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MALMO, SWEDEN – in a nationwide, retrospective cohort study.
“Anxiety and fear regarding adverse events are still very much alive and are associated with lack of acceptance of HPV vaccination,” Jozica Skufca, DVM, MIPH, observed while presenting the study findings at the annual meeting of the European Society for Paediatric Infectious Diseases.
“These results contribute valid evidence to combat public skepticism, anxiety, fears of adverse events, and possible opposition to HPV vaccination and consequently can contribute to increase HPV vaccination coverage in Finland as well as elsewhere,” added Dr. Skufca, who conducted this research while at the Finnish National Institute for Health and Welfare but is now an epidemiologist at P95, a privately held epidemiology and pharmacovigilance consulting firm in Heverlee, Belgium.
Finland introduced the bivalent HPV vaccine known as Cervarix, which is directed against HPV types 16 and 18, into the nation’s vaccination program in November 2013. The target population were girls aged 11-13 years, with catch-up vaccination at ages 14-15 years until 2015.
Dr. Skufca utilized Finland’s comprehensive system of national health care registries to conduct a study of all 240,605 Finnish girls aged 11-15 years who were eligible for the bivalent HPV vaccine from November 2013 to December 2016. Only 56% of the target population, or 134,615 girls, were actually vaccinated. All were subsequently followed for more than a year.
The investigators compared vaccinated and unvaccinated groups in terms of the subsequent rates of 38 selected outcomes of national and international interest. These included celiac disease, chronic fatigue syndrome, type 1 diabetes, Guillain-Barré syndrome, postural orthostatic tachycardia syndrome, ulcerative colitis, venous thromboembolism, psoriasis, vitiligo, scleroderma, autism, poyarteritis nodosa, asthma, Raynaud’s disease, systemic lupus erythematosus, Bell’s palsy, polycystic ovaries, juvenile arthritis, Hashimoto’s disease, and many others.
HPV vaccination rates varied considerably between hospital districts, so the results were adjusted for that potential confounder. Risks also were adjusted for the number of hospital visits 1-2 years prior to vaccination, because healthier girls – those with fewer hospital visits – turned out to be more likely to get vaccinated.
The study’s main result was that HPV vaccination wasn’t associated with a significantly higher risk of any of the 38 adverse outcomes. To the contrary, vaccination was associated with significantly reduced risk of several of them: The risk of chronic fatigue syndrome was reduced by 25%, epilepsy and recurrent seizures were reduced by 28%, the risk of Henoch-Schönlein purpura was an adjusted 52% lower in children vaccinated against HPV, and the risk of malaise and fatigue was reduced by 24%.
Dr. Skufca drew particular attention to the 400% increased risk of Guillain-Barré syndrome in vaccinated children. While this may look impressive, it wasn’t a statistically significant difference. Guillain-Barré was a rare event, with only six cases occurring during 186,934 person-years of follow-up of vaccinated individuals and a single case in unvaccinated girls. Two cases occurred within 180 days after vaccination, for an adjusted 200% increase in risk, which was nonsignificant.
Another two cases occurred more than 365 days postvaccination, for a whopping 3100% increased risk, compared with unvaccinated children; however, this too was a nonstatistically significant finding, with extraordinarily broad confidence intervals of 1.59-652.4. And there is no plausible mechanism to account for a true association between HPV vaccination and a complication, such as this, occurring more than 1 year later. It appeared to be a matter of chance, she added.
However, session cochair Ron Dagan, MD, commented that vaccine skeptics won’t find the Guillain-Barré findings reassuring.
“With HPV vaccination, there are a lot of issues related to mass perception. You say it’s not statistically significant, but some people will say, ‘Forget about the statistics – look at the confidence intervals, the risk could be more than 600 times increased.’ How do you answer this? It’s not easy, especially when we’re talking about a vaccine which has a strong adjuvant,” said Dr. Dagan, director of the pediatric infectious disease unit at Soroka University Medical Center and professor of pediatrics and infectious diseases at the Ben-Gurion University of the Negev, both in Beer-Sheva, Israel.
“I completely agree, how to communicate results to the public is one of the most challenging things. They don’t understand about statistics,” Dr. Skufca replied.
The ball is now in the court of the Finnish health ministry, she added. These study results are brand new. Ministry officials are now going over the details and developing a strategy to communicate the results to the media, the public, and affected families.
The study was funded by the Finnish National Institute for Health and Welfare. Dr. Skufca reported receiving research grants from GlaxoSmithKline and Pfizer.
MALMO, SWEDEN – in a nationwide, retrospective cohort study.
“Anxiety and fear regarding adverse events are still very much alive and are associated with lack of acceptance of HPV vaccination,” Jozica Skufca, DVM, MIPH, observed while presenting the study findings at the annual meeting of the European Society for Paediatric Infectious Diseases.
“These results contribute valid evidence to combat public skepticism, anxiety, fears of adverse events, and possible opposition to HPV vaccination and consequently can contribute to increase HPV vaccination coverage in Finland as well as elsewhere,” added Dr. Skufca, who conducted this research while at the Finnish National Institute for Health and Welfare but is now an epidemiologist at P95, a privately held epidemiology and pharmacovigilance consulting firm in Heverlee, Belgium.
Finland introduced the bivalent HPV vaccine known as Cervarix, which is directed against HPV types 16 and 18, into the nation’s vaccination program in November 2013. The target population were girls aged 11-13 years, with catch-up vaccination at ages 14-15 years until 2015.
Dr. Skufca utilized Finland’s comprehensive system of national health care registries to conduct a study of all 240,605 Finnish girls aged 11-15 years who were eligible for the bivalent HPV vaccine from November 2013 to December 2016. Only 56% of the target population, or 134,615 girls, were actually vaccinated. All were subsequently followed for more than a year.
The investigators compared vaccinated and unvaccinated groups in terms of the subsequent rates of 38 selected outcomes of national and international interest. These included celiac disease, chronic fatigue syndrome, type 1 diabetes, Guillain-Barré syndrome, postural orthostatic tachycardia syndrome, ulcerative colitis, venous thromboembolism, psoriasis, vitiligo, scleroderma, autism, poyarteritis nodosa, asthma, Raynaud’s disease, systemic lupus erythematosus, Bell’s palsy, polycystic ovaries, juvenile arthritis, Hashimoto’s disease, and many others.
HPV vaccination rates varied considerably between hospital districts, so the results were adjusted for that potential confounder. Risks also were adjusted for the number of hospital visits 1-2 years prior to vaccination, because healthier girls – those with fewer hospital visits – turned out to be more likely to get vaccinated.
The study’s main result was that HPV vaccination wasn’t associated with a significantly higher risk of any of the 38 adverse outcomes. To the contrary, vaccination was associated with significantly reduced risk of several of them: The risk of chronic fatigue syndrome was reduced by 25%, epilepsy and recurrent seizures were reduced by 28%, the risk of Henoch-Schönlein purpura was an adjusted 52% lower in children vaccinated against HPV, and the risk of malaise and fatigue was reduced by 24%.
Dr. Skufca drew particular attention to the 400% increased risk of Guillain-Barré syndrome in vaccinated children. While this may look impressive, it wasn’t a statistically significant difference. Guillain-Barré was a rare event, with only six cases occurring during 186,934 person-years of follow-up of vaccinated individuals and a single case in unvaccinated girls. Two cases occurred within 180 days after vaccination, for an adjusted 200% increase in risk, which was nonsignificant.
Another two cases occurred more than 365 days postvaccination, for a whopping 3100% increased risk, compared with unvaccinated children; however, this too was a nonstatistically significant finding, with extraordinarily broad confidence intervals of 1.59-652.4. And there is no plausible mechanism to account for a true association between HPV vaccination and a complication, such as this, occurring more than 1 year later. It appeared to be a matter of chance, she added.
However, session cochair Ron Dagan, MD, commented that vaccine skeptics won’t find the Guillain-Barré findings reassuring.
“With HPV vaccination, there are a lot of issues related to mass perception. You say it’s not statistically significant, but some people will say, ‘Forget about the statistics – look at the confidence intervals, the risk could be more than 600 times increased.’ How do you answer this? It’s not easy, especially when we’re talking about a vaccine which has a strong adjuvant,” said Dr. Dagan, director of the pediatric infectious disease unit at Soroka University Medical Center and professor of pediatrics and infectious diseases at the Ben-Gurion University of the Negev, both in Beer-Sheva, Israel.
“I completely agree, how to communicate results to the public is one of the most challenging things. They don’t understand about statistics,” Dr. Skufca replied.
The ball is now in the court of the Finnish health ministry, she added. These study results are brand new. Ministry officials are now going over the details and developing a strategy to communicate the results to the media, the public, and affected families.
The study was funded by the Finnish National Institute for Health and Welfare. Dr. Skufca reported receiving research grants from GlaxoSmithKline and Pfizer.
MALMO, SWEDEN – in a nationwide, retrospective cohort study.
“Anxiety and fear regarding adverse events are still very much alive and are associated with lack of acceptance of HPV vaccination,” Jozica Skufca, DVM, MIPH, observed while presenting the study findings at the annual meeting of the European Society for Paediatric Infectious Diseases.
“These results contribute valid evidence to combat public skepticism, anxiety, fears of adverse events, and possible opposition to HPV vaccination and consequently can contribute to increase HPV vaccination coverage in Finland as well as elsewhere,” added Dr. Skufca, who conducted this research while at the Finnish National Institute for Health and Welfare but is now an epidemiologist at P95, a privately held epidemiology and pharmacovigilance consulting firm in Heverlee, Belgium.
Finland introduced the bivalent HPV vaccine known as Cervarix, which is directed against HPV types 16 and 18, into the nation’s vaccination program in November 2013. The target population were girls aged 11-13 years, with catch-up vaccination at ages 14-15 years until 2015.
Dr. Skufca utilized Finland’s comprehensive system of national health care registries to conduct a study of all 240,605 Finnish girls aged 11-15 years who were eligible for the bivalent HPV vaccine from November 2013 to December 2016. Only 56% of the target population, or 134,615 girls, were actually vaccinated. All were subsequently followed for more than a year.
The investigators compared vaccinated and unvaccinated groups in terms of the subsequent rates of 38 selected outcomes of national and international interest. These included celiac disease, chronic fatigue syndrome, type 1 diabetes, Guillain-Barré syndrome, postural orthostatic tachycardia syndrome, ulcerative colitis, venous thromboembolism, psoriasis, vitiligo, scleroderma, autism, poyarteritis nodosa, asthma, Raynaud’s disease, systemic lupus erythematosus, Bell’s palsy, polycystic ovaries, juvenile arthritis, Hashimoto’s disease, and many others.
HPV vaccination rates varied considerably between hospital districts, so the results were adjusted for that potential confounder. Risks also were adjusted for the number of hospital visits 1-2 years prior to vaccination, because healthier girls – those with fewer hospital visits – turned out to be more likely to get vaccinated.
The study’s main result was that HPV vaccination wasn’t associated with a significantly higher risk of any of the 38 adverse outcomes. To the contrary, vaccination was associated with significantly reduced risk of several of them: The risk of chronic fatigue syndrome was reduced by 25%, epilepsy and recurrent seizures were reduced by 28%, the risk of Henoch-Schönlein purpura was an adjusted 52% lower in children vaccinated against HPV, and the risk of malaise and fatigue was reduced by 24%.
Dr. Skufca drew particular attention to the 400% increased risk of Guillain-Barré syndrome in vaccinated children. While this may look impressive, it wasn’t a statistically significant difference. Guillain-Barré was a rare event, with only six cases occurring during 186,934 person-years of follow-up of vaccinated individuals and a single case in unvaccinated girls. Two cases occurred within 180 days after vaccination, for an adjusted 200% increase in risk, which was nonsignificant.
Another two cases occurred more than 365 days postvaccination, for a whopping 3100% increased risk, compared with unvaccinated children; however, this too was a nonstatistically significant finding, with extraordinarily broad confidence intervals of 1.59-652.4. And there is no plausible mechanism to account for a true association between HPV vaccination and a complication, such as this, occurring more than 1 year later. It appeared to be a matter of chance, she added.
However, session cochair Ron Dagan, MD, commented that vaccine skeptics won’t find the Guillain-Barré findings reassuring.
“With HPV vaccination, there are a lot of issues related to mass perception. You say it’s not statistically significant, but some people will say, ‘Forget about the statistics – look at the confidence intervals, the risk could be more than 600 times increased.’ How do you answer this? It’s not easy, especially when we’re talking about a vaccine which has a strong adjuvant,” said Dr. Dagan, director of the pediatric infectious disease unit at Soroka University Medical Center and professor of pediatrics and infectious diseases at the Ben-Gurion University of the Negev, both in Beer-Sheva, Israel.
“I completely agree, how to communicate results to the public is one of the most challenging things. They don’t understand about statistics,” Dr. Skufca replied.
The ball is now in the court of the Finnish health ministry, she added. These study results are brand new. Ministry officials are now going over the details and developing a strategy to communicate the results to the media, the public, and affected families.
The study was funded by the Finnish National Institute for Health and Welfare. Dr. Skufca reported receiving research grants from GlaxoSmithKline and Pfizer.
REPORTING FROM ESPID 2018
Key clinical point: Human papillomavirus vaccination poses no significant increased risk of numerous potential adverse outcomes.
Major finding: There was no significantly increased risk of any of 38 potential adverse outcomes in girls aged 11-15 years following administration of a bivalent HPV vaccine.
Study details: This was a retrospective cohort study including more than 240,000 Finnish girls eligible for HPV vaccination following its introduction into the national immunization program.
Disclosures: The study was sponsored by the Finnish National Institute for Health and Welfare. The presenter reported receiving research grants from GlaxoSmithKline and Pfizer.