Amid the ever increasing problems in the delivery of medical care in the United States, there is actually some good news on the horizon. There will soon be available vaccines directed at the human papillomavirus (HPV) and herpes zoster virus (HZV), both of which could make major impacts worldwide.
Human Papillomavirus (Gardisil)
Up to 70% of sexually active women will become infected with HPV during their lifetime. Worldwide, HPV-related cervical cancer is the second leading cause of death in women. It is estimated that approximately 470,000 cases of cervical cancer are diagnosed annually causing nearly 31,000 deaths in Europe and 4000 in the United States annually. Human papillomavirus is also associated with genital warts which are usually recurrent, inconvenient, and difficult to treat, as well as the 3500 cases of vulvar and vaginal carcinomas diagnosed in the United States annually.
Although there have been more than 100 strains of HPV isolated, types 16 and 18 are associated with 70% of cervical cancers, and types 6 and 9 are associated with 90% of genital warts.
Multicenter placebo-controlled, double-blind clinical trials involving more than 27,000 patients in the United States and Europe done by Merck during a 10-year period with Gardisil (a preventative polyvalent vaccine containing serotypes 6, 9, 16, and 18) have revealed higher antibody levels in the recipients at 3 and 4 years after vaccination than in those with natural infection with HPV. Recipients of the vaccine also showed prevention of cervical dysplasia, vulvar intraepithelial neoplasia, and vaginal intraepithelial neoplasia and 100% protection against genital warts in those treated with the vaccine compared with those treated with placebo.
Based on these data which have been published in Lancet, the Food and Drug Administration's Vaccines and Related Biological Products Advisory Committee recently voted unanimously to approve Gardisil. The vaccine should be available later this year and is recommended for young adolescent girls not yet sexually active and exposed to HPV. How long the immunity will last and whether revaccination will be necessary are unknown at present, but nonetheless, the vaccine represents a significant breakthrough in both oncology and infectious diseases.
Initially, primary care physicians, gynecologists, and infectious disease specialists will be those asked the most questions concerning the vaccine, but ultimately, pediatricians will be the ones to deliver the vaccine as well as educate patients and parents.
Herpes Zoster Vaccine (Zostivax)
Herpes zoster is a manifestation of reactivation of varicella zoster virus, which as a primary infection causes chickenpox. Zoster is characterized by a unilateral, painful, cutaneous vesicular eruption with dermatomal distribution. It can be complicated by scarring, secondary bacterial infection, allodynia, cranial and motor neuron palsies, pneumonia, encephalitis, visual impairment, hearing deficits, and even death. Pain, unfortunately, can be associated with the prodrome, the acute eruptive phase, and the post-herpetic phase of the infection.
Zostivax is a lyophilized preparation of the Oka/Merck strain of live attenuated varicella zoster virus initially obtained from a child with naturally occurring chickenpox and propagated in cell cultures by Merck.
Zostivax was evaluated in a 38,000-patient, placebo-controlled, double-blind clinical trial in the United States. Patients were all older than 60 years and were followed up for a median of 3.1 years for the development of shingles and the degree of pain associated with the infection.
The study's conclusions were that the vaccine reduced the overall incidence of shingles by 50%, and for people between the ages of 60 and 69 years, it reduced the incidence by 64%. In those who developed shingles despite receiving the vaccine, the postherpetic neuralgia was decreased as well.
Because of these findings the Food and Drug Administration recently approved Zostivax and recommended its use in normal hosts 60 years and older. Patients with HIV disease, those receiving steroids or chemotherapy, those with underlying malignancies, and those with active untreated tuberculosis should not receive the vaccine.
This vaccine should also be available later this year and should be widely accepted. Again, duration of immunity, the need for revaccination, and whether it will be covered by third-party payers, including Medicare, are unknown at present.