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The safety of blood with regards to transmission of infectious diseases is guaranteed by European laws that regulate both the selection of donors through pre-donation questionnaires and serological screening. However, variability in the epidemiology of human immunodeficiency virus (HIV) infection in different countries and some differences in the selection of donors can influence the efficacy (with regards to the safety of blood) of these processes. In this study we compared the prevalence of HIV in blood donations in the three macro-areas of Europe and in various western European countries, analysed the criteria of selection and rewarding of donors in western European countries, and studied the trend in the prevalence of HIV in Italy from to 1995 and 2006.
European data were derived from the European Centre for the Surveillance of HIV; Italian data were obtained from the Transfusion-Transmitted Infections Surveillance System and National and Regional Register of blood and plasma. The information on eligibility criteria and rewarding offered to donors was derived from international sources.
The prevalence of HIV in blood donations was highest in eastern Europe, followed by central Europe and western Europe. Among the western European countries, Spain, Italy and Israel had the highest prevalences; the prevalence was noted to be higher in countries which did not offer any rewarding to the donor. In Italy the prevalence of HIV was 3.8 cases per 100,000 donations in 2006 and increased between 1995 and 2006, both among donations from repeat donors and first time donors.
The data highlight the need to continue improving the selection of donors and the coverage of the surveillance systems for HIV infection in transfusion services.
In agreement with Directive 2002/98/EC, passed by the European Parliament and the Council for Member States of the European Union1, blood donations throughout Europe systematically undergo screening tests for the presence of antibodies to human immunodeficiency virus (HIV) and donations which are positive are eliminated. The residual risk of HIV infection or other transfusion-transmissible diseases has been greatly reduced, in particular due to the obligatory screening of donations and the recent adoption of more sensitive tests such as nucleic acid amplification tests (NAT), which have been introduced for blood screening in all European countries in the last few years2–4.
Nevertheless, differences in the epidemiology of HIV infection between countries and some differences in the selection of donors4 can affect the safety of blood.
The aims of this study were to compare, for the year 2006, the prevalence of HIV infection in blood donations in the three macro-areas of Europe (east, centre, west) and in various western European countries, compare the criteria of selection and rewarding candidate donors in various western European countries, and analyse the trend in the prevalence of HIV infection in Italy between 1995 and 2006, both among donations from repeat donors and first-time donors.
The data on the number of donations and prevalence of HIV among blood donations were obtained:
All the analyses were carried out on data related to blood donations in 2006, except for Spain, for which the most recent data available are for 20055. Figure 1 illustrates the geographical division of the region of Europe according to the World Health Organization (WHO); this division was used to classify the countries into three macro-areas: western, central and eastern Europe30.
Table I shows the results of screening for HIV in blood donations in the three macro-areas of Europe. The prevalence of HIV in blood donations was 1.8 per 100,000 donations in western Europe, 3.8 per 100,000 donations in central Europe and 37.6 per 100,000 donations in eastern Europe.
Among the 14 western European countries for which data on HIV in donations were available, the prevalence of HIV in northern countries was less than 1.0 per 100,000 donations, the prevalence in central countries was between 1.0 and 1.5 per 100,000 donations and the prevalence in southern countries (Spain, Italy, Israel and Switzerland) was greater than 1.5 per 100,000 donations.
For 8 of the 14 western European countries analysed, were available data on HIV prevalence in blood donations specifically for repeat donors and first-time donors. In the absence of data from Spain, Italy was the country with the highest prevalence of HIV in both groups. In detail, the prevalence was higher than 10.0 per 100,000 donations among first-time donors in Italy and Switzerland.
Table II summarises the criteria used in 12 western European countries to exclude from donation subjects considered at high risk of infection (intravenous drug users, men who have sex with men-MSM, female sex workers-FSW) or subjects reporting at risk sexual behaviour (sexual intercourse with HIV-positive people, with drug users, with MSM, with several partners, with people from areas where HIV is endemic). Some of these groups of subjects are excluded from donating blood for variable periods in different countries, with the exclusion period ranging from a minimum of 3 months to lifelong. Almost all countries permanently exclude intravenous drug users, MSM and FSW from giving blood. Only Italy and Spain do not exclude MSM permanently.
Various countries provide some kind of rewarding for giving blood (Table II). In Germany blood donors are paid, while Switzerland “rewards” its repeat donors who make a certain number of blood donations. Other countries, such as Italy, guarantee a day’s paid leave from work, while Norway and France reimburse travelling expenses. In contrast, in the other countries the blood donation is not remunerated in any way. The prevalence of HIV is significantly higher in those countries that do not offer any type of compensation (2.2 per 100,000 donations) compared to those which do give some type of compensation (1.6 per 100,000 donations) (p=0.03).
In 2006, in Italy 2,404,267 blood donations were made; for 1,481,028 of these (61.6%) results of testing for HIV were forwarded to the SMITT. The prevalence of HIV was 3.8 per 100,000 donations. The SMITT data showed an increasing prevalence of HIV in blood donations between 1995 and 2006 among both repeat donors and first-time donors, with the prevalence always higher among the latter (Figure 2).
The data collected show a higher prevalence of HIV in donations in eastern European countries, reflecting the higher spread of HIV in this area compared with the rest of Europe30. In decreasing order of prevalence, the other areas are central Europe and western Europe, but in these cases the prevalence of HIV in the donations does not reflect the prevalence in the population, as reported by the European surveillance data, which show that the rate of new diagnoses of HIV in the general population is seven times higher in western Europe than in central Europe30.
In all countries, except Denmark, the prevalence of HIV was higher among first-time donations, due to the fact that occasional donors are generally less selected and less aware about the risk of infection. Among western European countries, the prevalence of HIV in blood donations was highest in Spain, Italy and Israel, contrasting with the European surveillance data which show medium-low prevalence of HIV in the general population in these countries: indeed, while the prevalence of HIV in the general population in Italy is lower than that in UK, Belgium, France, Switzerland and the Netherlands, the prevalence in blood donations is higher in Italy than in the above mentioned countries30.
The discrepancy between HIV epidemiological data in blood donations and in the general population suggest that the efficacy of the selection of blood donors in Italy and some other countries may be impaired for various reasons. In some cases the donor might not remember or not recognise his or her exposure to risk infection: Italian data have shown that one-third of the people who discover that they are seropositive (both in the general population31 and among blood donors2) were unaware of their source of infection, and that over half of the patients who are diagnosed with AIDS do not even suspect that they are infected32. In other cases the donor could be aware of having been exposed to the risk of infection but not declare this in the pre-donation questionnaire32, or could use the donation to be tested for HIV without raising suspicion in his or her family or partner33,34. Importantly, an Italian study found that most HIV-positive donors acquired their infection through sexual contacts2, reflecting the wide spread of HIV through the sexual route in Italy in recent years31.
The data show that the two western European countries with the highest prevalence of HIV, that is, Italy and Spain, are the only two countries that do not permanently exclude MSM from donating blood. In Italy, since 2001, only persons who report having had unprotected sex are excluded from donating blood. The prevalence of HIV in donations was, however, already tending to increase in the years before 2001, suggesting that other factors may be responsible for this trend. A study recently conducted in transfusion centres in Lombardy (Italy) showed no significant increase in the prevalence of HIV in blood donations from MSM before and after 200135. However, this finding should be verified in other regions of Italy and monitored over time.
The observation of a higher HIV prevalence in those countries that do not propose any form of rewarding for donation is interesting and can probably be attributed to fewer donors being regular clients and, therefore, to poorer selection of the donor population36.
The increase in the prevalence of HIV in Italian blood donations after 1995, in particular among repeat donors, does not match the Italian HIV surveillance data, which show a decrease in the incidence of new HIV diagnoses from 1990, followed, since 1998, by a stable incidence31. The increase in the prevalence in donations could be due to poor coverage of the surveillance system (varying between 57% and 89% in the years considered) which selects transfusion centres with a high HIV prevalence, poor efficacy of exclusion of HIV-positive subjects prior to donation, decreased perception of at-risk exposure by donors, or the introduction of NAT in the screening of donors. As far as concerns this last point, in Italy NAT screening of blood for HIV has been recommended since 2006, but was used by a substantial number of transfusion services already since 2002 when obligatory NAT screening for hepatitis C virus was introduced. The diagnostic gain obtained with these more sensitive tests could explain the increase in the observed HIV prevalence. This gain, estimated to be about 0.18 HIV-positive cases per 100,000 donations2, would imply a correction in the prevalence of HIV in 2006 in Italy from 3.80 to 3.62 per 100,000 donations in the absence of NAT screening, which would not substantially change the increased prevalence recorded. Furthermore, the increasing HIV prevalence trend in Italian donations was already observed before 2002.
In conclusion, the different prevalence rates of HIV found in blood donations in the three macro-areas of Europe and in various countries of western Europe reflect, in part, the geographical distribution of HIV and, in part, the effects of different national legislation on donor selection, highlighting the need to monitor the effect of new donor exclusion criteria over time. The high prevalence of HIV in Italian donations compared to that in other countries suggests that there is a low perception of the risk of acquiring HIV among Italian blood donors, even among repeat donors, who are traditionally more responsible with regards to infective risks. In this context, the role of unprotected sexual activity, in particular heterosexual contacts, seems important as it is not perceived at risk although currently constitutes the most frequent transmission route in Italy31.
As described above, the Italian epidemiological data on the spread of HIV generally indicate that HIV incidence is stabilising, although it is alarming that a new rise of the epidemic has been seen in some areas31. If this rising trend will be confirmed in coming years, screening donations with NAT could become inadequate because donors making donations in the “window phase” will escape NAT detection.
For this reason, in order to prevent the transmission not only of HIV, but also of other blood-transmitted infections, the coverage of the surveillance systems of transfusion services must be improved and attention focused on the selection of donors.
Important aspects that will have to be implemented are: greater clarity of the pre-donation questionnaires (detailing the possible exposures at risk), more privacy for the donor at the time of completing the questionnaire (private areas), systematic use of questionnaires for all donors (including repeat donors), and appropriate counselling that specifically investigates ‘at risk’ behaviours.