The results of the ESCUDDO study, conducted by the Costa Rican Agency for Biomedical Research of the Inciensa Foundation (ACIB-FUNIN), in collaboration with the National Cancer Institute of the United States, were published on December 3 in the prestigious scientific journal The New England Journal of Medicine (NEJM), considered the most important worldwide, due to its high level of scientific influence.
The Costa Rican Biomedical Research Agency of the INCIENSA Foundation published the results of the ESCUDDO study in The New England Journal of Medicine, which investigates the effectiveness of a single dose of the human papillomavirus vaccine.
One dose of a bivalent or novalent human papillomavirus (HPV) vaccine was protective against HPV16 and HPV18 infections, and showed non-inferiority to two doses, according to the ESCUDDO randomized trial.
- The ESCUDDO study was published by The New England Journal of Medicine, classified as one of the most prestigious journals for its high impact on medical science and health.
- This journal only accepts 5% of the manuscripts received.
San José, December 2025. The results of the ESCUDDO study, conducted by the Costa Rican Agency for Biomedical Research of the Inciensa Foundation (ACIB-FUNIN), in collaboration with the National Cancer Institute of the United States, were published this December 3 in the prestigious scientific journal The New England Journal of Medicine (NEJM), considered the most important worldwide, for its high level of scientific influence.
This journal only accepts 5% of the manuscripts received, since one of the aspects to be evaluated is that they are investigations whose results can guide medical practices, clinical guidelines and health policies, as it has been done by the Costa Rican ESCUDDO study.
This research, which began in Costa Rica in 2017, demonstrated that a single dose of either of the two main human papillomavirus (HPV) vaccines is no less effective than two doses in protecting against HPV types 16 and 18. These two HPV types are responsible for more than 70% of cervical cancer cases worldwide. Furthermore, one dose of the nonvalent vaccine is no less effective than two doses, meaning it protects against all nine HPV types that cause approximately 90% of cervical cancer and genital wart cases.
The first findings of ESCUDDO were announced last April at the annual meeting of the American Association for Cancer Research (AACR), globally considered one of the most important scientific events in this field.
“Currently, the World Health Organization recommends administering one or two doses of the vaccine to children aged 9 to 14, leaving the number of doses to the discretion of governments. The ESCUDDO results provide robust evidence for regulatory bodies to consolidate their recommendation of vaccination to a single dose, opening the door to broader global coverage, especially in low- and middle-income countries, where access to complete vaccination schedules has been limited for economic or logistical reasons,” emphasizes Dr. Carolina Porras, Director of Biomedical Research of ACIB-FUNIN, principal investigator of ESCUDDO and of the scientific article published in NEJM.
The ESCUDDO study is the only one worldwide that sought to verify whether the protection provided by one dose of the HPV vaccine was no less than that provided by two doses, so its results were of special attention to various international organizations and authorities.
Currently, 78% of Latin American and Caribbean countries use a single dose in their vaccination schedule, according to the Pan American Health Organization, highlighting the contribution of this Costa Rican study to global public health. In Costa Rica, two doses are still administered to 10-year-old girls and boys.
The publication of ESCUDDO’s scientific article in The New England Journal of Medicine reflects the outstanding work carried out in our country by Costa Rican scientists who have dedicated decades to researching ways to prevent HPV and cervical cancer. A study of this magnitude and importance is a national milestone in biomedical research, given that this journal has a 200-year history and is a leading publication in more than 150 countries, placing Costa Rica on a prominent global stage and on the height with other countries that have been recognized for years for their scientific contributions,” explains Dr. Rolando Herrero, Scientific Director of ACIB-FUNIN and senior author of the publication.
The ESCUDDO study was conducted in more than 50 cantons of Costa Rica, with the participation of over 23,000 women between the ages of 12 and 20. This research was carried out in collaboration with the National Cancer Institute of the United States (NCI).
“We extend our deepest gratitude to the young women and girls of Costa Rica who participated in the ESCUDDO study in an extraordinary display of solidarity with all women and their families,” emphasizes Dr. Porras.
ACIB-FUNIN will continue evaluating the duration of protection provided by a single dose. This Costa Rican non-governmental, non-profit organization has leading researchers who have dedicated more than 30 years to conducting biomedical research with a significant impact on global public health.
So far in 2025, the Ministry of Health reports 464 cases of the Human Papillomavirus, almost 50% more than last year. Women account for more than 90% of diagnoses, especially between 20 and 64 years of age.
Stomach cancer or gastric cancer has historically been one of the most common and deadly in Costa Rica. It is the third most common tumor and the deadliest cancer for men and the second deadliest for women, according to data from the National Tumor Registry and the National Institute of Statistics and Censuses (INEC).
The initial results of the ESCUDDO study, conducted in Costa Rica by the Costa Rican Agency for Biomedical Research (ACIB-FUNIN) in collaboration with the National Cancer Institute of the United States, confirm that a single dose of the Human Papillomavirus (HPV) vaccine offers the same protection as two doses.
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Summary of the news: These are the first results of ESCUDDO, a study launched in the country in 2017 to demonstrate the effectiveness of a single dose of the human papillomavirus vaccine.
Link of the news:
https://drive.google.com/file/d/18DOCVSw9nKbqBsFMZqpGFmUXkp2BR7Be/view?usp=sharing
A study conducted in Costa Rica with 19,460 women between the ages of 12 and 16 could transform decisions about human papillomavirus (HPV) vaccination made around the world.
San José, Costa Rica, April 2025. The first results of the ESCUDO study, conducted in Costa Rica by the Costa Rican Agency for Biomedical Research (ACIB-FUNIN) in collaboration with the National Cancer Institute of the United States, were announced at the annual meeting of the American Association for Cancer Research (AACR), considered one of the most important scientific events in this field worldwide.
The main findings confirm that a single dose of the Human Papillomavirus (HPV) vaccine offers the same protection as two doses against HPV types 16 and 18, which are responsible for more than 70% of cervical cancer cases worldwide.
The two vaccines used in the study demonstrated more than 95% efficacy in preventing HPV 16 and 18 infections, both when administered with one dose and when administered with two doses.
ESCUDDO is the only study worldwide that sought to verify whether the protection provided by one dose of the vaccine was not inferior to the provided by two doses in preventing HPV types 16 and 18 infections. This research, which has been conducted in more than 50 cantons of Costa Rica since 2017, involves more than 20,000 women between the ages of 12 and 20.
The study is supported by the U.S. National Cancer Institute (NCI), the Bill & Melinda Gates Foundation, the NIH Office of Research on Women’s Health, and the International Agency for Research on Cancer.
Global impact: greater access, greater equity
With scientific confirmation that a single dose is just as effective as the traditional two-dose regimen, it opens the door to broader global coverage, especially in low- and middle-income countries, where access to complete vaccination regimens has been limited for economic or logistical reasons.
“Reducing vaccination to a single dose represents a more efficient, accessible, and scalable strategy for saving lives,” said Dr. Carolina Porras, director of biomedical research at ACIB-FUNIN. She also expressed her gratitude to the thousands of young people who participated in the ESCUDDO study, whose contributions made such important findings possible.Principio del formulario
The ESCUDDO results provide robust evidence for regulatory agencies to definitely, change their vaccination recommendation to a single dose. Currently, the WHO recommends administering one or two doses to girls and boys aged 9 to 14, as well as to the 15 to 20-year-old group, leaving the number of doses to governments’ discretion.
“Now, with the results of the ESCUDDO study, the recommendation to administer a single dose is supported by highly scientifically rigorous data, and we know this will be a significant contribution to countries improving their vaccination coverage,” emphasizes Dr. Rolando Herrero, scientific director of ACIB-FUNIN.
ACIB-FUNIN will continue developing the ESCUDDO study in Costa Rica to further evaluate the duration of protection provided by one dose. This Costa Rican non-governmental, non-profit organization has distinguished researchers who, for more than 30 years, have dedicated themselves to conducting biomedical research with a significant impact on global public health.
The full manuscript of this study, currently under preparation, will include detailed analyses of the efficacy of one or two doses against the different types of viruses associated with this cancer, as well as details of the immune response to them.
The AACR Annual Meeting presents the latest discoveries in basic, translational, and clinical cancer research and brings together thousands of experts to share knowledge that will guide the future of the fight against cancer.
