[SaneVax: In 2008, Dr. Charlotte Haug urged caution when considering implementation of HPV (human papillomavirus) vaccination programs. Not many people in the medical establishment appeared to listen. Four years later, those reasons for caution still exist, with a few new ones added. Please take a few minutes to read Dr. Haug's letter to the editor of the New England Journal of Medicine. Educate yourself before consenting to any medical intervention, including HPV vaccines.]
Human Papillomavirus Vaccination – Reasons for Caution
By Charlotte Haug, MD, PhD, (N Engl J Med 2008; 359:861-862 August 21, 2008)
Despite great expectations and promising results of clinical trials, we still lack sufficient evidence of an effective vaccine against cervical cancer. Several strains of human papillomavirus (HPV) can cause cervical cancer, and two vaccines directed against the currently most important oncogenic strains (i.e., the HPV-16 and HPV-18 serotypes) have been developed. That is the good news. The bad news is that the overall effect of the vaccines on cervical cancer remains unknown. As Kim and Goldie1 point out in this issue of the Journal, the real impact of HPV vaccination on cervical cancer will not be observable for decades.
Although it was licensed for use in the United States in June 2006, the first phase 3 trials of the HPV vaccine with clinically relevant end points — cervical intraepithelial neoplasia grades 2 and 3 (CIN 2/3) — were not reported until May 2007, first in the Journal 2 and 1 month later in theLancet.3,4 The vaccine was highly successful in reducing the incidence of precancerous cervical lesions caused by HPV-16 and HPV-18, but a number of critical questions remained unanswered.5,6 For instance, will the vaccine ultimately prevent not only cervical lesions, but also cervical cancer and death? How long will protection conferred by the vaccine last? Since most HPV infections are easily cleared by the immune system, how will vaccination affect natural immunity against HPV, and with what implications? How will the vaccine affect preadolescent girls, given that the only trials conducted in this cohort have been on the immune response? The studies with clinical end points (i.e., CIN 2/3) involved 16- to 24-year-old women. How will vaccination affect screening practices? Since the vaccines protect against only two of the oncogenic strains of HPV, women must continue to be screened for cervical lesions. Vaccinated women may feel protected from cervical cancer and may be less likely than unvaccinated women to pursue screening. How will the vaccine affect other oncogenic strains of HPV? If HPV-16 and HPV-18 are effectively suppressed, will there be selective pressure on the remaining strains of HPV? Other strains may emerge as significant oncogenic serotypes.