¿Ensayos clínicos de superioridad, equivalencia o no inferioridad? / ¿Clinical trials of superiority, non-inferiority or equivalence?

La eficacia de una nueva intervención se establece generalmente a través de ensayos clínicos (EC) con asignación aleatoria (AA). Sin embargo, entre otros tantos desafíos metodológicos, el especificar la hipótesis de un EC con AA, sigue siendo un problema complejo de resolver para los investigadores clínicos. En este manuscrito discutimos las características de tres variantes de los EC con AA: EC de superioridad (ECS), EC de no-inferioridad (ECNI), y EC de equivalencia (ECE). Estos tres tipos de EC tienen supuestos diferentes sobre los efectos de una intervención, por lo que plantear hipótesis y definir objetivos requiere conocer algunos supuestos subyacentes a estos EC, incluso hasta elementos relacionados con la estimación del tamaño de muestra para cada cual. El objetivo de este manuscrito fue describir las diferencias metodológicas entre ECS, ECNI y ECE.

Efficacy and effectivity of new interventions are generally established through randomized clinical trials (RCTs). However, among many other methodological challenges, specifying the hypothesis of a RCT remains complex problem for clinical researchers. In this manuscript we discuss the characteristics of three variants of RCTs: superiority RCT (SRCT), non-inferiority RCT (NIRCT), and equivalence RCT (ERCT). These three types of RCT have different assumptions about the effects of an intervention, so setting hypotheses and defining objectives requires knowing some assumptions underlying these RCTs, including elements related to the estimation of the sample size for each one. The aim of this manuscript was to describe methodological differences between SRCT, NIRCT and ERCT.

Effectiveness of m-health-based core strengthening exercise and health education for public safety workers with chronic non-specific low back pain: study protocol for a superiority randomized controlled trial (SAFEBACK).

BACKGROUND: Low back pain (LBP) is the leading cause of years lived with disability worldwide. Public safety workers are highly exposed to physically demanding activities and inappropriate postures, increasing the risk of experiencing LBP. Smartphone app-based self-managed interventions may be an alternative for chronic non-specific LBP (CNSLBP) treatment. This study aims to evaluate the effectiveness of a smartphone app-based self-managed exercise program plus health education, compared to a health education program alone, on neuromuscular and perceptual outcomes in police officers and firefighters with CNSLBP. METHODS: This is a parallel, two-armed, blinded evaluator randomized clinical trial. Police officers and firefighters (from public safety institutions in the Rio Grande do Sul state, Brazil) will be randomly assigned to a m-health self-managed exercise program (twice a week) plus health education or health education alone. Self-management exercise program components are mobility and core resistance exercises, available on the app. Follow-ups will be conducted post-treatment (8 weeks) and 16 weeks after randomization. The co-primary outcomes will be pain intensity and disability post-treatment (8 weeks). Secondary outcomes will be biopsychosocial factors related to CNSLBP. DISCUSSION: We hypothesize that the effects of a smartphone app-based self-managed exercise program on co-primary and secondary outcomes will be superior, compared to the health education only in public safety workers with CNSLBP. TRIAL REGISTRATION: The study was prospectively registered at ClinicalTrials.gov (NCT05481996. Registered on August 01, 2022).

Mapeamento dos domínios da ANVISA para o padrão ISO IDMP / Mapping of ANVISA domains to the ISO IDMP standard / Mapeo de dominios de ANVISA al estándar ISO IDMP

Objetivo: Apresentar o mapeamento entre vocabulários controlados da Agência Nacional de Vigilância Sanitária (ANVISA) para listas do European Directorate for the Quality of Medicines and Healthcare (EDQM). Método: O mapeamento obedeceu aos princípios da ABNT NBR ISO 12300. Resultados: Foram mapeadas as listas: Via de Administração, Forma Farmacêutica e Embalagem. 47% dos mapeamentos foram classificados com grau de equivalência 4, onde o conceito fonte foi mais restrito com mais significado específico que o conceito/termo alvo. Conclusão: Entende-se que este estudo fornece subsídios para a ANVISA prosseguir no trabalho de harmonização das listas locais com o padrão IDMP.

Objective: To present the mapping between controlled Brazilian Health Regulatory Agency (ANVISA) vocabularies for European Directorate for the Quality of Medicines and Healthcare (EDQM) lists. Method: The mapping followed the principles described in the ABNT NBR ISO 12300. Results: Terms of three lists were mapped: Routes of Administration, Pharmaceutical Dose Forms and Packaging. Almost half of the mappings were classified with equivalence grade 4 meaning that the source concept was more restricted with more specific meaning than the target concept / term. Conclusion: This work provides the necessary subsidies for ANVISA to proceed with the work of harmonizing local lists with the IDMP standard.

Objetivo: Presentar el mapeo entre vocabularios controlados de Agencia Nacional de Vigilancia Sanitaria (ANVISA) para listas European Directorate for the Quality of Medicines and Healthcare (EDQM). Método: El mapeo siguió los principios descritos en lo estándar ABNT NBR ISO 12300. Resultados: Se mapearon los términos de las listas: Vía de administración, Forma farmacéutica y Embalajes. La mayoría se clasificaron como grado de equivalencia 4, donde el concepto fuente era más restringido con un significado más específico que el concepto/término objetivo. Conclusión: Se entiende que este estudio proporciona subsidios para ANVISA continúe el trabajo de armonizar las listas locales con el estándar IDMP.

The RESPECT trial-Replacement of peripheral intravenous catheters according to clinical reasons or every 96 hours: A randomized, controlled, non-inferiority trial.

BACKGROUND: Peripheral intravenous catheters are widely used for infusion therapy. To prevent phlebitis, routine catheter replacement at 72 or 96 hours remains widely practiced. OBJECTIVE: To investigate the non-inferiority of clinically indicated peripheral intravenous catheter replacement compared with routine replacement every 96 hours to prevent phlebitis. Phlebitis severity, catheter indwelling time, and other catheter failure types were also compared. SETTING: Multi-center trial in wards at two hospitals in Sao Paulo, Brazil. DESIGN: The REplacement of PEripheral intravenous CaTheters according to clinical signs or every 96 hours (RESPECT) trial was a Randomized, non-blinded, controlled, non-inferiority trial. PARTICIPANTS: 1319 patients were enrolled with the following inclusion criteria: aged ≥18 years, expected peripheral intravenous therapy for ≥96 hours; peripheral intravenous catheters inserted in the selected wards, intensive care units, or surgical centers; and informed consent provided. Exclusion criteria were: bloodstream infection and/or sepsis, neutrophil count of ≤1000/mm3, and simultaneous use of more than one peripheral intravenous catheter. Recruitment occurred within 96 hours of peripheral intravenous catheter insertion. Randomization was performed using a computer-generated, concealed list. METHODS: As intervention, clinically indicated replacement group patients underwent peripheral intravenous catheter removal only at the end of therapy or in the presence of phlebitis, infiltration, occlusion, displacement, accidental removal, or bloodstream infection. Routine 96-h replacement group patients (control) had their catheters replaced every 96-h, unless clinical reasons required earlier replacement. The primary outcome was Phlebitis and the analyses were carried out on intention-to-treat and per-protocol bases. RESULTS: Demographic and clinical variables were similar between groups, with the exception to type of admission (p = 0.025) more frequent in clinically indicated patients and surgical on routine replacement group. Of the 1319 patients, 119 (9.0%) developed phlebitis with no between-group difference (p = 0.162); these patients used 2747 peripheral intravenous catheters, being that 134 presented phlebitis. Phlebitis/1000 catheter-days, was 14.9 in the clinically indicated group and 23.8 in the routine replacement group (p = 0.006). The survival analysis showed no significant between-group difference in the occurrence of the first phlebitis episode. CONCLUSIONS: Clinically indicated peripheral intravenous catheter replacement was not inferior to routine (96 hours) replacement regarding phlebitis occurrence, and was associated with significantly less phlebitis per 1000 days. TRIAL REGISTRATION: Registered with www.clinicaltrials.gov (NCT02568670).

Safety and efficacy of step-down to oral outpatient treatment versus inpatient antimicrobial treatment in pediatric cancer patients with febrile neutropenia: A noninferiority multicenter randomized clinical trial.

BACKGROUND: It has been suggested that low-risk febrile neutropenia (FN) episodes can be treated in a step-down manner in the outpatient setting. This recommendation has been limited to implementation in middle-income countries due to concerns about infrastructure and lack of trained personnel. We aimed to determine whether early step-down to oral antimicrobial outpatient treatment is not inferior in safety and efficacy to inpatient intravenous treatment in children with low-risk FN. PROCEDURE: A noninferiority randomized controlled clinical trial was conducted in three hospitals in Mexico City. Low-risk FN was identified in children younger than 18 years. After 48 to 72 hours of intravenous treatment, children were randomly allocated to receive outpatient oral treatment (experimental arm, cefixime) or to continue inpatient treatment (standard of care, cefepime). Daily monitoring was performed until neutropenia resolution. The presence of any unfavorable clinical outcome was the endpoint of interest. We performed a noninferiority test for comparison of proportions. RESULTS: We identified 1237 FN episodes; 117 cases were randomized: 60 to the outpatient group and 57 for continued inpatient treatment. Of the FN episodes, 100% in the outpatient group and 93% in the inpatient group had a favorable outcome (P < 0.001). The mean duration of antibiotics was 4.1 days (SD 2.5; 95% CI, 3.4-4.8 days) in the outpatient group and 4.4 days (SD 2.5; 95% CI, 3.7-5.0 days) in the inpatient group (P = 0.70). CONCLUSIONS: In our population, step-down oral outpatient treatment of low-risk FN was as safe and effective as inpatient intravenous treatment. Clinical Trials Identifier: NCT04000711.

Study protocol for a randomized controlled trial on the effect of the Diabetic Foot Guidance System (SOPeD) for the prevention and treatment of foot musculoskeletal dysfunctions in people with diabetic neuropathy: the FOotCAre (FOCA) trial I.

BACKGROUND: This study is part of a series of two clinical trials. Taking into account the various musculoskeletal alterations of the foot and ankle in people with diabetic peripheral neuropathy (DPN) and the need for self-care to avoid more serious dysfunctions and complications, a self-manageable exercise protocol that focuses on strengthening the foot muscles is presented as a potentially effective preventive method for foot and gait complications. The aim of this trial is to investigate the effect of a customized rehabilitation technology, the Diabetic Foot Guidance System (SOPeD), on DPN status, functional outcomes and gait biomechanics in people with DPN. METHODS/DESIGN: Footcare (FOCA) trial I is a randomized, controlled and parallel two-arm trial with blind assessment. A total of 62 patients with DPN will be allocated into either a control group (recommended foot care by international consensus with no foot exercises) or an intervention group (who will perform exercises through SOPeD at home three times a week for 12 weeks). The exercise program will be customized throughout its course by a perceived effort scale reported by the participant after completion of each exercise. The participants will be assessed at three different times (baseline, completion at 12 weeks, and follow-up at 24 weeks) for all outcomes. The primary outcomes will be DPN symptoms and severity classification. The secondary outcomes will be foot-ankle kinematics and kinetic and plantar pressure distribution during gait, tactile and vibration sensitivities, foot health and functionality, foot strength, and functional balance. DISCUSSION: As there is no evidence about the efficacy of rehabilitation technology in reducing DPN symptoms and severity or improving biomechanical, clinical, and functional outcomes for people with DPN, this research can contribute substantially to clarifying the therapeutic merits of software interventions. We hope that the use of our application for people with DPN complications will reduce or attenuate the deficits caused by DPN. This rehabilitation technology is freely available, and we intend to introduce it into the public health system in Brazil after demonstrating its effectiveness. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04011267. Registered on 8 July 2019.

Ultrasound-Guided Percutaneous Dilational Tracheostomy: A Systematic Review of Randomized Controlled Trials and Meta-Analysis.

INTRODUCTION: Percutaneous dilational tracheostomy (PDT) is a common and increasingly used procedure in the intensive care unit (ICU). It is usually performed with bronchoscopy guidance. Ultrasound has emerged as a useful tool in order to assist PDT, potentially improving its success rate and reducing procedural-related complications. OBJECTIVE: To investigate whether the ultrasound-guided PDT is equivalent or superior to the bronchoscopy-guided or anatomical landmarks-guided PDT with regard to procedural-related and clinical complications. METHODS: A systematic review of randomized clinical trials was conducted comparing an ultrasound-guided PDT to the control groups (either a bronchoscopy-guided PDT or an anatomical landmark-guided PDT) in patients undergoing a PDT in the ICU. The primary outcome was the incidence of major procedural-related and clinical complication rates. The secondary outcome was the incidence of minor complication rates. Random-effect meta-analyzes were used to pool the results. RESULTS: Four studies fulfilled the inclusion criteria and they were analyzed. The studies included 588 participants. There were no differences in the major complication rates between the patients who were assigned to the ultrasound-guided PDT when compared to the control groups (pooled risk ratio [RR]: 0.48; 95% confidence interval [CI]: 0.13-1.71, I2 = 0%). The minor complication rates were not different between the groups, but they had a high heterogeneity (pooled RR: 0.49; 95% CI 0.16-1.50; I2 = 85%). The sensitivity analyzes that only included the randomized controlled trials that used a landmark-guided PDT as the control group showed lower rates of minor complications in the ultrasound-guided PDT group (pooled RR: 0.55; 95% CI: 0.31-0.98, I2 = 0%). CONCLUSION: The ultrasound-guided PDT seems to be safe and it is comparable to the bronchoscopy-guided PDT regarding the major and minor procedural-related or clinical complications. It also seems to reduce the minor complications when compared to the anatomical landmark-guided PDT.

Alternative HPV vaccination schedules in Latin America / Los esquemas alternativos de vacunación contra VPH en América Latina

Abstract: In 2008, the first HPV vaccination program in Latin America started in Panama, targeting girls aged 10-11 years with a 3-dose vaccine schedule, an initiative that was to be followed by other Latin American countries after local feasibility and population acceptability evaluations were completed. A 3-dose vaccine regimen over six months was originally chosen for HPV vaccines, copying the Hepatitis B vaccine schedule (0, 1-2, 6 months). Alternative vaccine schedules have been proposed afterwards based on: i) noninferior immunogenicity or immune response levels compared to those at which clinical efficacy has been proven (i.e., those observed in a 3-dose HPV vaccine schedule in women aged 15-26), and, ii) proven efficacy in clinical trials and/or effectiveness among women who were provided less than three doses due to a lack of adherence to a 3-dose vaccine schedule. In 2014, based on the available evidence and the potential increase in coverage by expansion of vaccination target groups, particularly in low and middle income countries (LMIC), the World Health Organization recommended a 2-dose schedule with at least a 6-month interval between doses for females up to 15 years of age and a 3-dose schedule for older women. More recently, it has been suggested that 1-dose HPV vaccination schemes may provide enough protection against HPV infection and may speed up the introduction of HPV vaccination in LMIC, where most needed.

Resumen: En 2008, se inició en Panamá el primer programa de vacunación contra el virus del papiloma humano (VPH), dirigido a niñas de 10 a 11 años, utilizando un esquema de tres dosis en seis meses, iniciativa que fue adoptada por otros países de la región tras evaluar la aceptabilidad en la población y la viabilidad de llevar a cabo el programa. Inicialmente, el esquema de tres dosis para las vacunas contra el VPH se basó en el utilizado en la vacunación contra la hepatitis B (0, 1-2, 6 meses). Posteriormente, se han propuesto esquemas de vacunación alternativos, utilizando evidencia sobre: i) la inmunogenicidad o niveles de respuesta inmune no inferiores a aquéllos con los cuales la eficacia clínica de la vacuna fue probada (es decir, aquéllos observados con tres dosis en mujeres de 15 a 26 años); y ii) la eficacia demostrada en ensayos clínicos y efectividad demostrada en mujeres a quienes se vacunó con menos de tres dosis debido a falta de adherencia al esquema completo de tres dosis. En 2014, la Organización Mundial de la Salud recomendó un esquema de dos dosis con al menos seis meses de intervalo entre dosis para mujeres de hasta 15 años de edad y uno de tres dosis para mujeres mayores. La recomendación se basó en la evidencia disponible hasta entonces y a un posible aumento en cobertura mediante la ampliación de los grupos etarios a vacunarse, particularmente en países de ingresos bajos y medios (PIBMs). Más recientemente, se ha sugerido un esquema de vacunación contra el VPH de una sola dosis, el cual podría proporcionar suficiente protección contra la infección por VPH y así acelerar la introducción de la vacunación contra el VPH en PIBMs donde más se necesita.

The efficacy of adding group behavioral activation to usual care in patients with fibromyalgia and major depression: design and protocol for a randomized clinical trial.

BACKGROUND: Fibromyalgia and major depression frequently co-occur. Patients with both conditions have a worse prognosis and higher disability, and their treatment options are scarce. Behavioral activation (BA) may be an especially useful intervention for these patients, as it targets mechanisms of action that seem to be common to both disorders. Nevertheless, its efficacy has not been examined in people with both conditions. We describe the design and rationale of a randomized clinical trial aimed to evaluate the efficacy of adding BA (applied in groups) to usual care in order to reduce the severity of depressive symptoms (primary outcome) among Chilean women with fibromyalgia and major depression (N = 90). Pain intensity, fibromyalgia impact, pain catastrophizing and hypervigilance, physical health symptoms, environmental reward, and BA will be evaluated as secondary outcomes. METHODS: Women will be randomized to an experimental arm (n = 45) which will receive usual care (UC) for fibromyalgia with comorbid depression plus BA; and a comparison arm, which will receive only UC for fibromyalgia with comorbid depression (n = 45). Outcome assessment will take place at four time points: (1) at baseline, (2) when the experimental arm is under treatment (between sessions 6 and 7), (3) immediately after the experimental arm complete the treatment, and (4) at a 3-month follow-up. The following instruments will be used: Chilean version of the Patient Health Questionnaire-9 (PHQ-9), Composed Pain Intensity Index, Fibromyalgia Impact Questionnaire Revised (FIQ-R), Pain Catastrophizing Scale (PCS), Pain Vigilance and Awareness Questionnaire (PVAQ), Patient Health Questionnaire (PHQ-15), Reward Probability Index (RPI), and the Activation subscale of the Behavioral Activation for Depression Scale (BADS). DISCUSSION: We expect that, after treatment, the group receiving BA should experience greater reductions in the primary and secondary outcomes than the group receiving only UC. These reductions should be both statistically and clinically significant and will be maintained at follow-up. This study will contribute to facilitate the integrated treatment of fibromyalgia and depression. TRIAL REGISTRATION: ClinicalTrials.gov under the name "Testing Interventions for Patients with Fibromyalgia and Depression," Identifier: NCT03207828 . Registered on 5 July 2017 (last update posted 21 September 2017).

Aerobic exercise program with or without motor complexity as an add-on to the pharmacological treatment of depression - study protocol for a randomized controlled trial.

BACKGROUND: Patients with major depression disorder presents increased rates of cognitive decline, reduced hippocampal volume, poor sleep quality, hypertension, obesity, suicidal ideation and behavior, and decreased functionality. Although continuous aerobic exercise (CAE) improves some of the aforementioned symptoms, comorbidities, and conditions, recent studies have suggested that performing aerobic exercise with motor complexity (AEMC) may be more beneficial for cognitive decline, hippocampal volume, and functionality. Therefore, this randomized controlled trial will compare the effects of CAE and AEMC on depression score, cognitive function, hippocampal volume, brain-derived neurotrophic factor expression, sleep parameters, cardiovascular risk parameters, suicidal behavior, functionality, and treatment costs in patients with depression. METHODS/DESIGN: Seventy-five medicated patients with depression will be recruited from a Basic Healthcare Unit to participate in this prospective, parallel group, single blinded, superiority, randomized controlled trial. Patients with depression according to DSM-V criteria will be balanced and randomly assigned (based on depression scores and number of depressive episodes) to a non-exercising control (C), CAE, and AEMC groups. The CAE and AEMC groups will exercise for 60 min, twice a week for 24 weeks (on non-consecutive days). Exercise intensity will be maintained between 12 and 14 points of the rating of perceived exertion scale (~ 70-80% of the maximum heart rate). The CAE group will perform a continuous aerobic exercise while the AEMC group will perform exercises with progressively increased motor complexity. Blinded raters will assess patients before and after the intervention period. The primary outcome measure will be the change in depression score measured by the Montgomery-Asberg Depression Rating Scale. Secondary outcomes will include measures of cognitive function, hippocampal volume, brain-derived neurotrophic factor expression, sleep parameters, cardiovascular risk parameters, suicidal behavior, functionality, and treatment costs. DISCUSSION: This study was selected in the call of public policy programs for the Brazilian Unified National Health System - "PPSUS 2015". To our knowledge, this is the first pragmatic trial to test the effect of adding AEMC to the pharmacological treatment of patients with depression and to evaluate the possible reductions in depression symptoms and healthcare costs. TRIAL REGISTRATION: Brazilian Clinical Trials Registry (ReBec) - RBR-9zgxzd - Registered on 4 Jan. 2017.

Comparable efficacy of adapalene 0.3% gel and tretinoin 0.05% cream as treatment for cutaneous photoaging.

BACKGROUND: Adapalene has been previously evaluated as a treatment for actinic keratosis (AK) and solar lentigines and shown to improve signs of photoaging. OBJECTIVES: To evaluate whether adapalene 0.3% gel is non-inferior to tretinoin 0.05% cream as treatment for photoaged skin. MATERIALS & METHODS: An investigator-blinded, parallel-group comparison study was conducted in Brazil. Subjects were randomised in a 1:1 ratio to receive, once daily, adapalene 0.3% gel or tretinoin 0.05% cream. Subjects were evaluated at Weeks 1, 4, 8, 12, 16, 20 and 24, based on clinical signs of cutaneous photoaging, histopathological and digital morphometric findings, as well as safety and tolerability. RESULTS: A comparison of clinical efficacy showed that both treatments did not differ significantly regarding clinical evaluation of the following criteria: global cutaneous photoaging, periorbital wrinkles, ephelides/melanosis, forehead wrinkles, and AK. CONCLUSION: Adapalene 0.3% gel showed non-inferior efficacy to tretinoin 0.05% cream as treatment for photoaged skin, with a similar safety profile. Adapalene 0.3% gel may therefore be considered a safe and effective option for the treatment of mild or moderate photoaging.

Multicenter, randomized, double-blind clinical trial to evaluate efficacy and safety of combined glucosamine sulfate and chondroitin sulfate capsules for treating knee osteoarthritis.

OBJECTIVES: To compare the efficacy and safety of a new fixed dose combination of glucosamine sulfate and chondroitin sulfate capsules (GS/CS) versus the fixed dose combination of glucosamine hydrochloride and chondroitin sulfate (Cosamin DS®) in capsules in patients with osteoarthritis (OA) of the knee. METHODS: Multicenter, randomized, double-blind study. Participants with knee OA Kellgren-Lawrence grades 1 to 3 and VAS of symptoms ≥4 cm were randomized to receive GS/CS or Cosamin DS® over 12 weeks. The primary efficacy endpoint was the evaluation of the analgesic efficacy by the investigator. Secondary efficacy endpoints included: joint pain and swelling, investigator efficacy of the medication, and the use of rescue medication. Adverse events and drug tolerability were analyzed. RESULTS: One hundred patients were randomized, and 50 patients were allocated to each group. The analgesic efficacy evaluated by the investigator in the GS/CS group was 88.9, 95%CI: 75.2, 95.8% and in the Cosamin DS® group was 85.4%; 95%CI: 70.1, 93.4%. The mean reduction in the pain intensity was significant in both groups (p < 0.001), with no difference between them. The primary efficacy analysis demonstrated the non-inferiority of the GS/CS group compared with the Cosamin DS® group; the lower limit of the 90% confidence interval (CI) between the two groups (- 8.39%) was higher than the established margin of non-inferiority of - 10.00%. Improvement in other efficacy outcomes was observed, again without differences between groups. Adverse events were similar between groups and both presented good tolerability. CONCLUSIONS: The new fixed-dose formulation of GS/CS is effective in treating knee OA, presenting a good safety and tolerability profile. TRIAL REGISTRATION: ( https://clinicaltrials.gov/ct2/show/NCT00955552?term=NCT00955552&rank=1 ; ClinicalTrials.gov ; register number NCT00955552; First randomized patient: 08/17/2010).

[Alternative HPV vaccination schedules in Latin America].

In 2008, the first HPV vaccination program in Latin America started in Panama, targeting girls aged 10-11 years with a 3-dose vaccine schedule, an initiative that was to be followed by other Latin American countries after local feasibility and population acceptability evaluations were completed. A 3-dose vaccine regimen over six months was originally chosen for HPV vaccines, copying the Hepatitis B vaccine schedule (0, 1-2, 6 months). Alternative vaccine schedules have been proposed afterwards based on: i) noninferior immunogenicity or immune response levels compared to those at which clinical efficacy has been proven (i.e., those observed in a 3-dose HPV vaccine schedule in women aged 15-26), and, ii) proven efficacy in clinical trials and/or effectiveness among women who were provided less than three doses due to a lack of adherence to a 3-dose vaccine schedule. In 2014, based on the available evidence and the potential increase in coverage by expansion of vaccination target groups, particularly in low and middle income countries (LMIC), the World Health Organization recommended a 2-dose schedule with at least a 6-month interval between doses for females up to 15 years of age and a 3-dose schedule for older women. More recently, it has been suggested that 1-dose HPV vaccination schemes may provide enough protection against HPV infection and may speed up the introduction of HPV vaccination in LMIC, where most needed.

En 2008, se inició en Panamá el primer programa de vacunación contra el virus del papiloma humano (VPH), dirigido a niñas de 10 a 11 años, utilizando un esquema de tres dosis en seis meses, iniciativa que fue adoptada por otros países de la región tras evaluar la aceptabilidad en la población y la viabilidad de llevar a cabo el programa. Inicialmente, el esquema de tres dosis para las vacunas contra el VPH se basó en el utilizado en la vacunación contra la hepatitis B (0, 1-2, 6 meses). Posteriormente, se han propuesto esquemas de vacunación alternativos, utilizando evidencia sobre: i) la inmunogenicidad o niveles de respuesta inmune no inferiores a aquéllos con los cuales la eficacia clínica de la vacuna fue probada (es decir, aquéllos observados con tres dosis en mujeres de 15 a 26 años); y ii) la eficacia demostrada en ensayos clínicos y efectividad demostrada en mujeres a quienes se vacunó con menos de tres dosis debido a falta de adherencia al esquema completo de tres dosis. En 2014, la Organización Mundial de la Salud recomendó un esquema de dos dosis con al menos seis meses de intervalo entre dosis para mujeres de hasta 15 años de edad y uno de tres dosis para mujeres mayores. La recomendación se basó en la evidencia disponible hasta entonces y a un posible aumento en cobertura mediante la ampliación de los grupos etarios a vacunarse, particularmente en países de ingresos bajos y medios (PIBMs). Más recientemente, se ha sugerido un esquema de vacunación contra el VPH de una sola dosis, el cual podría proporcionar suficiente protección contra la infección por VPH y así acelerar la introducción de la vacunación contra el VPH en PIBMs donde más se necesita.