Trends and projections of hepatitis C virus epidemiology in Latin America

Authors


Correspondence
Homie Razavi, Center for Disease Analysis, Kromite, 901 Front Street, Suite 291, Louisville, CO 80027, USA
Tel: +1 720 890 4848
Fax: +1 303 552 9119
E-mail: hrazavi@kromite.com

Abstract

Background and aim: The purpose of the present investigation is to provide an analysis of previous works on the epidemiology of the hepatitis C virus (HCV) infection from six countries throughout Latin America, to forecast the future HCV prevalence trends in Argentina, Brazil, Mexico and Puerto Rico, and to outline deficiencies in available data, highlighting the need for further research.

Methods: Data references were identified through indexed journals and non-indexed sources. Overall, 1080 articles were reviewed and 150 were selected based on their relevance to this work. When multiple data sources were available for a key assumption, a systematic process using multi-objective decision analysis (MODA) was used to select the most appropriate sources. When data were missing, analogues were used. Data from other countries with similar risk factors and/or population compositions were used as a proxy to help predict the future trends in prevalence.

Results: The review indicates that the dominant genotype is type 1. HCV prevalence in the analysed countries ranges from 1 to 2.3%. The Latin American countries have been very proactive in screening their blood supplies, thus minimizing the risk of transmission through transfusion. This suggests that other risk factors are set to play a major role in continued new infections. The number of diagnosed and treated patients is low, thereby increasing the burden of complications such as liver cirrhosis or hepatocellular carcinoma. The HCV prevalence, according to our modelling is steady or increasing and the number of infected individuals will increase.

Conclusions: The results herein reported should provide a foundation for informed planning efforts to tackle hepatitis.

Abbreviations
HCV,

hepatitis C virus;

I-C3,

International Conquer C Coalition;

IDU,

injection drug use;

PAHO,

Pan American Health Organization;

R-C3,

Regional Conquer C Coalition;

SUS,

Sistema Único de Saúde-Brazil National Health System;

SVR,

sustained viral response.

Chronic hepatitis C is a leading cause of cirrhosis and hepatocellular carcinoma (1, 2), and a major indication for liver transplantation (3). The burden of the disease is expected to increase around the world as the disease progresses in patients who contracted hepatitis C virus (HCV) years ago. A better understanding of HCV prevalence can help medical communities and government agencies manage the increase in the disease burden and develop strategies in light of the emergence of several potent anti-HCV therapies.

There have been numerous articles published describing the status of HCV infection in Latin America. The objective of this paper is to provide a review of previous works and forecast the future prevalence trends in the region based on data from select countries/territories: Argentina, Brazil, Mexico, Peru, Puerto Rico and Venezuela. In addition, it outlines deficiencies in available data, highlighting the need for further research.

Methodology

The methodology to assess the HCV epidemiology was described previously (4). This work focuses on applying this methodology to specific countries within Latin America.

References were identified through two sources: indexed journals and non-indexed sources. Indexed articles were found by searching PubMed, Medigraphic and Imbiomed using the following terms: ‘hepatitis C AND country name AND (incidence OR prevalence OR mortality OR viremia OR genotype OR diagnosis OR treatment OR svr).’ In this work, 1080 abstracts were reviewed and 150 articles were selected based on their relevance to this work. In addition, non-indexed sources were identified through searches of individual countries' ministry of health websites and international health agency reports. Finally, authors from each country provided government reports and proceedings of local conferences that were not published in the scientific literature. The search included publications in Spanish and Portuguese, although English articles accounted for about 90% of the data sources.

When multiple data sources were available for a key assumption, a systematic process using multi-objective decision analysis was used to select the most appropriate sources (4). When insufficient data were available, analogues were used. Data from other countries with similar risk factors and/or population compositions were used as a proxy to help predict the future trends in prevalence. Gaps in data were also highlighted to help guide future research. The future epidemiology trends were forecasted using a patient flow model as described previously (4).

Unless noted, the prevalence values referred to the prevalence of anti-HCV antibodies that included spontaneously cured and treated/cured individuals. The HCV genotype distribution values were based on studies in the viraemic, or HCV RNA-positive, population. Community-based studies were reported, but the focus of this study was to identify/estimate prevalence in the general population. Since the first- and second-generation immunoassay tests provided false-positive results, which overestimated the total infected population (5, 6), care was taken to use only those studies that used the latest tests to estimate the country's prevalence. In some countries, blood donor data were the main source available for prevalence. The infected general population was composed of high-risk groups [e.g. persons with a current or a previous history of injection drug use (IDU), dialysis patients and immune compromised persons] as well as non-high-risk groups that contracted the disease through contact with infected blood (e.g. nosocomial infections, dental procedures, etc.). The blood donor population was a good proxy for the latter group. The adult population was defined as ≥20 years old.

A key assumption in this paper was that flat or increasing prevalence among blood donors implied the same trend in the general population. Blood bank data underestimated the true HCV prevalence, but the trend in the donors provided a conservative estimate of the trend in the general population, given that the majority of the infected population in Latin America fell into non-high-risk groups. With the exception of Puerto Rico, IDU was not as common in Latin America as in the USA or the Western European countries. With most new cases arising from non-high-risk behaviour (nosocomial, vitamin injection, etc.), the trend in the general population was assumed to mirror the trend observed among blood donors.

In Argentina, Brazil and Mexico, the blood bank data suggested a flat prevalence rate. Using this observation, we calculated the incidence rate required to maintain the overall prevalence rate constant in 2004–2006. In our model, prevalence was calculated each year from incidence, mortality and number of cured individuals. Using the risk factors in each country along with the age and gender distributions, we estimated mortality among the infected individuals (4). The number of treated patients was calculated from IMS Health audit unit data in each country (7). Units sold in each year were converted to the number of treated patients using the genotype distribution in each country, the duration of treatment for each genotype and compliance (8, 9). Sustained viral response rates by genotype from clinical studies were used to estimate the number of cured cases (8, 9). The information was fed into the model, and the incidence rate required to maintain the prevalence constant was calculated utilizing solver®, a Microsoft excel® add-in. A viraemic rate of 80% was used (10).

Pan American Health Organization (PAHO) yearly blood bank data were used to estimate the number of individuals diagnosed. Blood donor populations were very large in Latin America, with Brazil reporting over three million blood donors annually. Since blood donors were screened for pre-existing HCV infection, all reported cases were assumed to be newly diagnosed. The total number of diagnosed individuals was estimated by assuming that half as many individuals were diagnosed through physicians and hospitals as compared with blood banks.

This work reports the results of one particular scenario; current trends in prevalence, incidence, mortality, diagnosis, treatment and response rates will continue at the same rate. However, it does not take into account future events like the introduction of new therapies or a significant increase in treatment rates because of changes in policy. Our model is designed to analyse numerous scenarios, but that is beyond the scope of this particular article.

Results

As part of this work, Argentina, Brazil, Mexico, Puerto Rico, Peru and Venezuela were selected for an in-depth analysis, and HCV prevalence was forecasted for the first four countries.

Argentina

To date, most seroprevalence studies were the result of spontaneous demand because of increases in reported cases (11) and have mainly focused on small communities or high-risk groups (12–16). In order to develop effective intervention and treatment programmes, a better understanding of the current trends in Argentina was necessary.

Risk factors

Studies reporting on transmission found multiple risk factors, making it difficult to establish the predominant source with certainty. Blood transfusion accounted for 7.5–22.5% of the current infections (12, 16, 17). Blood bank screening was initiated in 1993 with 70% coverage by 1995 (13) and 100% screening coverage in 2006, suggesting that newly acquired infections were likely arising from other sources. IDU was reported in 1.2–31.3% of the prevalent population (18–20). Other potential risk factors included nosocomial-related risks (surgeries, IV/IM injections, vial reuse, injections with glass syringes), inhalation drug use through contaminate tools, acupuncture and tattooing (12, 16, 17, 21–23).

Prevalence

The prevalence was estimated at 1.5% for all ages and 2.0–2.5% among adults. All studies to date were in select populations of blood donors and there were no general population studies available. The highest-ranking non-blood bank population study was the Insua study carried out in the Buenos Aires province in 1472 individuals through a cluster sample survey aged 1–100 years during 2003 (16). It reported a prevalence of 0.87%, with the highest prevalence in the 40–49-year age group (2.51%), although the data may not be representative of the entire country. According to the Argentine Consensus of 2007, the prevalence in the general population was projected at about 2% (23). In the absence of a general population study, we used Brazil as an analogue, with an estimated prevalence of 1.5% for all ages and 2.0–2.5% among adults.

The future trend of prevalence was inferred from blood bank data (21, 24–27) (Table 1). The donor prevalence remained flat at 0.65%, except for 2005–2006, when the composition of the blood donor sample changed. The CNRL-ANLIS data (18) (Table 2) showed a relatively flat prevalence rate between 2002 and 2006 in a smaller sample size. Altogether, these data suggested a relatively constant prevalence among blood donors.

Table 1.   Blood bank data reported by Pan American Health Organization for Argentina
Argentina200020012002200320042005*2006*2007
  • *

    2005 and 2006 data represent the public sector and correspond to 50% of the National Blood System.

Units donated804 018804 018680 439780 440NR365 313345 502NR
% screened98.33%98.33%99.30%99.30%NR100.00%100.00%NR
Prevalence (%)0.660.66NR0.65NR0.980.95NR
Diagnosed53075307 5073 35803282 
Table 2.   Argentina blood bank data reported by CNRL-ANLIS
Argentina2000200120022003200420052006
Units donated444 182430 890363 658380 793147 475109 432422 916
Prevalence (%)0.780.780.740.780.640.790.69

Using audit data, the number of treated individuals was calculated (Table 3). Although the number of treated persons increased significantly between 2004 and 2006, the treatment rate remained below 0.2%. To maintain a constant prevalence rate in 2004–2006, as indicated by blood donor data, an incidence rate of 44.7 per 100 000 was required. The model predicted a decline in the prevalence rate by 2021 because of an increase in mortality as the prevalent population ages; yet the total number of infections continued to increase. In the current scenario, we estimated a prevalent population size of 647 600 by 2021 (Fig. 1). The very low treatment rates did not offset new cases, leading to an overall growth in the number of infected individuals.

Table 3.   Projected hepatitis C virus-infected populations for Argentina
 200420062021
Prevalence rate (%)1.501.501.45
Overall prevalence575 600586 800647 600
Viraemic incidence13 70014 30218 700
Viraemic mortality (all causes)10 70011 00019 000
Treated patients600900 
Treatment rate (%)0.100.15 
Figure 1.

 Forecasted hepatitis C virus (HCV)-infected populations in Argentina.

Genotype

Genotype 1 was the most common (11, 15, 17, 19, 20, 28–31), with genotype 1b reported most frequently (15, 28, 32, 33). Ridruejo et al. (17) reported the following genotype distribution: G1 (59.1%), G2 (21.7%), G3 (17.8%) and G4 (1.3%).

Diagnosed

Diagnosis and treatment rates were not reported; however, we estimated the number of diagnosed individuals based on PAHO blood bank data. Accordingly, 61 700 cases were diagnosed in the blood donor population between 1995 and 2006, assuming that infected individuals were not allowed to donate again. Using a 50% gross up factor for individuals diagnosed through routine screening at clinics and hospitals, we estimate that by 2006, close to 17% (or 92 580 cases) of the prevalent population was diagnosed. This represents a significant gap between diagnosed and treated individuals, emphasizing the need for the establishment of a national programme to better address treatment needs (23).

Brazil

The National Health System [Sistema Único de Saúde (SUS)] in Brazil is one of the world's largest public health systems, providing healthcare for more than 180 million. In 2002, the government created the National Viral Hepatitis Program responsible for developing prevention, surveillance and assistance through the Ministry of Health (34). Given that the mortality rate associated with hepatitis C increased by 30% in the past decade, identification and treatment of infected individuals was recognized as important (34) and the government established a formalized system for reporting newly diagnosed cases of HCV infections (35, 36).

Risk factors

The primary risk factors were: (i) individuals who received blood and blood product transfusions before 1993 and (ii) IDU who were typically <30 years of age (37, 38). Using 219 patients seen at a hepatitis outpatient clinic in Sao Paulo from 1990 to 1997, transfusion was identified in 31% of patients and IDU in 11% (39). Given that blood screening started in 1992, transfusion applied primarily to a prevalent, not an incident, population although the risk of transfusion-transmitted HCV was still higher than that in Western European countries and the USA (40). Urban patients had a higher prevalence rate than those in rural communities (38). Regionally, a new risk factor emerged during the past 20 years. Gluconergan, an energetic drug, grew in popularity. This drug was self-administered intravenously and needle sharing and reuse were common (41). Its impact on the incidence and prevalence of HCV infection has yet to be determined. In one study, nearly half of the anti-HCV+blood donors had used Gluconergan (41).

Prevalence

The prevalence was estimated at 1.5% for all ages (6 months to 98 years) and 2.5% among adults. Most of the prevalence studies focused on specific subsets of the population, which could not be used for extrapolative purposes (37, 42–46). However, there were a limited number of community-based prevalence studies that spanned multiple age cohorts and sampled large metropolitan areas (Salvador and Sao Paulo) reporting relatively close prevalence rates (1.25–1.50%) (38, 47, 48). They were consistent with the Ministry of Health's (Ministério da Saúde) estimate of 0.9–1.9% (36, 49). Prevalence increased in the 30+ population, with a peak in ages 50–59 and 20+ population accounting for 95% of total infected (47, 50). We used a 2004 prevalence of 1.5% in line with Zarife's 1308 sampled community-based study (48). A prevalence of 2.5% among adults was calculated when a lower infection rate among the youth was taken into consideration (48, 50, 51).

Several studies quantified prevalence in blood donor populations, with a range of 0.3–1.7% (40, 52–59). PAHO reported a decrease in prevalence in blood donors from 2000 to 2002, which remained relatively constant thereafter (21, 26, 27) (Table 4).

Table 4.   Blood bank data reported by Pan American Health Organization for Brazil
 2000*2001*200220032004200520062007
  • *

    Reported from 27 centres only.

  • Partial data. Public services of the states of Paraná, Minas Gerais, Roraima, Tocantins, Ceará, Sergipe, Goiás, Mato Grosso, Mato Grosso do Sul and Amazonas.

Units donated1 827 9371 763 1303 014 1842 931 813NR3 738 5803 129 8821 305 785
% screened100.00%100.00%100.00%100.00%NR100.00%NR100.00%
Prevalence (%)0.670.780.520.51NR0.52NR0.53
Diagnosed12 24713 75215 67414 952 19 441 6 921

A summary of key infected populations is shown in Table 5. We estimated that the incidence rate required to maintain the 2004–2007 prevalence rate constant, after reducing for mortality and the number of cured individuals, was 44.5 per 100 000 persons. The size of the HCV prevalent population was projected to increase and exceed three million by 2011 (Fig. 2). Although Brazil has been very pro-active in treating HCV-infected individuals (22 700 in 2007), the number of new infections was projected to outweigh the treated and cured population. A strategy to significantly reduce incidence is also required.

Table 5.   Projected hepatitis C virus-infected populations for Brazil
 200420072021
Prevalence rate (%)1.501.501.46
Overall prevalence2 764 4002 875,5003 230 700
Viraemic incidence65 40071 748103 500
Viraemic mortality (all causes)40 70050 10099 900
Treated patients410022 700 
Treatment rate (%)0.150.79 
Figure 2.

 Forecasted hepatitis C virus (HCV)-infected populations in Brazil.

Genotype

There were multiple references reporting the genotype distribution in different populations (39, 41, 48, 60–70). Among these studies, there were some consistent findings: G1 was the most frequent genotype in all regions, followed by G3. The Campiotto study assessed 1688 HCV patients from multiple regions and reported the following genotype distribution: G1 (64.9%), G2 (4.6%), G3 (30.2%) and G4 (0.2%) (65).

Diagnosed

We estimated the number of diagnosed individuals based on PAHO blood bank data. Accordingly, 187 360 cases were diagnosed in the blood donor population in 1995–2007 assuming that infected individuals were not allowed to donate again. Using a 50% gross up factor for individuals diagnosed through routine screening at clinics and hospitals, we estimated that by 2007, close to 10% (or 281 040 cases) of the prevalent population was diagnosed. In comparison, there were 94 992 reported cases in 1994–2007 by SUS (71, 72), which included both acute and chronic cases and represented the total diagnosed population. This suggests that SUS is capturing a fraction of the total diagnosed population.

Mexico

Mexico has conducted one of the largest National Health Surveys in the region. In the 2000 study, a total of 90 916 random adult individuals across the country were included, from which 21 271 serums were randomly selected for anti-HCV analysis (73). The study excluded institutionalized individuals and active IDU, and it focused on adults aged 20–70.

Risk factors

The key historical risk factor was blood transfusion. Approximately 64–72% of the infected population contracted HCV from contaminated blood, while 2.5% was from IDU (mostly in the Northern part of the country) (74, 75). The blood transfusion risk factor applied only to the existing prevalent population, since blood screening started in 1993 and 80% coverage was achieved by 1996 (73). Today, over 95% of the blood supply is screened for HCV, and a contaminated blood supply is not a major issue. The risk factors in the incident population were nosocomial infections, dental, IDU (mainly in the North), tattooing and other procedures that involve contact with infected blood (e.g. cosmetic procedures).

Prevalence

The prevalence was estimated at 1.4% in the adults and 0.95% in the total population in 2000. A considerable number of studies assessed the overall HCV prevalence (76–89). In addition, two meta-analyses summarized the prevalence in different populations and geographies (5, 90). Valdespino et al. reported the results of the National Health Survey (73). The HCV prevalence was estimated at 1.4% of the adults aged 20–79 (700 000 infected individuals). It was the highest in the North section of the country (2.0%), followed by the South (1.5%) and Central Mexico (1.1%). The adults accounted for approximately 50% of the total population in 2000 (51). We estimated a 2004 prevalence rate of 0.95% for the total population with an infected population size of 982 700. This result was in line with unpublished data by the authors for a study that tested 3253 individuals, of whom 30 (0.92%) were positive by ELISA, and 23 (76.6%) were polymerase chain reaction positive with a TaqMan>12.

The National Health Survey study shows a bimodal age distribution among infected individuals, suggesting that an increase in hepatitis C disease burden will be observed starting in 2015 when the oldest of the 30–39 infected population starts to reach the age of 55 (Fig. 3).

Figure 3.

 Hepatitis C virus (HCV) prevalence rate by age and gender in Mexico, 2000 (73).

The PAHO blood bank data (Table 6) showed that prevalence among blood donors remained constant in 2003–2007 (21, 26, 27). Using this observation, we estimated an incidence rate of 35.2 per 100 000. Using our mortality model, we forecasted 24 800 infected individuals died in 2004. In the same year, we calculated that 1 400 patients were treated. Although the number of treated patients in 2004–2006 increased, the overall treatment rate remained below 0.35% (Table 7). The future prevalence is shown in Fig. 4. Given the very low treatment rate, the total prevalence will surpass 1.2 million in 2020.

Table 6.   Blood bank data reported by Pan American Health Organization for Mexico
 20002001200220032004200520062007
Units donated1 234 4141 135 3971 027 2531 136 047NR1 351 2041 400 1371 501 641
% screened100.00%100.00%100.00%100.00%NR96.47%93.98%95.37%
Prevalence (%)0.720.700.690.66NR0.640.680.66
Newly diag.8888794870887498NR864895219911
Table 7.   Projected hepatitis C virus-infected populations for Mexico
 200420062021
Prevalence rate (%)0.950.951.01
Overall prevalence982 7001 002 9001 227 600
Viraemic incidence29 00031 04447 700
Viraemic mortality (all causes)24 80025 30037 000
Treated patients14003300 
Treatment rate (%)0.140.33 
Figure 4.

 Forecasted hepatitis C virus (HCV)-infected populations in Mexico.

Genotype

There have been a number of studies looking at the genotype distribution (5, 74, 75, 77, 81, 91, 92). The largest study of 8802 chronic patients reported G1 (70.36%), G2 (21.77%), G3 (7.18%) and G4 (0.3%) (92). Genotype 1b was the most common genotype: 32–41% (75, 91, 92).

Diagnosed

Each year, 7000–9000 HCV-infected individuals were diagnosed through the blood banks alone (Table 6). Assuming that another 50% were diagnosed by hospitals and physicians, 139 820 cases, or 14% of the infected population, were diagnosed between 1994 and 2007.

Puerto Rico

The HCV prevalence reported by the National Health and Nutrition Examination Survey (10) excludes the Puerto Rican population. Fortunately, a number of investigators studied HCV prevalence locally.

Risk factors

Injection drug use was the single most important risk factor. In a national survey, 50% of prevalent cases reported a history of IDU (93). Similarly, 47% of the samples in the Rodriguez-Perez et al. (94) study reported drug use, with 81% of these reporting needle sharing. Blood transfusions were also a risk factor before 1992. Thirteen to 30% of prevalent study populations recorded a history of transfusion (93, 94). Blood screening started in 1992; therefore, transfusion risk factor rate applied to a prevalent and not an incident population.

Prevalence

The prevalence was estimated at 2.3% in the adults aged 21–64 (93). Most prevalence studies were conducted on subgroups, such as IDUs, haemodialysis patients, orthopaedic trauma surgical patients and pregnant women (95–98).

Perez reported two community-based studies (93, 99). In the 2005 study, they sampled the non-institutionalized population, aged 21–64 years, residing in San Juan. Of the 970 participants, 6.3% were anti-HCV positive. Previous studies of IDUs in San Juan indicated a consistently higher frequency of drug injection and higher levels of needle-sharing behaviour than that in the USA. In San Juan, there was less access to syringe exchange programmes, and consequently, less availability of sterile injecting equipment, which may explain the higher prevalence (100–102).

They expanded their research to a random sample of all households in Puerto Rico in 2010, where 1654 non-institutionalized 21–64-year-olds were surveyed. Weighted prevalence was 2.3%, with non-significant variances between age cohorts until the age of 50–64, when prevalence declined by more than 50% to 1.3% (93). Prevalence was significantly higher in men (4.0%) than that in women (1.0%). Extrapolating to the entire population, there were approximately 89 500 individuals in 2004 who were anti-HCV positive.

Based on audit data, there were approximately 700 patients treated in 2004, representing <1% of the prevalent population (Table 8). Given the lack of health care coverage for many Puerto Ricans and the higher transmission risk associated with IDU, it was assumed that the prevalence rate was remaining, at minimum, constant in 2004–2006. Using the data reported above, an incidence rate of 65.1 per 100 000 was necessary. With high incidence and low treatment rates, the overall infected pool will reach 97 300 in 2021 (Fig. 5). Of course, an increasing prevalence between 2004 and 2006 would imply a higher incidence rate and a faster growing infected population.

Table 8.   Projected hepatitis C virus-infected populations for Puerto Rico
 200420062021
Prevalence rate (%)2.302.302.35
Overall prevalence89 50090 30097 300
Viraemic incidence200021012800
Viraemic mortality (all causes)210021002700
Treated patients700800 
Treatment rate (%)0.780.89 
Figure 5.

 Forecasted hepatitis C virus (HCV)-infected populations in Puerto Rico.

Genotype

The Rodriguez-Perez study of 447 chronic HCV patients reported the following genotype distribution: G1 (82.1%), G2 (12.1%), G3 (3.8%) and G4 (2%) (94). Genotype 1a was the most common subtype, accounting for 39.8% of all cases consistent with IDU as a key risk factor.

Diagnosed

The diagnosis rate appeared low in Puerto Rico. Ninety-three per cent of the anti-HCV+ individuals in the San Juan community-based prevalence survey and 80% of individuals in the countrywide prevalence study were unaware of their infection status (93, 99). This implied that only 7–20% of the population was previously diagnosed.

Peru

Risk factors

The risk factors in the HCV-infected populations were studied by Ferrandiz and collaborators (103), showing that in 1998–2004, the most frequent risk factors were haemodialysis 54.1%, transfusion 39.0%, history of major surgery 15.7%, chemotherapy 5.2%, health personnel 4.9% and acupuncture and/or tattoo 0.8%. Given the high level of blood screening, as reported by PAHO (21, 26, 27), contaminated blood was not expected to be a major source of infection today. However, nosocomial infections, along with the other listed risk factors, were likely to be a continued source of new cases.

Prevalence

The best estimate for prevalence was a range of 1–1.9% for all ages and 2.0–2.9% among adults. A number of studies assessed HCV prevalence (104–110). Most focused on high-risk groups or small subgroups. In the absence of a large national study, the best estimate of prevalence came from the Colichon Yerosh study in 2004 (106), whereby the prevalence rate among 2769 health workers was measured at 1.16%.

Blood bank data by PAHO (Table 9) suggested that the HCV prevalence in Peru increased among donors (21, 26, 27), indicating a large increase in incidence since 2005, a significant change in the composition of the donor population or the diagnosis methodology in recent years.

Table 9.   Blood bank data reported by Pan American Health Organization for Peru
 20002001200220032004200520062007
Units donated332 800347 250149 077145 665NR179 721174 196178 060
% screened100.00%100.00%99.40%98.86%NR76.38%100.00%100.00%
Prevalence (%)0.300.500.670.55NR0.921.220.90
Newly diag.9981736999801 165321251603

Genotype

Similar to other countries in the region, the predominant genotype was 1. Two studies analysed the breakout of genotype distribution (109, 111). Neither were general population studies, and yet both reached the same conclusion, finding subtype 1a as the most frequent. The Sanchez study of 50 patients from Lima reported the following genotype distribution: G1 (86%), G2 (2%) and G3 (10%). Genotype 1a accounted for 74% of all cases.

Venezuela

Risk factors

According to unpublished data by the authors, blood transfusion was the main historical cause of infection. With blood screening in place, new sources of infection were nosocomial, dental procedures, tattooing and other procedures that involve contact with infected blood (e.g. cosmetic procedures). It was important to note that IDU was not common in the country.

Prevalence

The best estimate of the general population prevalence rate was 0.95% for all ages and 1.4% in adults in 2000 using Mexico as an analogue. A number of studies assessed HCV prevalence, but they were all in select populations (112–115). As shown in Table 10, blood bank data showed that the prevalence among the donor population was the lowest among the countries studied (21, 26, 27). The rate in the general population was expected to be low, given that IDU was not common and blood supply was 100% screened. Mexico was used as an analogue. Similar to Mexico, a large portion of Venezuela's population (45%) was under the age 20 or over 80 years old (51), resulting in a significant difference in prevalence among all ages and adults only.

Table 10.   Blood bank data reported by Pan American Health Organization for Venezuela
 20002001200220032004200520062007
Units donated323 860345 953369 440342 526NR403 625NRNR
% screened100.00%100.00%100.00%100.00%NR100.00%NRNR
Prevalence (%)0.600.560.510.56NR0.37NRNR
Newly diag.19431937 1918 1493  

Genotype

Two studies assessed the genotype distribution (116, 117). The Fortes study of 809 patients from Caracas and 11 states reported the following genotypes: G1 (65.1%) and G2 (34.4%) (116). Subtype 1b was the most common in this study, accounting for 43.4% of all cases. However, the other studies showed that the split between genotype 1a and 1b was dependent on the population, with 1a being more common in blood donors and haemophiliac patients, while 1b was more common in haemodialysed and chronic hepatitis C patients.

Discussion

Our investigation is in agreement with previous work (118–121). However, our analysis was performed at the country level, rather than at the regional level, because of lack of adequate representative regional studies and the absence of surveillance programmes. We therefore included all quantifiable information and assessed the studies in each country, identifying the best set of assumptions based on local available data. Overall, existing studies in Latin America are not designed to carry out longitudinal analyses and capture temporal epidemiological changes.

Despite these limitations, the data produced remarkably similar results for genotype distribution. The review indicates systematically that the dominant genotype is type 1, consistent with previous findings (122). The 2010 estimated prevalence of hepatitis C in the analysed countries ranges from 1.4 to 2.5% in the adult population (Fig. 6). We estimate that 6.8–8.9 million adults are anti-HCV positive in Latin America.

Figure 6.

 Hepatitis C virus prevalence among adults and genotype distribution in select Latin American countries/territories.

The Latin American countries have been very proactive in screening their blood supplies, thus minimizing the risk of transmission through transfusion. Injection drug use is not as large a problem in Latin America as compared with the USA and Europe, and yet the prevalence in most of the countries studied is remaining flat or increasing. This suggests that other risk factors play a major role in new infections. The suspected risk factors are nosocomial infections, non-IDU forms of injections such as vitamin shots, inadequate needle disposal, dental procedures, tattooing and other procedures that involve contact with infected blood (e.g. cosmetic procedures). Further research is needed to understand the transmission of this disease in Latin America in order to develop strategies to eradicate it.

Another consistent and comparable finding in the analysed countries is that the number of treated patients is low, suggesting that the burden of complications such as liver cirrhosis or hepatocellular carcinoma will continue to increase. Overall, the data suggest insufficient access to health services and/or lack of awareness and education of the disease among the general population. A key finding of this analysis is that the number of diagnosed individuals is likely to be higher than anticipated, given the large number of individuals diagnosed through blood banks alone. The HCV prevalence, according to our modelling, is steady or increasing. In addition, the number of infected individuals will increase unless measures are adopted to minimize new cases and treat existing infected individuals. The results reported herein should provide a foundation for informed planning efforts.

Table 11 summarizes the major gaps in data by country/territory and highlights areas of unmet need. A qualitative system of stars was used to indicate the availability and quality of HCV epidemiology data by country. Prevalence, genotype distributions and an estimate of diagnosed patients through blood banks were available for most countries. In addition, some risk factor data were also on hand. Incidence data were absent across the region, except Brazil, which has a patient registry in place. However, it does not distinguish between acute and chronic cases.

Table 11.   Availability and quality of hepatitis C virus epidemiology data by country
 Risk factorsPrevalence rateGenotype distributionIncidence rateDiagnosis rate
  1. Prevalence, Risk Factors, Genotype Distribution, Diagnosis Rate, Treatment Rate
    *Estimate without a formal study
    **Small study in a select population (prevalence & diagnosed<1000; genotype <100, risk factors <200) or blood donors study
    ***Large study in a select population (prevalence & diagnosed >1000; genotype >100, risk factors >200)
    ****Small study in the general population (prevalence & diagnosed <1,000; genotype <100, risk factors <200)
    *****Large study in the general population (prevalence and diagnosed >1000; genotype >100, risk factors>200)
    Incidence
    *Estimate new infections without a formal study
    **Incidence study
    ***Country-wide registry-voluntary or with a low level of participation
    ****Country-wide registry-mandatory or with a high level of participation
    *****Country-wide registry-distinction between new and existing infections
Argentina********* **
Brazil********************
Mexico*************** **
Peru******** **
Puerto Rico*************** *****
Venezuela ******* **

The present study should help to increase awareness of the disease through the region. The modelling used may be extended to other Latin American countries with the intention to predict the disease burden and implement informed interventions, particularly as new therapies are becoming available for chronic hepatitis C. It should also foster attentiveness towards the implementation of educational and preventive campaigns.

Acknowledgements

This study was completed through the International Conquer C Coalition (I-C3) organization. Funding for this programme was provided through an educational grant provided by Merck & Co. Inc. and support from the Center for Disease Analysis. We are indebted to all I-C3 and Regional Conquer C Coalitions (R-C3) members for their contributions and comments. Finally, we would like to acknowledge Regina Klein of Center for Disease Analysis for her assistance with data gathering and analysis in the preparation of this document.

Disclosures: DK Advisory Board: MSD. HAR, CW Grant: Merck. JFSA Nothing to disclose. FB Advisor: BMS. Advisory board member: MSD/Schering-Plough, Janssen-Cilag. HSC Advisory board member: MSD. LD Nothing to disclose. FLG I-C3 membership sponsored by Schering-Plough/MSD. JFQ Nothing to disclose. FRP Speaker: Merck, Three River and Genentech. BR Nothing to disclose. FN Advisor: Schering-Plough, Roche, Abbott & Gilead. MS Grants: Schering-Plough/MSD, Bristol Myers Squibb, Vertex, Janssen-Cilag, Boehringer, Novartis, Wyeth, Human Genome Sciences, & Bayer. Advisory board member: Schering-Plough/MSD, Abbott, Bristol-Myers Squibb, & Vertex. Speaker: MSD, Bristol-Myers Squibb.

Ancillary