of their boys as unnecessary.

Experts at the committee meeting noted an earlier analysis that showed vaccinating boys would not be cost-effective if the female vaccination were high.

“If you do reach high coverage of females, will you stop vaccinating males?” asked Dr. David Salisbury, director immunization for the United Kingdom’s Department of Health.

There are two vaccines against HPV, but the Oct. 25 vote applies only to Merck & Co.’s Gardasil, which costs $130 a dose. The other vaccine wasn’t tested for males.

The committee’s recommendation – and the greater insurance coverage of the vaccine that is expected to follow – will make it easier for more boys to get the shots, said Dr. Mark Feinberg, chief public health and science officer for Merck Vaccines.

Merck officials bristled at the idea that males would see the vaccine as mainly meant for gay men, noting that HPV-caused anal cancers can occur in heterosexual men.