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The human papillomavirus (HPV) vaccine is a feat of modern medicine that has proven to be both perfectly safe and highly effective.
After more than a decade of surveillance and research, scientists have found no solid evidence that the vaccine poses fertility problems. And yet there are still some who refuse to accept it.
Last year, a reported anti-vaxxer published misleading results suggesting that the lowest birth rate ever recorded in America is caused, at least in part, by the HPV vaccine. The paper was written by Gayle DeLong, who is neither a scientist nor a medical researcher and has always been involved in anti-vaccination organizations.
"The results suggest that women who received the HPV vaccine were less likely to have previously been pregnant than women of the same age group who did not receive the vaccine," says she in her article of 2018.
"If 100 [percent] In this study, women who received the HPV vaccine, the data suggest that the number of women who had already conceived would have decreased by 2 million. "
DeLong's findings raise a number of issues that need to be addressed in the context of his immunization history. In 2011, DeLong, Ph.D. in economics and finance, published an article in the same newspaper that claimed to link autism and childhood immunization rates in the United States.
This discovery contradicts years of research and has been criticized by scientists and experts in autism for its mediocre methodology and wild conclusions. A few years later, DeLong imputed her diagnosis of breast cancer to the stress of educating two autistic children.
His new claims are equally extraordinary and equally flawed. Shortly after the publication of his HPV study late last year, two medical researchers wrote a letter in another scientific journal explaining why the new discoveries were probably wrong.
The authors of this letter explain that if the HPV vaccine actually affects fertility, it would take several years before the national birth rate slips, because the vaccine is recommended for pre-adolescents.
Instead, they argue that this link is probably specious and that today's low birth rate is likely due to better access to contraception and the tendency to have children later in life . However, since DeLong's research did not report contraceptive rates – only birth rates – these factors went completely unnoticed.
The comments section of the document is full of equally skeptical shots. The microbiologist and science communicator Elisabeth Bik recently described the document as "very flawed and biased" with the potential to be "misinterpreted or misused".
The size of the sample is a good example of these flaws. Although DeLong assumes that his study analyzed data from the National Health and Nutrition Review, which represents 8 million women, his actual sample included only 700 women.
In addition, the two groups sampled – those who received the HPV vaccine and those who did not – were of a very different size, with over 400 more women in the group. do not vaccinated against HPV.
Looking at both groups side by side, there is another confounding factor that stands out much more than vaccinations. Bik explains that women with a university degree were more likely to be part of the vaccinated group and that they also tended to have babies at a later age.
"The author here limits her study on women aged 25 to 29, which is lower than the average age of female undergraduates," says Bik in a review.
"If you limit the study group to women under the age of 30, this means that middle-aged women with a university degree have not yet had their first baby." age is chosen too small to correlate with vaccination status. "
If you are wondering how this terrible methodology has managed to escape peer review, you also have an answer to that. In the same way as the author, the journal in which this research was published has a dubious history with vaccination.
In the past, the Journal of Toxicology and Environmental Health approved a series of questionable documents written by known anti-vaxxers and others with serious conflicts of interest. Among the misleading studies, several other articles present the long discredited link between vaccines and autism.
DeLong's recent claims are extremely out of sync with what most other studies have revealed, and it's unlikely that she'll be able to publish them in a reputable outlet.
Recent and more in-depth research on hundreds of thousands of women has revealed no link between the HPV vaccine and the risk of primary ovarian failure. In fact, experts say that the HPV vaccine actually protects women from future fertility problems caused by cervical cancer.
"The reports of premature menopause after HPV vaccination have attracted a lot of attention from the media, including social media," said Allison Naleway, Senior Epidemiologist at the Kaiser Permanente Center for Health Research. .
"However, these reports were based on a small number of isolated cases and should be interpreted with caution.To clarify this problem, we conducted a study of nearly 200,000 young women and found no high risk of POIs. after vaccination against HPV or other recommended vaccines. "
Experts agree that the safety of the HPV vaccine is clear, but it seems that anti-vaxxers like DeLong are doing everything in their power to scramble the tracks.
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