DISCUSIÓN DE RESULTADOS

This broad variation between regions can be partially explained by the frequency and extent to which different risk factors have contributed to the transmission of HCV (Alter 2006; Wasley and Alter 2000). The initial spread of HCV is said to have started in the early 20th century through the use of unsterile injections, invasive surgical procedures and the transfusion of blood products (Esteban, Sauleda, and Quer 2008). In 1966, Dr J Garrott Allen of Stanford University Medical School published findings (Allen 1966) of a community-based survey on residents of the very deprived area of Los Angeles commonly known as “Skid Row.” It was reported that the residents use of alcohol, drugs and unsterilized needles meant that they were highly likely to be infected with Hepatitis B, which was discovered earlier in 1967 (Starr and Rosen 1998). In the midst of headlines claiming a “transfusion roulette” and that “Prison Drug and Plasma Projects Leave Fatal Trail” (Rugaber 1969), Allen sent some of his findings to Professor Richard Titmus, a prominent social researcher based at the London School of Economics. In 1970, Titmuss published his classic work, “The Gift Relationship,” which was widely read in the USA and the UK.

Expanding on the growing anxiety around blood products and Allen’s findings, Titmuss discussed the values of private vs public healthcare. It was argued that blood donation in exchange for financial compensation would inevitably attract populations in most need of money. As was then as is now, it is those populations in more disadvantaged

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circumstances that are likely to suffer disproportionately the burden of poor health, and in countries where private healthcare predominates (as in the USA), the poor are also less likely to have received treatment for infection. Moreover, the exchange of blood for money meant that those in most need of money had financial incentive to hide any disqualifying medical condition, or to provide misleading information when questioned (Titmuss 1970).

By the mid-1970s, it was becoming more apparent that some patients were being infected with hepatitis that was not caused by the A or B variant, but by what was to be discovered nearly a decade later as HCV. The UK was a major importer of US-based commercially-manufactured blood products and it was thought amongst medical circles that the imported blood supply was major factor, with a report to the UK government in 1979 suggesting:

“[blood] products derived from paid donor plasma are known to carry a ten-fold increase in the risk of transmitting hepatitis over the risk from products derived from voluntary donations.”

(Archer 2009)

However, the Government continued to purchase the commercial blood products, with disasterous consequences. It has since been estimated that by the late 1980s, between 2 and 10% of blood transfusions in developed countries were infected with HCV (Alter,

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Purcell, Holland, Alling, and Koziol 1981; Colombo, Oldani, Donato, Borzio, Santese, Roffi, Vigano, and Cargnel 1987; Esteban, Gonzalez, Hernandez, Viladomiu, Sanchez, Lopez- Talavera, Lucea, Martin-Vega, Vidal, and Esteban 1990; Prati 2006). Most patients receiving clotting factor concentrates and blood transfusions (e.g. for haemophilia) were infected (Esteban, Esteban, Viladomiu, Lopez-Talavera, Gonzalez, Hernandez, Roget, Vargas, Genesca, and Buti 1989; Mannucci and Tuddenham 2001; Prati 2000; Prati 2002). In the UK, 4670 people treated with blood products in the 1970s and 1980s were infected with HCV, with 1243 also infected with HIV. Nearly 2000 people suffering haemophilia have died as a result. This was since been referred to by Robert Winston, a doctor and member of the House of Lords, as “the worst treatment disaster in the history of the NHS” (Dyer 2009).

Since the discovery of HCV, testing of blood donors (from 1992 onwards) has practically eradicated the spread of HCV through blood transfusions in many developed countries like the UK, with no further reported infections along this route since 1994 (Alter, Conry- Cantilena, Melpolder, Tan, Van Raden, Herion, Lau, and Hoofnagle 1997; Esteban, Sauleda, and Quer 2008; Gonzalez, Esteban, Madoz, Viladomiu, Genesca, Muniz, Enriquez, Torras, Hernandez, and Quer 1995; Hutchinson et al. 2006; Prati 2006; Shepard, Finelli, and Alter 2005). In developing countries, however, the situation is the obverse. Harvey J. Alter has recently put forward that HCV is now an epidemic “of two worlds” (Alter 2005). This is because in poorer countries, at least in part because of financial constraints (Miller and Pisani 1999), contaminated blood transfusions and the

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re-use of infected syringes are common, reported at 6.7 billion, or 39.3% of all injections, with an estimated 2.3 million new HCV infections per year, 200,000 HCV- related premature deaths, and 3.6 million years of life lost because of HCV-related liver complications (Hutin, Hauri, and Armstrong 2003).

Nowhere is this more evident than in Egypt (Figure 7.9), where infections targeting the liver have been likened to a curse (El-Zayadi 2004) and the prevalence of HCV has been estimated between 9% and over 20%, several times higher than any other country (Arafa, Hoseiny, Rekacewicz, Bakr, El-Kafrawy, Daly, Aoun, Marzouk, Mohamed, and Fontanet 2005; El-Raziky, El-Hawary, El-Koofy, Okasha, Kotb, Salama, Esmat, El-Raziky, Abouzied, and El-Karaksy 2004; Frank, Mohamed, Strickland, Lavanchy, Arthur, Magder, Khoby, Abdel-Wahab, Ohn, and Anwar 2000; Medhat, Shehata, Magder, Mikhail, Abdel- Baki, Nafeh, Abdel-Hamid, Strickland, and Fix 2002; Mohamed, Abdel-Hamid, Mikhail, Abdel-Aziz, Medhat, Magder, Fix, and Strickland 2005; Pybus, Drummond, Nakano, Robertson, and Rambaut 2003).

In rural areas and especially around the Nile delta, there have been staggering reports of HCV prevalence as high as 40-50% in the older adult population (Abdel-Aziz, Habib, Mohamed, Abdel-Hamid, Gamil, Madkour, Mikhail, Thomas, Fix, and Strickland 2000; Frank et al. 2000; Strickland 2006; Strickland, El-Kamary, Klenerman, and Nicosia 2008; Waked, Saleh, Moustafa, Raouf, Thomas, and Strickland 1995). Such is the extremity of the situation, Perz and Alter report:

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“Although the incidence of new infections in Egypt appears to have decreased in recent years, HCV has continued to be transmitted via iatrogenic exposures, blood transfusion, and other means ... Thus, an enormous swath of the population has been left with chronic HCV infection and the impact of the HCV epidemic in Egypt, which is already substantial, will manifest itself for decades to come”

(Perz and Alter 2006)

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Meanwhile, in the USA, Australia, the UK and other northern European countries, intravenous drug use (IDU) has become the dominant mode of HCV transmission for between 60 to 90% of infections during the last 35 years (Alter 2006; Alter 2007; Amon, Garfein, Ahdieh-Grant, Armstrong, Ouellet, Latka, Vlahov, Strathdee, Hudson, Kerndt, Des Jarlais, and Williams 2008; Crofts, Jolley, Kaldor, van Beek, and Wodak 1997; Dore, Law, MacDonald, and Kaldor 2003; Esteban, Sauleda, and Quer 2008; Hutchinson, Bird, and Goldberg 2005; Hutchinson et al. 2006; Pybus, Cochrane, Holmes, and Simmonds 2005; Wong 2000). The risk of infection through IDU is especially high during the first year (Sutton, Gay, Edmunds, Hope, Gill, and Hickman 2006), possibly when individuals might be trying IDU for the first time and most unaware of the dangers of sharing syringes. After 5 years of injecting, it is estimated that between 50% and 90% of individuals will have been exposed to HCV infection (Villano, Vlahov, Nelson, Lyles, Cohn, and Thomas 1997).

Other modes of transmission, although more unusual and less frequently cited within the literature include: vertical (mother-to-child); haemodialysis (kidney dialysis); sexual intercourse (especially if blood is present, for example during menstruation or anal sex); cocaine snorting; and unapparent percutaneous exposure. It is suggested that the UK has a similar rate of vertically transmitted infections to Western Europe at 3-7% (Gerner et al. 2006; Gibb, Goodall, Dunn, Healy, Neave, Cafferkey, and Butler 2000a; Hadzic 2001; Kowala-Piaskowska et al. 2004). HCV infection via sexual transmission, at approximately 5% (Leao, Teo, and Porter 2006), is considered to occur with much less efficiency

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compared with transmission through repeated percutaneous exposures. Similar comparisons are drawn with HCV infection via perinatal and occupational exposures, (Goldberg, Cameron, Sharp, Burns, Scott, Molyneaux, Scoular, Downie, and Taylor 2001b; Rischitelli, Harris, McCauley, Gershon, and Guidotti 2001; Roy, Kennedy, Bagg, Cameron, Hunter, and Taylor 2003b; Shepard, Finelli, and Alter 2005; Thorburn, Dundas, McCruden, Cameron, Goldberg, Symington, Kirk, and Mills 2001). (Bellentani et al. 2000) importantly note that there are lots of other risk factors which occur less frequently, however, and that many patients will have multiple risk factors for exposure that may interact to alter the course of the disease. (Alter 1997; Bellentani et al. 2000; Bronowicki, Venard, Botte, Monhoven, Gastin, Chone, Hudziak, Rihn, Delanoe, LeFaou, Bigard, and Gaucher 1997; Diseases 1998; Dore, Law, MacDonald, and Kaldor 2003; Gibb et al. 2000a; Gibb, Neave, Tookey, Ramsay, Harris, Balogun, Goldberg, Mieli-Vergani, and Kelly 2000b; Hadzic 2001; Haushofer et al. 2001; Hutchinson, Bird, and Goldberg 2005; Jenny-Avital 1998; Kowala-Piaskowska et al. 2004; Roy et al. 2003b; Ryder and Beckingham 2001b; Shepard, Finelli, and Alter 2005; Taylor, Goldberg, Hutchinson, Cameron, Gore, McMenamin, Green, Pithie, and Fox 2000; Thorburn et al. 2001; van Beek, Dwyer, Dore, Luo, and Kaldor 1998).

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