PharmaLive-The 'STD Shot'?

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http://www.pharmalive.com/News/index.cfm?articleid=349475 & categoryid=10 The 'STD Shot'? BRISTOL, Tenn., June 13, 2006--One of the more interesting developments in the field of medicine is the soon-to-be expected availability of the vaccine for human papillomavirus (HPV) produced by pharmaceutical giants Merck and GlaxoKline. The vaccines under development in the past few years are made up of virus particles and have shown to be very effective in preventing some of the infections caused by the targeted strains of HPV. The vaccines are designed to specifically prevent infections and the consequences of the most worrisome strains of HPV, especially those strains that are known to most commonly cause cervical cancer. The Merck vaccine also is meant to prevent some cases of genital warts, also caused by two strains of HPV.There are overall over 100 strains of HPV that infect humans. HPV is the most common sexually transmitted infection (STI) in the US, with an estimated 5.5 million new infections each year. Most infections with HPV resolve spontaneously and are cleared by the infected person’s immune system. However, certain HPV strains are more problematic, and when infections with these strains occur, they tend to persist. These persistent infections can last years, and they can cause abnormalities in the cervix. These abnormalities then over time can lead to the development of cervical cancer. HPV is responsible for nearly all cases of cervical cancer, about 10,000 total cases and about 4,000 deaths per year in the United States. Worldwide, cervical cancer caused by HPV is the second leading cause of cancer deaths in women with approximately 500,000 cases, and 280,000 resulting deaths. Hence, there is a huge public health interest in a vaccine to protect against HPV infections over a

lifetime. The advantage of the newly developed HPV vaccine is that by preventing some of the HPV infections, men and women will not get these high risk varieties. However, although the vaccine is effective against preventing infections with these strains of HPV, infections with other strains are still possible. It will not eliminate cervical cancer, but will greatly reduce its numbers. Dan Hinthorn MD, who is head of Infectious Diseases at the University of Kansas College of Medicine, says, “This vaccine will probably only prevent acquisition of no more than 70% of HPV viruses that cause cancer. It won't prevent most HPV that cause visible genital warts. But HPV induced cancers are so common that we should do all we can to prevent acquisition of the human papillomavirus by young people. It is important to recognize that HPV can be transmitted by skin to skin contact without the most intimate sexual contacts.”How vaccines become

“mandatory”It is important to realize that just because an immunization is approved by the FDA for use by the general public, it does not necessarily become commonly utilized or mandatory. Following FDA approval of a vaccine (which is expected for the Merck HPV vaccine in early 2006), the American Council on Immunization Practices (ACIP) meets and decides whether to recommend that a vaccine is added to the recommended list of vaccines for adults or children. ACIP is an advisory board to the Centers for Disease Control made up of immunization and public health experts from across the country. Even if recommended for the childhood or teen immunization schedule, the vaccine does not necessarily become “mandatory” at that point, although this is an important step in accomplishing this. Sometimes other organizations, such as the American Academy of Pediatrics and the America Academy of Family Physicians, will also lend their support for routine use of the

vaccine.At that point, after ACIP recommends a vaccine for routine use, each state considers whether to “require” the vaccine for school admission or advancement. Also, ACIP approval pressures insurance companies to begin to pay for people receiving the vaccine. These are huge steps in gaining public acceptance and widespread availability of any vaccine. Even though states may “require” the vaccine for school admission or for school advancement, parents invariably have an opt-out procedure they can use for religious, scientific, or moral objections, although the difficulty in the parents fulfilling this waiver will vary considerably from state to state.Comparison to HBV vaccinationHepatitis B vaccine (HBV) was recommended by the (ACIP) to be given to infants and children starting in 1991. The HBV ACIP vaccination approval is similar to this HPV situation in that HBV is an STI, although most cases are actually transmitted to

healthcare workers by exposure to infected blood. There is also a very large percentage of HBV cases that have no known risk factors. Since HBV causes a very serious viral infection, and causes many thousands of cases of liver cancer that result in deaths, the ACIP recommended that the vaccine be included in the standard series of immunizations given to infants and small children. It is therefore clearly not just an immunization against just a sexually transmitted infection, but a very serious public health concern that has been addressed by routine vaccination.There are some concerns that by having HPV being a routine or mandatory “shot against an STI,” there may be some implicit acknowledgement that teens are expected to be sexually active. This is a concern for many conservative and Christian organizations.Bill Toffler, MD, who is in the Family Medicine Department at the University of Oregon, is still in favor of use of the HPV vaccine: “As

with the hepatitis B vaccine, I will likely recommend that my children receive the vaccine. Despite the low probability of exposure in individuals who have committed themselves to abstinence or faithfulness to one relationship, there will still be those who may be exposed. I don't think that use of the vaccine implicitly endorses sexual activity. To me, using the vaccine is an effort to decrease a problem that has been increasing despite gains in the percentage of individuals who are choosing to be either abstinent or monogamous. Certainly giving hepatitis B vaccination to my patients has not encouraged them subsequently to use drugs or engage in risky sexual behavior.”Dr Hager, OB-GYN, Associate Professor at the University of Kentucky and an expert in gynecological infectious diseases states, “I would recommend HPV vaccine for my girls and for my grandchildren. Why? Because there are so many instances of innocent exposure, such as rape, incest,

statutory rape, and forced-unwanted sex. There is even the common situation where we have a young man or woman who has abstained until marriage and then marries a person who has had sex and exposes their partner to the disease.”More vaccinations on the way?This vaccination issue is an issue that will not just be an HPV issue. More immunizations against STIs appear to be on the way. Vaccinations against herpes simplex may be but a few years away. There has been a lot of work on developing a vaccine against Group B Streptococcus, gonococcus and possibly against Chlamydia trachomatis, but these will not be ready for several years. An HIV vaccine appears to be many years away, at best, in spite of millions of dollars of research money spent on the effort. Bradley G. Beck, MD, MS __________________________________________________