New data from Denmark shows the HPV vaccine’s powerful long-term impact, while also revealing why cervical cancer screening is still essential.
A Danish study published in the journal Eurosurveillance reports that women who received the human papillomavirus vaccine in their adolescence are significantly less likely to develop human papillomavirus infections later in life.
Background
Prolonged infection with human papillomavirus (HPV) is associated with an increased risk of developing cervical cancer. Early screening and vaccination against HPV are effective strategies to prevent this cancer type.
Screening for precancerous lesions has been a widely considered strategy for secondary prevention of cervical cancer in Europe. Vaccines covering both high-risk and low-risk HPV types have been introduced as a primary preventive intervention at the end of the 2000s.
In Denmark, free public HPV vaccination (4-valent vaccine) was initially offered to all girls aged 13 to 15 in October 2008. It was later introduced to all girls turning 12 in January 2009. In November 2017, a 9-valent vaccine, which covers high-risk HPV types responsible for up to 90% of cervical cancers, was introduced in the country.
Cervical cancer screening is offered to women living in Denmark from the age of 23 years until the age of 64 years. One of the first groups of women who received the 4-valent HPV vaccination as teenage girls in 2008 reached the screening age of 23 years in 2017.
To carefully monitor screening outcomes in these vaccinated women, Trial23, a public health study embedded in the Danish national cervical screening program, was designed to determine the prevalence of HPV infection in cervical cell samples collected during three consecutive rounds of screening invitations.
In the current study, researchers assessed the prevalence of HPV infection in these consecutive cervical samples and the changes in HPV persistence and incidence between the first, second, and third samples.
Key findings
A total of 17,252 women with at least one cervical cell sample were registered in the Trial23 between February 2017 and February 2024. In this study, researchers analyzed 16,955 cervical samples collected from 8,659 women.
The prevalence of any high-risk HPV infection in the first, second, and third rounds of cervical samples was 32%, 28%, and 31%, respectively. The prevalence of HPV types 16 and 18 (high-risk viruses covered by the 4-valent HPV vaccine) remained low over time in all analyzed samples.
The comparison between vaccinated and unvaccinated women revealed significantly lower prevalence of HPV types 16 and 18 in vaccinated women. The prevalence of this virus type was 15 to 17% before vaccination, which reduced to less than 1% in vaccinated women by 2021.
Notably, the study found that about one-third of women still have infections with high-risk HPV that are not covered by the vaccine, and that the incidence of these infections was significantly higher in vaccinated women compared to unvaccinated women. However, the prevalence differences were not statistically significant.
Regarding HPV infection persistence and incidence, the study found a high persistence for both vaccine-covered and non-covered virus types, irrespective of vaccination status. The incidence of HPV types 16 and 18 was significantly lower in vaccinated women compared to that in unvaccinated women. However, the incidence, but not prevalence, of non-covered high-risk HPV types was significantly higher in vaccinated women compared to that in unvaccinated women, a pattern the authors suggest may be due to type replacement or unmasking.
Study significance
The study reports the prevalence of HPV infection in three sets of cervical cell samples collected consecutively from young Danish women who received the 4-valent HPV vaccination in their adolescence.
According to the findings, the prevalence of infection with HPV types 16 and 18 in vaccinated women is currently less than 1%, a significant drop from the pre-vaccination prevalence. In unvaccinated women, the prevalence is 5%, which is also much lower than the pre-vaccination prevalence. The drop in prevalence in unvaccinated women indicates population immunity.
Regarding infections with high-risk HPV types that are not covered by the vaccine, the study reports a prevalence of 30% in vaccinated women and 27% in unvaccinated women, which is a non-significant difference. A persistently high prevalence of non-vaccine high-risk HPV types in both vaccinated and unvaccinated women highlights the need for continuous screening of these generations until women vaccinated as girls with the 9-valent vaccine covering all major HPV types reach the screening age. At this point, the screening model might be reconsidered, with the study suggesting that less intensive but continued screening could be appropriate.
The study finds no significant differences in the persistence of HPV 16 and 18 infections between vaccinated and unvaccinated women, which indicates that the 4-valent vaccine, which covers high-risk HPV types 16 and 18 and low-risk types 6 and 11, is a prophylactic (preventive) vaccine and not a therapeutic vaccine. The conclusion supports the finding that persistence rates were similar regardless of vaccination status.
Overall, the study findings highlight the long-term protective efficacy of the HPV vaccine and advise close monitoring of factors associated with vaccine hesitancy and low vaccine coverage, such as perceived side effects of the vaccine.Journal reference:
News
GLP-1 Drugs Like Ozempic Work, but New Research Reveals a Major Catch
Three new Cochrane reviews find evidence that GLP-1 drugs lead to clinically meaningful weight loss, though industry-funded studies raise concerns. Three new reviews from Cochrane have found that GLP-1 medications can lead to significant [...]
How a Palm-Sized Laser Could Change Medicine and Manufacturing
Researchers have developed an innovative and versatile system designed for a new generation of short-pulse lasers. Lasers that produce extremely short bursts of light are known for their remarkable precision, making them indispensable tools [...]
New nanoparticles stimulate the immune system to attack ovarian tumors
Cancer immunotherapy, which uses drugs that stimulate the body’s immune cells to attack tumors, is a promising approach to treating many types of cancer. However, it doesn’t work well for some tumors, including ovarian [...]
New Drug Kills Cancer 20,000x More Effectively With No Detectable Side Effects
By restructuring a common chemotherapy drug, scientists increased its potency by 20,000 times. In a significant step forward for cancer therapy, researchers at Northwestern University have redesigned the molecular structure of a well-known chemotherapy drug, greatly [...]
Lipid nanoparticles discovered that can deliver mRNA directly into heart muscle cells
Cardiovascular disease continues to be the leading cause of death worldwide. But advances in heart-failure therapeutics have stalled, largely due to the difficulty of delivering treatments at the cellular level. Now, a UC Berkeley-led [...]
The basic mechanisms of visual attention emerged over 500 million years ago, study suggests
The brain does not need its sophisticated cortex to interpret the visual world. A new study published in PLOS Biology demonstrates that a much older structure, the superior colliculus, contains the necessary circuitry to perform the [...]
AI Is Overheating. This New Technology Could Be the Fix
Engineers have developed a passive evaporative cooling membrane that dramatically improves heat removal for electronics and data centers Engineers at the University of California San Diego have created an innovative cooling system designed to greatly enhance [...]
New nanomedicine wipes out leukemia in animal study
In a promising advance for cancer treatment, Northwestern University scientists have re-engineered the molecular structure of a common chemotherapy drug, making it dramatically more soluble and effective and less toxic. In the new study, [...]
Mystery Solved: Scientists Find Cause for Unexplained, Deadly Diseases
A study reveals that a protein called RPA is essential for maintaining chromosome stability by stimulating telomerase. New findings from the University of Wisconsin-Madison suggest that problems with a key protein that helps preserve chromosome stability [...]
Nanotech Blocks Infection and Speed Up Chronic Wound Recovery
A new nanotech-based formulation using quercetin and omega-3 fatty acids shows promise in halting bacterial biofilms and boosting skin cell repair. Scientists have developed a nanotechnology-based treatment to fight bacterial biofilms in wound infections. The [...]
Researchers propose five key questions for effective adoption of AI in clinical practice
While Artificial Intelligence (AI) can be a powerful tool that physicians can use to help diagnose their patients and has great potential to improve accuracy, efficiency and patient safety, it has its drawbacks. It [...]
Advancements and clinical translation of intelligent nanodrugs for breast cancer treatment
A comprehensive review in "Biofunct. Mater." meticulously details the most recent advancements and clinical translation of intelligent nanodrugs for breast cancer treatment. This paper presents an exhaustive overview of subtype-specific nanostrategies, the clinical benefits [...]
It’s Not “All in Your Head”: Scientists Develop Revolutionary Blood Test for Chronic Fatigue Syndrome
A 96% accurate blood test for ME/CFS could transform diagnosis and pave the way for future long COVID detection. Researchers from the University of East Anglia and Oxford Biodynamics have created a highly accurate [...]
How Far Can the Body Go? Scientists Find the Ultimate Limit of Human Endurance
Even the most elite endurance athletes can’t outrun biology. A new study finds that humans hit a metabolic ceiling at about 2.5 times their resting energy burn. When ultra-runners take on races that last [...]
World’s Rivers “Overdosing” on Human Antibiotics, Study Finds
Researchers estimate that approximately 8,500 tons of antibiotics enter river systems each year after passing through the human body and wastewater treatment processes. Rivers spanning millions of kilometers across the globe are contaminated with [...]
Yale Scientists Solve a Century-Old Brain Wave Mystery
Yale scientists traced gamma brain waves to thalamus-cortex interactions. The discovery could reveal how brain rhythms shape perception and disease. For more than a century, scientists have observed rhythmic waves of synchronized neuronal activity [...]
