Impact case: Making cervical cancer disappear

By presenting data on an improved screening method for women, and providing efficacy and safety studies on vaccines, KI researchers have enabled worldwide efforts to eliminate cervical cancer.

The cervix is the lowest part of the uterus in women. It has a mucous membrane that may be infected with bacteria and viruses. Every year around 550 Swedish women are diagnosed with cervical cancer, and worldwide it causes more than 300 000 deaths per year. Practically all these cases are caused by a virus, the Human Papilloma Virus (HPV). Without that virus circulating in the population cervical cancer would be no more. And in 2018 the World Health Organisation called for a global action to eliminate cervical cancer.  

Portrait of Joakim Dillner.
Joakim Dillner, professor in infectious disease epidemiology at Karolinska Institutet. Photo: Ulf Sirborn.

More than twenty years ago, KI virologist and epidemiologist Joakim Dillner, published the first randomised clinical trial showing that a simple PCR test could reveal the presence of HPV better than the old screening method of cytology, where you looked for cytological abnormalities in a microscope.  

Others research groups could corroborate the results, and slowly the health care recommendations have changed, both in Sweden and internationally. The last of the Swedish health care regions to switch to the HPV PCR-test did so in 2021.    

"It takes time for things to change, and it is really hard to evaluate your impact, but we performed the first randomised studies, and we have continued to present new results ever since," says Joakim Dillner. "I guess that consistency means something."

A second important step in the fight against HPV is the national Swedish vaccination program.  

Karin Sundström
Karin Sundström, senior researcher at the Department of Laboratory Medicine, Karolinska Institutet, Photo: Martin Stenmark.

After the early studies, by KI researchers and international partners on the efficacy and safety of the vaccine, it was offered to teenage girls for a subsidised price, but cancer epidemiologist Karin Sundström could show that the cost was still too high for many.  

"It was misdirected. Mostly girls from socially privileged groups took the vaccine but they already had a lower cancer risk. So, we presented the data, and today the vaccine is offered free of charge to schoolgirls from age eleven. And now we can see the results of higher vaccination coverage as a lower incidence of cervical cancer among vaccinated women," says Karin Sundström.

Karin Sundström also stresses the importance of the strategic collaboration with the vaccine manufacturer MSD which has provided continued follow-up of vaccine effectiveness. 

The next step will be to include the last unvaccinated group of young adult women, those born between 1994 and -99.  

Together with the vaccination of boys that started in 2020, Sweden is now approaching full elimination of HPV in the population. That would mean the end of HPV-associated cervical cancer in Sweden.  

"I have been working with this issue since the nineties and sometimes I have torn my hair with impatience. But if you want to see results it is essential to keep going and not to lose hope," says Joakim Dillner.  

"Openness and cooperation with other groups are key factors for success," says Karin Sundström. "Being slow in disseminating your results inevitably leads to a low impact."