HPV Vaccine Is Credited in Fall of Teenagers’ Infection Rate, but Signs of Some Resistance Showing (403 hits)
There are some signs that resistance to the vaccine may be growing {although} The prevalence of dangerous strains of the human papillomavirus — the most common s*xually transmitted infection in the United States and a principal cause of cervical cancer — has dropped by half among teenage girls in recent years, a striking measure of success for a vaccine against the virus that was introduced only in 2006, federal health officials said on Wednesday.
The sharp decline in the infection rate comes at a time of deepening worry among doctors and public health officials about the limited use of the HPV vaccine in the United States. Health departments across the country are scrambling for ways to increase vaccination rates, while nonprofit groups are using postcard reminders and social media campaigns and pediatricians are being encouraged to convince families of the vaccine’s benefits.
{...} Health officials offered several possible explanations for why the drop was so sharp even though most girls in the United States are still not fully vaccinated.
One possible reason is a phenomenon known as herd immunity, in which people who are vaccinated reduce the overall prevalence of the virus in society, decreasing the chances that unvaccinated people would be exposed to someone who is infected. Another is the unexpected effectiveness of a partial dosage of the HPV vaccine, said Dr. Lauri E. Markowitz, a medical epidemiologist at the C.D.C. and the lead author of the study. About half of teenage girls in the United States have received at least one dose of the vaccine. ...
