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Wednesday, May 31, 2023

10,000 Guanacaste Women to Test Vaccine

GUANACASTE – Last month the firstdozens of what will be 10,000 womenbared their shoulders for an experimentalvaccine against Human Papillomavirus(HPV). The virus is the primary cause ofcervical cancer, and this northern Pacificprovince has one of the highest rates of thatcancer in the world.Called the Guanacaste Project, thesevaccinations are the final phase in aninvestigation that began 11 years ago. It isfunded by the U.S. National CancerInstitute and carried out in conjunctionwith the University of Costa Rica, theINCIENSA Foundation and the HealthMinistry. The drug is manufactured byGlaxo SmithKline Biologicals.Four clinics are now open; three moreare expected within the next few months.There, health workers are administering asix-month series of shots to 20,000 womenover the next six years. Half receive theHPV vaccine, the other half receive anover-the-counter Hepatitis-A vaccine asthe control group.“We were going to use a placebo, but itis not ethical, we thought, so we decided touse something that benefits people – in thiscase, Hepatitis-A, which is common in theregion,” said Dr. Concepción Bratti, one ofthe lead for the project.THE vaccine is directed against twotypes of HPV – type 16 and 18 – that togetheraccount for 70% of cervical cancers in theworld. It has been tested on nearly 700women in Brazil and the United States,according to the main U.S. investigator, Dr.Allan Hildesheim, and similar vaccineshave been used on thousands of women.The Guanacaste Project will determinewhether the vaccine helps the body fightthe virus better than how the body wouldfight it naturally.Guanacaste was chosen for its highincidence of cervical cancer. HPV, which isusually sexually transmitted, does notalways cause cancer, but it often triggers itin women from developing countries (seebox). Those countries do not have theresources to test women regularly, andoften women are diagnosed with cancerwhen it is already in advanced stages.THE high incidence of cervical cancerin Guanacaste has several causes. Dr. AnaCecilia Rodríguez, one of the three primaryresearchers for the project, said the firstcause is an historical predisposition toinfection.Also, for cultural reasons and the lackof clinics near their homes, women did notundergo exams as often as they shouldhave. And there were problems with thequality of the samples taken during theexams and the follow-up of the results.Now, Rodríguez said, after informationcampaigns, th opening of more clinics, andimprovements in examination procedures,women take exams more regularly andthey are better handled by clinic personnel.The region was chosen as the test sitenot only to help stop the spread of thevirus, but also because Costa Rica has agood registry of cancer rates, so it is easierto study, Hildesheim said.WOMEN ages 18-25 were interviewedand asked to participate in thestudy voluntarily. Each clinic has privateoffices for screening interviews to determineif the volunteers are eligible. Factorssuch as pregnancy at the time of thescreening, a hysterectomy, and allergies toprevious vaccinations can bar somewomen from the test.Those who can participate learn aboutthe procedure through a video, pamphletsand discussion with the project’s staff.They know before beginning the treatmentthat they may receive Hepatitis-A vaccinesinstead of HPV vaccines, though duringthe test, they will not know which they arereceiving.They are also told of the possible sideeffects,which can include fatigue,headaches, or fever, that generally dissipatewithin 24 hours after the injection.Should anything go wrong, the women aremedically insured before they begin theshots. A 24-hour medical service phoneline available to the participants as well(800-DOCTORA).Should the drug prove effective, at theend of the study those who received theHepatitis-A vaccine can opt to take theHPV vaccine, and vice-versa.Though there is concern about using adrug on people here that is consideredexperimental, Costa Rican health officialsand scientists involved in the projectallay those fears, and some said theywould prefer to use the drug here thanother places.Dr. Bratti wrote in an article publishedin the Pan-American Journal of PublicHealth, “We believe the women were willingto participate in the study not only fortheir own safety, but also in the hope thattheir efforts would guide the way toward adiminished risk of cervical cancer for thefollowing generations.”Using a vaccine could bring cancerprevention into the scope of the wallets ofthose from developing countries.Screening systems such as those in place inNorth America and Europe, for example,are too expensive to implement in poorcountries.THE project could also have someeconomic benefits. Dr. Rocio Sáenz,Minister of Health, pointed out that it willbe an important source of employment for120 people from different disciplines.Sáenz is also aware that the vaccinecould save lives. She said cancer is thesecond highest cause of death in CostaRica, that there are 8,000 new cases everyyear, and in 2003, 3,405 Costa Ricans diedof the disease. In that year, more than oneCosta Rican woman died every three daysfrom cervical cancer, she said.“I’m sure that the results of this newphase of research will be encouraging andwill contribute greatly to the prevention ofa cancer that has affected millions ofwomen around the world. Especially poorwomen in developing countries.”What Does the Vaccine Do?THE vaccine for Human Papillomavirusis a protein that mimics the formof the virus. It is not capable of infectingthe body, but it makes the body react toit as if it were the virus.The immune system generates antibodiesto defend against the invadingprotein that is actually harmless. Then, ifthe real virus should ever enter, a highernumber of antibodies are ready todefend against it.In a past test published in the NewEngland Journal of Medicine in 2002, of1,533 women ages 16-23, none contracteda persistent infection, while 41women in the control group contractedthose infections.What is Human Papillomavirus?HUMAN Papillomavirus (HPV) is one of the most common sexually transmitted diseasesin the world, according to the U.S. National Institute of Allergies and InfectiousDiseases. More than 100 types of HPV have been identified, of which 40 are sexuallytransmitted and most often affect young people who recently became sexually active.In Guanacaste, more than 20% of women 25 years old and younger are infected,according to the results of the first phases of the Guanacaste Project. Some people whohave the disease may not have any symptoms; others develop genital warts of varyingdegrees of severity.In some cases the body fights off the virus on its own. In others, the warts requiretreatment, such as with creams or clinical procedures such as cutting and laser removal.HPV has been associated with cervical and vulvar cancers in women, penis cancerin men (a rare cancer) and anal cancer. Factors that could cause the virus to trigger cancerare the number of pregnancies a women has had, smoking, the use of oral contraceptivesfor more than five years, other sexually transmitted diseases and genetic characteristics.According to the Pan-American Journal of Public Health, 466,000 new cases of invasivecervical cancer are reported in the world every year, most in developing countries.The highest incidence rates worldwide are in Latin America, the Caribbean, SoutheastAsia and Sub-Saharan Africa. Two hundred thousand women die from the disease everyyear.It is difficult to protect against the virus. Condoms are not effective because the wartscan occur outside the areas protected by condoms, and the disease cannot be detectedby simple blood tests, according to Dr. Rodolfo Herrero, head of the research team forthe Guanacaste Project.


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